264 research outputs found
An Alcohol Dehydrogenase Gene from Synechocystis sp Confers Salt Tolerance in Transgenic Tobacco
No full textSynechocystis salt-responsive gene 1 (sysr1) was engineered for expression in higher plants, and gene construction was stably incorporated into tobacco plants. We investigated the role of Sysr1 [a member of the alcohol dehydrogenase (ADH) superfamily] by examining the salt tolerance of sysr1-overexpressing (sysr1-OX) tobacco plants using quantitative real-time polymerase chain reactions, gas chromatography-mass spectrometry, and bioassays. The sysr1-OX plants exhibited considerably increased ADH activity and tolerance to salt stress conditions. Additionally, the expression levels of several stress-responsive genes were upregulated. Moreover, airborne signals from salt-stressed sysr1-OX plants triggered salinity tolerance in neighboring wild-type (WT) plants. Therefore, Sysr1 enhanced the interconversion of aldehydes to alcohols, and this occurrence might affect the quality of green leaf volatiles (GLVs) in sysr1-OX plants. Actually, the Z-3-hexenol level was approximately twofold higher in sysr1-OX plants than in WT plants within 1-2 h of wounding. Furthermore, analyses of WT plants treated with vaporized GLVs indicated that Z-3-hexenol was a stronger inducer of stress-related gene expression and salt tolerance than E-2-hexenal. The results of the study suggested that increased C-6 alcohol (Z-3-hexenol) induced the expression of resistance genes, thereby enhancing salt tolerance of transgenic plants. Our results revealed a role for ADH in salinity stress responses, and the results provided a genetic engineering strategy that could improve the salt tolerance of crops.
© 2017 Yi, Ku, Sim, Kim, Park, Lyu, So, Choi, Kim, Ahn, Kim, Park,
Jeong, Lim, Min and Liu. This is an open-access article distributed under the terms
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Arch structure concept in lightweight fill design
No full textConstruction of road embankment over soft soilscan cause significant non uniform excessive settlements that contribute touneven road surfaces. This is due to the properties of softsoil which havelow shear strength, high water content and high compressibility. These properties of soil are quite difficult and challenging to work with. This researchisfocusedon how to mitigate the non-uniform settlement of embankments on soft soil using an innovativearch structure concept design incorporating with thecurrent construction methodof expanded polystyrene (EPS)aslightweight fill material. EPS are lightweight fill materials which are low density,stable, inert, environmentally safe fillrigid mats for road construction.However, they are large bulky blocks and have high buoyancy characteristics which will be unstable when high water table arises. The arch structure design reduces the use of EPS block while achieving almost the same performance as the conventional design. Physical modelling is used in thisresearch to analyse the performance of this conceptual arch structureusing a test box, sandy soilas embankment andwooden blocks as EPS. The concept of arch structure is implemented by removing some of the blocks at the base and setting up three different layout arrangement ofspacing and thickness of the blocks which are called mixed staggering (a), mixed staggering (b) and lateral staggering. The performance of the design was measured by analyzing the settlement of the three arrangement layouts. The settlement observed was monitored photographically and measured with markings labelled on the test box. Itwas found that the layouts of mixed staggering (b) have is proven to reducethe excessive non-uniform settlements compared to the lateral staggering and mixed staggering (a). Hence, this research has established a suitable design guideusing a mixed staggering arch structurefill materialwhich is light and strong to withstand heavy loading toreduce ground settlement
Predictive direct power control for dual-active-bridge multilevel inverter based on conservative power theory
No full textThis paper explores the feasibility of multilevel dual-active bridge-inverter (DABMI) applications for grid-connected applications of a modern Model of Predictive Direct Power Control (MPDPC) based on the conservative power theory (CPT). In the case of unbalanced grid voltages, the objective of the study is to promote continued active and reactive energy in MPDPC without reducing effciency such as transient response and current harmonics. The nature of the instantaneous p-q theory permits only one out of three control targets to be fulfilled. The proposed control approached directly regulates the instantaneous active and reactive power to achieve three particular control objectives namely sinusoidal and symmetrical grid current, cancelling twice of fundamental grid frequency reactive power ripples, and removing twice grid frequency active power ripple. The techniques of complicated Grid part sequence extraction are unnecessary and improved at no extra expense, as is the case with current MPDPC fault-tolerant approaches. The instantaneous power at the next sampling instant is predicted with the newly developed discrete-time model. Each possible switching state will then be evaluated in the cost function defined until the optimal state which lead to the minimum power errors is determined. In MATLAB/Simulink simulation, the proposed CPT-based MPDPC measures reliability and performance at balanced and unbalanced grid voltages then compared with the conventional and existing MPDPC The proposed method manages to achieve all of three control targets which generates sinusoidal grid currents and attenuates active and reactive power ripple of twice the grid frequency exactly at the same time without losing its critical effciency including transient reaction and current harmonics
