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Purpose The purpose of this study is to employ magnetic fluid hyperthermia simulations in the precise computation of Specific Absorption Rate functions -SAR(T)-, and in the evaluation of the predictive capacity of different SAR calculation methods. Methods Magnetic fluid hyperthermia experiments were carried out using magnetite-based nanofluids. The respective SAR values were estimated through four different calculation methods including the initial slope method, the Box-Lucas method, the corrected slope method and the incremental analysis method (INCAM). A novel numerical model combining the heat transfer equations and the Navier-Stokes equations was developed to reproduce the experimental heating process. To address variations in heating efficiency with temperature, the expression of the power dissipation as a Gaussian function of temperature was introduced and the Levenberg-Marquardt optimization algorithm was employed to compute the function parameters and determine the function’s effective branch within each measurement’s temperature range. The power dissipation function was then reduced to the respective SAR function. Results The INCAM exhibited the lowest relative errors ranging between 0.62 and 15.03% with respect to the simulations. SAR(T) functions exhibited significant variations, up to 45%, within the MFH-relevant temperature range. Conclusions The examined calculation methods are not suitable to accurately quantify the heating efficiency of a magnetic fluid. Numerical models can be exploited to effectively compute SAR(T) and contribute to the development of robust hyperthermia treatment planning applications.

This paper reports developing an innovative method of anticorrosion protection based on organically modified silica (ORMOSIL) enriched with CeO

This paper reports developing an innovative method of anticorrosion protection based on organically modified silica (ORMOSIL) enriched with CeO2 ceramic nanocontainers loaded with 5-amino-1, 3, 4-thiadiazole-2-thiol (5-ATDT) on hot-dip galvanized zinc (HDG) steel used to strengthen cement in concrete. The chemistry of ORMOSIL coatings and the production of CeO2 ceramic nanocontainers are described in detail for reproduction by other researchers. The anticorrosion properties of these novel coatings were investigated through frequency response analysis (FRA). As a result, the coatings HDG-ORMOSIL + CeO2 (5-ATDT) were better than the samples of HDG steel, HDG-ORMOSIL, and HDG-ORMOSIL + CeO2 (EMPTY) by a factor of 1033.60, 109.21, and 7.76 in terms of anticorrosion protection, respectively.

The motivation of these days working in the field of corrosion protection of metals is to replace the existing hexavalent chromium protection found to be carcinogenic with new methods using environmentally friendly technology. One of the alternative technologies is based on conductive polymers. The present publication presents to the reader the results of the effects of doping organic and inorganic ions (organic acids: camphor sulfonic acid (CSA), p-toluenesulfonic acid (p-TSA), phenylphosphonic acid (PPA), and oxalic acid (OA); and inorganic salt: cerium nitrate (Ce(NO3)3) into the polypyrrole coatings as to the development of corrosion protection coatings that offer to aluminum alloy substrate 2024-T3 protection. Beyond, we report coatings developed by the solution of p-toluenesulfonic acid with the electrochemical introduction of cations cerium, cobalt, and manganese.

Self-healing was considered for repairing of destruction of reinforced concrete on bridges, houses, etc., that comes from corrosion of reinforcement metals as well as cracking in cement. The work was accomplished at producing and assessing through incorporate ceramic nanocontainers loaded with microorganisms. We produced various types of organic and inorganic nanocontainers that were incorporated into the cement that can act as carriers for the transport of bacteria. The microorganisms used in the work are Escherichia coli and Staphylococcus aureus. Precipitation of CaCO3 was observed by both bacteria. As microspheres do not affect the submersion of the mineral by the microorganism, additional studies were carried out to assess the interaction between transmission microsystems and bacterium. The mechanism of self-healing of building materials in this work was based on CaCO3 precipitation, through the ureolytic action of bacteria. When a crack appears in the cement, then the bacterium trapped in a nanocontainers is released and comes into contact with the water. In this way, the microorganism begins to metabolize and precipitate the mineral, in a way that eventually observes healing of the crack. CaCO3 microbial precipitation was based on the breakdown of urea (CO (NH2)2) into CO32− and NH3. Due to the high pK value of the NH3/NH4+ system (pKa = 9.2), the breakdown reaction led to an increase in pH, favoring the release of carbonated ions (CO32−), and in an environment rich in calcium ions (Ca2+), CaCO3 precipitation took place.

