97 results on '"structural investigation"'
Search Results
2. Growth of L-asparagine monohydrate organic single crystals: An experimental and DFT computational approach for nonlinear optical applications
- Author
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Md Anisur Rahman and Jiban Podder
- Subjects
L-asparagine monohydrate ,Structural investigation ,Linear and nonlinear optical characteristics ,HOMO-LUMO ,Density functional theory ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Good optical quality of L-asparagine monohydrate (C4H8N2O3.H2O) organic single crystal has been grown by adopting natural slow evaporation process at room temperature from aqueous solutions. The lattice parameters obtained by powder X-ray diffraction data revealed orthorhombic crystal system of the harvested crystal. The morphology and planes of the crystal have been identified. The molecular vibrations and functional groups have been specified by Fourier transform infrared (FTIR) spectroscopy studies. Energy dispersive X-ray (EDX) study has been availed to find out the elements constituting the crystal. Scanning electron microscopy, (SEM), provided the surface morphology of the crystal. The dependence of dielectric properties on frequency and temperature have been investigated and the electronic polarizability (α) has been determined. UV–vis spectral analysis shows that the crystal possesses good optical transmittance in the visible part of the energy spectrum. The optical band gap and the Urbach energy have been determined from lower absorption edge. Third order nonlinear susceptibility χ(3), nonlinear refractive index (n2), and linear susceptibility χ(1) have been calculated by Miller's generalized rule. The first-principle computation of band structure of electrons and the electron density of states have been discussed, which suggest that the crystals possess direct band gap. Density Functional Theory (DFT) with B3LYP function by Gaussian09W software was utilized to calculate HOMO-LUMO energy gap as well as non-linear optical parameters namely, linear polarizability (α), hyperpolarizability (β and γ) and dipole moment (μ) of L-asparagine monohydrate crystal. All the findings prove that L-asparagine monohydrate is a promising NLO crystal.
- Published
- 2024
- Full Text
- View/download PDF
3. Changes of Wood Surfaces Treated with Natural-based Products – Structural and Properties Investigation
- Author
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Magdalena-Cristina Stanciu and Carmen-Alice Teacă
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wood ,vegetable oils ,natural wax ,structural investigation ,properties ,Biotechnology ,TP248.13-248.65 - Abstract
Preservative systems based on vegetable seed oils and natural waxes from renewable sources may confer protection to wood under exposure to various environmental conditions. These, as non-toxic substances, can form an environmentally friendly and efficient protective layer on the wood surfaces, with beneficial effects on their water resistance and dimensional stability. Thus, these natural coatings may hinder biodegradation of wood products to a certain degree. In present paper, softwood samples (from Abies alba fir tree species), prepared as dried discs (25 to 30 mm diameter, 8 to 10 mm thickness), were surface impregnated by dipping using vegetable oils, namely Asclepias syriaca seed oil, and soybean oil, respectively. Beeswax treatment was also applied for comparison purposes. Surface chemistry and morphology, biodegradation process under controlled and simulated natural conditions, and water sorption behavior of wood samples were investigated. Fourier Transform Infrared spectroscopy, X-ray diffraction, and scanning electron microscopy methods were used for investigation of surface changes in wood samples before and after impregnation with natural based products, as well as under biodegradation conditions in soil burial tests.
- Published
- 2024
4. Changes of Wood Surfaces Treated with Natural-based Products - Structural and Properties Investigation.
- Author
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Stanciu, Magdalena-Cristina and Teacă, Carmen-Alice
- Subjects
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FOURIER transform infrared spectroscopy , *BIODEGRADATION of wood , *WOOD , *SOY oil , *NATURAL products - Abstract
Preservative systems based on vegetable seed oils and natural waxes from renewable sources may confer protection to wood under exposure to various environmental conditions. These, as non-toxic substances, can form an environmentally friendly and efficient protective layer on the wood surfaces, with beneficial effects on their water resistance and dimensional stability. Thus, these natural coatings may hinder biodegradation of wood products to a certain degree. In present paper, softwood samples (from Abies alba fir tree species), prepared as dried discs (25 to 30 mm diameter, 8 to 10 mm thickness), were surface impregnated by dipping using vegetable oils, namely Asclepias syriaca seed oil, and soybean oil, respectively. Beeswax treatment was also applied for comparison purposes. Surface chemistry and morphology, biodegradation process under controlled and simulated natural conditions, and water sorption behavior of wood samples were investigated. Fourier Transform Infrared spectroscopy, X-ray diffraction, and scanning electron microscopy methods were used for investigation of surface changes in wood samples before and after impregnation with natural based products, as well as under biodegradation conditions in soil burial tests. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. 4-arylbutan-2-ones: Starting Materials in the Synthesis of Novel Heme Oxygenase Inhibitors
- Author
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Gheorghe Roman and Walter A. Szarek
- Subjects
organic synthesis ,chemical intermediates ,ketones ,alkylation– cleavage ,structural investigation ,Medicine (General) ,R5-920 ,Science (General) ,Q1-390 - Abstract
Synthetic organic chemistry and medicinal chemistry are the most significant fields of research in chemistry, where 4-arylbutan-2-ones find applications by allowing access to chemical entities otherwise difficult to synthesize, or in the de novo development of drug candidates. Structure-aided design based on previous results from our group has led to advances in shaping the structure of a series of novel imidazolebased heme oxygenase inhibitors. The practical generation of these inhibitors requires the synthesis of a set of 4-arylbutan-2-ones to be employed as starting materials in a reaction sequence that would afford in the end the desired imidazole-containing inhibitor target compounds. The present report illustrates the use of an one-step alkylation–cleavage synthetic approach toward such 4-arylbutan-2-ones featuring, in most cases, a hydrophobic para-substituent in the aromatic ring, starting from low-cost, commercially available organic reagents (pentane-2,4-dione and the suitably substituted benzyl bromides). The work described in this study represents an extension of a synthetic entry to this type of organic compounds, previously exploited in our group for the preparation of several structural analogs. The identity of the obtained 4-arylbutan-2- ones was established using nuclear magnetic resonance spectroscopy and high resolution mass spectrometry.
- Published
- 2023
6. Glucuronidation Pathways of 5- and 7-Hydroxypropranolol: Determination of Glucuronide Structures and Enzyme Selectivity.
- Author
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Yang, Fan, Wenzel, Maxi, Bureik, Matthias, and Parr, Maria Kristina
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GLUCURONIDATION , *GLUCURONIDES , *ENZYMES , *DRUG metabolism , *THERAPEUTICS , *METABOLITES - Abstract
Propranolol, a non-selective beta-blocker medication, has been utilized in the treatment of cardiovascular diseases for several decades. Its hydroxynaphthyl metabolites have been recognized to possess varying degrees of beta-blocker activity due to the unaltered side-chain. This study achieved the successful separation and identification of diastereomeric glucuronic metabolites derived from 4-, 5-, and 7-hydroxypropranolol (4-OHP, 5-OHP, and 7-OHP) in human urine. Subsequently, reaction phenotyping of 5- and 7-hydroxypropranolol by different uridine 5'-diphospho-glucuronosyltransferases (UGTs) was carried out, with a comparison to the glucuronidation of 4-hydroxypropranolol (4-OHP). Among the 19 UGT enzymes examined, UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2A1, and UGT2A2 were found to be involved in the glucuronidation of 5-OHP. Furthermore, UGT1A6 exhibited glucuronidation activity towards 7-OHP, along with the aforementioned eight UGTs. Results obtained by glucuronidation of corresponding methoxypropranolols and MS/MS analysis of 1,2-dimethylimidazole-4-sulfonyl (DMIS) derivatives of hydroxypropranolol glucuronides suggest that both the aromatic and aliphatic hydroxy groups of the hydroxypropranolols may be glucuronidated in vitro. However, the analysis of human urine samples collected after the administration of propranolol leads us to conclude that aromatic-linked glucuronidation is the preferred pathway under physiological conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. On Modeling Missing Data in Structural Investigations Based on Tetrachoric Correlations With Free and Fixed Factor Loadings.
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Schweizer, Karl, Gold, Andreas, and Krampen, Dorothea
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- *
STATISTICS , *STRUCTURAL equation modeling , *RESEARCH , *REFERENCE values , *CONFIDENCE intervals , *SIMULATION methods in education , *DATABASE management , *FACTOR analysis , *CHI-squared test , *STATISTICAL models , *DATA analysis , *STATISTICAL correlation , *MAXIMUM likelihood statistics , *DATA analysis software , *SENSITIVITY & specificity (Statistics) , *PROBABILITY theory - Abstract
In modeling missing data, the missing data latent variable of the confirmatory factor model accounts for systematic variation associated with missing data so that replacement of what is missing is not required. This study aimed at extending the modeling missing data approach to tetrachoric correlations as input and at exploring the consequences of switching between models with free and fixed factor loadings. In a simulation study, confirmatory factor analysis (CFA) models with and without a missing data latent variable were used for investigating the structure of data with and without missing data. In addition, the numbers of columns of data sets with missing data and the amount of missing data were varied. The root mean square error of approximation (RMSEA) results revealed that an additional missing data latent variable recovered the degree-of-model fit characterizing complete data when tetrachoric correlations served as input while comparative fit index (CFI) results showed overestimation of this degree-of-model fit. Whereas the results for fixed factor loadings were in line with the assumptions of modeling missing data, the other results showed only partial agreement. Therefore, modeling missing data with fixed factor loadings is recommended. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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8. Localized failure analysis in a large reinforced concrete wall theater
- Author
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Marcos Alves da Silva, Luiz Carlos de Almeida, and Leandro Mouta Trautwein
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reinforced concrete ,numerical analysis ,failure mode ,structural investigation ,in-situ tests ,Building construction ,TH1-9745 - Abstract
Abstract Reinforced concrete structures must be designed in a manner that assures an acceptable level of safety and performance. However, accidents still occur nowadays causing interdiction, financial losses, or even human casualties. Therefore, succinct studies are required to give answers to such an undesirable situation, helping to prevent repetition and enlightening new design and construction methods. This paper analyzes the failure mechanism in a large reinforced concrete panel composed of one L-shaped cantilevered wall and structural walls in Campinas. The investigation was carried out using in-situ destructive and non-destructive tests and also through numerical simulation. In-situ tests revealed that the region where the fracture happened had no sufficient resisting steel area. The fracture line developed through the end of the wall’s horizontal rebars anchored within the column. It was concluded that the reinforced concrete panel failure happened due to structure misconception and incorrect design, once columns stirrups were responsible for the equilibrium of the cantilevered part of the building, as demonstrated by the nonlinear finite element study and in-situ investigations.
