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Background: Fluctuation in serotonin (5-HT) level is an essential manifestation of several neurological disorders. In view of such importance, it is necessary to monitor the levels of 5-HT with good sensitivity, selectivity, affordability and low response time. Zinc oxide (ZnO) based field effect transistors (FET) with attributes like minimized noise levels and large on-off ratio are regarded as emerging high performance biosensor platforms. However, their response is significantly non-linear and there has been no appreciable endeavor for improving the non-linearity. Method: In this paper, we have introduced embedded gate electrode encompassing the channel of the FET which improves the uniformity in electric field line distribution through the electrolyte and proportionately enhances the capture of target biomolecule at ultra low concentrations, thereby increasing the linearity. Further, we have incorporated the optimized parameters of ZnO nanorods reported previously, for rapid and selective detection of 5-HT. Results: It has been observed that the fabricated ZnO FET biosensor lowers the detection limit down to 0.1fM which is at least one order of magnitude lower than the existing reports. The sensor also has wide linear range from 0.1fM to 1nM with a detection time of about 20 minutes. Conclusion: The proposed zinc oxide nanorod-based sensor can be used as an excellent tool for future diagnosis of neurological disorders.

Steel-concrete composite beam is a typical construction which is made up of two dissimilar materials such as steel and concrete. It is used mainly for construction of commercial/residential high-rise buildings and bridges. From last few decades steel-concrete composite structure has been utilised in construction industry due to several advantages such as reduced time and cost of major construction and the avoidance of one of the major issues in present era, space scarcity. Shear connector is a basic component through which steel and concrete components are mechanically connected to transfer the load from concrete slab to steel beam in a conventional type of steel-concrete composite beam. Three dimensional numerical models are created using finite element analysis commercial software package ANSYS15 to study the flexural capacity of beam specimens. Earlier, validation has been done with the test results available in the literature and the proposed model is found to be capable of analysing the specimens with acceptable accuracy. Further numerical models are made to understand the behaviour of steel-concrete composite beam which is made up of two different flexible shear connectors such as stud and channel connector under four-point bending. Degree of shear connection, geometry and layout of shear connectors are taken into account as key parameters for this present numerical study. Normal strength of concrete is considered. The associated results such as ultimate load, mid-span deformation, interfacial slip capacity are presented. Diameter along with length of stud connector is found to influence the load carrying capacity of beams. Ultimate load capacity as well as stiffness of beams is found to enhance when channel section is considered with minimal spacing of connector. Thus finding the required degree of shear connection was also proved to be vital for assessing the performance of steel-concrete composite beams.

In the recent years, composite construction has gained its popularity due to achieving economy and providing higher sustainability compared to conventional steel structure or reinforced concrete structure. In various modern technologies, strengthened as well as sustainable materials are used in the present era for advanced infrastructure. This paper comes with a solution for several issues by introducing steel-concrete composite structure connected by shear connector. Strength of concrete is an important parameter for composite construction. In this paper, an attempt has been made to review the response of changing concrete property in composite beams. Constituent materials, their types and strength of concrete are the main parameters taken for this current paper. Concrete is highly efficient in compression whereas steel in tension. Thus with the use of these two materials, structure will become highly efficient in tension as well as compression. Steel concrete composite structure can be used in many applications in practical field but usually bridges and multistoried commercial buildings are the most used type of composite structure due to high load carrying capacity and reduced cost of maintenance.