5',8-Cyclo-2'-deoxyadenosine (cdA) and 5',8-cyclo-2'-deoxyguanosine (cdG) in their two diastereomeric forms, 5'S and 5'R, are tandem lesions produced by the attack of hydroxyl radicals to the purine moieties of DNA. Their formation has been found to challenge the cells' repair machinery, initiating the nucleotide excision repair (NER) for restoring the genome integrity. The involvement of oxidatively induced DNA damage in carcinogenesis and the reduced capacity of some cancer cell lines to repair oxidised DNA base lesions, intrigued us to investigate the implication of these lesions in breast cancer, the most frequently occurring cancer in women. Using liquid chromatography tandem mass spectrometry (LC-MS/MS), we measured the levels of diastereomeric cdA's and cdG's in estrogen receptor-alpha positive (ER-alpha) MCF-7 and triple negative MDA-MB-231 breast cancer cell lines before and after exposure to two different conditions: ionising radiations and hydrogen peroxide, followed by an interval period to allow DNA repair. An increase at the measured levels of all four lesions, i.e. 5'S-cdA, 5'R-cdA, 5'S-cdG and 5'R-cdG, was observed either after gamma-irradiation (5Gy dose) or hydrogen peroxide treatment (300muM) compared to the untreated cells (control), independently from the length of the interval period for repair. For comparison reasons, we also measured the levels of 8-oxo-2'-deoxyadenosine (8-oxo-dA), a well-known oxidatively induced DNA damage lesion and base excision repair (BER) substrate. The collected data indicate that MCF-7 and MDA-MB-231 breast cancer cells are highly susceptible to radiation-induced DNA damage, being mainly defective in the repair of these lesions.

Ion Beam Analysis (IBA) techniques are established as an indispensable tool for material analysis. They are very powerful when applied to the examination of uniform layers. In recent years they have been also used for the quality control of implanted layers, which improve the mechanical or chemical properties of common materials. The use of IBA techniques for the study of corrosion is impeded by the non-uniformity of such layers, which renders the analysis difficult. In the Material Analysis Laboratory of the Institute of Nuclear Physics, a combination of experimental techniques and analytical algorithms has been developed, which allows the non-destructive examination of corrosion layers on cultural artifacts. Ancient glass fragments from Kenchreai, Greece, were analyzed with ion beam techniques, in order to examine the applicability of the latter to the characterization of the surface. The relative distribution of heavy components was determined by X-Ray Fluorescence (XRF). Nuclear reactions were used to determine the depth distribution of H, O, C and Si. The Hydrogen distribution rises sharply from the surface, reaching a maximum of 9xl022 at/cm3 at 0.5 μπι and then decays smoothly to a depth of approximately 2 μπα. Examination of the same samples with aparticles, indicates a depletion of Silicon in the same surface region, while the Oxygen distribution is uniform. A detailed analysis, using the 28Si(p, p) reaction, which resonates at 2.095 MeV, confirms the depletion and other non-uniformities in the Silicon distribution.

A versatile drug delivery carrier that responds to external stimuli was synthesized via the emulsion polymerization process. This simple two-step process was carried out by using Poly (Methyl Methacrylate) as a soft template and a series of monomers, with desired properties, as coating monomers. It is noteworthy that during shell fabrication (2nd step) an inner cavity is created inside the nanocontainers that can be used as a host for small drug molecules. The thermo-, pH- and redox sensitive monomers used in the coating procedure were Dimethyl Amino Ethyl Methacrylate (DMAEMA), Acrylic Acid (AA) and N,N′-(disulfanediylbis(ethane-2,1-diyl))bis(2-methylacrylamide) (Disulfide or DS), respectively. It has to be noted that DMAEMA is also pH- sensitive and acts synergistically with AA. The surface of the multi-stimuli nanocontainers was functionalized with magnetite nanoparticles in order to induce an alternating magnetic field (AMF) sensitivity. By using AMF in various strenghts and frequencies, the temperature of the final multi-stimuli nanocontainers (Q-NCs) can be increased in a controlled manner resulting in the Hyperthermia phenomenon. Loading and release studies were carried out using the anthracycline drug, Doxorubicin, aiming at the confirmation of the release mechanism.