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- 2023
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9. Effects of Nd 2 O 3 Nanoparticles on the Structural Characteristics and Dielectric Properties of PVA Polymeric Films.
- Author
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Alshammari, Khulaif, Alashgai, Thamer, Alshammari, Alhulw H., Abdelhamied, Mostufa M., Alotibi, Satam, and Atta, Ali
- Subjects
- *
DIELECTRIC properties , *DIELECTRIC devices , *PERMITTIVITY , *X-ray diffraction , *POLYVINYL alcohol , *DIELECTRIC relaxation , *DIELECTRIC films - Abstract
Polyvinyl alcohol (PVA) and Neodymium (III) oxide (Nd2O3) were combined to synthesized flexible innovative PVA/Nd2O3 polymer composite samples utilizing a solution casting approach for use in dielectric devices. The XRD, FTIR, and SEM methods are all investigated to characterize the composite films. In a frequency of 50 Hz to 5 MHz, the effects of additive Nd2O3 on the dielectric behavior of PVA were recorded. The PVA/Nd2O3 composite films were successfully fabricated, as shown by XRD and infrared spectroscopy. The scanning microscopy pictures showed that the Nd2O3 was loaded and distributed uniformly throughout the PVA. After the incorporation of Nd2O3, the composite PVA/Nd2O3 has a conductivity of 6.82 × 10−9 S·cm−1, while the PVA has a conductivity of 0.82 × 10−9 S·cm−1. Another improvement is the decrease in the relaxation time from 14.2 × 10−5 s for PVA to 6.35 × 10−5 s for PVA/Nd2O3, and an increase in the dielectric constant of 0.237 for PVA to 0.484 at a frequency of 100 Hz. The results showed that the composite samples have considerable changes as flexible films in different applications, including batteries and electronic circuits. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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10. Synthesis and Characterization of Antibacterial Chitosan Films with Ciprofloxacin in Acidic Conditions.
- Author
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Sikorski, Dominik, Rosiak, Piotr, Janczewski, Łukasz, Potrzebowski, Marek J., Kregiel, Dorota, Kaźmierski, Sławomir, Neubauer, Damian, Kolesińska, Beata, Frączyk, Justyna, Adamczyk, Anna, and Draczyński, Zbigniew
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CIPROFLOXACIN , *ATTENUATED total reflectance , *CHITOSAN , *NUCLEAR magnetic resonance spectroscopy , *INFRARED spectroscopy , *ATOMIC force microscopy , *NUCLEAR magnetic resonance - Abstract
This work presents the results of research on obtaining chitosan (CS) films containing on their surface ciprofloxacin (CIP). A unique structure was obtained that not only gives new properties to the films, but also changes the way of coverage and structure of the surface. The spectroscopic test showed that in the process of application of CIP on the surface of CS film, CIP was converted from its crystalline form to an amorphic one, hence improving its bioavailability. This improved its scope of microbiological effect. The research was carried out on the reduction of CIP concentration during the process of CIP adhesion to the surface of chitosan films. The antibacterial activity of the CS films with and without the drug was evaluated in relation to Escherichia coli and Staphylococcus aureus, as well as Candida albicans and Penicillium expansum. Changes in the morphology and roughness of membrane surfaces after the antibacterial molecule adhesion process were tested with atomic force microscopy (AFM) and scanning electron microscopy (SEM). Structural analysis of CS and its modifications were confirmed with Fourier-transform spectroscopy in the infrared by an attenuated total reflectance of IR radiation (FTIR-ATR) and solid-state nuclear magnetic resonance (NMR). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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11. بازآفرینی، آسیب نگاری و بررسی ساختاری کتیبهٔ گریوار بقعهٔ دوازده امام یز د.
- Author
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صفیه حاتمی, زینب صمدنژاد آذر, and ابوالفضل عبداله&
- Abstract
Introduction The construction date of the ‘Twelve ImamsMausoleum’ in Yazd goes back to the end of the Buyidsand Daylamites periods. The architectural ornaments of this building include murals, plasterworks, faience mosaics, and brickworks; also, an inscription with decorative Kufic script has decorated its parts. The research conducted on this building is limited to the architecture and restoration of its external walls, while the dome has valuable ornaments, including the inscription of ‘Ayatul Kursi’ in its Grivar. This inscriptionis implemented using the technique of ‘painting on plaster’. This historical monument has been seriously damaged due to the age of the building and the destructive environmental effects on it. These damages are either erosion destroying the appearance of the building or the structural destruction destroying the foundation of the building; therefore, knowing the damage so as to prevent further destruction and reconstruction is of particular importance to preserving this thousand-year-old monument. Research Method This research tries to study the damages inflicted on this inscription with the help of reconstruction and damage photography. It, also, tries to to know the structure and motifs used in it in comparison with similar inscriptions. The questions raised in this research were: 1- What were the damages caused to the Grivar inscription in the Twelve Imams Mausoleum? 2- What was the general structure and decorations used for this ornament? This research was descriptive-analytical, and data collection was based on library studies and field surveys. Its approach in the image processing section of the inscription to determine the amount of damage was quantitative, and in the structural analysis it was qualitative. The primary research sources were provided using field photography; the damage mapping of the sides of the inscription was reconstructed based on photographs and images; image processing was provided using a computer program and a color analysis method. The images processed based on color; the numerical results were separated and analyzed based on tables, and the possibility of reproducing the inscription provided the conditions for its structural investigation concerning the analysis of external components and visual features. Research Findings The mentioned inscription is in Kufic (Moashaq Moshajar) script, written in dark azure color on a plaster base. This inscription began with "Bismillah" from the third side of the top of the entrance door and ended with the phrase ‘Al-Ali al-Azeem’ at the end of the eighth side. Over time, damages were imposed on this inscription, leading to the destruction of many parts. Among these damages were humidity, mud,and water flow from the upper parts on the surface of the inscription, the effect of suspended particles in the air, pollution, and dust, the change in the writing's color, the loosening of the paint layer, and its separation from the plaster bed due to the passage of time, penetration termites and the porosity caused by their activity in the lower layers, the cracks caused by earthquakes or other shocks and the forces entering the building, and the traces of droppings of birds or other creatures on the surface of the inscription. Measuring the accurate amount of damage on each side was done in the form of three separate images for each side: 1- The reproduced image of each side of the inscription was in black and white without destruction (the processing of this image provides the amount of positive (text) and negative (background) space to determine the amount of damage in other destructions). 2- The recreated image of each side showed infrastructure destruction in red and paint loss in blue 3- A black-and-white image of each side of the inscription was used to estimate surface pollution. Based on this damage imaging method, by comparing the white and black colors on each side and the percentage of white and black in the ‘initial recreated design’, it was noted whether the destruction damaged the writing itself or the background of the inscription. Accordingly, the fifth side had the most serious destruction of the background with 8%, and the the most serious destruction of the text with 7%. The results of the processing of the blue color, which represents the ‘paint loss’ showed that the first side had the highest amount of paint loss (7% loss), which caused the color of the design and the background to be the same. The lowest amount of paintloss was assigned to the second and the third sides. According to the results, ‘surface pollution,’ had a 100% extent in the inscription. Conclusion Based on the reconstruction of the destructed parts, damage imaging, and image processing with computer programs, the damages have been divided into three general categories: 1) destruction of infrastructure materials, 2) paint loss, 3) surface pollution. The results indicate that the most serious damage was caused mainly by the fall of infrastructure materials, paint loss, and environmental pollution. Structural analysis showed that this inscription had all three structural components of inscriptions including the plant system in the upper part, the geometric system in the middle part, and the writing system in the lower part. The greatest similarity was in the plantmotif, and the greatest diversity was seen in the knots of the geometric part. Although these systems were not necessarily used in all architectural inscriptions, this inscription had all three parts in a structured way showing that the designer had designed each component in harmony to achieve a coherent whole. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
12. Glucuronidation Pathways of 5- and 7-Hydroxypropranolol: Determination of Glucuronide Structures and Enzyme Selectivity
- Author
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Fan Yang, Maxi Wenzel, Matthias Bureik, and Maria Kristina Parr
- Subjects
UGTs ,hydroxypropranolol ,glucuronidation ,enzyme bags ,drug metabolism ,structural investigation ,Organic chemistry ,QD241-441 - Abstract
Propranolol, a non-selective beta-blocker medication, has been utilized in the treatment of cardiovascular diseases for several decades. Its hydroxynaphthyl metabolites have been recognized to possess varying degrees of beta-blocker activity due to the unaltered side-chain. This study achieved the successful separation and identification of diastereomeric glucuronic metabolites derived from 4-, 5-, and 7-hydroxypropranolol (4-OHP, 5-OHP, and 7-OHP) in human urine. Subsequently, reaction phenotyping of 5- and 7-hydroxypropranolol by different uridine 5’-diphospho-glucuronosyltransferases (UGTs) was carried out, with a comparison to the glucuronidation of 4-hydroxypropranolol (4-OHP). Among the 19 UGT enzymes examined, UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2A1, and UGT2A2 were found to be involved in the glucuronidation of 5-OHP. Furthermore, UGT1A6 exhibited glucuronidation activity towards 7-OHP, along with the aforementioned eight UGTs. Results obtained by glucuronidation of corresponding methoxypropranolols and MS/MS analysis of 1,2-dimethylimidazole-4-sulfonyl (DMIS) derivatives of hydroxypropranolol glucuronides suggest that both the aromatic and aliphatic hydroxy groups of the hydroxypropranolols may be glucuronidated in vitro. However, the analysis of human urine samples collected after the administration of propranolol leads us to conclude that aromatic-linked glucuronidation is the preferred pathway under physiological conditions.
