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Improving the quality of tissue-cultured plants by fixing the problems related to an inadequate water balance, hyperhydricity.
No full textIn vitro tissue culture is a technique for producing amongst others high numbers of uniform plants. This technique is excellent for accelerating plant propagation and establishment and supplying high quality starting material which can have a positive impact on product commercialization. Also for breeding purposes tissue culture techniques are indispensable for instance for the establishment of plants from embryos rescued from intra- or interspecific crosses or for the production of doubled haploids and genetically modified plants after transformation. Several obstacles may occur during the culture process, one of which is hyperhydricity (HH). HH is a serious problem since it can affect shoot development, the survival and the quality of micropropagated plants after transfer to ex vitro
conditions. Hyperhydric shoots are characteri ed by a high water content which causes several morphological abnormalities e.g. curled, brittle, wrinkled, elongated petioles and/or translucent leaves. Hyperhydric shoots can display a range of changed anatomical characteristics and several types of abnormal structures can be recognized. Understanding the underlying mechanisms and factors involved in the control of plant growth in vitro can greatly improve the quality of micropropagated plants. In the present study, quantitative and qualitative physiological, anatomical and biochemical analyses were carried out in normal and hyperhydric Arabidopsis thaliana and
Limonium sinuatum (Statice) in vitro grown plants. To elucidate factors which may regulate the occurrence of HH, the effects of
medium components like cytokinin (CK) and gelling agents were evaluated using two different Arabidopsis thaliana ecotypes (Col-0 and Ler; Chapter 2). Our results indicated that CK concentration and type and gelrite-solidified medium induced HH. The effects of these were more accumulation of water in the apoplast which caused stomatal closure, higher water retention capacity and declining transpiration in the seedlings compared to their corresponding controls. We found that the application of CK to the medium increased the chance of HH development, with the phenylurea-type CK being worse than the adenine-type CK. Furthermore, we looked at histological and ultrastructural patterns of hyperhydric leaves to identify the changes promoted by this phenomenon and found a disorganized cellular organization and large intercellular spaces in the HH leaves. The water availability of the medium was changed by lowering or raising the concentration of gelling agent and this was found to be of great influence on the level of HH. The results showed that media components were one of the most critical factors of HH. No significant differences in HH symptoms or development were observed between the two Arabidopsis thaliana ecotypes Observations of stomatal closure and apoplast flooding in previous studies prompted us to investigate whether these processes are linked and which of them comes first and might be the true cause of HH in Arabidopsis (Chapter 3). We evaluated the response patterns of stomatal characteristics by examining the effect of plant growth regulators such as the stomatal aperture enhancers, 5-Aminolevulinic acid (ALA) and coronatine, and the stomatal closure inducer salicylic acid (SA) as well as by using mutants affected in stomatal characteristics and transpiration rate. Exogenously applied ALA significantly inhibited stomatal closure and decreased the symptoms of HH. However, another enhancer of stomatal opening, coronatine, caused extensive anthocyanin formation in the seedlings as an indication for enhanced stress and the leaves of plantlets treated with this compound were found to accumulate more apoplastic water, even while stomata were still open. SA application as a compound known to induce stomatal closure, resulted in severe hyperhydric seedlings. Combining ALA together with CK showed HH symptoms and apoplast flooding, accompanied by stomatal closure and a decline in transpiration rate, albeit to a lesser extent than on gelrite alone. We could confirm these findings in the Arabidopsis stomatal density mutants, epidermal patterning factor1 (epf1) and four lips (flp) and found HH symptoms on
the seedlings of these mutants even on Micro-agar. Taken together, this indicated that stomatal closure was not the causal factor of HH but when observed, it was a consequence
of apoplast flooding leading to HH. In order to determine the fundamental reason for the occurrence of the HH phenomenon and to investigate the hypothesis that CK could affect the characteristics of the cell walls bordering the intercellular spaces, thus influencing HH, we exogenously applied
