Search results for: inertial mechanism

Authors: Zeyad Abdelmageid, Xianbin Wang

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Choosing the operational channel for a WLAN access point (AP) in WLAN networks has been a static channel assignment process initiated by the user during the deployment process of the AP, which fails to cope with the dynamic conditions of the assigned channel at the station side afterward. However, the dramatically growing number of Wi-Fi APs and stations operating in the unlicensed band has led to dynamic, distributed, and often severe interference. This highlights the urgent need for the AP to dynamically select the best overall channel of operation for the basic service set (BSS) by considering the distributed and changing channel conditions at all stations. Consequently, dynamic channel selection algorithms which consider feedback from the station side have been developed. Despite the significant performance improvement, existing channel selection algorithms suffer from very high feedback overhead. Feedback latency from the STAs, due to the high overhead, can cause the eventually selected channel to no longer be optimal for operation due to the dynamic sharing nature of the unlicensed band. This has inspired us to develop our own dynamic channel selection algorithm with reduced overhead through the proposed low-overhead, cluster-based station reporting mechanism. The main idea behind the cluster-based station reporting is the observation that STAs which are very close to each other tend to have very similar channel conditions. Instead of requesting each STA to report on every candidate channel while causing high overhead, the AP divides STAs into clusters then assigns each STA in each cluster one channel to report feedback on. With the proper design of the cluster based reporting, the AP does not lose any information about the channel conditions at the station side while reducing feedback overhead. The simulation results show equal performance and, at times, better performance with a fraction of the overhead. We believe that this algorithm has great potential in designing future dynamic channel selection algorithms with low overhead.

Keywords: channel assignment, Wi-Fi networks, clustering, DBSCAN, overhead

Procedia PDF Downloads 116

Authors: Yixin Yan, Miao Yan, Irini Angelidaki, Ioannis Fotidis

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Ammonia, which derives from the degradation of urea and protein-substrates, is the major toxicant of the commercial anaerobic digestion reactors causing loses of up to 1/3 of their practical biogas production, which reflects directly on the overall revenue of the plants. The current experimental work is aiming to alleviate the ammonia inhibition in anaerobic digestion (AD) process by developing an innovative bioaugmentation method of ammonia tolerant methanogenic consortia. The ammonia tolerant consortia were cultured in batch reactors and immobilized together with biochar in agar (customized inocula). Three continuous stirred-tank reactors (CSTR), fed with the organic fraction of municipal solid waste at a hydraulic retention time of 15 days and operated at thermophilic (55°C) conditions were assessed. After an ammonia shock of 4 g NH4+-N L-1, the customized inocula were bioaugmented into the CSTR reactors to alleviate ammonia toxicity effect on AD process. Recovery rate of methane production and methanogenic activity will be assessed to evaluate the bioaugmentation performance, while 16s rRNA gene sequence will be used to reveal the difference of microbial community changes through bioaugmentation. At the microbial level, the microbial community structures of the four reactors will be analysed to find the mechanism of bioaugmentation. Changes in hydrogen formation potential will be used to predict direct interspecies electron transfer (DIET) between ammonia tolerant methanogens and syntrophic bacteria. This experimental work is expected to create bioaugmentation inocula that will be easy to obtain, transport, handled and bioaugment in AD reactors to efficiently alleviate the ammonia toxicity, without alternating any of the other operational parameters including the ammonia-rich feedstocks.

Keywords: artisanal fishing waste, acidogenesis, volatile fatty acids, pH, inoculum/substrate ratio

Procedia PDF Downloads 125

Authors: Hasan Izhar Khan, Naiqiang Zhang, Hong Xu, Zhongliang Zhu, Dongfang Jiang

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Inconel 625 is a nickel-based alloy having outstanding corrosion resistance and developed for use at service temperatures ranging from cryogenic to 980°C. It got a wide range of applications in nuclear, petrochemical, chemical, marine, aeronautical, and aerospace industries. Currently, it is one of the candidate materials to be used as a structural material in ultra-supercritical (USC) power plants. In the high-temperature corrosive medium environment, metallic materials are susceptible to corrosion fatigue (CF). CF is an interaction between cyclic stress and corrosive medium environment that acts on a susceptible material and results in initiation and propagation of cracks. For the application of Inconel 625 as a structural material in USC power plants, CF behavior must be evaluated in steam and supercritical water (SCW) environment. Fatigue crack growth rate (FCGR) curves obtained from CF experiments are required to predict residual life of metallic materials used in power plants. In this study, FCGR tests of Inconel 625 were obtained by using compact tension specimen at 550-650 °C in steam (8 MPa) and SCW (25 MPa). The dissolved oxygen level was kept constant at 8000 ppb for the test conducted in steam and SCW. The tests were performed under sine wave loading waveform, 1 Hz loading frequency, stress ratio of 0.6 and maximum stress intensity factor of 32 MPa√m. Crack growth rate (CGR) was detected by using direct current potential drop technique. Results showed that CGR increased with an increase in temperature in the tested environmental conditions. The mechanism concerning the influence of temperature on FCGR are further discussed.

Keywords: corrosion fatigue, crack growth rate, nickel-based alloy, temperature

Procedia PDF Downloads 130

Authors: Pragathi Gurumurthy, Christina Hagen, Patricia Ulloa, Martin A. Koch, Thorsten M. Buzug

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Obstructive sleep apnea (OSA) is a sleep disorder where the patient suffers a disturbed airflow during sleep due to partial or complete occlusion of the pharyngeal airway. Recently, numerical simulations have been used to better understand the mechanism of pharyngeal collapse. However, to gain confidence in the solutions so obtained, an experimental validation is required. Therefore, in this study an experimental validation of computational fluid dynamics (CFD) used for the study of human pharyngeal flow patterns during OSA is performed. A stationary incompressible Navier-Stokes equation solved using the finite element method was used to numerically study the flow patterns in a computed tomography-based human pharynx model. The inlet flow rate was set to 250 ml/s and such that a flat profile was maintained at the inlet. The outlet pressure was set to 0 Pa. The experimental technique used for the validation of CFD of fluid flow patterns is phase contrast-MRI (PC-MRI). Using the same computed tomography data of the human pharynx as in the simulations, a phantom for the experiment was 3 D printed. Glycerol (55.27% weight) in water was used as a test fluid at 25°C. Inflow conditions similar to the CFD study were simulated using an MRI compatible flow pump (CardioFlow-5000MR, Shelley Medical Imaging Technologies). The entire experiment was done on a 3 T MR system (Ingenia, Philips) with 108 channel body coil using an RF-spoiled, gradient echo sequence. A comparison of the axial velocity obtained in the pharynx from the numerical simulations and PC-MRI shows good agreement. The region of jet impingement and recirculation also coincide, therefore validating the numerical simulations. Hence, the experimental validation proves the reliability and correctness of the numerical simulations.

