The aim of this study was to evaluate the adhesion of different bioceramic coatings deposited by radio frequency magnetron sputtering on the biodegradable implant-type magnesium-calcium (MgCa) ...alloys. Hydroxyapatite (HA) and bioactive glass (BG) were chosen as coating materials, due to their remarkable biological potential. The morphology, composition, structure and adhesion of the deposited thin coatings was characterized by scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectroscopy, grazing incidence X-ray diffraction, Fourier transform infrared spectroscopy and pull-out adherence measurements. A variation of the coating-to-substrate adhesion has been recorded and correlated with the physico-chemical results. The bonding strength values of the coatings were promising (being superior to the ISO13779-2:2008 fabrication standard for load-bearing biomedical coatings), and thus, encourage us to further proceed with the biological evaluation of the HA or BG coatings-MgCa substrate couples.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•Laser pyrolysis technique was employed for gamma iron oxide nanoparticles synthesis.•Hydrophobicity was induced by higher synthesis temperature due to C2H4 decomposition.•They show or ferro or ...superpamagnetic behavior and 70emu/g saturation magnetization.•Nanoparticles (20g/l)/l-DOPA aqueous suspensions have enhanced thermal conductivity.•The suspensions show no cytotoxic effects on human tumor or normal mouse immune cells.
γFe2O3-based nanoparticles were synthesized by laser pyrolysis using various optimized Fe(CO)5, O2 and C2H4 flow ratios in the reactive mixture, and different laser power values. Depending on particular conditions, two different iron oxide-based nanoparticles (MNPs) were synthesized, with a hydrophilic or hydrophobic behavior, both presenting a high magnetization saturation (around 70emu/g). TEM, EDX, XRD and magnetic analyses were performed for a comprehensive characterization. The raw powders were successfully dispersed in aqueous media using l-DOPA as stabilizing agent. Dispersed samples, with or without stabilization agents, have been tested and DLS measurements proved their good stability, with the hydrodynamic diameter varying between 70 and 150nm when the stabilizing agent was used. Thermal conductivity and viscosity tests on l-DOPA-functionalized MNPs suspensions reveal the increasing (up to 40%) of their thermal conductivity, accompanied by a viscosity increase of only 5%, validating them as thermal transfer fluids. Water-based nanoparticle dispersions and also those stabilized with l-DOPA proved a good biocompatibility, as demonstrated by a preliminary in vitro study on mouse primary leukocytes and human breast carcinoma cell line MCF-7; although ingested by the investigated cells, MNPs do not decrease cellular viability and proliferation.
Women are under-represented in research on suicidality to date. Although women have a lower rate of suicide completion than men, due in part to the less-violent methods used, they have a higher rate ...of suicide attempts. Our group has previously identified genomic (blood gene expression biomarkers) and clinical information (apps) predictors for suicidality in men. We now describe pilot studies in women. We used a powerful within-participant discovery approach to identify genes that change in expression between no suicidal ideation (no SI) and high suicidal ideation (high SI) states (n=12 participants out of a cohort of 51 women psychiatric participants followed longitudinally, with diagnoses of bipolar disorder, depression, schizoaffective disorder and schizophrenia). We then used a Convergent Functional Genomics (CFG) approach to prioritize the candidate biomarkers identified in the discovery step by using all the prior evidence in the field. Next, we validated for suicidal behavior the top-ranked biomarkers for SI, in a demographically matched cohort of women suicide completers from the coroner's office (n=6), by assessing which markers were stepwise changed from no SI to high SI to suicide completers. We then tested the 50 biomarkers that survived Bonferroni correction in the validation step, as well as top increased and decreased biomarkers from the discovery and prioritization steps, in a completely independent test cohort of women psychiatric disorder participants for prediction of SI (n=33) and in a future follow-up cohort of psychiatric disorder participants for prediction of psychiatric hospitalizations due to suicidality (n=24). Additionally, we examined how two clinical instruments in the form of apps, Convergent Functional Information for Suicidality (CFI-S) and Simplified Affective State Scale (SASS), previously tested in men, perform in women. The top CFI-S item distinguishing high SI from no SI states was the chronic stress of social isolation. We then showed how the clinical information apps combined with the 50 validated biomarkers into a broad predictor (UP-Suicide), our apriori primary end point, predicts suicidality in women. UP-Suicide had a receiver-operating characteristic (ROC) area under the curve (AUC) of 82% for predicting SI and an AUC of 78% for predicting future hospitalizations for suicidality. Some of the individual components of the UP-Suicide showed even better results. SASS had an AUC of 81% for predicting SI, CFI-S had an AUC of 84% and the combination of the two apps had an AUC of 87%. The top biomarker from our sequential discovery, prioritization and validation steps, BCL2, predicted future hospitalizations due to suicidality with an AUC of 89%, and the panel of 50 validated biomarkers (BioM-50) predicted future