PURPOSE To survey the preparation of novel hybrid microspheres of quaternary silicate glassy composition (SiO2 P2 O5 CaONa2 O) and the prospect of using them as an osteogenic system with enhanced bioactive properties for the development of hydroxyapatite. METHOD In line with our previous synthetic procedure a two-step process was followed, wherein polystyrene (PS) microspheres were prepared by the emulsifier free-emulsion polymerization method and constituted the core for the sol-gel coating of the silicate inorganic shell. The development of the hybrid microspheres was based on silane and phosphate precursors and was assesses at different ratio of ethanol/water (of 9/1, 4/1, and 2/1, in mL) and at varied ammonia concentration of 4.8-1.0 mL. RESULTS The hybrid microspheres had an average size ranged between 350 and 550 nm according to SEM, depending on the ethanol/water solution rate and ammonia content. The final microspheres probably exhibited a porous-like structure through the formation of diffused voids along with the low carbon content of the EDX analysis, which could be regulated by the catalyst content. The hybrid microspheres exhibited effective in vitro bioactivity assessed in simulated body fluids (SBF). CONCLUSION Quaternary hybrid silica microspheres were effectively synthesized. The bioassay evaluation of the final microspheres revealed the rapid in vitro formation of a bone-like apatite layer. The results verify the bioactivity of the microspheres and promote further research of their suitability on regenerative treatment of bone abnormalities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 112-120, 2018.

Lowering the growth temperature of single layer graphene by chemical vapor deposition (CVD) is important for its real-life application and mass production. Doing this without compromising quality requires advances in catalytic substrates. It is shown in this work that deposition of Zn and Bi metals modify the surface of nickel suppressing the uncontrollable growth of multiple layers of graphene. As a result, single layer graphene is obtained by CVD at 600 °C with minimum amount of defects, showing substantial improvement over bare Ni. In contrast, Cu, and Mo suppress graphene growth. We also show that graphene grown with our method has a defect density that is strongly dependent on the roughness of the original nickel foil. Good quality or highly defective holey single layer graphene can be grown at will by selecting a smooth or rough foil substrate respectively.

Recent years research in the field of medicinal chemistry, led to the development of drug delivery systems to improve the efficacy and effectiveness of various therapeutic agents for a variety of diseases. Such systems are used for the transport of diagnostic and therapeutic factors, either experimentally or clinically. Particularly, the use of colloidal carriers made of polysaccharides, has emerged as a promising alternative, for improving the transport of pharmaceutical agents on pathogenic areas. In the present work, bio-compatible microspheres-with a synthetic polymeric core and three layers of polysaccharides [PMMA@HPC@CS@CH microspheres (Poly(methylmethacrylate)@hydroxypropyl cellulose@cellulose succinate@chitosan)] were synthesized by combining two techniques. PMMA nanospheres were used as a core in order to coat the surface with polysaccharides via layer by layer deposition. This composition is advantageous in comparison with other synthetic routes because at all stages of the synthesis, it is used only water as a solvent and not organic solvents and includes all of the unique properties of two polysaccharides (cellulose and chitosan) in one vehicle. Fabricated vehicles were characterized structurally by FT-IR spectroscopy and morphologically by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Finally, daunorubicin an anticancer agent was encapsulated as a drug model into the vehicles in order to evaluate their loading and releasing behavior.