Keywords: computational fluid dynamics, experimental validation, phase contrast-MRI, obstructive sleep apnea

Procedia PDF Downloads 309

Authors: Johanrik, Arini Aprilliani, Fikri Haikal, Diyas Yuca, Muhammad A. Latif, Edijanti Goenarwo, Nurita P. Sari

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Diarrhea is one of the leading causes of morbidity and mortality in many countries, as well as responsible for the deaths of millions of people each year. Previous research showed that the leaves, bark, and root bark of kedondong contains saponins, tannins, and flavonoids. Tannins have anti-diarrheal effects that work as the freeze of protein / astrigen, and may inhibit the secretion of chloride over the tannate bonding between protein in the intestines. Chemical compounds of flavonoids also have an effect as anti-diarrheal block receptors Cl ˉ in intestinal thus reducing the secretion of Cl ˉ to the intestinal lume. This research aims to know the anti-diarrheal activity of extracts kedondong leaf in mice Balb/C strain males in vivo. This research also proves kedondong leaves as an anti-diarrhea through trial efficacy of kedondong leaves as antisekretori and antimotilitas. This research using post-test only controlled group design. Analysis of statistical data normality and homogenity were tested by Kolmogorov Smirnov. If the data obtained homogenous then using ANOVA test. This research using ethanolic extracts kedondong leaf 200, 400 and 800 mg/kgBW to prove there is anti-diarrhea it makes into six treatment groups, for anti-secretory it makes into five treatment groups and anti-motility became five treatment groups. The result showed dose of ethanolic extracts kedondong leaf 800 mg/kgBW have significant value (p < 0.005). The conclusion from this extracts kedondong leaf research 800 mg/kgBW have pharmacological effects as antidiarrhea on Balb/C strain male mice with a mechanism of action as antisecretory and antimotility.

Keywords: anti-diarrhea, anti-secretory, anti-motility, kedondong leaf

Procedia PDF Downloads 462

Authors: Huda Al-Awisi, Mohammed Al-Azri, Samira Al-Rasbi, Mansour Al-Moundhri

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Cancer diagnosis is invariably a profound and catastrophic life-changing experience for individuals and their families. It has been found that cancer patients and survivors are distressed with the fragility of their life and their mortality. Based on the literature, cancer patients /survivors value their spiritual experience and connecting with unknown power either related to religious belief or not as an important coping mechanism. Health care professionals including nurses are expected to provide spiritual care for cancer patients as holistic care. Yet, nurses face many challenges in providing such care mainly due to lack of clear definition of spirituality. This study aims to explore coping mechanisms of Omani women diagnosed with breast cancer throughout their cancer journey including spirituality using a qualitative approach. A purposive sample of 19 Omani women diagnosed with breast cancer at different stages of cancer treatment modalities were interviewed. Interviews were tape recorded and transcribed verbatim. The framework approach was used to analyze the data. One main theme related to spirituality was identified and called “The power of faith”. For the majority of participants, faith in God (the will of God) was most important in coping with all stages of their breast cancer experience. Some participants thought that the breast cancer is a test from God which they have to accept. Participants also expressed acceptance of death as the eventual end and reward from God. This belief gives them the strength to cope with cancer and seek medical treatment. In conclusion, women participated in this study believed faith in God imposed spiritual power for them to cope with cancer. They connected spirituality with religious beliefs. Therefore, regardless of nurses’ faith in spirituality, the spiritual care needs to be tailored and provided according to each patient individual need.

Keywords: breast cancer, spiritual, religion, coping, diagnosis, oman, women

Procedia PDF Downloads 326

Authors: Musse Mohamud Ahmed, Tina Linda Achilles, Mohammad Kamrul Hasan

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Deterioration of the mother nature is evident these day with clear danger of human catastrophe emanating from greenhouses (GHG) with increasing CO2 emissions to the environment. PV technology can help to reduce the dependency on fossil fuel, decreasing air pollution and slowing down the rate of global warming. The objective of this paper is to propose, develop and design the production of clean water supply to rural communities using an appropriate technology such as Internet of Things (IOT) that does not create any CO2 emissions. Additionally, maximization of solar energy power output and reciprocally minimizing the natural characteristics of solar sources intermittences during less presence of the sun itself is another goal to achieve in this work. The paper presents the development of critical automated control system for solar energy power output optimization using several new techniques. water pumping system is developed to supply clean water with the application of IOT-renewable energy. This system is effective to provide clean water supply to remote and off-grid areas using Photovoltaics (PV) technology that collects energy generated from the sunlight. The focus of this work is to design and develop a submersible solar water pumping system that applies an IOT implementation. Thus, this system has been executed and programmed using Arduino Software (IDE), proteus, Maltab and C++ programming language. The mechanism of this system is that it pumps water from water reservoir that is powered up by solar energy and clean water production was also incorporated using filtration system through the submersible solar water pumping system. The filtering system is an additional application platform which is intended to provide a clean water supply to any households in Sarawak State, Malaysia.

Keywords: IOT, automated production and control system, water filtration, automated submersible water pump, solar energy

Procedia PDF Downloads 86

Authors: Binod Shrestha, Sandrine Hoppe, Thierry Ghislain, Phillipe Marchal, Nicolas Brosse, Anthony Dufour

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The thermochemical conversion of lignin has received an increasing interest in the frame of different biorefinery concepts for the production of chemicals or energy. It is needed to better understand the physical and chemical conversion of lignin for feeder and reactor designs. In-situ rheology reveals the viscoelastic behaviour of lignin upon thermal conversion. The softening, re-solidification (char formation), swelling and shrinking behaviours are quantified during pyrolysis in real-time [1]. The in-situ rheology of an alkali lignin (Protobind 1000) was conducted in high torque controlled strain rheometer from 35°C to 400°C with a heating rate of 5°C.min-1. The swelling, through glass phase transition overlapped with depolymerization, and solidification (crosslinking and “char” formation) are two main phenomena observed during lignin pyrolysis. The onset of temperatures for softening and solidification for this lignin has been found to be 141°C and 248°C respectively. An ex-situ characterization of lignin/char residues obtained at different temperatures after quenching in the rheometer gives a clear understanding of the pathway of lignin degradation. The lignin residues were sampled from the mid-point temperatures of the softening range and solidification range to study the chemical transformations undergoing. Elemental analysis, FTIR and solid state NMR were conducted after quenching the solid residues (lignin/char). The quenched solid was also extracted by suitable solvent and followed by acetylation and GPC-UV analysis. The combination of 13C NMR and GPC-UV reveals the depolymerization followed by crosslinking of lignin/char. NMR and FTIR provide the evolution of functional moieties upon temperature. Physical and chemical mechanisms occurring during lignin pyrolysis are accounted in this study. Thanks to all these complementary methods.