p-coumaric acid, a hydroxyl derivative of cinnamic acid and a precursor for lignin and flavonoids, to gelrite medium (Chapter 4). Exogenously applied p-coumaric acid to Arabidopsis thaliana wild-types, Ler and Col-0, led to increases in apoplastic air and
lowering of apoplastic water in seedlings grown on medium solidified with gelrite. Application of p-coumaric acid on Arabidopsis less-lignin-mutants ref 3-3 and ref 3-1 resulted in the same pattern; more apoplastic air and less water which confirmed the role of lignin in HH. Moreover, the results revealed that exogenously applied p-coumaric acid inhibited root growth and increased the total lignin content in both wild-types and less-lignin mutants. We conducted additional experiments to mimic the C4H mutants (ref3) by culturing control seedlings with piperonylic acid (PIP, a specific inhibitor of C4H) on Micro-agar medium in order to prove that lignin plays a central role in HH. The results showed that the seedlings developed HH symptoms accompanied by significant increases in the percentage of apoplastic water and concurrent decreases in the percentage of apoplastic air. In fact, the seedlings after PIP treatment also demonstrated a reduction in total lignin when compared to the control treatment without PIP. Cellular disorganization and cell wall defects were observed in transverse sections of Arabidopsis less-lignin-mutant and Arabidopsis seedlings treated with PIP. Based on our results, we postulate that these cellular deficiencies with large intercellular spaces (ICs) and little lignin deposition are responsible for rendering the apoplast more hydrophilic and together with the effect of higher root pressure and high relative humidity in the headspace eventually cause HH. Increasing lignin content appeared to diminish the symptoms of HH and suggests an important role for lignin in HH. In Chapter 5, we determined the effect of calcium (Ca2+) in preventing the occurrence of HH. Applying exogenous Ca2+ reduced the amount of apoplastic water and increased the amount of apoplastic air. We confirmed the effect of Ca2+ in reducing HH, by demonstrating that culturing the seedlings on Micro-agar medium without Ca2+ resulted in HH symptoms. This result showed that Ca2+ has a direct effect on preventing or reducing HH. Exogenously applied Ca2+ led to increases in internal ion levels of Ca2+, Cl-, and NO3
-. Correlation analysis showed Ca2+ to be significantly positively correlated with the lignin content. Moreover, we looked at the effect of Ca2+ to another component of the cell wall, namely pectin in Arabidopsis wild-type Col-0 and a less-pectin mutant (gae 6-1). Addition of Ca2+ to the medium increased total pectin content further and decreased PME activity in both genotypes. The studies of cell wall lignin, pectin and PMEs in relation with Ca2+ will help to elucidate the biochemical processes induced by the physiological state of HH. In Chapter 6, we validated the critical factors in the development of HH by investigating the roles of water retention and lignin levels. We hypothesized that capillary action might be the underlying mechanism involved in water translocation and thus might be a critical factor in development of HH. Our results showed that addition of a surfactant (Tween 20®) to the medium induced HH on Arabidopsis thaliana wild-type Col-0 in vitro seedlings. The present research showed that seedlings cultured in liquid medium led to the development of HH and an inhibition of lignin synthesis (which resulted in lower lignin content); all in line with our previous findings with seedlings grown on gelrite (Chapter 4). In order to extend further the evidence for the role of lignin on HH, we examined phenylalanine ammonia-lyase (PAL) activity and found that in hyperhydric leaves PAL activity was significantly decreased compared to normal leaves. Moreover, we observed by histochemical staining using Toluidine Blue O that the development of epidermis and cuticle on hyperhydric leaves was seriously affected in a negative way. Earlier, several individual compounds were identified that could mitigate the negative effect of culture on gelrite. Based on these results, we decided to combine three of those compounds and found that together they compensated the generally negative effect of adding CK to gelrite medium, thereby reducing the symptoms of HH in Arabidopsis seedlings. Extrapolating and validating the
beneficial effect of Ca(NO3)2 in Arabidopis seedlings we studied another crop, Limonium sinuatum (Statice), and showed a reduction in HH and an increase of lignin production when applying Ca2+ to in vitro cultures of this ornamental plant. In Chapter 7, the main achievements of this study are discussed and directions for future experiments are mentioned and highlighted