Graphene synthesis on single crystal Rh(1 1 1) catalytic substrates is performed by Chemical Vapor Deposition (CVD) at 1000 °C and atmospheric pressure. Raman analysis shows full substrate coverage with few layer graphene. It is found that the cool-down rate strongly affects the graphene stacking order. When lowered, the percentage of AB (Bernal) -stacked regions increases, leading to an almost full AB stacking order. When increased, the percentage of AB-stacked graphene regions decreases to a point where almost a full non AB-stacked graphene is grown. For a slow cool-down rate, graphene with AB stacking order and good epitaxial orientation with the substrate is achieved. This is indicated mainly by Raman characterization and confirmed by Reflection high-energy electron diffraction (RHEED) imaging. Additional Scanning Tunneling Microscopy (STM) topography data confirm that the grown graphene is mainly an AB-stacked structure. The electronic structure of the graphene/Rh(1 1 1) system is examined by Angle resolved Photo-Emission Spectroscopy (ARPES), where σ and π bands of graphene, are observed. Graphene's ΓK direction is aligned with the ΓK direction of the substrate, indicating no significant contribution from rotated domains.

This chapter summarizes what it has been accomplished in the last 12 years in the Sol–Gel Laboratory of NCSR “Demokritos” on targeted quadrupole stimuli nanocontainers loaded with anticancer commercial drugs to solve the outstanding problem of “How can the delivered therapeutic dose to the tumor be increased while at the same time reducing the dose in healthy tissue?” Our preliminary animal study gave hope in that course. We attempted to accomplish this goal via a ground-breaking and original healing method based on new polymeric nanocarriers, which enables targeted drug delivery in tumors. The in vivo results suggest that both Nano4Dox and Nano4Cis platforms outperform the commercial standards, such as Doxil and Lipoplatin, respectively. This platform may be expanded to personalized chemotherapy, metastasis, and many more problems related to this vicious disease.

Multilayer reflecting thin films of the systems TiO2-SiO2 and ZrO2-SiO2 were deposited on glass surface using the sol-gel technique. A 12C beam was utilized in RBS analysis to investigate the inner structure of these multilayer stacks. No evidence for defects or diffusion between the layers were found. Optical Spectroscopy showed wavelength selectivity in the reflection of an 8-layer TiO2-SiO2 sample.

The aim of the present study was to investigate the impact of intravenous administration of newly fabricated nanocontainers (NCs) on the last third of pregnancy in rats. Fifteen pregnant 3-month-old Wistar rats were separated into 3 groups. On the 15th and 17th day of pregnancy all animals received an intravenous administration of 1 ml of 15 mg of NCs (Group A), 1 ml of 5 mg NCs (Group B) while Control group received 1 ml of 0.9% NaCl. On the 14th and 17th of pregnancy ultrasonography was performed and the parameters evaluated were the width of placenta, the length and width of the embryonic sac, the foetus length and the heart rate. On parturition the number of pups per dam was evaluated. Half of the pups were euthanised the day after parturition and their liver and kidney was histologically evaluated and for the rest of the pups the body growth curve was evaluated until the age of 14 week. At the end of the 14th week the remaining pups were euthanised and their liver and kidney was histologically evaluated. At weaning the dams were euthanised and their liver and kidney was histologically evaluated. Ultrasonography: Baseline measurements of the width of placenta, the length and width of embryonic sac, the foetus length and the heart rate on the 14th day of pregnancy, revealed no statistical significant differences between groups. Comparison of the same values on the 17th day of pregnancy after 2 intravenous administrations of NCs showed no statistical significant effect on the respective parameters. The administration of NCs had no impact on the mean number of pups per dam. Additionally, no impact of the NCs on the body weights of the pups was observed on the 1st day after parturition. Moreover, comparisons between groups, for both sexes showed no difference on growth rate. During the histological evaluation no inflammatory, degenerative or neoplastic lesions were observed as far as the newborn, adult offspring and dams were concerned. According to our results no toxic impact of the low and high doses of the NCs was observed on the parameters selected to be evaluated., Highlights • Nanocontainers toxicity study. • Toxicological study on pregnant rats, foetuses and offspring. • Ultrasonographic evaluation. • Histological evaluation.