Keywords: pyrolysis, bio-chemicals, valorization, mechanism, softening, solidification, cross linking, rheology, spectroscopic methods

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Authors: Paras Gupta, Rohit Goyal, Yamini Chauhan, Pyare Lal Sharma

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Background: Bombax ceiba Linn., commonly called as Semal, is used in various gastro-intestinal disturbances. It contains lupeol which inhibits PTP-1B, adipogenesis, TG synthesis and accumulation of lipids in adipocytes and adipokines whereas the flavonoids isolated from B. ceiba has FAS inhibitory activity. The present study was aimed to investigate ameliorative potential of Bombax ceiba to experimental obesity in Wistar rats, and its possible mechanism of action. Methods: Male Wistar albino rats weighing 180–220 g were employed in present study. Experimental obesity was induced by feeding high fat diet for 10 weeks. Methanolic extract of B. ceiba extract 100, 200 and 400 mg/kg and Gemfibrozil 50 mg/kg as standard drug were given orally from 7th to 10th week. Results: Induction with HFD for 10 weeks caused significant (p < 0.05) increase in % body wt, BMI, LEE indices; serum glucose, triglyceride, LDL, VLDL, cholesterol, free fatty acid, ALT, AST; tissue TBARS, nitrate/nitrite levels; different fat pads and relative liver weight; and significant decrease in food intake (g and kcal), serum HDL and tissue glutathione levels in HFD control rats. Treatment with B. ceiba extract and Gemfibrozil significantly attenuated these HFD induced changes, as compared to HFD control. The effect of B. ceiba 200 and 400 mg/kg was more pronounced in comparison to Gemfibrozil. Conclusion: On the basis of results obtained, it may be concluded that the methanolic extract of stem bark of Bombax ceiba has significant ameliorative potential against HFD induced obesity in rats, possibly through modulation of FAS and PTP-1B signaling due to the presence of flavonoids and lupeol.

Keywords: obesity, Bombax ceiba, free fatty acid, protein tyrosine phosphatase-1B, fatty acid synthase

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Authors: Mehdi Habibagahi, Shami Nejadi, Ata Aminfar

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A significant degradation factor that impacts the durability of concrete structures is the alkali-silica reaction. Engineers are frequently charged with the challenges of conducting a thorough safety assessment of concrete structures that have been impacted by ASR. The alkali-silica reaction has a major influence on the structural capacities of structures. In most cases, the reduction in compressive strength, tensile strength, and modulus of elasticity is expressed as a function of free expansion and crack widths. Predicting the effect of ASR on flexural strength is also relevant. In this paper, a nonlinear three-dimensional (3D) finite-element model was proposed to describe the flexural strength degradation induced byASR.Initial strains, initial stresses, initial cracks, and deterioration of material characteristics were all considered ASR factors in this model. The effects of ASR on structural performance were evaluated by focusing on initial flexural stiffness, force–deformation curve, and load-carrying capacity. Degradation of concrete mechanical properties was correlated with ASR growth using material test data conducted at Tech Lab, UTS, and implemented into the FEM for various expansions. The finite element study revealed a better understanding of the ASR-affected RC beam's failure mechanism and capacity reduction as a function of ASR expansion. Furthermore, in this study, decreasing of the residual mechanical properties due to ASRisreviewed, using as input data for the FEM model. Finally, analysis techniques and a comparison of the analysis and the experiment results are discussed. Verification is also provided through analyses of reinforced concrete beams with behavior governed by either flexural or shear mechanisms.

Keywords: alkali-silica reaction, analysis, assessment, finite element, nonlinear analysis, reinforced concrete

Procedia PDF Downloads 156

Authors: Alafara A. Baba, Kuranga I. Ayinla, Folahan A. Adekola, Rafiu B. Bale

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Due to increasing demands and diverse applications of copper oxide as pigment in ceramics, cuprammonium hydroxide solution for rayon, p-type semi-conductor, dry cell batteries production and as safety disposal of hazardous materials, a study on the hydrometallurgical operations involving leaching, solvent extraction and precipitation for the recovery of copper for producing high grade copper oxide from a Nigerian chalcopyrite ore in chloride media has been examined. At a particular set of experimental parameter with respect to acid concentration, reaction temperature and particle size, the leaching investigation showed that the ore dissolution increases with increasing acid concentration, temperature and decreasing particle diameter at a moderate stirring. The kinetics data has been analyzed and was found to follow diffusion control mechanism. At optimal conditions, the extent of ore dissolution reached 94.3%. The recovery of the total copper from the hydrochloric acid-leached chalcopyrite ore was undertaken by solvent extraction and precipitation techniques, prior to the beneficiation of the purified solution as copper oxide. The purification of the leach liquor was firstly done by precipitation of total iron and manganese using Ca(OH)2 and H2O2 as oxidizer at pH 3.5 and 4.25, respectively. An extraction efficiency of 97.3% total copper was obtained by 0.2 mol/L Dithizone in kerosene at 25±2ºC within 40 minutes, from which ≈98% Cu from loaded organic phase was successfully stripped by 0.1 mol/L HCl solution. The beneficiation of the recovered pure copper solution was carried out by crystallization through alkali addition followed by calcination at 600ºC to obtain high grade copper oxide (Tenorite, CuO: 05-0661). Finally, a simple hydrometallurgical scheme for the operational extraction procedure amenable for industrial utilization and economic sustainability was provided.

Keywords: chalcopyrite ore, Nigeria, copper, copper oxide, solvent extraction

Procedia PDF Downloads 392

Authors: Chi Nguyen Thi Quynh, Steven Schilizzi, Atakelty Hailu, Sayed Iftekhar

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Territorial Use Rights for Fisheries (TURFs) have been emerged as a promising tool for fisheries conservation and management. However, illegal fishing has undermined the effectiveness of TURFs, profoundly degrading global fish stocks and marine ecosystems. Conservation and management of fisheries, therefore, largely depends on effectiveness of enforcing fishing regulations, which needs co-enforcement by fishers. However, fishers tend to resist monitoring participation, as their views towards monitoring scheme design has not been received adequate attention. Fishers’ acceptability of a monitoring scheme is likely to be achieved if there is a mechanism allowing fishers to engage in the early planning and design stages. This study carried out a choice experiment with 396 fishers in Vietnam to elicit fishers’ preferences for monitoring scheme and to estimate the relative importance that fishers place on the key design elements. Preference heterogeneity was investigated using a Scale-Adjusted Latent Class Model that accounts for both preference and scale variance. Welfare changes associated with the proposed monitoring schemes were also examined. It is found that there are five distinct preference classes, suggesting that there is no one-size-fits-all scheme well-suited to all fishers. Although fishers prefer to be compensated more for their participation, compensation is not a driving element affecting fishers’ choice. Most fishers place higher value on other elements, such as institutional arrangements and monitoring capacity. Fishers’ preferences are driven by their socio-demographic and psychological characteristics. Understanding of how changes in design elements’ levels affect the participation of fishers could provide policy makers with insights useful for monitoring scheme designs tailored to the needs of different fisher classes.

