Light-Sensing Properties of Amorphous Vanadium Oxide Films Prepared by RF Sputtering

In this study we analyzed the structure and light-sensing properties of as-deposited vanadium oxide thin films, prepared by RF sputtering in different Ar:O2 flow rate conditions, at low temperature (e.g., 65 °C). X-ray diffraction (XRD), Scanning Electron Microscopy (SEM-EDX), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to analyze the film microstructure, composition and the oxidation states of vanadium ions. The SEM micrographs evidence VxOy films with smooth surfaces, whereas the XRD patterns show their amorphous structure. Raman spectra indicate an increased structural disorder in the films deposited in Ar:O2 flow comparatively with those deposited solely in Ar flow. The XPS data suggest the modification of the oxidation state from V4+ to V5+, thus proving the formation of the V2O5 phase when increasing the oxygen content, which further affects the films’ optical properties. We observed a good stability of the photogenerated current in Si/SiO2/VxOy/TiN heterostructures upon excitation with pulses of UV (360 nm), VIS (white light) and NIR (860 nm) light. The responsivity, detectivity and linear dynamic range parameters increase with the O/V ratio in the VxOy films, reaching comparable values with photodetectors based on crystalline V2O5 or VO2

Light-Sensing Properties of Amorphous Vanadium Oxide Films Prepared by RF Sputtering

In this study we analyzed the structure and light-sensing properties of as-deposited vanadium oxide thin films, prepared by RF sputtering in different Ar:O2 flow rate conditions, at low temperature (e.g., 65 °C). X-ray diffraction (XRD), Scanning Electron Microscopy (SEM-EDX), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to analyze the film microstructure, composition and the oxidation states of vanadium ions. The SEM micrographs evidence VxOy films with smooth surfaces, whereas the XRD patterns show their amorphous structure. Raman spectra indicate an increased structural disorder in the films deposited in Ar:O2 flow comparatively with those deposited solely in Ar flow. The XPS data suggest the modification of the oxidation state from V4+ to V5+, thus proving the formation of the V2O5 phase when increasing the oxygen content, which further affects the films’ optical properties. We observed a good stability of the photogenerated current in Si/SiO2/VxOy/TiN heterostructures upon excitation with pulses of UV (360 nm), VIS (white light) and NIR (860 nm) light. The responsivity, detectivity and linear dynamic range parameters increase with the O/V ratio in the VxOy films, reaching comparable values with photodetectors based on crystalline V2O5 or VO2

Engineering Graphene Quantum Dots for Enhanced Ultraviolet and Visible Light p‑Si Nanowire-Based Photodetector

In this work, a significant improvement of the classical silicon nanowire (SiNW)-based photodetector was achieved through the realization of core–shell structures using newly designed GQD^PEIs via simple solution processing. The poly­(ethyleneimine) (PEI)-assisted synthesis successfully tuned both optical and electrical properties of graphene quantum dots (GQDs) to fulfill the requirements for strong yellow photoluminescence emission along with large band gap formation and the introduction of electronic states inside the band gap. The fabrication of a GQD^PEI-based device was followed by systematic structural and photoelectronic investigation. Thus, the GQD^PEI/SiNW photodetector exhibited a large photocurrent to dark current ratio (<i>I</i>_ph/<i>I</i>_dark up to ∼0.9 × 10² under 4 V bias) and a remarkable improvement of the external quantum efficiency values that far exceed 100%. In this frame, GQD^PEIs demonstrate the ability to arbitrate both charge-carrier photogeneration and transport inside a heterojunction, leading to simultaneous attendance of various mechanisms: (i) efficient suppression of the dark current governed by the type I alignment in energy levels, (ii) charge photomultiplication determined by the presence of the PEI-induced electron trap levels, and (iii) broadband ultraviolet-to-visible downconversion effects