- Published
- 2023
- Full Text
- View/download PDF
13. On Modeling Missing Data of an Incomplete Design in the CFA Framework
- Author
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Karl Schweizer, Andreas Gold, Dorothea Krampen, and Tengfei Wang
- Subjects
missing data ,incomplete design ,structural investigation ,confirmatory factor analysis ,quantitative methods ,planned missing data design ,Psychology ,BF1-990 - Abstract
The paper reports an investigation on whether valid results can be achieved in analyzing the structure of datasets although a large percentage of data is missing without replacement. Two types of confirmatory factor analysis (CFA) models were employed for this purpose: the missing data CFA model with an additional latent variable for representing the missing data and the semi-hierarchical CFA model that also includes the additional latent variable and reflects the hierarchical structure assumed to underlie the data. Whereas, the missing data CFA model assumes that the model is equally valid for all participants, the semi-hierarchical CFA model is implicitly specified differently for subgroups of participants with and without omissions. The comparison of these models with the regular one-factor model in investigating simulated binary data revealed that the modeling of missing data prevented negative effects of missing data on model fit. The investigation of the accuracy in estimating the factor loadings yielded the best results for the semi-hierarchical CFA model. The average estimated factor loadings for items with and without omissions showed the expected equal sizes. But even this model tended to underestimate the expected values.
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- 2020
- Full Text
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14. On Modeling Missing Data of an Incomplete Design in the CFA Framework.
- Author
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Schweizer, Karl, Gold, Andreas, Krampen, Dorothea, and Wang, Tengfei
- Subjects
MISSING data (Statistics) ,LATENT variables ,CONFIRMATORY factor analysis ,DATA modeling ,EXPECTED returns - Abstract
The paper reports an investigation on whether valid results can be achieved in analyzing the structure of datasets although a large percentage of data is missing without replacement. Two types of confirmatory factor analysis (CFA) models were employed for this purpose: the missing data CFA model with an additional latent variable for representing the missing data and the semi-hierarchical CFA model that also includes the additional latent variable and reflects the hierarchical structure assumed to underlie the data. Whereas, the missing data CFA model assumes that the model is equally valid for all participants, the semi-hierarchical CFA model is implicitly specified differently for subgroups of participants with and without omissions. The comparison of these models with the regular one-factor model in investigating simulated binary data revealed that the modeling of missing data prevented negative effects of missing data on model fit. The investigation of the accuracy in estimating the factor loadings yielded the best results for the semi-hierarchical CFA model. The average estimated factor loadings for items with and without omissions showed the expected equal sizes. But even this model tended to underestimate the expected values. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
15. Spectroscopic and Structural Properties of β-Tricalcium Phosphates Ca9RE(PO4)7 (RE = Nd, Gd, Dy)
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Veronica Paterlini, Asmaa El Khouri, Marco Bettinelli, Daniele Maria Trucchi, and Francesco Capitelli
- Subjects
TCP ,rare-earth elements ,luminescence spectroscopy ,structural investigation ,Crystallography ,QD901-999 - Abstract
Rare-earth-based Ca9RE(PO4)7 (RE = Nd, Gd, Dy) materials were synthesized by solid-state reaction at T = 1200 °C. The obtained tricalcium phosphate (TCP) materials are efficient light emitters due to the presence of RE3+ ions, although these ions are present at high concentrations. Moreover, in these host structures, these ions can be used as optical probes to study their local environments. Thus, photoluminescence (PL) emission spectra of the powder samples clearly indicated, for Dy3+ and Gd3+ ions, the presence of the RE3+ ion in low-symmetry sites with some local structural disorder, and the spectra show the presence of vibrational features (in the case of Gd3+). For the Nd3+ phase, emission bands are present around 900, 1050, and 1330 nm, originating from the 4F3/2 level. In general, these RE-TCP samples are interesting luminescent materials in the visible (Dy), UV (Gd), and NIR (Nd) regions, due to weak concentration quenching even for high concentrations of the emitting ion.
- Published
- 2021
- Full Text
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16. The Diverse World of Foldamers: Endless Possibilities of Self-Assembly
- Author
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Samuele Rinaldi
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self-assembly ,foldamers ,structural investigation ,secondary structure ,higher-order structures ,morphology ,Organic chemistry ,QD241-441 - Abstract
Different classes of foldamers, which are synthetic oligomers that adopt well-defined conformations in solution, have been the subject of extensive studies devoted to the elucidation of the forces driving their secondary structures and their potential as bioactive molecules. Regardless of the backbone type (peptidic or abiotic), the most important features of foldamers are the high stability, easy predictability and tunability of their folding, as well as the possibility to endow them with enhanced biological functions, with respect to their natural counterparts, by the correct choice of monomers. Foldamers have also recently started playing a starring role in the self-assembly of higher-order structures. In this review, selected articles will be analyzed to show the striking number of self-assemblies obtained for foldamers with different backbones, which will be analyzed in order of increasing complexity. Starting from the simplest self-associations in solution (e.g., dimers of β-strands or helices, bundles, interpenetrating double and multiple helices), the formation of monolayers, vesicles, fibers, and eventually nanostructured solid tridimensional morphologies will be subsequently described. The experimental techniques used in the structural investigation, and in the determination of the driving forces and mechanisms underlying the self-assemblies, will be systematically reported. Where applicable, examples of biomimetic self-assembled foldamers and their interactions with biological components will be described.
- Published
- 2020
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17. Synthesis, electrochemical investigation and structural analysis of doped Li[Ni0.6Mn0.2Co0.2-xMx]O2 (x = 0, 0.05; M = Al, Fe, Sn) cathode materials.
- Author
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Eilers-Rethwisch, Matthias, Winter, Martin, and Schappacher, Falko Mark
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LITHIUM compounds , *CHEMICAL synthesis , *CATHODES , *ELECTROCHEMICAL analysis , *DOPING agents (Chemistry) , *COPRECIPITATION (Chemistry) , *X-ray diffraction - Abstract
Layered Ni-rich Li[Ni 0.6 Mn 0.2 Co 0.2- x M x ]O 2 cathode materials ( x = 0, 0.05; M = Al, Fe, Sn) are synthesized via a co-precipitation synthesis route and the effect of dopants on the structure and electrochemical performance is investigated. All synthesized materials show a well-defined layered structure of the hexagonal α -NaFeO 2 phase investigated by X-ray diffraction (XRD). Undoped LiNi 0.6 Mn 0.2 Co 0.2 O 2 exhibits a discharge capacity of 170 mAh g −1 in Li-metal 2032 coin-type cells. Doped materials reach lower capacities between 145 mAh g −1 for Al and 160 mAh g −1 for Sn. However, all doped materials prolong the cycle life by up to 20%. Changes of the lattice parameter before and after delithiation yield information about structural stability. A smaller repulsion of the transition metal layer during delithiation in the Sn-doped material leads to a smaller expansion of the unit cell, which results in enhanced structural stability of the material. The improved structural stability of Sn-doped NMC cathode active material is proven by thermal investigations with the help of Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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18. Molecular Dynamics and Structural Studies of Zinc Chloroquine Complexes
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Mirko Paulikat, Daniele Vitone, Florian K. Schackert, Nils Schuth, Alessandra Barbanente, GiovanniMaria Piccini, Emiliano Ippoliti, Giulia Rossetti, Adam H. Clark, Maarten Nachtegaal, Michael Haumann, Holger Dau, Paolo Carloni, Silvano Geremia, Rita De Zorzi, Liliana Quintanar, Fabio Arnesano, Paulikat, Mirko, Vitone, Daniele, Schackert, Florian K, Schuth, Nil, Barbanente, Alessandra, Piccini, Giovannimaria, Ippoliti, Emiliano, Rossetti, Giulia, Clark, Adam H, Nachtegaal, Maarten, Haumann, Michael, Dau, Holger, Carloni, Paolo, Geremia, Silvano, De Zorzi, Rita, Quintanar, Liliana, and Arnesano, Fabio
- Subjects
structural investigation ,General Chemical Engineering ,Chloroquine ,General Chemistry ,Zinc complex ,Library and Information Sciences ,Computer Science Applications - Abstract
Chloroquine (CQ) is a first-choice drug against malaria and autoimmune diseases. It has been co-administered with zinc against SARS-CoV-2 and soon dismissed because of safety issues. The structural features of Zn-CQ complexes and the effect of CQ on zinc distribution in cells are poorly known. In this study, state-of-the-art computations combined with experiments were leveraged to solve the structural determinants of zinc-CQ interactions in solution and the solid state. NMR, ESI-MS, and X-ray absorption and diffraction methods were combined with ab initio molecular dynamics calculations to address the kinetic lability of this complex. Within the physiological pH range, CQ binds Zn2+ through the quinoline ring nitrogen, forming [Zn(CQH)Clx(H2O)3-x](3+)-x (x = 0, 1, 2, and 3) tetrahedral complexes. The Zn(CQH)Cl3 species is stable at neutral pH and at high chloride concentrations typical of the extracellular medium, but metal coordination is lost at a moderately low pH as in the lysosomal lumen. The pentacoordinate complex [Zn(CQH)(H2O)4]3+ may exist in the absence of chloride. This in vitro/in silico approach can be extended to other metal-targeting drugs and bioinorganic systems.
- Published
- 2022
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19. Structural properties of transparent Ti-V oxide semiconductor thin films
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Sieradzka Karolina, Kaczmarek Danuta, Morgiel Jerzy, Domaradzki Jaroslaw, Prociow Eugeniusz, and Adamiak Bogdan
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titanium ,vanadium ,oxide ,magnetron sputtering ,structural investigation ,transparent semiconductor ,Physics ,QC1-999 - Published
- 2013
- Full Text
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20. Synthesis and characterisation of 2-tscnd and ITS -Chloro derivative with Ni(II)
- Author
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Gaikwad, Sanjay, Gaikwad, Charushila, Khansole, Sandip, and Kankariya, Rajendra
- Published
- 2010
21. Fatigue Strength Degradation of AlSi12CuNiMg Alloy Due to High Temperature Exposure: A Structural Investigation.
- Author
-
Konečná, R., Nicoletto, G., Kunz, L., Svoboda, M., and Bača, A.