Keywords: Design of monitoring scheme, Enforcement, Heterogeneity, Illegal Fishing, Territorial Use Rights for Fisheries

Procedia PDF Downloads 323

Authors: Frank Jaksoni Mweta, Nozomu Adachi, Yoshikazu Todaka, Hirokazu Sato, Yuta Sato, Hiromi Miura, Masakazu Kobayashi, Chihiro Watanabe, Yoshiteru Aoyagi

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Advances in the consumption of hydrogen fuel increase demands of high strength steel pipes and storage tanks. However, high strength steels are highly sensitive to hydrogen embrittlement. Because the introduction of hydrogen into steel during the fabrication process or from the environment is unavoidable, it is essential to improve hydrogen embrittlement resistance of high strength steels through microstructural control. In the present study, the heterogeneous nanostructure with a tensile strength of about 1.8 GPa and the homogeneous nanostructure with a tensile strength of about 2.0 GPa of 316LN steels were generated after 92% heavy cold rolling and high-pressure torsion straining, respectively. The heterogeneous nanostructure is composed of twin domains, shear bands, and lamellar grains. The homogeneous nanostructure is composed of uniformly distributed ultrafine nanograins. The influence of heterogeneous and homogenous nanostructures on the hydrogen embrittlement resistance was investigated. The specimen for each nanostructure was electrochemically charged with hydrogen for 3, 6, 12, and 24 hours, respectively. Under the same hydrogen charging time, both nanostructures show almost the same concentration of the diffusible hydrogen based on the thermal desorption analysis. The tensile properties of the homogenous nanostructure were severely affected by the diffusible hydrogen. However, the diffusible hydrogen shows less impact on the tensile properties of the heterogeneous nanostructure. The difference in embrittlement behavior between the heterogeneous and homogeneous nanostructures was elucidated based on the mechanism of the cracks' growth observed in the tensile fractography. The hydrogen embrittlement was suppressed in the heterogeneous nanostructure because the twin domain became an obstacle for crack growth. The homogeneous nanostructure was not consisting an obstacle such as a twin domain; thus, the crack growth resistance was low in this nanostructure.

Keywords: diffusible hydrogen, heterogeneous nanostructure, homogeneous nanostructure, hydrogen embrittlement

Procedia PDF Downloads 121

Authors: Frodouard Minani

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Since last decade, wireless sensor networks (WSNs) have been used in many areas like health care, agriculture, defense, military, disaster hit areas and so on. Wireless Sensor Networks consist of a Base Station (BS) and more number of wireless sensors in order to monitor temperature, pressure, motion in different environment conditions. The key parameter that plays a major role in designing a protocol for Wireless Sensor Networks is energy efficiency which is a scarcest resource of sensor nodes and it determines the lifetime of sensor nodes. Maximizing sensor node’s lifetime is an important issue in the design of applications and protocols for Wireless Sensor Networks. Clustering sensor nodes mechanism is an effective topology control approach for helping to achieve the goal of this research. In this paper, the researcher presents an energy efficiency protocol to prolong the network lifetime based on Energy efficient clustering algorithm. The Low Energy Adaptive Clustering Hierarchy (LEACH) is a routing protocol for clusters which is used to lower the energy consumption and also to improve the lifetime of the Wireless Sensor Networks. Maximizing energy dissipation and network lifetime are important matters in the design of applications and protocols for wireless sensor networks. Proposed system is to maximize the lifetime of the Wireless Sensor Networks by choosing the farthest cluster head (CH) instead of the closest CH and forming the cluster by considering the following parameter metrics such as Node’s density, residual-energy and distance between clusters (inter-cluster distance). In this paper, comparisons between the proposed protocol and comparative protocols in different scenarios have been done and the simulation results showed that the proposed protocol performs well over other comparative protocols in various scenarios.

Keywords: base station, clustering algorithm, energy efficient, sensors, wireless sensor networks

Procedia PDF Downloads 143

Authors: Bhenjamin Jordan L. Ona

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Weather modification is an act of altering weather systems that catches interest on scientific studies. Cloud seeding is a common form of weather alteration. On the same principle, tropical cyclone mitigation experiment follows the methods of cloud seeding with intensity to account for. This study will present the effects of aerosol to tropical cyclone cloud microphysics and intensity. The framework of Weather Research and Forecasting (WRF) model incorporated with Thompson aerosol-aware scheme is the prime host to support the aerosol-cloud microphysics calculations of cloud condensation nuclei (CCN) ingested into the tropical cyclones before making landfall over the Philippine coast. The coupled microphysical and radiative effects of aerosols will be analyzed using numerical data conditions of Tropical Storm Ketsana (2009), Tropical Storm Washi (2011), and Typhoon Haiyan (2013) associated with varying CCN number concentrations per simulation per typhoon: clean maritime, polluted, and very polluted having 300 cm-3, 1000 cm-3, and 2000 cm-3 aerosol number initial concentrations, respectively. Aerosol species like sulphates, sea salts, black carbon, and organic carbon will be used as cloud nuclei and mineral dust as ice nuclei (IN). To make the study as realistic as possible, investigation during the biomass burning due to forest fire in Indonesia starting October 2015 as Typhoons Mujigae/Kabayan and Koppu/Lando had been seeded with aerosol emissions mainly comprises with black carbon and organic carbon, will be considered. Emission data that will be used is from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). The physical mechanism/s of intensification or deintensification of tropical cyclones will be determined after the seeding experiment analyses.

