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  • 1
    Online Resource
    Online Resource
    MDPI AG ; 2020
    In:  International Journal of Environmental Research and Public Health Vol. 17, No. 12 ( 2020-06-22), p. 4470-
    In: International Journal of Environmental Research and Public Health, MDPI AG, Vol. 17, No. 12 ( 2020-06-22), p. 4470-
    Abstract: This paper examines the impact of the internet usage and knowledge intensive activities on households’ healthcare expenditures Similarly, the paper aims to recognize and understand, from a value-creation perspective, the correlation between: internet access of households (IA), individuals frequently using the internet (IU), individuals searching on internet for health-related information (HI), payments made by households for healthcare (PHH), expressed as euro per inhabitant and employment in knowledge-intensive activities (KIA). The approach utilized in the present study consists of two steps. First, a theoretical framework was conducted to determine the existing relationship between major variables. Next, the Vector Autoregressive (VAR) approach was applied in a case study at European level to prove the three hypothesis we consider. By analyzing the connection between the major variables, a positive and long- lasting impulse response function was revealed, followed by an ascending trend. This suggests that a self-multiplying effect is being generated; and it reasonable to assume that the more individuals use the Internet, the more electronic acquisitions occur. We can thus reasonably conclude that the improvement of the internet usage and knowledge intensive activities on households’ healthcare expenditures process is strongly dependent on people’s capability. Improving IU and KIA is the new reading key in the decision-making process in health system approach.
    Type of Medium: Online Resource
    ISSN: 1660-4601
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2175195-X
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  • 2
    In: Micromachines, MDPI AG, Vol. 14, No. 6 ( 2023-05-23), p. 1096-
    Abstract: The progress of advanced materials has invoked great interest in promising novel biosensing applications. Field-effect transistors (FETs) are excellent options for biosensing devices due to the variability of the utilized materials and the self-amplifying role of electrical signals. The focus on nanoelectronics and high-performance biosensors has also generated an increasing demand for easy fabrication methods, as well as for economical and revolutionary materials. One of the innovative materials used in biosensing applications is graphene, on account of its remarkable properties, such as high thermal and electrical conductivity, potent mechanical properties, and high surface area to immobilize the receptors in biosensors. Besides graphene, other competing graphene-derived materials (GDMs) have emerged in this field, with comparable properties and improved cost-efficiency and ease of fabrication. In this paper, a comparative experimental study is presented for the first time, for FETs having a channel fabricated from three different graphenic materials: single-layer graphene (SLG), graphene/graphite nanowalls (GNW), and bulk nanocrystalline graphite (bulk-NCG). The devices are investigated by scanning electron microscopy (SEM), Raman spectroscopy, and I-V measurements. An increased electrical conductance is observed for the bulk-NCG-based FET, despite its higher defect density, the channel displaying a transconductance of up to ≊4.9×10−3 A V−1, and a charge carrier mobility of ≊2.86×10−4 cm2 V−1 s−1, at a source-drain potential of 3 V. An improvement in sensitivity due to Au nanoparticle functionalization is also acknowledged, with an increase of the ON/OFF current ratio of over four times, from ≊178.95 to ≊746.43, for the bulk-NCG FETs.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2620864-7
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  • 3
    In: Micromachines, MDPI AG, Vol. 13, No. 10 ( 2022-10-04), p. 1671-
    Abstract: The selective and rapid detection of tumor cells is of critical consequence for the theragnostic field of tumorigenesis; conventional methods, such as histopathological diagnostic methods, often require a long analysis time, excessive analytical costs, complex operations, qualified personnel and deliver many false-positive results. We are considering a new approach of an electrochemical biosensor based on graphene, which is evidenced to be a revolutionary nanomaterial enabling the specific and selective capture of tumor cells. In this paper, we report a biosensor fabricated by growing vertically aligned graphene nanosheets on the conductive surface of interdigitated electrodes which is functionalized with anti-EpCAM antibodies. The dielectric signature of the three types of tumor cells is determined by correlating the values from the Nyquist and Bode diagram: charge transfer resistance, electrical double layer capacity, Debye length, characteristic relaxation times of mobile charges, diffusion/adsorption coefficients, and variation in the electrical permittivity complex and of the phase shift with frequency. These characteristics are strongly dependent on the type of membrane molecules and the electromagnetic resonance frequency. We were able to use the fabricated sensor to differentiate between three types of tumor cell lines, HT-29, SW403 and MCF-7, by dielectric signature. The proposed evaluation method showed the permittivity at 1 MHz to be 3.63 nF for SW403 cells, 4.97 nF for HT 29 cells and 6.9 nF for MCF-7 cells.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2620864-7
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  • 4