- Subjects
MATERIAL fatigue ,STRENGTH of materials ,ALUMINUM alloys ,HIGH temperatures ,CHEMICAL decomposition ,COMBUSTION chambers - Abstract
Abstract: The strengthening mechanism based on the formation of precipitates (Guinier-Preston (GP) zones) during decomposition of a metastable supersaturated solid solution is stable and effective below temperatures, which are typically overcome in the piston region facing the combustion chamber. Therefore, pistons experience a progressive loss of strength due to over-aging during service. This contribution reports of a structural investigation on a eutectic AlSi12CuNiMg alloy before and after fatigue testing at high temperatures (up to 350°C). Metallography, color etching, SEM and TEM are used to elucidate the following aspects: 1) the structural features of the alloy (dendrites of α−phase, primary Si particle size and distribution, morphology and distribution of intermetallic phases); 2) the evolution of the strengthening mechanism (GP zones) with high temperature exposure. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
22. Solvent effects on structural changes in self-healing epoxy composites
- Author
-
Radović, Ivana, Stajčić, Aleksandar, Radisavljević, Anđela, Veljković, Filip M., Čebela, Maria, Mitić, Vojislav V., Radojević, Vesna, Radović, Ivana, Stajčić, Aleksandar, Radisavljević, Anđela, Veljković, Filip M., Čebela, Maria, Mitić, Vojislav V., and Radojević, Vesna
- Abstract
Nowadays, there is a very high importance of composite research and variety of their applications in the modern world. In that sense, we researched hollow glass capillaries filled with dissolved Grubbs catalyst (GC) and dicyclopentadiene (DCPD) were incorporated into a fiber-reinforced epoxy with the aim of improving the flow of healing agents to the crack site. The morphological investigation of the crack site was performed using field emission scanning electron microscopy (FESEM), showing the difference between the samples depending on the used solvent. The software analysis of sample photographs has been performed by calculating the fractured/healed surface area of the samples, revealing that approximately 20% of the volume was affected by the impact. Fourier transform infrared spectroscopy (FTIR) revealed that poly (dicyclopentadiene) (PDCPD) formed at the healed interface. However, the FTIR investigation of catalyst stability in different solvents showed structural changes in GC and partial deactivation. The mechanical tests of the samples showed that a recovery of 60% after 24 h at room temperature could be achieved through the use of a solvent and very low concentration of GC. The performed research results are a good base to develop the model for predicting the processes and morphology, with the goal to design the final mechanical and in the future, thermal, properties in advance. This opens a new direction for future research in the field of composite healing. © 2020 Elsevier B.V.
- Published
- 2020
23. Solvent effects on structural changes in self-healing epoxy composites
- Author
-
Radović, Ivana M., Stajčić, Aleksandar, Radisavljević, Anđela, Veljković, Filip M., Čebela, Maria, Mitić, Vojislav V., Radojević, Vesna, Radović, Ivana M., Stajčić, Aleksandar, Radisavljević, Anđela, Veljković, Filip M., Čebela, Maria, Mitić, Vojislav V., and Radojević, Vesna
- Abstract
Nowadays, there is a very high importance of composite research and variety of their applications in the modern world. In that sense, we researched hollow glass capillaries filled with dissolved Grubbs catalyst (GC) and dicyclopentadiene (DCPD) were incorporated into a fiber-reinforced epoxy with the aim of improving the flow of healing agents to the crack site. The morphological investigation of the crack site was performed using field emission scanning electron microscopy (FESEM), showing the difference between the samples depending on the used solvent. The software analysis of sample photographs has been performed by calculating the fractured/healed surface area of the samples, revealing that approximately 20% of the volume was affected by the impact. Fourier transform infrared spectroscopy (FTIR) revealed that poly (dicyclopentadiene) (PDCPD) formed at the healed interface. However, the FTIR investigation of catalyst stability in different solvents showed structural changes in GC and partial deactivation. The mechanical tests of the samples showed that a recovery of 60% after 24 h at room temperature could be achieved through the use of a solvent and very low concentration of GC. The performed research results are a good base to develop the model for predicting the processes and morphology, with the goal to design the final mechanical and in the future, thermal, properties in advance. This opens a new direction for future research in the field of composite healing. © 2020 Elsevier B.V.
- Published
- 2020
24. Structural investigation of composite wind turbine blade considering structural collapse in full-scale static tests
- Author
-
Yang, Jinshui, Peng, Chaoyi, Xiao, Jiayu, Zeng, Jingcheng, Xing, Suli, Jin, Jiaotong, and Deng, Hang
- Subjects
- *
WIND turbine blades , *COMPOSITE materials , *STRUCTURAL analysis (Engineering) , *STRUCTURAL failures , *STATICS , *AERODYNAMICS - Abstract
Abstract: This study is concerned with an actual collapse testing under the flap-wise loading for a large full-scale composite wind turbine blade, and a discussion is conducted to assess and evaluate the structural response of the blade during loading and after collapse by correlating experimental findings with numerical model predictions. A videometrics technique is adopted to measure the integral deformation and the local deformation of the wind turbine blade under the flap-wise loading. The measured results show that the displacement of the blade tip is up to 11m at the ultimate load which is 160% of the extreme design load for the tested blade. A simple method is proposed to identify the exact failure location of the blade based on the deformation data. The thorough analysis results indicate that the aerodynamic shells debonding from the adhesive joints is the initial failure mechanism causing a progressive collapse of the blade structure. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
25. Application of videometric technique to deformation measurement for large-scale composite wind turbine blade
- Author
-
Yang, Jinshui, Peng, Chaoyi, Xiao, Jiayu, Zeng, Jingcheng, and Yuan, Yun
- Subjects
- *
WIND turbine blades , *TURBINE blades , *PERFORMANCE , *STRUCTURAL analysis (Engineering) , *DEFORMATIONS (Mechanics) , *CINEANGIOGRAPHY , *LARGE scale systems , *DATA analysis ,DESIGN & construction - Abstract
Abstract: The size of wind turbine blades is expected to increase considerably in the future. Since the modern wind turbine blade is generally large-scale, faulty design production results in high expense. To achieve a desired wind turbine blade, a better understanding of the structural behavior on different scale is necessary. Although the structural deformation of the full-scale blade under various loads is an important parameter in the analysis of structural behavior and the blade’s performance, there are many difficulties in an accurate deformation measurement of the large-scale wind turbine blade. A videometric technique reported here was developed to determine the large-scale blade deformations. The technique principle and methodology will be presented in the current paper, which involves the detail of implementation in the large-scale blade deformation measurement. Some application examples with the obtained data and their analysis are presented, which demonstrates the technique’s application on large-scale wind turbine blade, and which is relevant to understanding the structural behavior of wind turbine blade in the full-scale tests and during operation. The videometric technique will be useful for structural investigation of composite wind turbine blades. A wide variety of other applications, especially those involving fieldwork, could exploit this implementation of videometric. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
26. Structural study of liposomes loaded with a GM3 lactone analogue for the targeting of tumor epitopes
- Author
-
Ristori, Sandra, Di Cola, Emanuela, Lunghi, Carlotta, Richichi, Barbara, and Nativi, Cristina
- Subjects
- *
LIPOSOMES , *EPITOPES , *LACTONES , *TUMOR antigens , *CANCER vaccines , *IMMUNE response , *SMALL-angle X-ray scattering , *LIGHT scattering , *THERAPEUTICS - Abstract
Abstract: Therapeutic vaccination with tumor antigens is a new approach in cancer treatment, which aims at inducing immune response while avoiding the side effects generally associated to many conventional therapies. To improve the efficacy of vaccines, suitable carriers may be used. Herein the insertion of a thioether analogue of GM3 lactone (SNeuAC-C14) into liposomes is reported. SNeuAC-C14 is a potential vaccine for the targeting of saccharide-based tumor epitopes. Different liposome formulations were designed to act as carriers and to generate recognition by tumor epitopes. The structural study of pure and loaded liposomes was carried out by synchrotron Small Angle X-ray Scattering and was complemented by Dynamic Light Scattering and Zeta potential measurements. This provided detailed information on relevant properties of the investigated host-guest structures and showed that the active unit of SNeuAC-C14, i.e. its spiro tricyclic moiety, was located in the polar head region of the liposome bilayer, which is an important requirement for recognition phenomena. Moreover, it was found that most of the SNeuAC-C14/liposome complexes were positively charged. The obtained results allow these systems to be considered as candidates to promote immunoresponse in tumor cells. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
