211 research outputs found

    Biosynthesis of silver nanoparticles by plants crude extracts and their characterization using UV, XRD, TEM and EDX

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    Plant extracts are very cost effective and eco-friendly, thus, can be an economic and efficient alternative for the large-scale synthesis of nanoparticles. The preparation of stable, uniform silver nanoparticles by reduction of silver ions with Emblica officinalis, Terminalia catappa and Eucalyptus hybrida extract is reported in the present paper. It is a simple process of global research interest for obtaining silver nanoparticles in least amount of time. These nanoparticles were  characterized with UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy diffraction X- ray (EDX analysis which revealed that the silver nanoparticles are polydisperse and of different morphologies ranging from 20 to 80 nm in size. XRD results reveal that these nanostructures exhibit a face-centered cubic crystal structure. The UV/Vis spectra absorption peak confirms their production. Pioneering of reliable and eco-friendly process for synthesis of metallic nanoparticles biologically is an important step in the field of application of nanobiotechnology. Thus, these silver nanoparticles (Ag- NPs) may prove as a better candidate for drugs and can potentially eliminate the problem of chemical agents because of their biogenic nature. The indiscriminate use of antibiotics has fuelled the development of drug resistance at an alarming rate. To overpower this burning problem, the Ag-NPs may prove to be a universal solution.Key words: Nanobiotechnology, silver nanoparticles (Ag-NPs), Emblica officinalis, Terminalia catappa and Eucalyptus hybrida

    Magnetorheological landing gear: 2. Validation using experimental data

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    Aircraft landing gears are subjected to a wide range of excitation conditions with conflicting damping requirements. A novel solution to this problem is to implement semi-active damping using magnetorheological (MR) fluids. In part 1 of this contribution, a methodology was developed that enables the geometry of a flow mode MR valve to be optimized within the constraints of an existing passive landing gear. The device was designed to be optimal in terms of its impact performance, which was demonstrated using numerical simulations of the complete landing gear system. To perform the simulations, assumptions were made regarding some of the parameters used in the MR shock strut model. In particular, the MR fluid's yield stress, viscosity, and bulk modulus properties were not known accurately. Therefore, the present contribution aims to validate these parameters experimentally, via the manufacture and testing of an MR shock strut. The gas exponent, which is used to model the shock strut's nonlinear stiffness, is also investigated. In general, it is shown that MR fluid property data at high shear rates are required in order to accurately predict performance prior to device manufacture. Furthermore, the study illustrates how fluid compressibility can have a significant influence on the device time constant, and hence on potential control strategies

    Glutamine addiction promotes glucose oxidation in triple-negative breast cancer

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    Glutamine is a conditionally essential nutrient for many cancer cells, but it remains unclear how consuming glutamine in excess of growth requirements confers greater fitness to glutamine-addicted cancers. By contrasting two breast cancer subtypes with distinct glutamine dependencies, we show that glutamine-indispensable triple-negative breast cancer (TNBC) cells rely on a non-canonical glutamine-to-glutamate overflow, with glutamine carbon routed once through the TCA cycle. Importantly, this single-pass glutaminolysis increases TCA cycle fluxes and replenishes TCA cycle intermediates in TNBC cells, a process that achieves net oxidation of glucose but not glutamine. The coupling of glucose and glutamine catabolism appears hard-wired via a distinct TNBC gene expression profile biased to strip and then sequester glutamine nitrogen, but hampers the ability of TNBC cells to oxidise glucose when glutamine is limiting. Our results provide a new understanding of how metabolically rigid TNBC cells are sensitive to glutamine deprivation and a way to select vulnerable TNBC subtypes that may be responsive to metabolic-targeted therapies

    Mobile phone based mini-spectrometer for rapid screening of skin cancer

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    We demonstrate a highly sensitive mobile phone based spectrometer that has potential to detect cancerous skin lesions in a rapid, non-invasive manner. Earlier reports of low cost spectrometers utilize the camera of the mobile phone to image the field after moving through a diffraction grating. These approaches are inherently limited by the closed nature of mobile phone image sensors and built in optical elements. The system presented uses a novel integrated grating and sensor that is compact, accurate and calibrated. Resolutions of about 10 nm can be achieved. Additionally, UV and visible LED excitation sources are built into the device. Data collection and analysis is simplified using the wireless interfaces and logical control on the smart phone. Furthermore, by utilizing an external sensor, the mobile phone camera can be used in conjunction with spectral measurements. We are exploring ways to use this device to measure endogenous fluorescence of skin in order to distinguish cancerous from non-cancerous lesions with a mobile phone based dermatoscope

    A factor analysis to establish a group of causes of deferred maintenance at Malaysia’s public university buildings

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    The building has deferred the maintenance activities either planned or scheduled and delayed from the original schedules by some factors and therefore cause dissatisfaction of the building users commonly become a familiar issue. The public university buildings are an important place, everyone gathers to learn and share knowledge. They are producing future leaders, engineers and industry players. Therefore, it is also the heart of the development of a country. Hence, this study is intended to establish a group of causes factors of deferred maintenance of public university buildings in Malaysia. Questionnaires survey were carried out amongst the targeted respondent and the Statistical Package for the Social Sciences (SPSS) software were used to analyse 220 data collections for factor analysis. The study reveals 42 factors of causes are then classified into three groups. Group 1 is the organization and it displays 20 factors, group 2 is the resources which display 13 factors and group 3 is financial display 9 factors. This study shared useful information and insight knowledge of deferred maintenance of public university buildings in Malaysia

    The effect of the UP4FUN pilot intervention on objectively measured sedentary time and physical activity in 10-12 year old children in Belgium: the ENERGY-project

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    <p>Abstract</p> <p>Bakckground</p> <p>The first aim was to examine the effect of the UP4FUN pilot intervention on children’s total sedentary time. The second aim was to investigate if the intervention had an effect on children’s physical activity (PA) level. Finally, we aimed to investigate demographic differences (i.e. age, gender, ethnicity, living status and having siblings) between children in the intervention group who improved in sedentary time and PA at post-test and children in the intervention group who worsened in sedentary time and PA at post-test.</p> <p>Methods</p> <p>The six weeks UP4FUN intervention was tested in a randomized controlled trial with pre-test post-test design with five intervention and five control schools in Belgium and included children of the 5<sup>th</sup> and 6<sup>th</sup> grade. The children wore accelerometers for seven days at pre- and post-test. Analyses included children with valid accelerometer data for at least two weekdays with minimum 10h-wearing time and one weekend day with 8h-wearing time.</p> <p>Result</p> <p>Final analyses included 372 children (60% girls, mean age = 10.9 ± 0.7 years). There were no significant differences in the change in sedentary time or light PA between intervention and control schools for the total sample or for the subgroup analyses by gender. However, children (specifically girls) in the intervention group had a higher decrease in moderate-to-vigorous PA than children in the control group. In the intervention group, children who lived with both parents and children with one or more siblings were less likely to reduce sedentary time after exposure to the intervention. Older children, girls and children who lived with both parents were less likely to increase light PA after the intervention.</p> <p>Conclusion</p> <p>The UP4FUN intervention did not result in an effect on children’s sedentary time. Based on the high amounts of accelerometer-derived sedentary time in this age group, more efforts are needed to develop strategies to reduce children’s sedentary time.</p
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