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A simple process of gas sensing is represented here using Ce doped tin oxide nanomaterial based thin film sensor. A novel flow metric gas chamber has been designed and utilized for gas sensing. Doping plays a vital role in enhancing the sensing properties of nanomaterials. Ce doped tin oxide was prepared by hydrothermal method and the same has been used to fabricate a thin film for sensing. The microstructure and morphology of the prepared materials were analysed by SEM, XRD, and FTIR analysis. The SEM images clearly show that doping can clamp down the growth of the large crystallites and can lead to large agglomeration spheres. Thin film gas sensors were formed from undoped pure SnO2and Ce doped SnO2. The sensors were exposed to ammonia and ethanol gases. The responses of the sensors to different concentrations (50–500 ppm) of ammonia and ethanol at different operating temperatures (225°C–500°C) were studied. Results show that a good sensitivity towards ammonia was obtained with Ce doped SnO2thin film sensor at an optimal operating temperature of 325°C. The Ce doped sensor also showed good selectivity towards ammonia when compared with ethanol. Pure SnO2showed good sensitivity with ethanol when compared with Ce doped SnO2thin film sensor. Response time of the sensor and its stability were also studied.

ABSTRACTgens are essential for the potential treatment of the diseases. However, it is difficult to treat for gram negative and positive bacteria due to inherent and acquired resistance to antimicrobial agents. Endospore-forming grampositive bacteria produce a unique resting cell called an endospore. Bacillus Anthrax spore formers cause anthrax in domestic animals, which may be transmitted to humans. Pseudomonas aeruginosa pathogen is generated from gram-negative bacteria. It is the quintessential opportunistic pathogen of humans. It is a leading cause of hospital-acquired infections (nosocomial infections). It is difficult to eradicate due to its resistance to most antimicrobial agents. There is probably no tissue that cannot become infected by Pseudomonas if the host defenses are weakened. It is usually involved in soft tissue infections, urinary tract infections and pneumonia. The best known and most widely studied species is Coryne Bacterium Diptheria, gram-positive bacteria, the causal agent of Diptheria. The genus corynebacterium consists of a diverse group of bacteria including animal and plant pathogens, as well as saprophytes. Some coryne bacteria are part of the normal flora of humans, finding a suitable niche in virtually every anatomic site. One of the major pathogens of humans from spirochetes a phylogenetically distinct group of bacteria, is Treponema pallidum, the agent of syphilis, a sexually transmitted disease. Infectious diseases are generally detected with immunohistochemistry (IHC), flow cytometry, immuno-electron microscopy, ELISA, western blotting, polymerase chain reaction (PCR) etc. These systems use an antibody-based method to detect a specific protein. One of the main drawbacks with IHC staining is difficulties in overcoming specific or non-specific background. Optimisation of fixation methods and times, pretreatment with blocking agents, incubating antibodies with high salt, and optimising post-antibody wash buffers and wash times influence the quality immunostaining. Flow cytometry is less effective for detecting extremely rare cell populations. Immuno-electron microscopy can be technically challenging, expensive and require rigorous optimisation. ELISA test does not identify the amount of antigen present in