27. Micellar Properties of Nonionic Surfactant Tween 40 in Water: Small-Angle X-Ray Scattering Study.
- Author
-
Bešter-Rogač, Marija
- Subjects
- *
SURFACE active agents , *WATER , *SMALL-angle X-ray scattering , *TEMPERATURE , *FOURIER transforms - Abstract
The structural properties of a nonionic surfactant polyoxyethylenesorbitan monopalmitate (C62H122O26, commercial names Tween 40®, Polysorbate 40) in aqueous solutions in the temperature range between 15 and 45 °C have been studied by small-angle X-ray scattering (SAXS) technique. Low concentration experimental data were evaluated using the model free indirect Fourier transformation method (IFT), whereas at higher concentration a generalized indirect Fourier transformation method (GIFT) based on the simultaneous determination of intra- and interparticle scattering contributions was applied. It was found that in Tween 40® aqueous solutions globular micelles with maximum distance within one particle of about 9 nm and radii of the hydrophobic core between 2.1-2.4 nm are present. The concentration and the temperature do affect neither the size nor the shape of the micelles considerably, however the presence of the non-spherical and/or elongated aggregates at higher concentrations at all temperatures could be assumed. [ABSTRACT FROM AUTHOR]
- Published
- 2007
28. Electrospun nanofibers of PVDF-HFP composites containing magnetic nickel ferrite for energy harvesting application
- Author
-
Omar Aljarod, Hemalatha Parangusan, Deepalekshmi Ponnamma, and Mariam Al Ali Al-Maadeed
- Subjects
Materials science ,Nanofibers ,Piezoelectricity ,Spinel ,Nanoparticle ,02 engineering and technology ,Dielectric ,engineering.material ,010402 general chemistry ,Filled polymers ,Iron compounds ,01 natural sciences ,Interfacial interaction ,Nanocomposites ,Coprecipitation ,Nickel ,Dielectric properties of solids ,Magnetic nano-particles ,Fluorine compounds ,General Materials Science ,Nanomagnetics ,Nickel compounds ,Composite material ,Piezoelectric devices ,chemistry.chemical_classification ,Polymer characteristics ,Nanocomposite ,Crystallography ,Electrospinning ,Energy harvesting ,Nickel ferrite nanoparticle ,Ferrite ,Chemical coprecipitation method ,Polymer ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Ferroelectricity ,0104 chemical sciences ,Structural investigation ,chemistry ,Synthesis (chemical) ,Nickel ferrite ,engineering ,Magnetic nanoparticles ,Nanoparticles ,0210 nano-technology - Abstract
Nickel ferrite nanoparticles (NiFe2O4) synthesized by chemical co-precipitation method, are added to poly(vinylidene fluoride-co-hexafluoroproplyene) (PVDF-HFP) in specific concentrations (1, 2, and 3 wt%) and the composite nanofibers are fabricated by electrospinning. Structural investigation and morphology of the synthesized NiFe2O4 magnetic nanoparticles reveal its spinel nature. The crystalline behavior in addition to the ferroelectric properties of NiFe2O4 enhance the interfacial interaction with the polymer chains and creates better dipole alignment and phase transformations within the nanocomposite. The nanocomposite with 1 wt% NiFe2O4 shows the maximum dielectric constant of 118 at 1 Hz frequency, which is about 24 times higher than that of the neat polymer. At the typical concentration of 2 wt% NiFe2O4 in PVDF-HFP, the nanocomposite is capable to generate an output voltage of 4 V suggesting the possible use of those flexible and magnetic polymer nanocomposites in designing piezoelectric devices. The structural performance, dielectric properties and the energy harvesting performance of the PVDF-HFP/NiFe2O4 nanocomposites are demonstrated here based on the filler and polymer characteristics. This publication was made possible by NPRP grant 6-282-2-119 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. Scopus
- Published
- 2020
29. Solvent effects on structural changes in self-healing epoxy composites
- Author
-
Vesna Radojević, Vojislav V. Mitić, Andjela Radisavljevic, Aleksandar Stajcic, Ivana Radovic, Maria Čebela, and Filip M. Veljković
- Subjects
Materials science ,structural investigation ,Composite number ,02 engineering and technology ,mechanical properties ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,self-healing ,General Materials Science ,Composite material ,Fourier transform infrared spectroscopy ,solvent effect ,Epoxy ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Solvent ,Grubbs' catalyst ,chemistry ,morphological properties ,visual_art ,Dicyclopentadiene ,Self-healing ,visual_art.visual_art_medium ,Solvent effects ,0210 nano-technology - Abstract
Nowadays, there is a very high importance of composite research and variety of their applications in the modern world. In that sense, we researched hollow glass capillaries filled with dissolved Grubbs catalyst (GC) and dicyclopentadiene (DCPD) were incorporated into a fiber-reinforced epoxy with the aim of improving the flow of healing agents to the crack site. The morphological investigation of the crack site was performed using field emission scanning electron microscopy (FESEM), showing the difference between the samples depending on the used solvent. The software analysis of sample photographs has been performed by calculating the fractured/healed surface area of the samples, revealing that approximately 20% of the volume was affected by the impact. Fourier transform infrared spectroscopy (FTIR) revealed that poly (dicyclopentadiene) (PDCPD) formed at the healed interface. However, the FTIR investigation of catalyst stability in different solvents showed structural changes in GC and partial deactivation. The mechanical tests of the samples showed that a recovery of 60% after 24 h at room temperature could be achieved through the use of a solvent and very low concentration of GC. The performed research results are a good base to develop the model for predicting the processes and morphology, with the goal to design the final mechanical and in the future, thermal, properties in advance. This opens a new direction for future research in the field of composite healing. © 2020 Elsevier B.V.
- Published
- 2020
30. A new increasing delocalization of M=3d-elements (Ti, Fe, Co) in the channels network of the ternary MyMo6Se8 Chevrel phases
- Author
-
Mançour-Billah, A. and Chevrel, R.
- Subjects
- *
CRYSTALS , *COPPER - Abstract
A structural investigation on single crystals of MyMo6Se8 Chevrel phases (M=3d: Ti, Fe, and Co) has been carried out. These latter compounds as well as others with Cr, Mn, and Ni atoms make part of a new original family of Chevrel phases. The M ions occupy new interstices in the tridimensional channels network never observed in the other classical Chevrel phases as Liy, Cuy Mo6X8. They occupy only cavity 2 centered on
( and ↩ with a progressive delocalization of the M cation versus the nature of the cation from the center of the cavity to the outside . The position in cavity 2 is different from the position of the Cu (2) atoms, the second position of the copper atoms in the channels of the CuyMo6X8 compounds. This new position reinforces the interaction with the Mo6 cluster, and may be able to involve new remarkable physical properties as thermoelectric properties. [Copyright &y& Elsevier]1 /200)- Published
- 2003
- Full Text
- View/download PDF
31. Structural Investigations of Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics by Solid State NMR
- Author
-
Pershina, S. V., Dzuba, M. Y., Vlasova, S. G., Baklanova, Y. V., Pershina, S. V., Dzuba, M. Y., Vlasova, S. G., and Baklanova, Y. V.
- Abstract
NASICON-type conductors based on LiGe2(PO4)3 are very promising lithium-conducting electrolytes for all-solid-state lithium-ion and lithium batteries. Al-doped LiGe2(PO4)3 solid electrolytes possessed higher conductivity (∼10-4 S/cm at room temperature) and stability versus metallic Li. In this paper, we present the structure study of Li1.5Al0.5Ge1.5(PO4)3 compound. Fast lithium-ion conductor Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte have been obtained through glass crystallization at 820 °C during 8 h. Structural positions occupied by atoms have been examined by solid state nuclear magnetic resonance experiments. 6Li, 7Li, 27Al 31P NMR measurements have been performed at room temperature. © Published under licence by IOP Publishing Ltd.
- Published
- 2019
32. Spectroscopic and Structural Properties of β-Tricalcium Phosphates Ca 9 RE (PO 4) 7 (RE = Nd, Gd, Dy).
- Author
-
Paterlini, Veronica, El Khouri, Asmaa, Bettinelli, Marco, Trucchi, Daniele Maria, and Capitelli, Francesco
- Subjects
GADOLINIUM ,PHOSPHATES ,MOLECULAR spectra ,LUMINESCENCE spectroscopy - Abstract
Rare-earth-based Ca
9 RE(PO4 )7 (RE = Nd, Gd, Dy) materials were synthesized by solid-state reaction at T = 1200 °C. The obtained tricalcium phosphate (TCP) materials are efficient light emitters due to the presence of RE3+ ions, although these ions are present at high concentrations. Moreover, in these host structures, these ions can be used as optical probes to study their local environments. Thus, photoluminescence (PL) emission spectra of the powder samples clearly indicated, for Dy3+ and Gd3+ ions, the presence of the RE3+ ion in low-symmetry sites with some local structural disorder, and the spectra show the presence of vibrational features (in the case of Gd3+ ). For the Nd3+ phase, emission bands are present around 900, 1050, and 1330 nm, originating from the4 F3/2 level. In general, these RE-TCP samples are interesting luminescent materials in the visible (Dy), UV (Gd), and NIR (Nd) regions, due to weak concentration quenching even for high concentrations of the emitting ion. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
33. Structural Investigations for the Refurbishment Project of the Municipal Building of Gjakova
- Author
-
Nela, Bledian and Francesco, Rucci
- Subjects
refurbishment ,structural investigation ,retrofitting ,non-destructive techniques ,structural investigation, non-destructive techniques, refurbishment, retrofitting, reinforced concrete structures ,reinforced concrete structures - Published
- 2019
34. Self-assembled nanostructures for applications in plasmonic metamaterials
- Author
-
Grillo, Rossella and Buergi, Thomas
- Subjects
Optical properties ,Physics::Optics ,Self-assembly ,Layer-by-layer ,Polyelectrolytes ,Electrostatic interaction ,Nanostructures ,Electromagnetic ,Coupling ,Structural investigation ,Large scale particles arrays ,Metamaterials ,ddc:540 ,Physics::Atomic and Molecular Clusters ,Plasmonics ,Gold nanoparticles ,Bottom-up ,Functionalization ,Core-shell nanoclusters - Abstract
This work involves the design, fabrication and characterization of metamaterials based on meta-atoms and its assemblies. The aim is to tailor the optical properties that emerge from choosing material and geometry of their basic unit cells. The approach starts with the bottom-up preparation of nanoresonators, which consist in core-shell structures made of plasmonic nanoparticles covering a dielectric core. The coupling between the plasmonic units leads to new plasmon resonances that have a magnetic dipole character. The next step involves the meta-atoms organization on surfaces and the characterization of their structural and optical properties. Highly ordered monolayers and patterns of meta-atoms over large area were obtained via blade coating deposition. The samples are then characterized by spectral high-resolution interference microscopy, which provides information on the scattering intensity and the phase shift induced by the meta-atom. In this way, the scattering response of different meta-atoms is studied in an unprecedented manner.
- Published
- 2019
- Full Text
- View/download PDF
35. Synthese und Charakterisierung von neuen Sodalithen, Cancrinithen sowie deren Intermediären Phase
- Author
-
Petersen, Hilke, Buhl, Josef-Christian, Gesing, Thorsten M., and Depmeier, Wulf
- Subjects
structural investigation ,ddc:540 ,temperature-dependent behavior ,540 Chemistry ,Cancrinites ,Sodalites ,Intermediate Phase ,phase transitions - Abstract
The thermal behavior and occuring phase transitions of three sodalites, a permanganate-, a perrhenate and a mixed permanganate/perrhenate-sodalite are investigated. Below 300 K a loss of dynamic motion of the templating anions could be observed, causing a phase transition of perrhenate-sodalite. At elevated temperatures all sodalites show a phase transition to the fully expanded structure (P-43n to Pm-3n). At 900 K the permangante-sodalite shows a second phase transition to P23.Further a comprehensive study on cancrinites containing different divalent tetrahedral coordinated anions (XO4 2-; X = Mn, Cr, Se, Mo, W) and their effect on the thermal behavior is performed. Thirdly, a structural investigation of the one-dimensional disordered Intermediate phase is carried out. By correlating the lattice parameter c with the existing zeolite-cages and the chemical composition of the sample the structure of the intermediate phase could be modeled.