    Online Resource
    Online Resource
    MDPI AG ; 2020
    In:  Sustainability Vol. 12, No. 3 ( 2020-02-04), p. 1119-
    In: Sustainability, MDPI AG, Vol. 12, No. 3 ( 2020-02-04), p. 1119-
    Abstract: The ever-changing external environment and the challenges and signals transmitted by the European Single Market have greatly contributed to the dynamism of SMEs in Europe. From the privileged place held by the entrepreneur in SMEs, the present study aims to investigate the role of managerial skills in the sustainable development of small and medium enterprises, focused on self-awareness, emotional intelligence, and interpersonal skills of entrepreneurs. The investigation method consisted of the distribution of anonymous questionnaires to a representative sample of entrepreneurs, in the Mehedinți County, Romania. The collected data were centralized, processed, and assessed. The results of this analysis revealed, besides the emotional intelligence and interpersonal skills which have reached a suitable level, a low level of self-awareness. Therefore, this has been considered as a potential barrier towards sustainable development of SMEs in the analyzed region. However, the high level of emotional intelligence, accompanied by an increasing trend of interpersonal skills as the manager’s experience in working with people increases, is a strong argument for the sustainable development of SMEs. The study comes to support the public policies concerning small and medium-sized entities by using a model of managerial skills testing for applicants. In this way, an increase of the transparency of financing decision and the effectiveness of financial support are ensured.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2518383-7
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  • 5
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Micromachines Vol. 13, No. 6 ( 2022-06-20), p. 974-
    In: Micromachines, MDPI AG, Vol. 13, No. 6 ( 2022-06-20), p. 974-
    Abstract: The evolution of an interface between two immiscible liquids in a three-branch symmetric microchannel is numerically and experimentally investigated. The main goals of the paper are to correlate the numeric data with the experimental results for the tested flow case and to assess the quality of the VOF procedure to trace the interface using the Fluent commercial code. The focus of the experiments was to characterize the dynamics of the oil–water interface formed in the vicinity of the bifurcation, at the entrance in the main microchannel of 400 microns width and 50 microns height. The oil core surrounded by water is visualized and micro-PIV measurements are performed in water. Experimental results qualitatively and quantitatively confirm the 3D numerical simulations. We propose the present investigated flow as a benchmark case for the study of the interface in a branching microchannel geometry.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2620864-7
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  • 6
    In: Micromachines, MDPI AG, Vol. 13, No. 11 ( 2022-10-27), p. 1833-
    Abstract: This study proposes a feasible approach for the rapid, sensitive, and label-free identification of cancerous cells based on dielectrophoretic (DEP) manipulation and electrical characterization. In this method, the concentration of target cells at the level of customized microelectrodes via DEP is first determined, followed by an electrical impedance evaluation. The study demonstrates the capacity of the methodology to electrically differentiate HT-29 cancer cells from healthy blood cells based on their impedance spectra. Within a higher frequency domain, the electrical impedance of trapped cancer cells was significantly lower compared with the normal ones. In order to evaluate the functionality and reproducibility of the proposed method, the influence of the DEP and EIS (electrical impedance spectroscopy) operating voltages on the electrical characterization of trapped HT-29 cells was analyzed.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2620864-7
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  • 7
    In: Gels, MDPI AG, Vol. 8, No. 10 ( 2022-09-21), p. 604-
    Abstract: The study and discovery of bioactive compounds and new formulations as potential tools for promoting the repair of dermoepidermal tissue in wound healing is of continuing interest. We have developed a new formulation of amorphous hydrogel based on sodium alginate (NaAlg); type I collagen, isolated by the authors from silver carp tails (COL); glycerol (Gli); Aloe vera gel powder (AV); and silver nanoparticles obtained by green synthesis with aqueous Cinnamomum verum extract (AgNPs@CIN) and vitamin C, respectively. The gel texture of the amorphous hydrogels was achieved by the addition of Aloe vera, demonstrated by a rheological analysis. The evaluations of the cytotoxicity and cell proliferation capacity of the experimental amorphous hydrogels were performed against human foreskin fibroblast Hs27 cells (CRL-1634-ATCC). The developed gel formulations did not show a cytotoxic effect. The hydrogel variant containing AgNPs@CIN in a concentration of 8 µg Ag/gel formulation and hydrogel variant with vitamin C had proliferative activity. In addition, the antibacterial activity of the hydrogels was evaluated against S. aureus ATCC 6538, Ps. aeruginosa ATCC 27853, and E. coli ATCC 25922. The results demonstrated that the gel variant based on AgNPs@CIN in a concentration of 95 µg Ag/gel formulation and the hydrogel based on vitamin C show antibacterial activity. Therefore, the developed hydrogels with AgNPs@CIN and vitamin C could be promising alternatives in wound healing.