hospitalizations due to suicidality with an AUC of 94%. The best overall single blood biomarker for predictions was PIK3C3 with an AUC of 65% for SI and an AUC of 90% for future hospitalizations. Finally, we sought to understand the biology of the biomarkers. BCL2 and GSK3B, the top CFG scoring validated biomarkers, as well as PIK3C3, have anti-apoptotic and neurotrophic effects, are decreased in expression in suicidality and are known targets of the anti-suicidal mood stabilizer drug lithium, which increases their expression and/or activity. Circadian clock genes were overrepresented among the top markers. Notably, PER1, increased in expression in suicidality, had an AUC of 84% for predicting future hospitalizations, and CSNK1A1, decreased in expression, had an AUC of 96% for predicting future hospitalizations. Circadian clock abnormalities are related to mood disorder, and sleep abnormalities have been implicated in suicide. Docosahexaenoic acid signaling was one of the top biological pathways overrepresented in validated biomarkers, which is of interest given the potential therapeutic and prophylactic benefits of omega-3 fatty acids. Some of the top biomarkers from the current work in women showed co-directionality of change in expression with our previous work in men, whereas others had changes in opposite directions, underlying the issue of biological context and differences in suicidality between the two genders. With this study, we begin to shed much needed light in the area of female suicidality, identify useful objective predictors and help understand gender commonalities and differences. During the conduct of the study, one participant committed suicide. In retrospect, when the analyses were completed, her UP-Suicide risk prediction score was at the 100 percentile of all participants tested.
•Magnetic titania/Fe-based nanocomposites were obtained in single-step laser pyrolysis.•The pyrolysis flame have an inner reductive zone surrounded by an oxidative periphery.•The high Fe-doping ...nanocomposites contain anatase, rutile and metallic/carbidic Fe.•The low Fe-doping sample contains only anatase and rutile crystalline phases.•All Fe-doped samples show prevalent weak ferromagnetic behavior.
We report the continuous, single step synthesis of titania/iron-based magnetic nanocomposites in a single step using gas-phase laser pyrolysis technique by separately and simultaneously introducing the precursors (together with C2H4 sensitizer) in the reaction zone: Fe(CO)5 on the central flow and, using air as carrier, TiCl4 on the annular coflow. The laser power and, for the last experiment, the injection geometry were modified in order to change the Fe/Ti ratio in the resulted nanopowders. Due to the specific geometry, the reaction zone (visible as a flame) have a reductive inner central zone surrounded by and oxidative environment, allowing the formation of the metallic–carbidic iron and/or iron-doped titania and iron oxide nanophases. The raw Fe-containing nanopowders have a ferromagnetic behavior, those synthesized at higher laser power and gas velocities show significant saturation magnetization Ms values (10–12emu/g), whereas those obtained (with higher yield and carbon content) at lower laser power and gas velocities (using wider central nozzle cross-section) have a very weak magnetization (Ms∼0.05emu/g) in spite of the higher ethylene carried Fe(CO)5 flow. The powders were annealed in air at 400°C show lower carbon content and, for those highly Fe-doped, the hematite phase formation. Preliminary tests using UV light confirm the photocatalytic action of the annealed nanopowders in salicylic acid degradation process in solution.
In this paper, silver microparticles were proposed as an additive (wetting agent) in the sintering of bovine bone-derived hydroxyapatite, and their well-known antibacterial properties were evaluated ...for the newly-developed materials. Hydroxyapatite was prepared by thermal processing of bovine bones, followed by milling and sorting. After silver addition, the samples were tested as precursors, green compacts and adhered particles-sintered compacts, using complementary morphological, compositional and structural evaluation techniques (scanning electron microscopy coupled with energy dispersive spectrometry, Fourier infrared spectroscopy, X-ray diffraction). The antibacterial effect was assessed on bacterial strains popular for their association with post-implantation infections. The study was designed to evaluate the precursors, investigate the surface, morphology and/or structure changes during forming and adhesion by sintering, and explore the relationship between the silver concentration and the antibacterial effect of the material. The results confirmed the benefits of adding silver as a wetting agent in sintering bovine bone-derived hydroxyapatite as well as its antibacterial effect (with best results at 2 wt%Ag). In spite of the great potential as a wetting agent and antibacterial factor in hydroxyapatite, the proper evaluation of these results requires extensive testing for elevating the control level in designing the material properties, and for establishing optimal concentrations of silver in order to achieve proper antibacterial and biocompatible behaviours.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•Magnetic titania@silica nanoparticles were synthesized by the single step laser pyrolysis.•Fe(CO)5, TiCl4, HMDSO and O2 from air were the precursors and C2H4 was the sensitizer.•Samples present a ...typical character of diluted magnetic oxide systems.•Samples have a lower bandgap energy (down to Eg=1.85eV) than the P25 Degussa.