Keywords: aerosol, CCN, IN, tropical cylone

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Authors: Meng-Na Dai, Bao-Fang Wen, Gao-Pei Zhu, Chen-Xi Zhang, Jing Sun, Chang-Hai Tang, Zhi-Qiang Feng, Wen-Qiang Yin

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Based on the analysis of literature in the health emergency management in China with recent 10 years, this paper discusses the Chinese current research hotspots, development trends and shortcomings in this field, and provides references for scholars to conduct follow-up research. CNKI(China National Knowledge Infrastructure), Weipu, and Wanfang were the databases of this literature. The key words during the database search were health, emergency, and management with the time from 2009 to 2018. The duplicate, non-academic, and unrelated documents were excluded. 901 articles were included in the literature review database. The main indicators of abstraction were, the number of articles published every year, authors, institutions, periodicals, etc. There are some research findings through the analysis of the literature. Overall, the number of literature in the health emergency management in China has shown a fluctuating downward trend in recent 10 years. Specifically, there is a lack of close cooperation between authors, which has not constituted the core team among them yet. Meanwhile, in this field, the number of high-level periodicals and quality literature is scarce. In addition, there are a lot of research hotspots, such as emergency management system, mechanism research, capacity evaluation index system research, plans and capacity-building research, etc. In the future, we should increase the scientific research funding of the health emergency management, encourage collaborative innovation among authors in multi-disciplinary fields, and create high-quality and high-impact journals in this field. The states should encourage scholars in this field to carry out more academic cooperation and communication with the whole world and improve the research in breadth and depth. Generally speaking, the research in health emergency management in China is still insufficient and needs to be improved.

Keywords: health emergency management, research situation, bibliometrics, literature

Procedia PDF Downloads 135

Authors: Amit Kumar

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Accurate identification of deteriorated air quality regions is very helpful in devising better environmental practices and mitigation efforts. In the present study, an attempt has been made to identify the air pollutant dispersion patterns especially NOX due to vehicular and industrial sources over a rapidly developing urban city, Visakhapatnam (17°42’ N, 83°20’ E), India, during April 2009. Using the emission factors of different vehicles as well as the industry, a high resolution 1 km x 1 km gridded emission inventory has been developed for Visakhapatnam city. A dispersion model AERMOD with explicit representation of planetary boundary layer (PBL) dynamics and offline coupled through a developed coupler mechanism with a high resolution mesoscale model WRF-ARW resolution for simulating the dispersion patterns of NOX is used in the work. The meteorological as well as PBL parameters obtained by employing two PBL schemes viz., non-local Yonsei University (YSU) and local Mellor-Yamada-Janjic (MYJ) of WRF-ARW model, which are reasonably representing the boundary layer parameters are considered for integrating AERMOD. Significantly different dispersion patterns of NOX have been noticed between summer and winter months. The simulated NOX concentration is validated with available six monitoring stations of Central Pollution Control Board, India. Statistical analysis of model evaluated concentrations with the observations reveals that WRF-ARW of YSU scheme with AERMOD has shown better performance. The deteriorated air quality locations are identified over Visakhapatnam based on the validated model simulations of NOX concentrations. The present study advocates the utility of tNumerical Simulation of Air Pollutant Using Coupled AERMOD-WRF Modeling System over Visakhapatnam: A Case Studyhe developed gridded emission inventory of NOX with coupled WRF-AERMOD modeling system for air quality assessment over the study region.

Keywords: WRF-ARW, AERMOD, planetary boundary layer, air quality

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Authors: Hai-Ying Liu, Yi-Hao Chen, Shu-Yin Pang, Feng-Hua Wang, Xiao-Fang Peng, Li-Yuan Yang, Zheng-Rong Chen, Yi Chen, Bing Zhu

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Objective: Biliary atresia (BA) is characterized by progressive liver fibrosis. Epithelial-mesenchymal transition (EMT) has been implicated as a key mechanism in the pathogenesis of organ fibrosis. MiR-200a has been shown to repress EMT. We aim to explore the role of miR-200a in the fibrogenesis of BA. Methods: We obtained the plasma samples and liver samples from patients with BA or controls to examine the role of miR-200a. Histological liver fibrosis was assessed using the Ishak fibrosis scores. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to detect the expression of miR-200a in plasma. We also evaluated the expression of miR-200a in liver tissues using tyramide signal amplification fluorescence in situ hybridization (TSA-FISH). The expression of EMT related proteins zinc finger E-box-binding homeobox 1 (ZEB1), E-cadherin and α-smooth muscle actin (α-SMA) in the liver sections were detected by immunohistochemical staining. Results: We found that the expression of miR-200a was both elevated in the plasma and liver tissues from BA patients compared with the controls. The hepatic expression of ZEB1 and α-SMA were markedly increased in the liver sections from BA patients compared to the controls, whereas E-cadherin was downregulated in the BA group. Simultaneously, we noted that the hepatic expression of miR-200a, E-cadherin and α-SMA were upregulated with the progression of liver fibrosis in the BA group, while ZEB1 was downregulated with the progression of liver fibrosis in BA patients. Conclusion: These findings suggest EMT has a critical effect on the fibrotic process of BA, and the interaction between miR-200a and ZEB1 may regulate EMT and eventually influence liver fibrogenesis of BA.

Keywords: biliary atresia, liver fibrosis, MicroRNA, epithelial-mesenchymal transition, zinc finger E-box-binding homeobox 1

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Authors: Ping Ren, Mao Wen, Kan Zhang, Weitao Zheng

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The improvement of comprehensive properties including hardness, toughness, wear, and corrosion resistance in the transition metal carbides/nitrides TMCN films, especially avoiding the trade-off between hardness and toughness, is strongly required to adapt to various applications. Although incorporating ductile metal DM phase into the TMCN via thermally-induced phase separation has been emerged as an effective approach to toughen TMCN-based films, the DM is just limited to some soft ductile metal (i.e. Cu, Ag, Au immiscibility with the TMCN. Moreover, hardness is highly sensitive to soft DM content and can be significantly worsened. Hence, a novel preparation method should be attempted to broaden the DM selection and assemble much more ordered nanocomposite structure for improving the comprehensive properties. Here, we provide a new strategy, by activating solid-state dewetting during layered deposition, to accomplish the self-assembly of ordered TaC@Ta core-shell-like nanocomposite film consisting of TaC nanocrystalline encapsulated with thin pseudocrystal Ta tissue. That results in the superhard (~45.1 GPa) dominated by Orowan strengthening mechanism and high toughness attributed to indenter-induced phase transformation from the pseudocrystal to body-centered cubic Ta, together with the drastically enhanced wear and corrosion resistance. Furthermore, very thin pseudocrystal Ta encapsulated layer (~1.5 nm) in the TaC@Ta core-shell-like structure helps for promoting the formation of lubricious TaOₓ Magnéli phase during sliding, thereby further dropping the coefficient of friction. Apparently, solid-state dewetting may provide a new route to construct ordered TMC(N)@TM core-shell-like nanocomposite capable of combining superhard, high toughness, low friction, superior wear with corrosion resistance.