Display Omitted ZrSe2 films and ZrSe2/MoSe2 structures are grown by MBE on AlN/Si(111) substrates.High quality heteroepitaxial growth is confirmed.The band alignment of the ZrSe2/MoSe2 heterostructures is determined.ZrSe2/MoSe2 interface shows type II band alignment configuration. Using molecular beam epitaxy (MBE) of ZrSe2 and ZrSe2/MoSe2 heterostructures are grown on crystalline AlN(0001)/Si(111) substrates. Electron diffraction (RHEED) and valence band imaging by angle resolved photoelectron spectroscopy (ARPES) indicate high quality heteroepitaxial growth with very good in-plane crystallographic alignment with the substrate. The workfunction and band offsets are estimated by photoelectron spectroscopy and compared with first principles calculations. The constructed band alignments show that the heterostructure could form the basis for atomically thin p-n junction and 2D vertical tunneling devices.

Bioactive microspheres represent an extremely developing field in biomedical applications, such as bone tissue engineering and bone pathologies (metabolic bone disease, trauma or bone cancer). Their innate osteogenic properties have turned them to biomaterials with improved added value. The aim of this study was to prepare binary and ternary hybrid silica microspheres with enhanced bioactive properties according to our previous synthetic procedure. In brief, the synthetic approach based on the emulsifier free-emulsion polymerization method, by which polystyrene (PS) microspheres were produced and used as core template for the sol–gel coating method. During the coating reaction an inorganic shell was fabricated by silane and phosphate precursors (tetraethoxysilane, trimethylphosphate). The final microspheres were treated by different catalyst concentrations, during the coating process, which resulted in the formation of diffused voids (a porous-like structure). The in vitro bioactivity of the resultant microspheres was studied by treatment in simulated body fluids (SBF). The bioassay evaluation indicates the deposition of a bone-like apatite layer on microspheres' surface with enhanced bioresorbability, which verifies their bioactivity and permits their application in the treatment of bone pathologies.

Nanoscale drug delivery systems represent a promising strategy to treat cancer and to overcome the side effects of chemotherapy. In particular, hollow polymeric nanocontainers have attracted great interest because of their structural and morphological advantages and the variety of polymers that can be used, allowing the synthesis of stimuli-responsive materials capable of responding to the biochemical alterations of the tumour microenvironment. Here are reported the synthesis, characterization and in vitro evaluation of a three-stimuli-sensitive hollow nanocontainer consisting of three different shells, each one sensitive to a specific tumoral stimulus: in order pH, temperature and reducing environment. To test its properties, daunorubicin was used as a model drug, for which the nanocontainers exhibited excellent encapsulation ability. The in vitro drug release behaviour was studied under different conditions, where the system proved capable of responding to the selected tumoral stimuli by releasing a larger amount of drug than in physiological environment. The hollow system itself showed negligible cytotoxicity but the loaded nanocontainers and free drug showed identical cytotoxicity and intracellular localization. Therefore, this formulation can be considered as a promising platform to develop an injectable delivery system capable of improving systematic toxicity without affecting or reducing the activity of the encapsulated drug.

This paper deals with the synthesis, characterization and biological evaluation of mixed ligand zinc complexes with the third generation quinolones’ representative, levofloxacin. Two novel zinc (II) complexes of fluoroquinolone drug levofloxacin (H-levo), containing 1,10-phenanthroline (phen) (complex 1) and 2,2′-bipyridine (bipy) (complex 2) were synthesized and evaluated as antimicrobial agents, antitumor antibiotics and fluorescent probes. The highlight of this work is the ability of the aforementioned complexes to penetrate the cell membrane inducing fluorescence. The complexes structural characterization was performed by means of elemental and thermogravimetric analysis, FT-IR, RAMAN, 1H NMR, 13C NMR, and UV–Vis. The complexation of zinc (II) metal ion with the deprotonated ligand levofloxacin and heteroligands reveals that levofloxacin coordinated to zinc through one pyridone and one carboxylato oxygen as well as with two nitrogen atoms from the heteroligands. Additionally, complexes have been tested for their antimicrobial activity, revealing an increased potency in comparison with the free H-levo ligand. The cytotoxic behavior of the synthesized mixed complexes in comparison with the free ligands was performed by MTT assay. It was found that the proliferation rate and viability of MCF-7 cells decreased after treatment with the above complexes. Zinc levofloxacin mixed complex with 1,10-phenanthroline (complex 1) presents the highest effect in comparison with zinc levofloxacin complex with 2,2′-bipyridine (complex 2). Furthermore, it was investigated the ability of mixed zinc complexes to penetrate the cell membrane inducing fluorescence. The results show that both complexes penetrate the cell membrane acting both, as fluorescent probes and as new cytotoxic drugs.