- Published
- 2018
36. Structural investigation of crystallized Ge-Ga-Se chalcogenide glasses
- Author
-
Oleh Shpotyuk, Halyna Klym, Laurent Calvez, Ivan Karbovnyk, Anatoli I. Popov, Ivan Franko National University of Lviv, Jan Dlugosz University in Czestochowa, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Latvia (LU), Ministry of Education and Science of Ukraine, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
- Subjects
Materials science ,Chalcogenide ,Functional materials ,In-process ,02 engineering and technology ,01 natural sciences ,Selenium compounds ,Annealing ,chemistry.chemical_compound ,Atomic force microscopy ,Germanium compounds ,0103 physical sciences ,Nanotechnology ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS ,010302 applied physics ,Gallium compounds ,High temperature modification ,021001 nanoscience & nanotechnology ,3. Good health ,Crystallography ,Crystallization transformations ,Structural investigation ,chemistry ,Surface crystallization ,Chalcogenide glass ,Glass ,0210 nano-technology ,Chalcogenides - Abstract
H. Klym thanks to the Ministry of Education and Science of Ukraine for support and Dr. P. Demchenko for the assistance in XRD experiments., Crystallization transformation in the 80GeSe2-20Ga2Se3 chalcogenide glasses caused by annealing at 380 °C during different duration (25, 50, 80 and 100 hours) are studied using X-ray diffraction and atomic force microscopy methods. It is established that GeGa4Se phase of low- and high-temperature modification, Ga2Se3 phase (α- and γ-modification) and GeSe2 phases are crystallized during this process. It is shown that annealing duration over 50 h does not lead to further internal structural crystallization, while annealing for 80 h result in processes of surface crystallization., Ministry of Education and Science of Ukraine; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²
- Published
- 2018
- Full Text
- View/download PDF
37. A pilot study to test the reliability of the ERT method in the identification of mixed sulphides bearing dykes: The example of Sidi Flah mine (Anti-Atlas, Morocco)
- Author
-
Stefano Bernardinetti, Aziz Harroud, Enrico Mugnaioli, Marilena Trotta, Franco M Talarico, Diego Pieruccioni, and Emanuele Tufarolo
- Subjects
010504 meteorology & atmospheric sciences ,Mixed sulphides ,Multidisciplinary study ,Geochemistry ,Geology ,Anti-Atlas ,ERT ,Morocco ,Petrographical analyses ,Structural investigation ,Geochemistry and Petrology ,Economic Geology ,010502 geochemistry & geophysics ,01 natural sciences ,Initial phase ,Economic geology ,0105 earth and related environmental sciences - Abstract
A multidisciplinary study, comprising geological, petrographical and geophysical methods, was carried out for the identification and the geometrical and volumetric assess of the main mineralized bodies (mixed sulphides, Zn-Pb and Fe-Cu) in the area of the Anti-Atlas chain, located at SW of the town of Sidi Flah (Ouarzazate, Morocco). The initial phase of exploration involved an extensive fieldwork (structural investigations and sampling) and a detailed survey for verifying the effectiveness and reliability of the Electrical Resistivity Method (ERT). Geological fieldworks and laboratory analyses played a fundamental role in identifying the resistivity anomalies and constraining tomographic results. Main issues we focused on are: i) mineralized bodies imaging according to the electrodic step; ii) consistency with geometry of mineralized bodies; iii) contrast of electrical resistivity between mineralized dykes and host rocks; iv) possible correlations between the type and amount of sulphides and electrical resistivity.
- Published
- 2018
38. Structural Investigations of Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics by Solid State NMR
- Author
-
M. Y. Dzuba, S. G. Vlasova, Y. V. Baklanova, and S. V. Pershina
- Subjects
History ,Materials science ,SOLID ELECTROLYTES ,GLASS CRYSTALLIZATION ,STRUCTURAL INVESTIGATION ,Education ,GLASS CERAMICS ,LITHIUM IONS ,ALL-SOLID STATE ,ALUMINUM COMPOUNDS ,NUCLEAR MAGNETIC RESONANCE ,GERMANIUM COMPOUNDS ,Ceramic ,LITHIUM-ION BATTERIES ,LITHIUM COMPOUNDS ,SOLID-STATE BATTERIES ,LITHIUM ION CONDUCTORS ,CONDUCTING ELECTROLYTE ,NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY ,Computer Science Applications ,POTENTIOMETRIC SENSORS ,Solid-state nuclear magnetic resonance ,SOLID-STATE NUCLEAR MAGNETIC RESONANCE ,visual_art ,visual_art.visual_art_medium ,Physical chemistry ,SOLID STATE NMR - Abstract
NASICON-type conductors based on LiGe2(PO4)3 are very promising lithium-conducting electrolytes for all-solid-state lithium-ion and lithium batteries. Al-doped LiGe2(PO4)3 solid electrolytes possessed higher conductivity (∼10-4 S/cm at room temperature) and stability versus metallic Li. In this paper, we present the structure study of Li1.5Al0.5Ge1.5(PO4)3 compound. Fast lithium-ion conductor Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte have been obtained through glass crystallization at 820 °C during 8 h. Structural positions occupied by atoms have been examined by solid state nuclear magnetic resonance experiments. 6Li, 7Li, 27Al и 31P NMR measurements have been performed at room temperature.
- Published
- 2019
- Full Text
- View/download PDF
39. The Diverse World of Foldamers: Endless Possibilities of Self-Assembly †.
- Author
-
Rinaldi, Samuele and Dodero, Veronica
- Subjects
- *
POSSIBILITY , *DIMERS , *OLIGOMERS , *MONOMOLECULAR films - Abstract
Different classes of foldamers, which are synthetic oligomers that adopt well-defined conformations in solution, have been the subject of extensive studies devoted to the elucidation of the forces driving their secondary structures and their potential as bioactive molecules. Regardless of the backbone type (peptidic or abiotic), the most important features of foldamers are the high stability, easy predictability and tunability of their folding, as well as the possibility to endow them with enhanced biological functions, with respect to their natural counterparts, by the correct choice of monomers. Foldamers have also recently started playing a starring role in the self-assembly of higher-order structures. In this review, selected articles will be analyzed to show the striking number of self-assemblies obtained for foldamers with different backbones, which will be analyzed in order of increasing complexity. Starting from the simplest self-associations in solution (e.g., dimers of β-strands or helices, bundles, interpenetrating double and multiple helices), the formation of monolayers, vesicles, fibers, and eventually nanostructured solid tridimensional morphologies will be subsequently described. The experimental techniques used in the structural investigation, and in the determination of the driving forces and mechanisms underlying the self-assemblies, will be systematically reported. Where applicable, examples of biomimetic self-assembled foldamers and their interactions with biological components will be described. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
40. Fatigue Strength Degradation of AlSi12CuNiMg Alloy Due to High Temperature Exposure: A Structural Investigation
- Author
-
Ludvík Kunz, Gianni Nicoletto, Radomila Konečná, Adrián Bača, and Milan Svoboda
- Subjects
Materials science ,fatigue strength ,structural investigation ,Al-Si alloy ,Alloy ,Metallurgy ,Intermetallic ,General Medicine ,engineering.material ,Fatigue limit ,law.invention ,Piston ,law ,Etching (microfabrication) ,engineering ,Metallography ,age hardening ,precipitates ,Particle size ,Engineering(all) ,Eutectic system - Abstract
The strengthening mechanism based on the formation of precipitates (Guinier-Preston (GP) zones) during decomposition of a metastable supersaturated solid solution is stable and effective below temperatures, which are typically overcome in the piston region facing the combustion chamber. Therefore, pistons experience a progressive loss of strength due to over-aging during service. This contribution reports of a structural investigation on a eutectic AlSi12CuNiMg alloy before and after fatigue testing at high temperatures (up to 350 °C). Metallography, color etching, SEM and TEM are used to elucidate the following aspects: 1) the structural features of the alloy (dendrites of α−phase, primary Si particle size and distribution, morphology and distribution of intermetallic phases); 2) the evolution of the strengthening mechanism (GP zones) with high temperature exposure.
- Published
- 2014
- Full Text
- View/download PDF
41. Synthesis, structural, optical, morphological and magnetic characterization of copper substituted nickel ferrite (CuxNi1−xFe2O4) through co-precipitation method
- Author
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Abdelmajid Lassoued, Fabienne Karolak, Abdellatif Gadri, Mohamed Saber Lassoued, Santiago García-Granda, Brahim Dkhil, Salah Ammar, UREME (UR17ES45), Faculté des Sciences de Gabes - Tunisie, Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Physical and Analytical Chemistry, University of Oviedo, École Centrale Paris, and Université de Gabès
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Precipitation (chemical) ,Scanning electron microscope ,Analytical chemistry ,High resolution transmission electron microscopy ,02 engineering and technology ,7. Clean energy ,01 natural sciences ,[SPI.MAT]Engineering Sciences [physics]/Materials ,Lattice constant ,Gravimetric analysis ,Coprecipitation ,Copper substitution ,010302 applied physics ,Differential thermal analysis ,Magnetism ,Particle size ,Thermogravimetric analysis ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Grain size ,3. Good health ,Electronic, Optical and Magnetic Materials ,Energy gap ,Structural investigation ,Transmission electron microscopy ,symbols ,Ferrite (magnet) ,0210 nano-technology ,Scanning electron microscopy ,Fourier transform infra reds ,Materials science ,X ray diffraction ,Magnetic characterization ,chemistry.chemical_element ,symbols.namesake ,0103 physical sciences ,Magnetic properties ,Electron microscopy ,Vibrating sample magnetometer ,Electrical and Electronic Engineering ,Ferrite ,Chemical coprecipitation method ,Single-phase spinel structure ,Thermoanalysis ,Copper ,chemistry ,Coprecipitation method ,Raman spectroscopy - Abstract
The CuxNi1−xFe2O4 (x = 0.0, 0.2, 0.5, 0.8, 1.0) nanoferrite powder were synthesized through chemical co-precipitation method using only (FeCl3, 6H2O), (NiCl2, 6H2O), (CuCl2, 4H2O), NaOH and acid oleic as raw materials. The synthesized powder was characterized by X-ray diffraction (XRD); it was used to determine the structural properties. The transmission electron microscopy and the scanning electron microscopy were used to determine the morphology and particle size. The Fourier Transform Infra-Red (FT-IR) spectroscopy is used to deduce the structural investigation and confirmation of ferrite. Raman spectroscopy is used to verify that we have synthesized CuxNi1−xFe2O4 and determines their phonon modes. The thermo gravimetric analysis findings allow the thermal cycle determination of samples whereas differential thermal analysis findings allow the phase transition temperature identification. The optical study UV–Visible is used to calculate the band gap energies. The vibrating sample magnetometer was used to obtain the hysteresis parameters. In conclude, the XRD confirmed the single phase spinel structure. The lattice constant increased with the increased copper contents. The size of nanoparticles decreased with the increased copper contents. The magnetic property of the CuxNi1−xFe2O4 shows remarkable changes with change of Cu2+.The variation of copper substitution has a significant influence on the optical, grain size and magnetic properties. The mean crystalline size of the synthesized ferrite was in the range of 14–43 nm., The present work was supported by the Research Funds of Electrochemistry, Materials and Environment Research Unit UREME (UR17ES45), Faculty of Sciences Gabes University, Tunisia and Structures, Properties and Modeling of Solids (SPMS) Laboratory, Ecole Centrale Paris, France.
