Papers by Keyword: Viability

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Authors: Alex Mason, Kazunari Ozasa, Olga Korostynska, Ismini Nakouti, Montserrat Ortoneda-Pedrola, Mizuo Maeda, Ahmed Al-Shammaa
Abstract: Euglena is a naturally occurring algae which can be found in any fresh water source.It is non-toxic, easy to handle, visualize and relatively resilient to variation in environment.This, along with the relatively large size of Euglena, means it can be readily used as a modelfor environmental monitoring of other smaller pathogenic micro-organisms (e.g. Escherichiacoli ). Currently the behavior of Euglena is observed through the use of an optical microscopefor sensing purposes. However, this method su ers from following major pitfalls: (1) the sizeand expense of the microscope; (2) the small observation volume (approx. 1 L); (3) the imageprocessing requirements and (4) need for a skilled human operator to acquire those images. Byusing electromagnetic (EM) wave technology in the GHz frequency range we seek to overcomethese challenges, since it has been demonstrated by the authors to be cost e ective, have alarge sensing volume (> 100L) and produce comparatively simple output data. Furthermoreit is possible to use simple software algorithms to process the sensor output data, and providereal-time information on Euglena gracilis viability and quantity. This paper shows proof ofconcept work to verify the feasibility of the proposed EM wave technology as an alternative tothe current optical microscopy methods.
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Authors: Elvis K. Tiburu, Ali Salifu, Edmund O. Aidoo, Heidimarie N.A. Fleischer, Gloria Manu, Abu Yaya, Han Zhou, Johnson K. Efavi
Abstract: This work reports the isolation and characterization of chitin from green algae using XRD, 13C CP/MAS NMR, FTIR and Microscopy. The XRD diffraction pattern confirmed orthorhombic structure of the crystalline polysaccharide, whereas the FTIR spectra revealed strong absorption bands at 896.9 cm-1 and 852 cm-1 typical of C–H axial and C–H equatorial vibrations within the anomeric center of the glucopyranosicyclic moiety. Another strong absorption band was observed at 1039.9 cm-1 and was assigned to C–O–C, C–O stretching bands. The purity and structure of the deacetylated chitin was confirmed using 13C NMR, showing overlapping peaks around 65 ppm assigned to both the sugar carbon at C2, as well as a methylene carbon at C6. An intense peak at 74 ppm is assigned to C3 and C5 with corresponding resonances at 81 and 104 ppm assigned to C4 and C1 respectively. Zeolite/Chitosan nanocomposites were synthesized by ionic cross-linking of chitosan with sodium tripolyphosphate. Chitosan nanoparticles and LTA of different concentrations were incubated with HeLa cancer cells to investigate their cytotoxicity effects. The exposure of the cells to chitosan nanoparticles resulted in a decreased in cell growth and this was concentration-dependent. Our results revealed the utility of locally available materials to produce new biodegradable nanoparticles to investigate their biological nanotoxicity.
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Authors: Suryani Dyah Astuti, Dwi G.D. Nike, Agus Supriyanto, Kuwat Triyana
Abstract: This paper reports the influence of light exposure (photodynamic) and magnetic field application on viability activation of anaerobic photosynthetic bacteria (rhodobacter sphaeroides). For photosynthetic process, the rhodobacter sphaeroides have bacteriochlorophyll and carotenoid as major and accessory pigments, respectively. A customized equipment was developed for investigating the effect of light and magnetic field applications on the growth of the bacterial colonies. It was consisted of three main parts, namely a sample holder, an array of light emitting diode (LED) as light source and Helmholtz coils as magnetic field source. The systems of this equipment were controlled by a microntroller of AVR ATMega-8535. Prior to the application in vitro, all LEDs were calibrated, both their intensity and wavelength. After the treatments, all bacteria substances were grown in photosynthetic media (PMS) for 48 hours followed by calculating the number bacterial colonies growth using a total plate count (TPC) method and Quebec colony counter. It was found that the growths of bacterial colonies were influenced by both light intensity and wavelength of LED array. At the same intensities, the wavelength of 430 nm showed highest effect on the growth of bacterial colonies. In addition, upon application of the optimum light combined with magnetic field, the highest growth of bacterial colonies was achieved more than 110% when the optimized light source of energy dose was 204 J/cm2 and magnetic field was 1.8 mT.