A simple disc wind model for broad absorption line quasars
No full textApproximately 20 per cent of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disc winds. These winds may represent the ‘quasar’ mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disc wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line (BAL) QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, and the wind does not yet produce collisionally excited line emission at the level observed in non-BAL QSOs. As a first step towards addressing these shortcomings, we discuss the sensitivity of our results to changes in the assumed X-ray luminosity and mass-loss rate, Ṁwind. In the context of our adopted geometry, Ṁwind ∼ Ṁacc is required in order to produce significant BAL features. The kinetic luminosity and momentum carried by such outflows would be sufficient to provide significant feedback
The etiology of esophageal cancer in high- and low- risk areas of Jiangsu province, China
No full text [Background]Esophageal cancer (EC) remains one of the most common and fatal malignancies worldwide. The geographic variation in EC occurrence is striking, and China is an area with one of the highest incidences of EC. A number of epidemiological studies have been conducted toward EC in the past decades, results suggested that tobacco smoking, alcohol drinking, unhealthy dietary factors and chronic injuries of the esophageal mucosa are important in the development of this disease. Genetic polymorphisms in enzymes involved in metabolism of carcinogens may also influence individual susceptibility. However, the effects of major lifestyle and hereditary risk factors on the development of EC remain poorly understood in China. Moreover, little attention has been paid to the etiological heterogeneity between similar areas with great risk gradient. [Methods]From 2003 to 2007, a large population-based case-control study of EC has been conducted in a selected high-risk area and a selected low-risk area of Jiangsu Province, one of the highest cancer incidence areas in China. In total, 1,520 cases and 3,879 controls were recruited. In this thesis, we evaluated the role of major lifestyle factors such as tobacco smoking, alcohol drinking and dietary factors, as well as inherited determinants including family history of cancer and genetic polymorphisms of alcohol-metabolizing related genes on the risk of EC. In addition, we investigated how much of the risk gradient between two areas could be explained by variation in the distributions of major risk factors. [Results] Tobacco smoking and alcohol drinking moderately increased the risk of EC, while the positive associations were only found among men but not among women. Dietary factors were observed to play important roles in the development of EC. Specific dietary habits i.e., fast eating speed, and hot eating and/or drinking substantially elevated EC risk and could explain more than 20% of EC cases each. High intake of salty foods and fried foods, low consumption of raw garlic were also observed to increase the risk of EC. In addition to environmental and lifestyle factors, we confirmed that a positive family history can significantly increase EC risk, and found the inheritance may modify the effect of some unhealthy lifestyles. Moreover, we further explored the relationship between EC and single nucleotide polymorphismsof ADH1B, ADH1C and ALDH2 genes. Results showed that the slow metabolizing ADH1B G allele, ADH1C G allele and ALDH2 A allele significantly increased EC risk among moderate-to-heavy alcohol drinkers, and a significant interaction was observed between ALDH2 gene and alcohol consumption. Lastly, we found that more than 60% of EC cases could be attributable to major lifestyle risk factors in the study population; furthermore, dissimilar distribution of several lifestyle factors, together with variations of hereditary factors may be largely responsible for the incidence difference between two study areas. [Conclusion]The findings in this thesis confirm that unhealthy lifestyles including smoking, alcohol drinking and some dietary factors are the predominant risk factors of EC in China, and a large proportion of incidence difference between regions at varying risk could be attributed to the different prevalence of lifestyle factors. As most of the identified risk factors are modifiable, these could be translated into risk reduction prevention programs in China, and a substantial proportion of new EC cases are expected to be prevented by eliminating or avoiding these risk factors in the population. </p
族群意识与经济社会的重塑 ：讲华语运动作为文化资本 = Reconstruction of race consciousness and socioeconomic status : speak Mandarin campaign as cultural capital
No full text新加坡的讲华语运动自从1979年开始至今，是国家持续最久的运动之一。在这43年里，讲华语运动的对象和焦点不停地改变，再加上华人优势/特权的言论，本论文将探讨两者之间的关系。本文将运用布尔迪厄的资本理论框架并以讲华语运动的开幕典礼演讲和部长的言论为主要文本，理解新加坡的种族和经济社会地位是如何遭受讲华语运动的重新塑造。
关键词：讲华语运动、族群意识、经济社会地位、文化资本、华人优势、华人特权
The Speak Mandarin Campaign is one of Singapore’s longest-running state campaigns since 1979. In these 43 years, the target audience and focus of the Campaign has been evolving and with the contention of Chinese Privilege, this paper seeks to discuss the relationship between the two. This paper will adopt Bourdieu’s Capital Theory, to understand how the races and socioeconomic statuses are reconstructed, through the Speak Mandarin Campaign promotional materials as text.
