Adsorption challenge in the PDMS-based microfluidic systems for drug screening application

Drug screening is one of the demand areas due to close and direct dependency on human health. On the other hand, recently microfluidic systems have been increasingly used for drug development and screening purposes. However, this system has some challenges such as adsorption issue which can effect pharmacokinetic-pharmacodynamic (PK-PD) of the drugs. Thus, in this research, the issue was characterized and evaluated by UV-Vis spectrophotometry and FTIR spectroscopy devices as a model drug of cisplatin. Despite of strong relationship between logP and adsorption, and the very low value of logP in the drug candidate, the results for both apical and basal planes of the microfluidic chip confirmed the adsorption. In the UV-Vis spectrophotometry, the basal plane show 5%, and 10% higher adsorption compared to apical and control polydimethylsiloxane (PDMS)-based microfluidic. Additionally, the FTIR patterns were a good coincide with UV-Vis results

Studies on the morphological, structural, optical and electrical properties of Fe-doped Zno magnetic nano-crystal thin films

In this work, the effect of substrate material on the morphological, structural, optical and electrical properties of Fe-doped ZnO magnetic nano-crystal thin films was investigated. Fe-doped ZnO is a magnetic material and shows ferromagnetism at room temperature. FeO phases were detected in x-ray diffraction patterns. The surfaces of the films are fully occupied-spherical-like nano crystalline. The Fe/Zn ratios were calculated 1.6 and 5.9%. The optical transmittance value of the film is approximately 40%. The band gap value was shifted toward to lower value and the value was found as 3.15 eV. The maximum magnetic moments were obtained at 4000 and 2500 Oe for the film deposited onto glass and Si substrates, respectively. The electrical properties were determined at the maximum magnetic moment situation for the nano crystallites. It was found that diluted Fe-doped ZnO magnetic semiconductors have giant magnetic moment and electrical conductivity

The effect of Cu doping on optical and surface properties of ZnO thin films fabricated by thermionic vacuum arc (TVA) deposition

In this work, copper as a dopant was utilized in the ZnO thin film, and furthermore the structural, optical, elemental, and topological properties of the films have been carried out upon glass and Si substrates. All coating processes were operated via plasma-based thermionic vacuum arc technology. The mean crystallite sizes of the films were calculated as 78 and 30 nm on glass and Si substrates, respectively. According to the topological results, the RMS value of the films coated onto Si substrate are higher than the film deposited onto glass substrates. The surface images show smooth, compact, and free-crack characteristics of the films. Both films onto the aforementioned substrates have agglomeration. In the optical measurements performed by UV-Vis spectrophotometry, interferometry, and photoluminescence (PL), the refractive indices of the films were 1.63 and 1.82 on glass and Si substrates, respectively. The thicknesses of the films were ascertained as 84 and 80 nm onto the glass and Si substrates. Also, the reflection values of Cu-doped ZnO films were obtained 0.076 and 0.058. These values have revealed the suitability of using the film in the antireflective application. The PL patterns show a defect in the ZnO lattice as well as the shift in the center of the peaks due to copper substitution. The band gap was assessed as 3.17 eV. This narrowing in the band gap value is a demonstration of dopant substitution

Production of AgCu:NiO/Ni foam electrode with high charge accumulation and long cycling stability

Nickel oxide is a promising material for electrochemical energy storage devices due to its high specific surface area, rapid redox reactions, and short diffusion path in the solid electrode. It has been known that the loading of metallic elements into the NiO matrix enhances these superior properties. NiO material is electrochemically deposited on Ni foam, and then, Ag and Cu thin layers are coated on NiO by thermal evaporation. The produced NiO/Ni foam and AgCu:NiO/Ni foam electrodes are annealed at 400 degrees C for 1 h. Those are utilized as anode for high-performance energy storage electrode in an alkaline solution. The former has an energy density of 56.9 Wh kg(-1) at 3155.5 W kg(-1), while the latter has a high energy density of 107.6 Wh kg(-1) at the corresponding power density of 2957.7 W kg(-1). Although specific capacitance of the former decreases to 46.2% of its original capacitance at 10 A g(-1) after 5000 cycles, the latter exhibits higher cycling stability with 71.0% retention after 5000 charge-discharge cycles owing to the loading of Ag and Cu into NiO matrix. Charge transfer resistance of NiO/Ni foam, which is inversely proportional to electroactive surface area, reduces from 19.4 to 0.28 omega after the incorporation of Ag and Cu. Compared to NiO/Ni foam, AgCu:NiO/Ni foam with a higher electroactive surface area is more appropriate for charge accumulation. As mention above, the features of AgCu:NiO/Ni foam indicate that it is a promising material as an effective start-of-art energy storage device.Turkey Scientific and Technological Research Council (TUBITAK) [119F251]; TUBITAKThis work was supported by the Turkey Scientific and Technological Research Council (TUBITAK), Project number 119F251. The authors thank to TUBITAK for financial support