Three novel copper(II) complexes of the antibacterial drug Levofloxacin (LVX), in the presence or absence of heterocyclic ligands such as 1,10-phenanthroline and 2,2-bipyridine, have been synthesized and fully characterized. The interaction of copper(II) with the deprotonated ligand LVX reveals that LVX coordinated to copper atom through the pyridone and one carboxylato oxygen. In case of the mixed ligand complexes the Cu atom is coordinated with two O atoms from LVX ligand and with two N atoms from the hetero-ligands. According to our results the formation of dimers is a typical characteristic for almost all of them. The presence of dimers in the crystal structure is also evident in the EPR spectra and this method can be used as a probe for the existence of such species. A significant characteristic of the structure is the intra- and inter-dimer π–π stacking interaction which governs the packing of complexes in the structure. The synthesized compounds were biologically evaluated. All the complexes show an increased biological activity in comparison with the free ligand.

Conventional chemotherapy drugs show lack of specificity, inducing reduced activity on the cancer treatment. They exhibit high toxicity and after a prolonged period of administration the cancer cells develop resistance (multiple-drug resistance, MDR). This situation leads to increasing the side effects of drugs and affect the quality of the patients׳ life. In order to overcome the above mentioned problems, the recent research community is focused primarily on developing smart drug delivery systems which respond in different stimulus, in the range of nanometer [1] , [2] , [3] . The objective of this work is the biological evaluation of synthesized double- layer microspheres based on cellulose coating, for delivery of chemotherapeutic drugs with low water-solubility. In a previous published work, we have designed double-layer microspheres, based on the co-polymerization of widely-used sensitive polymers (Methyl acrylic acid and N-isopropylacrylamide) and modified cellose׳s coating. Briefly, we have synthesized and fully characterized Poly(methyl acrylic acid-co-N-isopropylacrylamide-co-ethyleneglycol dimethacrylate)@cellulose succinate (P(MAA-co-NIPAAM-co-EGDMA)@CS) microspheres by a combination of sol–gel method, distillation precipitation co-polymerization and chemical deposition. The resulting spheres were characterized structural through spectroscopy as well as morphological. The anticancer agent daunorubicin was encapsulated in the spheres, and drug׳s release behavior was evaluated at acidic and slightly basic pH conditions. The highlight of the previous evaluation is the microspheres׳ response at acidic pH environment for targeted release of the drug at the tumor affected area in contrary to neutral pH. This fact was a sign that our system may be a potential drug delivery vehicle for cancer treatment, as it is well known that tumor׳s environment is acidic. For that purpose we evaluated the cytotoxic effects of spheres, spheres loaded with daunorubicin and free daunorubicin via MTT assay in MCF-7 (breast cancer) and HeLa cells (cervical cancer) as a function of concentration and in different time intervals. Finally, HEK 293 (Human Embryonic Kidney) cells were incubated with unloaded microspheres in order to evaluate the cytotoxic activity in healthy cells.

This work aims at investigating the corrosion protection effectiveness of multifunctional epoxy coatings modified with pigments such as ceramic nanocontainers loaded with corrosion inhibitor, chloride and water traps, applied on AA2024-T3. Characterizations on the morphology, composition and structure of the coatings were conducted. The corrosion resistance was studied by electrochemical impedance spectroscopy, localized electrochemical impedance spectroscopy and scanning vibrating electrode technique. The mechanical behaviour of the coatings was examined through nanoindentation and nanoscratching tests. Electrochemical and nanomechanical testing results, evidenced the improvement of the corrosion protective properties and mechanical behaviour of the coatings in the presence of the various pigments.