    Type of Medium: Online Resource
    ISSN: 2310-2861
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2813982-3
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  • 8
    In: Processes, MDPI AG, Vol. 9, No. 5 ( 2021-05-12), p. 850-
    Abstract: Melissa officinalis is a medicinal herb with an extensive pharmacological profile that has been proven to have beneficial effects in oral and gastrointestinal disorders. However, the effects of this plant in oral, pharyngeal, and colorectal malignancies, types of cancer with an increased incidence in recent years, are less investigated. The present study aims to evaluate the pharmacological profile of a Melissa officinalis total extract for potential benefits in oral, pharynx and colorectal carcinoma. The LC-MS profile of MO total extract (MOte) indicated a rich content in polyphenols, data that support the potent antioxidant capacity exhibited and the antimicrobial activity against both Gram-negative and Gram-positive bacteria. In addition, MOte triggered a dose-dependent and selective decrease in the viability of tumor cells (tongue and pharynx squamous cell carcinomas, and colorectal adenocarcinoma), with the most significant effect being recorded at 100 μg/mL. At the same concentration, MOte exhibited an antiangiogenic effect by inhibiting the process of angiogenesis in ovo. Overall, our findings support the potential benefits of Melissa officinalis leaf total extract as a valuable candidate for the prophylaxis of oral, pharyngeal and colorectal neoplasms.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2720994-5
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  • 9
    In: Processes, MDPI AG, Vol. 10, No. 4 ( 2022-04-08), p. 723-
    Abstract: Screen-printed electrodes-based sensors can be successfully used to determine all kinds of analytes with great precision and specificity. However, obtaining a high-quality sensor can be difficult due to factors such as lack of reproducibility, surface contamination or other manufacturing challenges. An important step in ensuring reproducible results is the cleaning step. The aim of the current work is to help researchers around the world who struggle with finding the most suitable method for cleaning screen-printed electrodes. We evaluated the cleaning efficiency of different chemical compounds and cleaning methods using cyclic voltammetry and electrochemical impedance spectroscopy. The percentage differences in polarization resistance (Rp) before and after cleaning were as follows: acetone—35.33% for gold and 49.94 for platinum; ethanol—44.50% for gold and 81.68% for platinum; H2O2—47.34% for gold and 92.78% for platinum; electrochemical method—3.70% for gold and 67.96% for platinum. Thus, we concluded that all the evaluated cleaning methods seem to improve the surface of both gold and platinum electrodes; however, the most important reduction in the polarization resistance (Rp) was obtained after treating them with a solution of H2O2 and multiple CV cycles with a low scanning speed (10 mV/s).
    Type of Medium: Online Resource
    ISSN: 2227-9717
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720994-5
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  • 10
    In: Chemosensors, MDPI AG, Vol. 11, No. 4 ( 2023-03-24), p. 204-
    Abstract: In recent research, 3D printing has become a powerful technique and has been applied in the last few years to carbon-based materials. A new generation of 3D-printed electrodes, more affordable and easier to obtain due to rapid prototyping techniques, has emerged. We propose a customizable fabrication process for flexible (and rigid) carbon-based biosensors, from biosensor design to printable conductive inks. The electrochemical biosensors were obtained on a 50 µm Kapton® (polyimide) substrate and transferred to a 500 µm PDMS substrate, using a 3D-extrusion-based printing method. The main features of our fabrication process consist of short-time customization implementation, fast small-to-medium batch production, ease of electrochemical spectroscopy measurements, and very good resolution for an extrusion-based printing method (100 µm). The sensors were designed for future integration into a smart wound dressing for wound monitoring and other biomedical applications. We increased their sensibility with electro-deposited gold nanoparticles. To assess the biosensors’ functionality, we performed surface functionalization with specific anti-N-protein antibodies for SARS-CoV 2 virus, with promising preliminary results.
    Type of Medium: Online Resource
    ISSN: 2227-9040
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2704218-2
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