Serum Interleukins 8, 17, and 33 as Potential Biomarkers of Colon Cancer

This research investigated the serum levels of three interleukins (IL8, IL17A, and IL33) and the possible relationships between them in healthy people and colon cancer patients at different stages. This study involved 82 participants, 42 of whom had colon cancer and 40 were healthy individuals. The cancer patients were classified into four groups according to the TNM staging classification of colon and rectal cancer. Serum levels of the interleukins were measured by the ELISA test. The data were analyzed statistically to compare the demographic characteristics, the interleukin levels across cancer stages, and the correlation between interleukins in both groups. The results showed that women had more early-stage colon cancer diagnoses, while men had more advanced-stage cancer diagnoses. Stage two colon cancer was more common in older people. Younger people, men, and those with early-stage colon cancer had higher levels of interleukins. The levels of IL8 and IL17A were higher in the cancer group, while the level of IL33 was higher in the healthy group. There was a strong correlation between IL8 and IL17A levels in both groups (p = 0.001). IL17A influenced the level of IL33 in the cancer group (p = 0.007). This study suggested that cytokine variation profiles could be useful for detecting colon cancer and predicting its outcome

Self-Sustained Three-Dimensional Macroporous TiO2-Graphene Photocatalyst for Sunlight Decolorization of Methyl Orange

The development of highly efficient sunlight-driven photocatalysts has triggered increased attention due to their merit in effluent treatment through a chemically green approach. To this end, we present herein the synthesis and characterization of the TiO2/3D-GF/Ni hybrid emphasizing the main structural and morphological properties and the photodegradation process of a highly resistant aromatic azo dye, methyl orange, under both UV light and simulated sunlight. Three-dimensional (3D) graphene was grown by the thermal CVD method on the nickel foam and subsequently coated with thin films of anatase employing the sol&ndash;gel method. Thereafter, it was gratifyingly demonstrated that the hybrid nanomaterial, TiO2/3D-GF-Ni, was able to bring about more than 90% decolorization of methyl orange dye after 30 min under simulated sunlight irradiance. Moreover, the efficiency of the methyl orange decolorization was 99.5% after three successive cycles. This high-performance photocatalyst which can effectively decolorize methyl orange will most likely make a great contribution to reducing environmental pollution by employing renewable solar energy

A novel synthetic flavonoid with potent antibacterial properties: In vitro activity and proposed mode of action.

The emergence of pathogenic multidrug-resistant bacteria demands new approaches in finding effective antibacterial agents. Synthetic flavonoids could be a reliable solution due to their important antimicrobial activity. We report here the potent in vitro antibacterial activity of ClCl-flav-a novel synthetic tricyclic flavonoid. The antimicrobial effects were tested using the minimum inhibitory concentration (MIC), time kill and biofilm formation assays. Fluorescence microscopy and scanning electron microscopy were employed to study the mechanism of action. MTT test was used to assess the cytotoxicity of ClCl-flav. Our results showed that Gram positive bacteria were more sensitive (MIC = 0.24 μg/mL) to ClCl-flav compared to the Gram negative ones (MIC = 3.9 μg/mL). We found that our compound showed significantly enhanced antibacterial activities, 32 to 72-fold more active than other synthetic flavonoids. ClCl-flav showed bactericidal activity at concentrations ranging from 0.48 to 15.62 μg/mL. At twice the MIC, all Escherichia coli and Klebsiella pneumoniae cells were killed within 1 h. Also ClCl-flav presented good anti-biofilm activity. The mechanism of action is related to the impairment of the cell membrane integrity. No or very low cytotoxicity was evidenced at effective concentrations against Vero cells. Based on the strong antibacterial activity and cytotoxicity assessment, ClCl-flav has a good potential for the design of new antimicrobial agents

New Amorphous Hydrogels with Proliferative Properties as Potential Tools in Wound Healing

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

SEM photomicrographs showing the effects of ClCl-flav on bacterial cell morphology: a, c, e, g—controls; b, d, f, h—ClCl-flav exposed cells (2 × MIC).

<p>Arrows indicate irreversible morphological damage of treated bacterial cells. These scanning electron photomicrographs are representative of a typical result.</p

Time-kill curves after treatment with ClCl-flav at different concentrations.

<p>a–<i>S</i>. <i>aureus</i>; b–<i>B</i>. <i>subtilis</i>; c–<i>E</i>. <i>coli</i>; d–<i>K</i>. <i>pneumoniae</i>. Each symbol indicates the means for at least three replicates. Bars represent confidence interval (P < 0.05).</p

Cytotoxicity assessment of HeLa and Vero cells incubated with ClCl-flav at different concentrations.

<p>All experiments were performed in at least triplicate.</p