Violeta Dediu

Rapid developing antimicrobial resistance due to broad antibiotic utilisation in healthcare and food industries and the non-availability of novel antibiotics represents one of the most critical public health issues worldwide. The current advances in nanotechnology allow new materials to address drug-resistant bacterial infections in specific, focused and biologically safe ways. The unique physicochemical properties, biocompatibility, and wide range of adaptability of nanomaterials that exhibit photothermal capability can be employed to develop the next generation of photothermally induced controllable hyperthermia as antibacterial nanoplatforms. Here, we review the current state-of-the-art in different functional classes of photothermal antibacterial nanomaterials and the strategies to optimise antimicrobial efficiency. The recent achievements and trends in developing photothermally active nanostructures, including plasmonic metals, semiconductor, carbon-based, and organic photother...

Urbanization and the rise in the standard of living generated both a higher quantity of waste and the expansion of cities with the incorporation of solid waste landfills located originally outside. In many cities across Romania, landfills are placed very close to settlements, and in some cases even inside cities. Beside landfill activities, other companies that deal with waste sorting, recycling and treatment operates nearby. All these activities generate odorous compounds that create odour nuisance. The current study was conducted in order to evaluate the impact of a landfill located in a highly urbanized area using dynamic olfactometry with the main objective to assess the level of odour concentration and the impact on the population. Samples were taken around the landfill always from a point opposite to the wind direction. Also, in parallel with odour sampling it was determined the concentration of two main chemical specific compounds, NH3 and H2S, in order to verify the complian...

This paper presents a comparative study on the thermal decomposition in air and FTIR analyses of complex sol-gel precursors used for the deposition of three titania based mesoporous thin films: TiO2, Nb-doped TiO2 and carbon nanotubes (MWCNT)-doped TiO2. The effect of doping with Nb or adding MWCNT on the thermal decomposition of titanium isopropoxide-based precursor and crystallization of TiO2 was investigated through thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Fourier Transform Infrared (FTIR) data. TG-DTA results showed two main exothermic peaks were observed in all samples for the temperature range 280-300 oC and 429-444 oC, corresponding to isopropoxide oxidative decomposition and anatase crystallization. In case of Nb doped TiO2 an oxidative decomposition of Nb ethoxide appears at 198 �C. The acidified MWCNT are thermally stable up to 500�C. Doping TiO2 causes peaks shift to higher temperatures. Also, the effect of heating rate on thermal decompo...

Deposition parameters of tetraethylorthosilicate (TEOS) layers on silicon substrate using Plasma Enhanced Chemical Vapor Deposition (PECVD) method were investigated We design the experiment taking into consideration chamber pressure, substrate temperature, RF Power and mass flow rate (oxygen and TEOS) to asses their influence on deposition rate, film uniformity, refractive index uniformity and film stress. All the results were evaluated for applications that require low temperature processing in order to avoid damage of Microelectromechanical Systems (MEMS) devices.

Some natural adsorbents were evaluated for the advanced removal of pollutants from aqueous systems. The sorption capacity of walnut shells and volcanic zeolite tuff (from Mirsid-Cluj Romania) to remove the chrome and cadmium at different experimental conditions was studied. The concentration of metal ions in aqueous systems was evaluated with an inductively coupled plasma mass spectrometer (ICPMS) and an atomic absorption spectrometer. The effect of time, initial concentration of the metals and solution pH on the adsorption at room temperature was studied. pH of the solutions was found to influence the adsorption. Higher Cr(VI) adsorption was observed at lower pH and at low concentration of metal ions. The maximum efficiency of volcanic tuff in acidic media was 97.12% for chrome and 57.04% for cadmium, respectively, for 0.1 mg/L initial concentration. Moreover, in the same experimental conditions, the maximum efficiency of walnut shells was 61.24% and 44.51% for chrome and cadmium. ...

The deleterious effects of the coronavirus disease 2019 (COVID-19) pandemic urged the development of diagnostic tools to manage the spread of disease. Currently, the “gold standard” involves the use of quantitative real-time polymerase chain reaction (qRT-PCR) for SARS-CoV-2 detection. Even though it is sensitive, specific and applicable for large batches of samples, qRT-PCR is labour-intensive, time-consuming, requires trained personnel and is not available in remote settings. This review summarizes and compares the available strategies for COVID-19: serological testing, Point-of-Care Testing, nanotechnology-based approaches and biosensors. Last but not least, we address the advantages and limitations of these methods as well as perspectives in COVID-19 diagnostics. The effort is constantly focused on understanding the quickly changing landscape of available diagnostic testing of COVID-19 at the clinical levels and introducing reliable and rapid screening point of care testing. The...

Copper-doped zinc oxide thinfilms, (1, 3,5 at. %) have been synthesized via sol-gel spin coating technique. Main objectives of the reported -work are to investigate the effect of copper doping on morphology, compositional, structure and on opto-electrical properties of ZnO thin films. To achieve the mentioned objectives, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), X- Ray Diffraction (XRD), UV-vis techniques and the current-voltage (I-V) measurements -were performed. SEM result show a porous morphology. The % Cu concentration, determined by EDX analysis, are 0.66%, 3.73% and 6.26% in good agreement with the Cu theoretical concentration. XRD analysis shows that the films are nanocrystalline zinc oxide with the wurtzite structure. From optical measurements, a significant decrease in average optical transmission from 93 to 76 % is observed for all doped samples and the band gap value decreased from 3.20 to 3.00 eV which are related to the presence of defects due t...

In this work, an aqueous sol–gel route involving zinc acetate dihydrate and cupric chloride as precursors was used to obtain intrinsic and Cu-doped ZnO thin films onto SiO2/n-Si and glass substrates. Various concentrations of Cu ranging from 1 to 5% were used to modify the ZnO crystal structure. The effect of Cu-doping was evaluated by means of various microscopic and spectroscopic techniques. Scanning electron microscopy (SEM) proved increased grain density and evolution of grain shape from circular to hexagonal with Cu incorporation in the ZnO host lattice. Furthermore, atomic force microscopy (AFM) revealed that grain size increases with increasing Cu concentration. Moreover, X-ray diffraction (XRD) investigations reported a small influence of Cu-doping on the lattice constant value. However, Cu-doping level impacts the mean crystallite size, and consequently, the amount of dislocations emerging from the boundaries of the mosaic blocks. Finally, optical measurements proved the de...

The preparation and structural characterization of titanium oxide nanowires as functional materials for the development of chemical sensors is presented in this work. The new types of materials for sensorics, aspects of material preparation relevant for gas sensing applications is presented .The functional characterization is focused on the detection of alcohols. Titanium oxide thin films prepared by solvotermalthermal method in highly alkaline conditions and the performance of 1D nanostructure is compared with mesoporous thin film prepared by sol-gel method.

Real-time “on-body” monitoring of human physiological signals through wearable systems developed on flexible substrates (e-skin) is the next target in human health control and prevention, while an alternative to bulky diagnostic devices routinely used in clinics. The present work summarizes the recent trends in the development of e-skin systems. Firstly, we revised the material development for e-skin systems. Secondly, aspects related to fabrication techniques were presented. Next, the main applications of e-skin systems in monitoring, such as temperature, pulse, and other bio-electric signals related to health status, were analyzed. Finally, aspects regarding the power supply and signal processing were discussed. The special features of e-skin as identified contribute clearly to the developing potential as in situ diagnostic tool for further implementation in clinical practice at patient personal levels.