Browsing by Author "Ali, Z."

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    Infra-Red Thermal Measurement on a Low Power Infra-Red Emitter in CMOS Technology
    (IET, 2019-01-17) Pandey, P.; Oxley, C.; Hopper, Richard; Ali, Z.; Duffy, A. P.
    This paper presents high temperature characterisation of a novel infra-red (IR) emitter chip based on CMOS technology, using IR thermal microscopy. The performance and reliability of the thermal source is highly dependent on the operating temperature and temperature uniformity across the micro-heater which is embedded within the silicon dioxide membrane. To date, the accuracy of the IR measurement has been limited by the optical transparency of the semiconductor material forming the membrane, which has poor emissivity compared to a black-body source. In this paper, a high emissivity micro-particle sensor is used improve the accuracy of the temperature measurements. IR measurements on the emitter chip were validated with reference to temperature measurements made using an electrical technique where good temperature uniformity across the membrane heater was found.
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    Lactobacillus rhamnosus GG conditioned media modulates acute reactive oxygen species and nitric oxide in J774 murine macrophages.
    (Biochem Biophys Rep., 2016-03-07) Seenappanahalli Nanjundaiah, Y.; Wright, D. A.; Baydoun, Anwar; O'Hare, W. T.; Ali, Z.; Khaled, Z.; Sarker, M. H.
    Phagocytes such as macrophages are capable of detecting and killing pathogenic bacteria by producing reactive oxygen and nitrogen species. Formation of free radicals in macrophages may be regulated by probiotics or by factors released by probiotics but yet to be identified. Thus, studies were carried out to determine whether cell-free conditioned medium obtained from cultures of Lactobacillus rhamnosus GG (LGG-CM) regulate production of reactive oxygen species (ROS) and/or nitric oxide (NO) in macrophages. J774 macrophages in culture were loaded with either H2DCFDA for monitoring ROS or with DAFFM-DA for NO detection. Free radical production was measured on a fluorescence microplate reader and changes were analysed by Cumulative sum (CuSum) calculations. Low concentration of LGG-CM (10% LGG-CM) or LPS did not cause any significant change in basal levels of ROS or NO production. In contrast, high concentration of LGG-CM (75% and 100%) significantly enhanced ROS generation but also significantly reduced NO level. These findings are novel and suggest for the first time that probiotics may release factors in culture which enhance ROS production and may additionally reduce deleterious effects associated with excessive nitrogen species by suppressing NO level. These events may account, in part, for the beneficial bactericidal and anti-inflammatory actions ascribed to probiotics and may be of clinical relevance.