Keywords: corrosion, nanocomposite film, solid-state dewetting, tribology

Procedia PDF Downloads 134

Authors: Diptiman Dinda, Shyamal Kumar Saha

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In the 21st century, sensitive and selective detection of trace amounts of explosives has become a serious problem. Generally, nitro compound and its derivatives are being used worldwide to prepare different explosives. Recently, TNP (2, 4, 6 trinitrophenol) is the most commonly used constituent to prepare powerful explosives all over the world. It is even powerful than TNT or RDX. As explosives are electron deficient in nature, it is very difficult to detect one separately from a mixture. Again, due to its tremendous water solubility, detection of TNP in presence of other explosives from water is very challenging. Simple instrumentation, cost-effective, fast and high sensitivity make fluorescence based optical sensing a grand success compared to other techniques. Graphene oxide (GO), with large no of epoxy grps, incorporate localized nonradiative electron-hole centres on its surface to give very weak fluorescence. In this work, GO is functionalized with 2, 6-diamino pyridine to remove those epoxy grps. through SN2 reaction. This makes GO into a bright blue luminescent fluorophore (DAP/rGO) which shows an intense PL spectrum at ∼384 nm when excited at 309 nm wavelength. We have also characterized the material by FTIR, XPS, UV, XRD and Raman measurements. Using this as fluorophore, a large fluorescence quenching (96%) is observed after addition of only 200 µL of 1 mM TNP in water solution. Other nitro explosives give very moderate PL quenching compared to TNP. Such high selectivity is related to the operation of FRET mechanism from fluorophore to TNP during this PL quenching experiment. TCSPC measurement also reveals that the lifetime of DAP/rGO drastically decreases from 3.7 to 1.9 ns after addition of TNP. Our material is also quite sensitive to 125 ppb level of TNP. Finally, we believe that this graphene based luminescent material will emerge a new class of sensing materials to detect trace amounts of explosives from aqueous solution.

Keywords: graphene, functionalization, fluorescence quenching, FRET, nitroexplosive detection

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Authors: Thanusha D. Abeywickrama, Inoka C. Perera, Genji Kurisu

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Tuberculosis, considered being as the ninth leading cause of death worldwide, cause from a single infectious agent M. tuberculosis and the drug resistance nature of this bacterium is a continuing threat to the world. Therefore TB preventing treatment is expanding, where this study designed to analyze the regulatory mechanism of GntR transcriptional regulator gene Rv0792c, which lie between several genes codes for some hypothetical proteins, a monooxygenase and an oxidoreductase. The gene encoding Rv0792c was cloned into pET28a and expressed protein was purified to near homogeneity by Nickel affinity chromatography. It was previously reported that the protein binds within the intergenic region (BS region) between Rv0792c gene and monooxygenase (Rv0793). This resulted in binding of three protein molecules with the BS region suggesting tight control of monooxygenase as well as its own gene. Since monooxygenase plays a key role in metabolism, this gene may have a global regulatory role. The natural ligand for this regulator is still under investigation. In relation to the Rv0792 protein structure, a Circular Dichroism (CD) spectrum was carried out to determine its secondary structure elements. Percentage-wise, 17.4% Helix, 21.8% Antiparallel, 5.1% Parallel, 12.3% turn and 43.5% other were revealed from CD spectrum data under room temperature. Differential Scanning Calorimetry (DSC) was conducted to assess the thermal stability of Rv0792, which the melting temperature of protein is 57.2 ± 0.6 °C. The graph of heat capacity (Cp) versus temperature for the best fit was obtained for non-two-state model, which concludes the folding of Rv0792 protein occurs through stable intermediates. Peak area (∆HCal ) and Peak shape (∆HVant ) was calculated from the graph and ∆HCal / ∆HVant was close to 0.5, suggesting dimeric nature of the protein.

Keywords: CD spectrum, DSC analysis, GntR transcriptional regulator, protein structure

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Authors: Jasna Prester, Ivana Rašić Bakarić, Božidar Matijević

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Various prominent scholars and substantial practitioner-oriented literature on innovation orientation have shown positive effects on firm performance. There is a myriad of factors that influence and enhance innovation but it has been found in the literature that new product innovations accounted for an average of 14 percent of sales revenues for all firms. If there is one thing that has changed in innovation management during the last decade, it is the growing reliance on external partners. As a consequence, a new task for purchasing arises, as firms need to understand which suppliers actually do have high potential contributing to the innovativeness of the firm and which do not. Purchasing function in an organization is extremely important as it deals on an average of 50% or more of a firm's expenditures. In the nineties the purchasing department was largely seen as a transaction-oriented, clerical function but today purchasing integration provides a formal interface mechanism between purchasing and other firm functions that services other functions within the company. Purchasing function has to be organized differently to enable firm innovation potential. However, innovations are inherently risky. There are behavioral risk (that some partner will take advantage of the other party), technological risk in terms of complexity of products and processes of manufacturing and incoming materials and finally market risks, which in fact judge the value of the innovation. These risks are investigated in this work since it has been found in the literature that the higher the technological risk, higher will be the centralization of the purchasing function as an interface with other supply chain members. Most researches on organization of purchasing function were done by case study analysis of innovative firms. This work actually tends to prove or discard results found in the literature based on case study method. A large data set of 1493 companies, from 25 countries collected in the GMRG 4 survey served as a basis for analysis.

Keywords: purchasing function organization, innovation, technological risk, GMRG 4 survey

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Authors: Najla Alhkalaf

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The focus of this study is answering the following question: How do e-government services in Bahrain support the productivity of SMEs? This study examines the current E-government function in enhancing SME productivity in Bahrain through analysing the efficiency of e- government by viewing its facilitators and barriers from the perspective of different stakeholders. The study aims to identify and develop best practice guidelines with the end-goal of creating a standardised channel of communication between e-government and SMEs that fulfil the requirement of SME owners, and thus achieve the prime objective of e-government. E-government services for SMEs have been offered in Bahrain since 2005. However, the current services lack the required mechanism for SMEs to fully take advantage of these services because of lagging communication between service provider and end-user. E-government employees believe that a lack of awareness and trust are the main stumbling block, whereas the SME owners believe that there is a lack of sufficiency in the content and efficiency provided through e- services. A questionnaire has been created based on a pilot study that highlighted the main indicators of e-government efficiency and SMEs productivity as well as previous studies conducted on this subject. This allowed for quantitative data to be extracted. Also interviews were conducted with SME owners and government employees from both case studies, which formed the qualitative data for this study. The findings portray that both the service provider and service receiver largely agree on the existence of most of the technical and administrative barriers. However, the data reflects a level of dissatisfaction from the SME side, which contradicts with the perceived level of satisfaction from the government employees. Therefore, the data supports the argument that assures the existence of a communication gap between stakeholders. To this effect, this research would help build channels of communication between stakeholders, and then induces a plan unlocking the potential of e-government application. The conclusions of this study will help devise an optimised E-government strategy for Bahrain.

