Search

Introduction Epithelial ovarian cancer (EOC) is a disease with a poor survival rate mostly due to its discovery in late stages. The aim of this study was to investigate the metabolomic profile of ovarian cancer with the intention of identifying and describing novel biomarkers with diagnostic potential. Material and methods Targeted serum metabolomic profiling was performed on 15 patients with ovarian cancer, 21 healthy controls and 21 patients with benign ovarian conditions, using HPLC–TQ/MS. Results Panel of 49 top performing biomarkers shows separation between EOC and controls with 87% specificity and 87% sensitivity with AUC of 93% (CI 90%–95%). Using only 5 top biomarkers, specificity of 80% and sensitivity of 83% was achieved on extended sample set. Most significant biomarkers belong to sphingolipid classes, especially long chain ceramides and sphingomyelins. Different concentrations of various fatty acid chain lengths ceramides and sphingomyelins are also implying their respective roles in cell proliferation and growth inhibition. Conclusion Long chain ceramides and sphingomyelins may serve as a novel biomarker for epithelial ovarian cancer detection and may also offer insight into the role of sphingolipid metabolism in cell proliferation.

The preparation of ZnO nanoparticles with a multi-step process is reported. The preparation path included zinc hydroxide nitrate (ZnHN) or zinc hydroxide carbonate (ZnHC) precipitation, their thermal treatment and nano-milling. ZnO preparation was followed in detail by STEM, FT-IR, XRD and TG-MS analyses. In order to demonstrate the efficiency of the nano-milling process, the obtained ZnO nanoparticles were characterized with regard to their photo-catalytic activity of caffeine degradation. The smallest ZnO nanoparticles (∼20 nm) with the highest BET surface (∼80 m2 g−1) were prepared from ZnHC at 300 °C.

Zinc oxide (ZnO) powders with diverse morphologies were synthesized with various solvothermal techniques. Water, 1-butanole and ethylene glycol were used as the solvents, while the temperature of the solvothermal synthesis was varied from 90 °C to 120 °C. Resazurin and caffeine were used for the evaluation of the photocatalytic activity of all the prepared samples, and in particular to compare ZnO with commercial titanium dioxide photocatalytic material (P25 Evonik Degussa) using UV–vis spectroscopy. The composition, crystallinity, and morphology of the prepared materials were investigated with FTIR, XRD, TEM and FEG-SEM techniques. The band gaps of the obtained semiconductors were measured because the band gap of hydrozincite, determined in this study to be 4.1 eV, has not been reported previously. The specific surface area (BET) and the porosity of the prepared particles were estimated. The crystal size in one dimension was estimated and was found to play an important role in the photocatalytic activity, which increased with a smaller size. A higher degree of aggregation caused the opposite effect. Thus, a more aggregated material with a larger surface area than a less aggregated one exhibited a lower photocatalytic activity. The particle morphology strongly influenced the photocatalytic process, while the degree of crystallinity was not comparably significant. The external mass-transfer (diffusion to the catalytic surface) resistance was negligible, and consequently the first-order, second-order, and Langmuir–Hinshelwood mechanism kinetics of the photocatalysis were examined.

Layered ZnO microspheric particles were prepared by the thermal decomposition of layered hydrozincite (LZnHC), which was synthesized from zinc nitrate and urea in a water/PEG400 mixture. The influence of the starting reagents, their concentrations, and the amount of PEG in the water/PEG400 mixture on the particle growth was observed. The chemical aspect of the particle growth was proposed in the frame of the partial charge model (PCM), and the formation of [Zn(OH)(2)(OH(2))(4)](0) and [Zn(OH)(HCO(3))(OH(2))(3)](0) was predicted for the solid phase. The assumed growth mechanism, which follows the "nonclassical crystallization" concept of a self-assembling mechanism, was observed in situ by small-angle X-ray scattering (SAXS) and predicts the rapid formation of approximately 6 nm sized building units. The size of these nano building units, stable only in the reaction medium, remains nearly constant during the synthesis, as the concentration of the nano building units increases throughout the reaction. The nano building units connect into leaves of LZnHC with a thickness of 20 nm. These leaves of LZnHC are further agglomerated into porous, microsphere-like particles with sizes up to 4 μm.