- Published
- 2017
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42. The N Terminus of the Prion Protein Mediates Functional Interactions with the Neuronal Cell Adhesion Molecule (NCAM) Fibronectin Domain
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Ivana Biljan, Giulia Salzano, Gabriele Giachin, Blaž Zupančič, Giuseppe Legname, Urška Slapšak, Gregor Ilc, Janez Plavec, Romany Abskharon, and Ladan Amin
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0301 basic medicine ,Scaffold protein ,Cell signaling ,animal diseases ,Settore BIO/09 - Fisiologia ,Biochemistry ,Hippocampus ,protein-protein interaction ,NCAM ,NMR spectroscopy ,STED ,cell adhesion ,fibronectin ,fibronectin type-3 domain ,nuclear magnetic resonance (NMR) ,prion ,prion protein ,stimulated emission depletion microscopy ,Animals ,Humans ,Mice ,Neural Cell Adhesion Molecules ,Neurons ,Nuclear Magnetic Resonance, Biomolecular ,PrPC Proteins ,Protein Domains ,Mammals ,Transmissible spongiform encephalopathy ,biology ,Neurodegenerative diseases ,Cell biology ,Structural investigation ,Protein Structure and Folding ,Stimulated emission ,Gene isoform ,Protein-protein interactions ,Cells ,Nuclear Magnetic Resonance ,Biomolecules ,Cell adhesion ,Cell membranes ,Cytology ,Molecules ,Nuclear magnetic resonance spectroscopy ,Proteins ,Functional interaction ,Peripheral nervous system ,Scaffolding proteins ,Stimulated emission depletion ,Structural determinants ,Transmissible spongiform encephalopathies ,Scaffolds (biology) ,Protein–protein interaction ,03 medical and health sciences ,medicine ,Molecular Biology ,Cell Biology ,medicine.disease ,nervous system diseases ,Fibronectin ,030104 developmental biology ,nervous system ,biology.protein ,Neural cell adhesion molecule ,Neuronal Cell Adhesion Molecule ,Biomolecular - Abstract
The cellular form of the prion protein (PrPC) is a highly conserved glycoprotein mostly expressed in the central and peripheral nervous systems by different cell types in mammals. A misfolded, pathogenic isoform, denoted as prion, is related to a class of neurodegenerative diseases known as transmissible spongiform encephalopathy. PrPC function has not been unequivocally clarified, and it is rather defined as a pleiotropic protein likely acting as a dynamic cell surface scaffolding protein for the assembly of different signaling modules. Among the variety of PrPC protein interactors, the neuronal cell adhesion molecule (NCAM) has been studied in vivo, but the structural basis of this functional interaction is still a matter of debate. Here we focused on the structural determinants responsible for human PrPC (HuPrP) and NCAM interaction using stimulated emission depletion (STED) nanoscopy, SPR, and NMR spectroscopy approaches. PrPC co-localizes with NCAM in mouse hippocampal neurons, and this interaction is mainly mediated by the intrinsically disordered PrPC N-terminal tail, which binds with high affinity to the NCAM fibronectin type-3 domain. NMR structural investigations revealed surface-interacting epitopes governing the interaction between HuPrP N terminus and the second module of the NCAM fibronectin type-3 domain. Our data provided molecular details about the interaction between HuPrP and the NCAM fibronectin domain, and revealed a new role of PrPC N terminus as a dynamic and functional element responsible for protein-protein interaction.
- Published
- 2016
43. Characterization and structural investigation of lead borophosphate glasses modified by tungsten oxide
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Koudelka, Ladislav, Roesslerova, Ivana, Kalenda, Petr, Mošner, Petr, Montagne, Lionel, Revel, Bertrand, Koudelka, Ladislav, Roesslerova, Ivana, Kalenda, Petr, Mošner, Petr, Montagne, Lionel, and Revel, Bertrand
- Abstract
The effect of WO3 on the properties and structure of PbO-B2O3-P2O5-WO3 quaternary system was studied. Glasses containing up to 60 mol% WO3 were prepared and the variation of several physical properties was determined with respect to chemical composition in a broad compositional range. Chemical durability of WO3-containing glasses is very high and their thermal stability as well. Glass transition temperature increases with increasing WO3 content up to 566°C. Glass structure was studied by Raman spectroscopy and 31P and 11B MAS NMR spectroscopy. NMR spectroscopy reveals the formation of B-O-W linkages and also the existence of tetrahedral BO4 units and trigonal units BO3 in the glass structure. With increasing WO3 content in the glasses, the number of starting tetrahedral B(OP)3O units decreases and B-O-P bridges are replaced gradually by B-O-W and B-O-B bridges, while the number of BO3 units increases. Raman spectra of the studied glasses possess a doublet of strong vibrational bands in the range at 800-1000 cm-1, assigned to vibrations of W-O- a W=O bonds in tungstate structural units. In glasses with a higher WO3 content WO6 octahedra form tungstate clusters interconnected by W-O-W bridges as reflected in the Raman spectra.. The formation of strong P-O-W and B-O-W linkages in the studied glasses explains high chemical durability of the glasses and the observed increase in the glass transition temperature., Byl studován vliv WO3 na vlastnosti a strukturu skel systému PbO-B2O3-P2O5-WO3. Byla připravena skla s obsahem až 60 mol.% WO3 a byly stanoveny změny řady fyzikálních vlastností na složení skel v širokém rozsahu složení. Teplota skelné transformace roste s obsahem WO3 až na 566°C. Struktura skel byla studována Ramanovouz spektroskopií and MAS NMR spektroskopií jader 31P a 11B. NMR spectroskopie ukázala na tvorbu vazeb B-O-W a též existenci of tetraedrický celků BO4 trigonálních celků BO3 ve strukturní síti skel. in the glass structure. S růstem obsahu WO3 počet celků B(OP)3O klesá a můstky B-O-P jsou nahrazovány celky B-O-W a B-O-B, přičemž počet celků BO3 roste. Tvorba silných vazeb P-O-W a B-O-W je příčinou vysoké chemické odolnosti skel a růstu teploty skelné treansformace.
- Published
- 2017
44. Physicochemical and morphological characterizations of glyceryl tristearate/castor oil nanocarriers prepared by the solvent diffusion method
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Frédéric Dubreuil, Elenara Lemos-Senna, Jean-Luc Putaux, Valdir Soldi, Isabelle Pignot-Paintrand, Redouane Borsali, Cristiana Lima Dora, inconnu, Inconnu, Centre de Recherches sur les Macromolécules Végétales (CERMAV), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
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nanoemulsions ,structural investigation ,Stereochemistry ,nanostructured lipid carriers ,02 engineering and technology ,drug delivery systems ,0404 agricultural biotechnology ,Differential scanning calorimetry ,Dynamic light scattering ,Solid lipid nanoparticle ,PEG ratio ,medicine ,ComputingMilieux_MISCELLANEOUS ,Chemistry ,04 agricultural and veterinary sciences ,General Chemistry ,Poloxamer ,021001 nanoscience & nanotechnology ,040401 food science ,Solvent ,solid lipid nanoparticles ,Castor oil ,lipids (amino acids, peptides, and proteins) ,0210 nano-technology ,Drug carrier ,Nuclear chemistry ,medicine.drug - Abstract
Neste estudo, nanocarreadores lipidicos foram preparados a partir do triestearato de glicerila e oleo de ricino em diferentes proporcoes pela tecnica de difusao do solvente a quente. Estearato de PEG-660 ou Poloxamer 188 e lecitina de soja foram usados como surfactante e cossurfactante, respectivamente. Caracteristicas estruturais e fisico-quimicas das particulas foram investigadas por meio de espalhamento de luz dinâmico (DLS), calorimetria exploratoria diferencial (DSC), espalhamento de raios X a altos ângulos (WAXS), microscopia de forca atomica (AFM) e microscopia eletronica de transmissao (TEM e cryo-TEM). A analise por DLS indicou que particulas menores foram obtidas quando o lipidio liquido foi usado sozinho para obter as nanoemulsoes (NEs). Tecnicas microscopicas (TEM e cryo-TEM) mostraram que as NEs apresentaram formas esfericas, enquanto as nanoparticulas lipidicas solidas (NLSs) e os carreadores lipidicos nanoestruturados (CLNs) apresentaram formas mais complexas. As NLSs exibiram estrutura cristalina lamelar, enquanto os CLNs exibiram uma estrutura mista composta de fase cristalina lamelar em contato com compartimento oleoso. Estes experimentos contribuem para um melhor entendimento da capacidade de incorporacao e liberacao de farmacos destes nanocarreadores. In this study, drug delivery nanocarriers based on glyceryl tristearate and castor oil at different ratios were prepared by the hot solvent diffusion method. PEG 660-stearate or Poloxamer 188 and soybean lecithin were used as surfactant and co-surfactant, respectively. Structural and physicochemical characteristics of the particles were investigated by means of dynamic light scattering (DLS), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), atomic force microscopy (AFM) and transmission electron microscopy (TEM and cryo-TEM). DLS data indicated that smaller particles were obtained when the liquid lipid was used alone to prepare nanoemulsions (NEs). TEM and cryo-TEM images showed that NEs presented spherical particles, whereas solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) presented more complex shapes. SLNs exhibited lamellar crystal structure, while NLCs displayed a hybrid structure composed of a lamellar crystalline phase in contact with a liquid oil compartment. These experiments contribute to a better understanding of the structure and release performance of these drug carrier systems.