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Authors: Dong Wook Han, H.H. Kim, Hyun Joo Son, Hyun Sook Baek, Kwon Yong Lee, Suong Hyu Hyon, Jong Chul Park
Abstract: The potential protective roles played by green tea compounds (GTPCs) against reactive oxygen species-induced oxidative stress in cultured fetal human dermal fibroblasts (fHDFs) were investigated according to cell viability measurement methods, such as fluorescence double staining followed by flow cytometry (FCM), MTT assay and crystal violet uptake. Oxidative stress was induced in the fHDFs, either by adding 50 mM H2O2 or by the action of 40 U/L xanthine oxidase (XO) in the presence of xanthine (250 µM). FCM analysis was the most suitable to show that both treatments produced a significant (p < 0.05) reduction in the fHDF viability, attributed to its high sensitivity. On the microscopic observations, the cell death with necrotic morphology was appreciably induced by both treatments. These oxidative stress-induced damages were significantly (p < 0.05) prevented by pre-incubating the fHDFs with 200 µg/ml GTPC for 1 h. These results suggest that GTPC can act as a biological antioxidant in a cell culture experimental model and prevent oxidative stress-induced cytotoxicity in cells.
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Authors: Maria Roseta, Carlos Pina dos Santos
Abstract: The interest of the study on the implementation of expanded agglomerated cork as exterior wall covering derives from two critical factors in a perspective of sustainable development: the use of a product consisting of a renewable natural material – cork – and the concern to contribute to greater sustainability in construction. The study aims to assess the feasibility of its use by analyzing the corresponding behaviour under different conditions. Since this application is relatively recent, only about ten years old, there is still much to learn about the reliability of its long-term properties. In this context, this study aims to deepen and approach aspects, some of them poorly studied and even unknown, that deal with characteristics that will make the agglomerate a good choice for exterior wall covering. The analysis of these and other characteristics is being performed by testing both under actual exposure conditions, on an experimental cell at LNEC, and on laboratory. In this paper the main laboratory tests are presented and the obtained results are compared with the outcome of the field study.
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Authors: S.K.P.N. Silva, H.S.C. Perera, G.D. Samarasinghe
Abstract: Lean Manufacturing can be considered as a business strategy which was originated and developed in Japan. It tries to identify waste and eliminate it. Thus it leads to improvement in productivity and quality and companies can achieve a competitive advantage over others. Sri Lankan industries, especially apparel sector have attempted to implement this, but a little research work is carried out in regarding its suitability. This research is an attempt to identify a suitable Lean model for the apparel industry in Sri Lanka. As the initial stage of this study, a literature review is carried out to study about the Lean Manufacturing. It starts by looking at how Lean Manufacturing first began. Then it seeks to identify the core principles, tools and techniques and how those tools and techniques are currently being used worldwide. After studying the global scenario the next step is to look at the Sri Lankan context using real world data. This was undertaken by means of structured surveys, observations, and on site interviews. Also the study will reveal period of Lean implementation, suitable implementation methods, order of implementation, tools which are avoided, sustainability of different tools, challenges faced, ways of overcoming challenges and benefits achieved after applying Lean Manufacturing concepts in the apparel sector of Sri Lanka. The findings state Lean Manufacturing can be applied to mass production apparel industries and has created a positive mindset on employees. As implementation of Lean concepts is still in developmental stage, the full benefit is not yet achieved. But current situation suggests that the industry can go forward with Lean and capitalize on its full potential. In this research the authors have proposed a model which can be used to implement Lean in a systematic manner and each manufacturer must develop their own Lean system through training, experiments, employee empowerment, right leadership and kaizen mindset. Originality of the research— The research builds up a Lean Model which is not yet developed for the apparel sector in Sri Lanka. It can be further modified to suit the global apparel industry and other industries as well.
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