We present a solution-phase preparation method for the synthesis of ZnO in an open reactor (with constant stirring) or in a closed reactor (autoclave). The method is based on a combination of the polyol method and the homogeneous precipitation of zinc nitrate with urea. ZnO particles with a rod-like shape and with a regular bipod structure were prepared in an open reactor, while needle-like shapes were prepared in the autoclave. A detailed characterization of the planar base-plane and prismatic defects obtained in the hexagonal ZnO bipod particles with electron microscopy revealed that in the middle of the bipod the planar defects contain a small amount of silicon. A rough estimation indicated that there was a single atomic layer of silicon at the defect. From convergent-beam electron-diffraction experiments, we found that these planar defects were inversion domain boundaries (IDBs) with a head-to-head orientation of the polar axis. In the needle-like particles, besides IDBs on the basal planes, prismatic...

A simple urea aqueous solution process at low temperature (85 °C) was employed for the preparation of zinc hydroxide carbonate from zinc nitrate. The influence of different additives on the final particle morphology was studied. Porous spherical particles in the shape of chrysanthemums with an average size of 4 μm and a surface area of 16 m 2 /g were obtained in the presence of poly-vinyl pyrrolidone (PVP-K30). After heat treatment ZnO particles were formed that preserved the size and shape of the hydrozincite precursor. The morphology and crystallinity of the solids obtained before and after the heat treatment were characterized by FE-SEM, XRD, FTIR, BET and TG methods.

The growth mechanism of ZnO is investigated by a combination of electron microscopy and in situ small-angle X-ray scattering (SAXS). The particles are prepared by the precipitation of zinc nitrate with urea. Depending on the reaction conditions, ZnO, hydrozincite, or a mixture of both phases is detected in our system. The molecular precursors and complexation reactions of the formation process are numerically predicted by the partial-charge model. The condensation and complexation reactions lead to the formation of nanoparticle building units up to a size of 10 nm. Afterwards, the nanoparticles immediately self-assemble into micro-sized particles.

We have investigated nanosized thin films ofα-Fe2O3(hematite) andα-Fe2O3with addition of Li, by the impedance spectroscopy (IS), the Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Combining all of these methods, and earlier obtained thermally stimulated currents (TSC) on the same samples, the dependence of structural and electrical properties upon percentage of Li added into the matrix of these metal-oxide films was found. The comparison of IS, Raman, SEM, XRD, and TSC results reveals the increase of the size of nanoparticles upon inducing 1% of Li inFe2O3matrix followed by the decrease of the size of nanoparticles in the case of samples with 10% Li, as well as the decrease (increase) of conductivity, respectively. These changes are explained by the structural and morphological changes caused by the impact ofLi+ions in the charge transfers. This material is suitable for application in the galvanic cell of second generation that could be used as solar-cells backup.

The preparation of nano- and submicrometre-sized one-dimensional (1D) zinc oxides (ZnOs) from zinc nitrate was performed by precipitation with urea in two types of solvents (water and water/polyol mixtures). The influence of different polyols (ethylene glycol, diethylene glycol and tetraethylene glycol) on the size of the final particles (length and diameter) is presented for the first time. As well as the influence of the solvents used, the ratio of water/polyol, temperature, pH and time of synthesis was correlated with the size and morphology of the final particles. In all cases crystalline ZnO was synthesized in the form of hexagonal bipods. The morphological and crystalline properties of the samples obtained were characterized by SEM, IR, and XRD. (C) 2008 Elsevier Ltd. All rights reserved.

ZnO nanorods were prepared at relatively low temperatures by homogeneous precipitation from zinc nitrate and urea in a water/ethylene glycol mixture. Crystal size and morphology are controlled by growth time and solvent composition. We observed a strong correlation between nanocrystals’ size/morphology and their optoelectronic defect-related properties. Smaller crystallites exhibited intense deep-defect luminescence and enhanced emission related to near-surface excitonic recombination. Longer growth times lead to formation of well-defined nanorods with hexagonal symmetry exhibiting reduced defect emission.