The growing number of patient morbidity related to nosocomial infections has placed an importance on the development of new antibacterial coatings for medical devices. Here, we utilize the versatile adhesion property of polydopamine (pDA) to design an antibacterial coating that possesses low-fouling and nitric oxide (NO)-releasing capabilities. To demonstrate this, glass substrates were functionalized with pDA via immersion in alkaline aqueous solution containing dopamine, followed by grafting of low-fouling polymer (poly(ethylene glycol) (PEG)) via Michael addition and subsequent formation of N-diazeniumdiolate functionalities (NO precursors) by purging with NO gas. X-ray photoelectron spectroscopy confirmed the successful grafting of PEG and formation of N-diazeniumdiolate on polydopamine-coated substrates. NO release from the coating was observed over 2 days, and NO loading is tunable by the pDA film thickness. The antibacterial efficiency of the coatings was assessed using Gram-negative Pseudomonas aeruginosa (i.e., wild-type PAO1 and multidrug-resistant PA37) and Gram-positive Staphylococcus aureus (ATCC 29213). The NO-releasing PEGylated pDA film inhibited biofilm attachment by 96 and 70% after exposure to bacterial culture solution for 24 and 36 h, respectively. In contrast, films that do not contain NO failed to prevent biofilm formation on the surfaces at these time points. Furthermore, this coating also showed 99.9, 97, and 99% killing efficiencies against surface-attached PAO1, PA37, and S. aureus bacteria. Overall, the combination of low-fouling PEG and antibacterial activity of NO in pDA films makes this coating a potential therapeutic option to inhibit biofilm formation on medical devices.
Microwave absorption properties were systematically studied for double-layer carbon black/epoxy resin (cB) and ni 0.6 Zn 0.4 fe 2 o 4 /epoxy resin (F) nanocomposites in the frequency range of 8 to 18 GHz. The ni 0.6 Zn 0.4 fe 2 o 4 nanoparticles were synthesized via high energy ball milling with subsequent sintering while carbon black was commercially purchased. The materials were later incorporated into epoxy resin to fabricate double-layer composite structures with total thicknesses of 2 and 3 mm. The CB1/F1, in which carbon black as matching and ferrite as absorbing layer with each thickness of 1 mm, showed the highest microwave absorption of more than 99.9%, with minimum reflection loss of −33.8 dB but with an absorption bandwidth of only 2.7 GHz. Double layer absorbers with F1/CB1(ferrite as matching and carbon black as absorbing layer with each thickness of 1 mm) structure showed the best microwave absorption performance in which more than 99% microwave energy were absorbed, with promising minimum reflection loss of −24.0 dB, along with a wider bandwidth of 4.8 GHz and yet with a reduced thickness of only 2 mm.In order to address issues induced by high proliferation of electromagnetic interferences in both civil and military applications, efficient microwave absorbers are becoming highly desirable and necessary. For that reason, such material is required to effectively reduce the reflection of electromagnetic (EM) signals over a broad absorption bandwidth. In order to improve the performance of microwave absorption properties, microwave absorbers are designed to meet the specific requirements of simultaneously having strong absorption, wide frequency band, lightweight and small thickness. Improvements can certainly be made to the designs by physical assembling of different types of absorbents 1-5 , chemical decorated absorbents 6,7 as well as by designing multi-layer structures [8][9][10][11] .Microwave absorbers are produced using different kinds of materials including one dimensional (1D) materials such as carbon nanotubes 12-15 , two dimensional (2D) materials such as graphene 16,17 and bulk three dimensional (3D) materials such as ferrites 9,18-21 . The difference in the dimensional structure of the materials would largely affect the microwave absorption performances since different kinds of structures contribute to different www.nature.com/scientificreports www.nature.com/scientificreports/ the F1/CB1 sample showed the best all round performance, in which more than 99% microwave energy was absorbed, with a reflection loss of −24.0 dB and a widest bandwidth of 4.8 GHz at −10 dB, yet it is the thinnest among the three designs, having a total thickness of only 2 mm.
Two-dimensional materials are one of the most studied materials for many applications in recent years. Among the two-dimensional (2D) metal carbide, MXene is seen as one of the most promising materials for energy storage systems. Among the MXene family, Ti3C2Tx, the lightest material, is one of the electrode materials due to its unique electrochemical performance. In this study, Ti3C2Tx MXene structure was obtained by removing Al layer from Ti3AlC2 MAX structure by selective etching. Exceptional electrochemical performance and high electronic conductivity of Ti3C2Tx was obtained and surface and morphological analyzes were performed with FESEM, EDS, XRD. FESEM has demonstrated that synthesized MXene is a layered solid structure. In addition, synthesized MXene was tested for electrochemical behavior against electrochemical energy storage applications using techniques such as cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS). Characterization and electrochemical tests have shown promising performance in electrochemical charge storage applications.
In this work, iron oxide were derived from millscale has been used as a potential scavenging agent in wastewater treatment due to its high adsorption capacity and its shorter sedimentation time during wastewater treatment. Iron oxide obtained from the magnetic separation technique was subjected to high energy ball milling (HEBM) at different milling time to produce different size of nanoparticles of iron oxide. X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Scanning Trasmission Electron microscopy (STEM) were performed to study the morphological properties of the iron oxide nanoparticles. After HEBM, iron oxide nanoparticles was modified with Hexadecyltrimethylammonium Bromide (CTAB) to study the adsorption possibility of iron oxide nanoparticle modified with CTAB (Iron oxide– CTAB nanoparticles) in dye wastewater. The variation effect of particle size of derived Iron oxide– CTAB were studied. Permanent magnet was used to separate iron oxide nanoparticles from the solution. The clear part of the solution (treated wastewater) was filtered out and adsorption efficiency of Iron oxide– CTAB nanoparticles was measured using UV – Visible spectroscopy. Efficiency adsorption of iron oxide nanoparticles modified with CTAB greatly achieved above 99 % and the size of iron oxide nanoparticles affected its performance in dye wastewater treatment.
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