Keywords: Speak Mandarin Campaign, Race Consciousness, Socioeconomic Status, Cultural Capital, Chinese Advantage, Chinese Privilege Bachelor of Arts in Chines
Power forecasting from solar panels using artificial neural network in UTHM Parit Raja
No full textThis paper presents a step-by-step procedure for the simulation of photovoltaic modules with numerical
values, using MALTAB/Simulink software. The proposed model is developed based on the mathematical model of
PV module, which based on PV solar cell employing one-diode equivalent circuit. The output current and power
characteristics curves highly depend on some climatic factors such as radiation and temperature, are obtained by
simulation of the selected module. The collected data are used in developing Artificial Neural Network (ANN)
model. Multilayer Perceptron (MLP) and Radial Basis Function (RBF) are the techniques used to forecast the
outputs of the PV. Various types of activation function will be applied such as Linear, Logistic Sigmoid,
Hyperbolic Tangent Sigmoid and Gaussian. The simulation results show that the Logistic Sigmoid is the best
technique which produce minimal root mean square error for the system
An expanded optimal control policy for a coupled tanks system with random disturbance
No full textIn this paper, an expanded optimal control policy is proposed to study the coupled tanks system, where the random disturbance is added into the system. Since the dynamics of the coupled tanks system can be formulated as a nonlinear system, determination of the optimal water level in the tanks is useful for the operation decision. On this point of view, the coupled tanks system dynamics is usually linearized to give the steady state operating height. In our approach, a model-based optimal control problem, which is adding with adjusted parameters, is considered to obtain the true operating height of the real coupled tanks system. During the computation procedure, the differences between the real plant and the model used are measured repeatedly, where the optimal solution of the model used is updated. On this basis, system optimization and parameter estimation are integrated. At the end of the iteration, the iterative solution approximates to the correct optimal solution of the original optimal control problem, in spite of model-reality differences. In conclusion, the efficiency of the approach proposed is shown
Development of Appropriate Power Distribution Design for Can-Sized Satellite (CANSAT)
No full textCan-sized satellite (canSAT) is a small satellite that is used for educational purpose. CanSAT offer student to build their satellites with their creativity which make the learning process more effective. In Malaysia, SiswaSAT is held by the Malaysia Space Agency for students in different categories to participate and build their satellites according to rules set and it should be a low-cost project. CanSAT can be divided into few parts which are communication system, onboard data acquisition, ground control station and power system. The power system is one of the important and heaviest subsystems, it needed to supply power, but weight and size are one of the main concerned as the canSAT should not exceed the required weight and selecting power supply that is matched with the overall power budget that has small size and lightweight is challenging. Therefore, the power supply selection should consider this detail. The power distribution design should be able to supply an appropriate amount of current and voltage to the components according to their specification. This study aims to develop and test the proposed prototype which is named ScoreSAT able to provide data and have enough power supply for the whole operation. Therefore, an initiative to develop the appropriate power distribution design for canSAT is taken to overcome the problem of the power system. Moreover, each subsystem needs to be tested by obtaining the results from the onboard data acquisition and transmit the data using the communication system before integrating into the power system. ScoreSAT prototype needs to carry the system that is mounted inside, thus the space inside the prototype needs to be fully utilized for the whole system to fit in. ScoreSAT completes the mission by obtaining data acquisition during the operatio
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