Investigation of the structural, magnetic, and cooling performance of AlFe thin film and AlFeGd nanometric giant magnetocaloric thin films

Giant magnetocaloric thin films are promising materials for new generation energy-efficient cooling systems. To investigate the cooling performance of AlFe and AlFeGd alloys, thin films have been deposited onto a glass substrate by thermionic vacuum arc (TVA) deposition system. TVA is a physical vapor deposition technology; it works in high vacuum and low-temperature conditions. AlFe and AlFeGd thin films are of significant importance for giant magnetocaloric materials. The surface and magnetic properties of a magnetic material are strongly dependent on the deposition process. In this paper, the structural, magnetic, and cooling performances of AlFe alloys with and without the Gd element have been investigated. When the Gd elements are added to AlFe alloys, the size of crystallite and the surface morphology of the giant nanometric magnetocaloric thin films are altered. The size of crystallite decreases to a lower value due to the Gd element added. According to the results of the elemental analysis, the elemental ratios of the AlFe and AlFeGd thin films were measured as (87:13) and (84:4:12), respectively, which are different from the ones reported previously. Magnetic cooling performance and magnetization strongly depend on these ratios. The mean values of crystallite size for the AlFe thin film and AlFeGd nanometric giant magnetocaloric thin film were measured as 50 nm and 12 nm, respectively. Following the Curie temperature of AlFeGd thin film, and the temperature difference it produces in the studied magnetic fields, 60 successive units of this material are assumed to form a magnetic refrigeration cycle. The coefficient of performance of this cycle is calculated to be 2.084—nearly two times better than the suggested cascade vapor-compression cycles in the same temperature range. This fact alongside the solid-state and environmentally friendly attributes of magnetic refrigeration cycles makes the AlFeGd thin films a strong candidate for accomplishing an efficient refrigeration system

Investigation of TiO2 thin films as a cathodic material for electrochromic display devices

Titanium dioxide is a preferred material in many fields of applications and is also used as one of best electrochromic display (ECD) candidates due to its chemical stability. Electrochromic devices are innovative, low-cost and low energy consumption for using as displays. In this work, electrochromic, morphological, structural, and some optical properties of tandem structures were comprehensively investigated. The mean thicknesses of the samples were measured as 86 and 120 nm on ITO- and FTO-coated glass substrates, respectively. The chronoamperometry test was performed to determine some electrochromic properties of the ECD. It was observed that the amounts of ions intercalated/de-intercalated from the coated TiO2 layer were almost equal to each other. According to the chronocoulometric analysis, the superior reversibility and coloration efficiency of the assembled ECD were found to be 83% and 26 cm(2)/C, respectively, onto ITO substrates. Higher reversibility is revealed in thinner films, which is consistent with the obtained thickness results. In a similar manner, highest coloration efficiency obtained for our ECD has demonstrated good contact between the TiO2-deposited layer and the ITO-coated glass substrate. Also, the highest porosity was reached by taking the highest coloration efficiency value into account. Moreover, coloration efficiencies and Delta T ratios are changed due to the interlayer transparent conductive oxide layers. Raman spectroscopy measurement reveals the anatase phase of TiO2 films on both substrates. Another important finding is related to the defect structures of the TiO2 phase. TiO2, TiO3 and TiO4 mixed phases show the lower coloration efficiency according to the TiO2 phase, for the first time. TiO3 and TiO4 phases were grown by using the FTO-coated glass substrate. Comparing results with reports has shown that our investigated design and technology for ECD applications are good candidates for such applications.Eskişehir Osmangazi Üniversitesi BAP (201719041

Detailed transmittance analysis of high-performance SnO₂-doped WO₃thin films in UV-Vis region for electrochromic devices

WO(3)is a popular electrochromic device and therefore it has extensively used for the electrochromic (EC) devices such as display and smart window applications. In this study, SnO2-doped WO(3)thin films have been deposited to obtain high-performance EC device and detailed transmittance analysis was determined. At the end of this study, general coloring-bleaching mechanism for SnO2-doped WO(3)active layer is presented. Li ion intercalation/de-intercalation is seen in Nyquist graph for the SnO2-doped WO(3)thin film deposited onto ITO coated glass substrate. All tests were done in 80 s in coloring and bleaching of the SnO2-doped WO(3)layer. Reversibility values of the EC devices mounted in this study were calculated to be 79 and 90% for the device with ITO or FTO conductive layers, respectively. According to the morphological analysis, grain distribution on the surfaces defined as to be perfect. Thanks to Raman analyses, the SnO2-WO(3)phases are seen. Finally, the EC devices have been working in the UV-Vis region. As a result, to obtain the high-performance EC device, SnO2-doped WO(3)active layer is a good choice. TVA method is also proper technology to device manufacturing.Eskişehir Osmangazi Üniversitesi - 20171904