Keywords: e-government, SME, e-services, G2B, government employees' perspective, entrepreneurs' perspective, enterprise

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Authors: Suelen C. Lima, André C. de Oliveira, Rosemary A. Roque

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Dengue is fatal arboviruses transmitted by the A. aegypti mosquito to more than 100 countries, for which the WHO estimates that 2.5 million people will be infected by these disease. The widespread of these diseases is due, among other factors, to the resistance that A. aegypti has to several commercial insecticides. On the other hand, natural products based on plants of the genus Piper (Piperaceae) are characterized by their insecticidal activities against mosquitoes. Piper longepetiolatum and Piper brachypetiolatum are species with wide distribution in the State of Amazonas. However, there is no investigation of phytochemical or biological of these plants against mosquitoes such as A. aegypti. The main of this study was to identify the chemical composition of the essential oil (EOs) from P. longepetiolatum and P. brachypetiolatum and to evaluate the biological activity against A. aegypti. The EOs were extracted by hydrodistillation from leaves (200 g) of P. longepetiolatum and P. brachypetiolatum and analyzed by GC-MS and GC-FID. The main compounds β-caryophyllene (99.9% of purity) and E-nerolidol (99.4% of purity) were purchased from Sigma-Aldrich® Brazil. The larvicidal activity of EOs (20 to 100 ppm), β-caryophyllene and E-nerolidol (10 to 50 ppm) was performed according to WHO protocol against A. aegypti larvae. The GC-MS and GC-FID analysis of EOs from P. longepetiolatum and P. brachypetiolatum indicated the majority presence of β-caryophyllene (35.42%) and E-nerolidol (49.79%), respectively. The results showed that all natural products presented larvicidal activity against A. aegypti. In this aspect, the OE from P. brachypetiolatum (LC50 of 15.51 ppm and LC90 of 22.79 ppm) was more active than the OE from P. longepetiolatum (LC50 of 47.17 ppm and LC90 of 69.60 ppm) (p < 0.05). Regarding of main compounds, E-nerolidol (LC50 of 9.50 ppm and LC90 of 23.89 ppm) showed higher larvicidal activity than the β-caryophyllene compound (LC50 of 79.00 ppm and LC90 of 230.91 ppm) (p < 0.05). The larvae treated with these natural products showed tremors and lethargic movements, suggesting that these natural products have neurotoxic action. These observations support studies to investigate the mechanism of action. This is the first record of the chemical composition and larvicidal activity of the EO from P. longepetiolatum and P. brachypetiolatum rich in β-caryophyllene and E-nerolidol against A. aegypti larvae.

Keywords: piperaceae, aedes, sesquiterpenes, biological control

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Authors: Sajjad Shojaeidoust, Mohsen Ghanbarzadeh, Abdolhamid Habibi

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Exercise-induced bronchospasm (EIB) is a transitory condition of airflow obstruction that is associated with physical activities. It is noted that high ventilation can lead to an increase in the heat and reduce in the moisture in airways resistance of trachea. Also causes of pathophysiological mechanism are EIB. Accordingly, studying some parameters of pulmonary function (FVC, FEV1) among active people seems quintessential. The aim of this study was to analyze bronchospasm following the implementation of a program of maximum aerobic exercise in active men at Chamran University of Ahwaz. Method: In this quasi-experimental study, the population consisted of all students at Chamran University. Among from 55 participants, of which, 15 were randomly selected as the experimental group. In this study, the size of the maximum oxygen consumption was initially measured, and then, based on the maximum oxygen consumed, the active individuals were identified. After five minutes’ warm-up, Strand treadmill exercise test was taken (one session) and pulmonary parameters were measured at both pre- and post-tests (spirometer). After data normalization using KS and non-normality of the data, the Wilcoxon test was used to analyze the data. The significance level for all statistical surveys was considered p≤0/05. Results: The results showed that the ventilation factors and bronchospasm (FVC, FEV1) in the pre-test and post-test resulted in no significant difference among the active people (p≥0/05). Discussion and conclusion: Based on the results observed in this study, it appears that pulmonary indices in active individuals increased after aerobic test. The increase in this indicator in active people is due to increased volume and elasticity of the lungs as well. In other words, pulmonary index is affected by rib muscles. It is considered that progress over respiratory muscle strength and endurance has raised FEV1 in the active cases.

Keywords: aerobic active maximum, bronchospasm, pulmonary function, spirometer

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Authors: Abbasali Abouei Mehrizi, Hao Wang

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The thin film region is so important in heat transfer process due to its low thermal resistance. On the other hand, the dynamic contact angle is crucial boundary condition in numerical simulations. While different modeling contains different assumption of the microscopic contact angle, none of them has experimental evidence for their assumption, and the contact line movement mechanism still remains vague. The experimental investigation in complete wetting is more popular than partial wetting, especially in nanoscale resolution when there is sharp variation in thin film profile in partial wetting. In the present study, an experimental investigation of water film morphology near the triple phase contact line during the condensation is performed. The state-of-the-art tapping-mode atomic force microscopy (TM-AFM) was used to get the high-resolution film profile goes down to 2 nm from the contact line. The droplet was put in saturated chamber. The pristine silicon wafer was used as a smooth substrate. The substrate was heated by PI film heater. So the chamber would be over saturated by droplet evaporation. By turning off the heater, water vapor gradually started condensing on the droplet and the droplet advanced. The advancing speed was less than 20 nm/s. The dominant results indicate that in contrast to nonvolatile liquid, the film profile goes down straightly to the surface till 2 nm from the substrate. However, small bending has been observed below 20 nm, occasionally. So, it can be claimed that for the low condensation rate the microscopic contact angle equals to the optically detectable macroscopic contact angle. This result can be used to simplify the heat transfer modeling in partial wetting. The experimental result of the equality of microscopic and macroscopic contact angle can be used as a solid evidence for using this boundary condition in numerical simulation.