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- 2012
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45. Hyaluronan-carbon nanotube derivatives: Synthesis, conjugation with model drugs, and DOSY NMR characterization
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Maurizio Prato, Francesca Dinon, Riccardo Marega, Massimo Bergamin, Erminio Murano, Vincent Aroulmoji, Department of Chemistry, University of Namur, Rue Bruxelles 61, Namur, 5000, Belgium, PROTOS Research Institute, Via Flavia 23/1 c/o BIC Incubatori FVG, 34148 Trieste, Italy, Cimteclab Spa, c/o Area Science Park, Padriciano 99, Trieste, 34149, Italy, Department of Chemical and Pharmaceutical Sciences, University of Trieste, Piazzale Europa 1, Trieste, 34127, Italy, R., Marega, M., Bergamin, V., Aroulmoji, F., Dinon, Prato, Maurizio, and E., Murano
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Biocompatibility ,structural investigation ,[SDV]Life Sciences [q-bio] ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,01 natural sciences ,law.invention ,law ,[CHIM]Chemical Sciences ,Organic chemistry ,carbon nanotube ,Physical and Theoretical Chemistry ,ComputingMilieux_MISCELLANEOUS ,chemistry.chemical_classification ,carbon nanotubes ,Organic Chemistry ,Nuclear magnetic resonance spectroscopy ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,nuclear magnetic resonance ,chemistry ,Covalent bond ,Drug delivery ,Amine gas treating ,0210 nano-technology ,Merge (version control) - Abstract
Carbon nanotube (CNTs) derivatives are nowadays under thorough investigation as biomedically interesting materials. In this paper we describe a method for the preparation of water-soluble CNTs by condensation of the carboxylic groups introduced onto the carbon framework and the primary amine moieties inserted in the naturally occurring biopolymer hyaluronan (HA). The covalent conjugation between CNTs and HA should merge the biocompatibility and further processability of the HA chains with the well-known cellular penetration properties of the CNT derivatives to produce novel drug delivery platforms. In fact, thanks to the primary amino groups introduced in the HA chains, HA-CNT derivatives can be further covalently modified with model drugs like ibuprofen and methotrexate. We describe also the monitoring of all the CNT derivatization steps by diffusion-ordered NMR spectroscopy (DOSY), a technique that allows fast and reliable characterization of these novel derivatives.
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- 2011
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46. Structural study of liposomes loaded with a GM3 lactone analogue for the targeting of tumor epitopes
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Sandra Ristori, Emanuela Di Cola, Barbara Richichi, Cristina Nativi, Carlotta Lunghi, Ristori S., Di Cola E., Lunghi C., Richichi B., and Nativi C.
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Stereochemistry ,Lipid Bilayers ,Biophysics ,Cancer Vaccines ,Vaccine adjuvant ,Biochemistry ,Epitope ,Epitopes ,Structure-Activity Relationship ,Immune system ,Antigen ,Neoplasms ,Zeta potential ,Moiety ,G(M3) Ganglioside ,Cationic liposome ,Liposome ,Chemistry ,SAXS ,Cell Biology ,Structural investigation ,Liposomes ,lipids (amino acids, peptides, and proteins) ,Immunoresponse - Abstract
Therapeutic vaccination with tumor antigens is a new approach in cancer treatment, which aims at inducing immune response while avoiding the side effects generally associated to many conventional therapies. To improve the efficacy of vaccines, suitable carriers may be used. Herein the insertion of a thioether analogue of GM3 lactone (SNeuAC-C14) into liposomes is reported. SNeuAC-C14 is a potential vaccine for the targeting of saccharide-based tumor epitopes. Different liposome formulations were designed to act as carriers and to generate recognition by tumor epitopes. The structural study of pure and loaded liposomes was carried out by synchrotron Small Angle X-ray Scattering and was complemented by Dynamic Light Scattering and Zeta potential measurements. This provided detailed information on relevant properties of the investigated host-guest structures and showed that the active unit of SNeuAC-C14, i.e. its spiro tricyclic moiety, was located in the polar head region of the liposome bilayer, which is an important requirement for recognition phenomena. Moreover, it was found that most of the SNeuAC-C14/liposome complexes were positively charged. The obtained results allow these systems to be considered as candidates to promote immunoresponse in tumor cells. © 2009 Elsevier B.V. All rights reserved.
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- 2009
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47. L'investigazione antincendio sugli aspetti strutturali: una proposta di codifica
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Mangione, Marcello, Bontempi, Franco, and Crosti, Chiara
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Structural Investigation ,Fire Investigation ,Fire Investigation, Structural Investigation - Published
- 2015
48. C ion-implanted TiO2 thin film for photocatalytic applications
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Giuliana Impellizzeri, Ruy Sanz, Enrico Napolitani, Robert Carles, Lucia Romano, Viviana Scuderi, V. Privitera, MATIS CNR-INFM Dipartimento di Metodologie Fisiche e Chimiche (DMFCI) (MATIS), Università degli studi di Catania = University of Catania (Unict)- Istituto Nazionale di Fisica Nucleare (INFN), Nano-Optique et Nanomatériaux pour l'optique (CEMES-NeO), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Catania [Catania]- Istituto Nazionale di Fisica Nucleare (INFN), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
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Secondary ion mass spectrometry ,Materials science ,WATER, ANATASE, NANOMATERIALS, TECHNOLOGY ,Light ,X ray diffraction ,General Physics and Astronomy ,Photochemistry ,7. Clean energy ,Heavy ions ,chemistry.chemical_compound ,Luminescence spectroscopy ,ANATASE ,Photodegradation ,Rutherford backscattering spectroscopy ,TiO2 ,WATER ,Semiconductor doping ,ion implantation ,TECHNOLOGY ,Irradiation ,Thin film ,Environmental applications ,NANOMATERIALS ,Ions ,[PHYS]Physics [physics] ,Mass spectrometry ,Spectrometry ,carbon ,Rutherford back-scattering spectrometry ,Rutherford backscattering spectrometry ,Energy gap ,Ion implantation ,Structural investigation ,VIS ,chemistry ,water ,Titanium dioxide ,Optical characterization ,Photocatalysis ,Degradation of organic compounds ,Synthesized materials ,Photocatalytic application ,photocatalysis ,Visible spectrum - Abstract
cited By 18; International audience; Third-generation TiO2 photocatalysts were prepared by implantation of C+ ions into 110nm thick TiO2 films. An accurate structural investigation was performed by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, Raman-luminescence spectroscopy, and UV/VIS optical characterization. The C doping locally modified the TiO2 pure films, lowering the band-gap energy from 3.3eV to a value of 1.8eV, making the material sensitive to visible light. The synthesized materials are photocatalytically active in the degradation of organic compounds in water under both UV and visible light irradiation, without the help of any additional thermal treatment. These results increase the understanding of the C-doped titanium dioxide, helpful for future environmental applications.
- Published
- 2015
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49. Synthesis and characterization of La2NiO4+δ coatings deposited by reactive magnetron sputtering using plasma emission monitoring
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Alain Billard, Pascal Briois, Ghislaine Bertrand, Jérémie Fondard, Laboratoire d'Études et de Recherches sur les Matériaux, les Procédés et les Surfaces (IRTES - LERMPS), Université de Technologie de Belfort-Montbeliard (UTBM)-Institut de Recherche sur les Transports, l'Energie et la Société - IRTES, Laboratoire Commun de Belfort : Hydrogène et Pile à Combustible pour les applications au transport (FC LAB), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Laboratoire Transports et Environnement (IFSTTAR/AME/LTE), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université de Lyon-Université de Lyon-Laboratoire des Technologies Nouvelles (IFSTTAR/COSYS/LTN), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Technologie de Belfort-Montbeliard (UTBM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Technologie de Belfort-Montbeliard (UTBM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Laboratoire des Technologies Nouvelles (IFSTTAR/COSYS/LTN), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Laboratoire Transports et Environnement (IFSTTAR/AME/LTE), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université de Lyon-Université de Lyon, Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Franche-Comté (FRANCE), Université de Technologie de Belfort-Montbéliard - UTBM (FRANCE), Centre Interuniversitaire de Recherche et d'Ingénierie des Matériaux - CIRIMAT (Toulouse, France), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
- Subjects
Reactive magnetron ,Materials science ,La2NiO4 ,Annealing (metallurgy) ,Matériaux ,Analytical chemistry ,chemistry.chemical_element ,Argon flow ,General Chemistry ,Plasma ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Condensed Matter Physics ,Reactive magnetron sputtering ,Deposition rate ,Nickel ,Plasma emission monitoring ,Structural investigation ,chemistry ,Sputtering ,Electrical properties ,General Materials Science - Abstract
International audience; This work focuses on the structural and electrical characterization of La-Ni-O coatings deposited by reactive magnetron sputtering using Plasma Emission Monitoring (PEM) which allows high deposition rate. The optimal regulation setpoint for lanthanumdeposition is determined and then the current dissipated on the nickel target is adjusted to obtain the convenient La/Ni ratio to achieve the K2NiF4 structure. After an appropriate annealing treatment, all coatings exhibit crystalline structures that depend on the La/Ni ratio. Some cracks appear on samples deposited on alumina substrates depending to the argon flow rate and influence their electrical behavior.
- Published
- 2014
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50. 重要伝統的建造物群保存地区における木造建物群の構造調査と地震防災対策への応用
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Jiao, Jian, 林, 康裕, 吹田, 啓一郎, and 神吉, 紀世子
- Subjects
Structural investigation ,Questionnaire survey ,Non-destructive test ,Seismic risk management ,Traditional wooden buildings ,Important preservation districts - Published
- 2014
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