Magnetic titania nanoparticles covered/embedded in SiO2 shell/matrix were simultaneously manufactured by the single-step laser pyrolysis. The present study is a continuation of our previous investigations on the TiO2/Fe and TiO2/HMDSO (hexamethyldisiloxane) derived-systems. The aim of this work is to study the synthesis by IR (Infrared) laser pyrolysis of magnetic TiO2 based nanocomposites which implies many concurrent processes induced in the gas phase by the laser radiation. The dependence between characteristic properties and the synthesis parameters was determined by many analytical and complementary methods: XRD (X-ray diffraction) structural analysis, UV–vis (ultraviolet–visible) and EDAX (energy-dispersive X-ray) spectroscopy, TEM and HRTEM (transmission electron microscopy at low and high resolution) analysis and magnetic measurements. The results of analysis indicate the presence of disordered silica, Fe, α-Fe2O3 and mixtures of anatase and rutile phases with mean crystallite dimensions (in the 14–34nm range) with typical character of diluted magnetic oxide systems and a lower bandgap energy (Eg=1.85eV) as compared with TiO2 P25 Degussa sample.
Biosensors, combining a selective biological recognition element and a sensitive transducer, are versatile analytical tools applied more and more in different fields, such as medicine, food quality ...and safety control, and environment pollution monitoring. They are expected to play an increasingly important role in the improvement of life quality. In this context, the present work covers recent approaches in design and development of biosensors applied for analysis of real samples of medical, environmental or industrial relevance. The described sensors meet the sensitivity, selectivity, and response time required by their applications. Moreover, they are designed to avoid contamination of the monitored systems with undesirable components and to minimise the damage of living organisms (when it comes to in vivo monitoring).
The paper proposes a modified kinematics for the crank-slider mechanism of a nails machine. The variable rotational motion of the driven gear allows to slow down the velocity of the slider in the ...head forming phase and increases the period for the forming forces to be applied, improving the quality of the final product. The noncircular gears are designed based on a hybrid function for the gear transmission ratio whose parameters enable multiple variations of the noncircular driven gears and crack-slider mechanism kinematics, respectively. The AutoCAD graphical and programming facilities are used (i) to analyse and optimize the slider-crank mechanism output functions, in correlation with the predefined noncircular gears transmission ratio, (ii) to generate the noncircular centrodes using the kinematics hypothesis, (iii) to generate the variable geometry of the gear teeth profiles, based on the rolling method, and (iv) to produce the gears solid virtual models. The study highlights the benefits limits that the noncircular gears transmission ratio defining hybrid functions have on both crank-slider mechanism kinematics and gears geometry.
Pterygoid hamulus syndrome, a painful oral and facial syndrome, has been described in literature to be correlated with morphological changes in the length of the pterygoid hamulus of the sphenoid ...bone.
The current case report describes the treatment for severe, continuous pain in the posterior right palate. Despite numerous conservative treatments given to the patient, no improvement was seen. Cone beam computed tomography (CBCT) measurements revealed an elongation as well as a significant medial deviation of the lower extremity of the medial pterygoid plate. The surgical resection was performed under local anesthesia. The pain subsided two days after the surgery, and there were no relapses in the weeks that followed.
The medial deviation of the hamulus appeared to be important in the etiology of this painful syndrome. Additional research based on CBCT measurements will be required.
The authors present their results concerning the decomposition in air of the homopolynuclear coordination compound CoC
2
O
4
·2.5H
2
O
n
. In the temperature range 20–300 °C, the heating curves TG, ...DTG and DTA allowed to evidence three decomposition steps. The kinetic analysis was performed on the second step which proved to be the only workable one. The application of nonlinear regression procedure shows that this is a complex process consisting in three successive steps. The checking of the mechanism and corresponding kinetic parameters for quasi-isothermal data (
T
= 150 °C) shows that the obtained results could be used for prediction of the thermal behaviour of the investigated compound in both isothermal and non-isothermal conditions.
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