Keywords: advancing, condensation, microscopic contact angle, partial wetting

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Authors: Fangyuan Shao, Wei Liu, Deli Gao

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Polycrystalline diamond compact (PDC) bits have occupied a large market of unconventional oil and gas drilling. The application of PDC bits benefits from the efficient rock breaking of PDC cutters. In response to increasingly complex formations, many shaped cutters have been invited, but many of them have not been solved by the mechanism of rock breaking. In this paper, two kinds of PDC cutters: a new axe-shaped (NAS) cutter and cylindrical cutter (benchmark) were studied by laboratory experiments. NAS cutter is obtained by optimizing two sides of axe-shaped cutter with curved surfaces. All the cutters were put on a vertical turret lathe (VTL) in the laboratory for cutting tests. According to the cutting distance, the VTL tests can be divided into two modes: single-turn rotary cutting and continuous cutting. The cutting depth of cutting (DOC) was set at 1.0 mm and 2.0 mm in the former mode. The later mode includes a dry VTL test for thermal stability and a wet VTL test for wear resistance. Load cell and 3D optical profiler were used to obtain the value of cutting forces and wear area, respectively. Based on the findings of the single-turn rotary cutting VTL tests, the performance of A NAS cutter was better than the benchmark cutter on elastoplastic material cutting. The cutting forces (normal forces, tangential force, and radial force) and special mechanical energy (MSE) of a NAS cutter were lower than that of the benchmark cutter under the same condition. It meant that a NAS cutter was more efficient on elastoplastic material breaking. However, the wear resistance of a new axe-shaped cutter was higher than that of a benchmark cutter. The results of the dry VTL test showed that the thermal stability of a NAS cutter was higher than that of a benchmark cutter. The cutting efficiency can be improved by optimizing the geometric structure of the PDC cutter. The change of thermal stability may be caused by the decrease of the contact area between cutter and rock at given DOC. The conclusions of this paper can be used as an important reference for PDC cutters designers.

Keywords: axe-shaped cutter, PDC cutter, rotary cutting test, vertical turret lathe

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Authors: Yasir Arafat, Asma Shah, Hua Shao

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Background and Aims: Legume/cereal intercropping is used worldwide for enhancement in biomass and yield of cereal crops. However, because of intercropping, the belowground biological and chemical interactions and their effect on physiological parameters and yield of crops are limited. Methods: Wheat faba bean (WF) intercropping was designed to understand the underlying changes in the soil's chemical environment, soil microbial communities, and effect on growth and yield parameters. Experimental plots were established as having no root partition (NRP), semi-root partition (SRP), complete root partition (CRP), and their sole cropping (CK). Low molecular weight organic acids (LMWOAs) were determined by GC-MS, and high throughput sequencing of the 16S rRNA gene was carried out to screen microbial structure and composition in different root partitions of the WF intercropping system. Results: We show that intercropping induced a shift in the relative abundance of some genera of plant growth promoting rhizobacteria (PGPR) such as Allorhizobium, Neorhizobium, Pararhizobium, and Rhizobium species and resulted in better growth and yield performance of wheat. Moreover, as the plant's distance of wheat from faba beans decreased, the diversity of microbes increased, and a positive effect was observed on physiological traits and crop yield. Furthermore, an abundance and positive correlations of palmitic acid, arachidic acid, stearic acid, and 9-Octadecenoic with PGPR were recorded in the root zone of WF intercropping, which can play an important role in this facilitative mechanism of enhancing growth and yield of cereals. Conclusion: The two treatments clearly affected soil microbial and chemical composition, which can be reflected in growth and yield enhancement.

Keywords: intercropping, microbial community, LMWOAs, PGPR, soil chemical environment

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Authors: Shamim Ahsan

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Abstract Global digital advances associated with consumer’s strong inclination for the state of art digital technologies is causing overwhelming social and environmental challenges for global community. During recent years not only economic advances of electronic industries has taken place at steadfast rate, also the generation of e-waste outshined the growth of any other types of wastes. The estimated global e-waste volume is expected to reach 65.4 million tons annually by 2017. Formal recycling practices in developed countries are stemming economic liability, opening paths for illegal trafficking to developing countries. Informal crude management of large volume of e-waste is transforming into an emergent environmental and health challenge in. Contrariwise, in several studies formal and informal recycling of e-waste has also exhibited potentials for economic returns both in developed and developing countries. Some research on China illustrated that from large volume of e-wastes generation there are recycling potential in evolving from ∼16 (10−22) billion US$ in 2010, to an anticipated ∼73.4 (44.5−103.4) billion US$ by 2030. While in another study, researcher found from an economic analysis of 14 common categories of waste electric and electronic equipment (WEEE) the overall worth is calculated as €2.15 billion to European markets, with a potential rise to €3.67 billion as volumes increase. These economic returns and environmental protection approaches are feasible only when sustainable policy options are embraced with stricter regulatory mechanism. This study will critically review current researches to stipulate how global e-waste generation and sustainable e-waste recycling practices demonstrate future economic development potential in terms of both quantity and processing capacity, also triggering complex some environmental challenges.

Keywords: E-Waste, , Generation, , Economic Potential, Recycling

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Authors: Szu-Chieh Yu, Pei-Chin Chiand, Chih-Yi Lin, Yi-Wen Chien

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UV radiation from sunlight cause numbers of acute and chronic skin damage which can result in inflammation, immune changes, physical changes and DNA damage that facilitates skin aging and the development of skin carcinogenesis. Reactive oxygen species (ROS) are generated by excessive solar UV radiation, resulting in oxidative damage to cellar components, proteins, lipids, and nucleic acids. Thus, antioxidation plays an important role that protects skin against ROS-induced injury. Safflower (Carthamus tinctorius L.) is an important Chinese medicine contained abundance flavones and hydroxysafflor yellow A (HSYA) which is main active ingredient. HSYA is part of quinochalcone and has unique structures of hydroxy groups that provided the antioxidant effect. In this study, the aim was to investigate the protective role of HYSA in human keratinocytes (HaCaT) against UVA-induced oxidative damage and the possible mechanism. The HaCaT cells were UVA-irradiated and the effects of HYSA on cell viability, reactive oxygen species generation, DNA fragmentation and lipid peroxidation were measured. The mRNA expression of matrix metalloproteinase Ι (MMP Ι), cyclooxygenase-2 (COX-2) were determined by RT-PCR. In this study, UVA exposure lead to decrease in cell viability and increase in reactive oxygen species generation in HaCaT cells. HYSA could effectively increase the viability of HaCaT cells after UVA exposure and protect them from UVA-induced oxidative stress. Moreover, HYSA can reduce inflammation through inhibition the mRNA expression of MMP Ι and COX-2. Our results suggest that HSYA can act as a free radical scavenger while keratinocytes were photodamaged. HYSA could be a useful natural medicine for the protection of epidermal cells from UVA-induced damage and will be developed into products for skin care.

Keywords: HaCaT keratinocytes, hydroxysafflor yellow A (HSYA), MMP Ι, oxidative stress

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