SIZE-DEPENDENT GRAPHENE OXIDE AND NICKEL-COBALT/GRAPHENE OXIDE HYBRID COATINGS FOR CORROSION PROTECTION
No full textCorrosion is an inevitable phenomenon especially when a metal is exposed to a corrosive environment. Owing to the impermeability, high hardness, and hydrophobicity of graphene, there is a growing demand for the developments of graphene-based coatings. However, it is reported that graphene might induce galvanic corrosion due to its high conductivity. As an alternative, graphene oxide (GO) is used for the coating. Therefore, in this study, corrosion protection coating has been
developed from different size GO sheets. Then, the surface of the small-sized GO coating was adapted to the nickel-cobalt (Ni-Co) nanoparticles to form a Ni-Co/GO hybrid coating. The hybrid coatings were made using the second-step electrodeposition method at different periods of deposition (50, 200, 400 and 600 s). It is observed that the size of the GO sheets obtained from ultrasonication at 1,3, 5, 7, and 10 h varied
from 297 to 103 nm as a function of time and the changes in the it-n electronic transition was observed using UV-visible spectrophotometer (UV-Vis). During longer ultrasonication time, the GO sheets fragmented, and some of the oxygen functional
groups were removed as showed in the reduction of the d-spacing (measured by X-ray diffraction). It was found that at 10 h of ultrasonication, the GO sheets tend to restack and caused a slight increment in the lateral size as observed using Transmission electron microscopy. The GO suspension with various sheets sizes were further electrophoretically deposited (EPD) onto the copper (Cu) substrates. After EPD, the
structural and morphological properties of the coatings were examined using Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. It was found that coating from 7 h suspension (7h-
GO/Cu) exhibited lowest oxygen-related band at 0.36, the thin and smooth film with a thickness of 1.52 pm and surface roughness, Ra of 26.41 nm. A higher value of Id/Ig ratio, water contact angle, and Rockwell hardness was observed at 1.35, 91.4°, and 50.6, respectively. The corrosion performance of the coatings was measured using Tafel plots and electrochemical impedance spectroscopy (E1S). It was found that the corrosion
potential, ECOtr was shifted towards a positive position at -0.154 V, lower corrosion current, 7Con-at 0.0788 pA/cm2 and corrosion rate (CR) of 0.91x10’3 mm/yr. Detailed EIS analysis showed that the coating from smaller GO sheets size exhibited lower water permeation into the coating due to higher surface activation energy. Meanwhile, the hybrid coatings exhibited higher nickel (II) hydroxide, Ni(OH)z (28.8 wt%) and cobalt
(II) hydroxide, Co(OH)2 (66.3 wt%) compositions as compared to the pure Ni-Co coating when measured using X-ray photoelectron spectroscopy. The morphological and elemental study using field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed that the Co content increase as the deposition time increased. The hybrid coating formed at 400 s of electrodeposition time shows
significant improvement in the ECOn and IC0Tr at -0.165 V and 0.039 pA/cm2, respectively. The CR was found to be 0.45x10’3 mm/yr, and it shows 2-times magnitude lower than the 7h-GO/Cu while -36.9 times lower than the CR for pure Ni-Co coating
THE MODERATING ROLE OF RELIGIOSITY ON THE RELATIONSHIP BETWEEN FACTORS AFFECTING JOB PERFORMANCE
No full textThis study of employee performance in four main industries in Malaysia was conducted with three main objectives : first, to investigate the relationship between working environment, work-family culture, integrity, sexual harassment awareness,
and employee job performance among workers in four industries in Malaysia, namely manufacturing, hospitality, education and public administration industries; second to determine the role of religiosity as a moderator in the relationship between working environment, work-family culture, integrity, sexual harassment and employee job performance; and third to determine the effects of demographic factors
such as age, gender, religion and marital status on employee job performance. Result of analysis in this study supported that working environment, integrity, and sexual harassment awareness were positively related to employee performance while work family culture and religiosity were have negative relationships towards employee job performance. The religiosity as moderator in this study resulted as not have any moderating effect between working environment, work-family culture, integrity, and sexual harassment and employee performance. The results of this study were considered as crucial to be looked into so that management team and employers
could have ample understanding and guidelines if they were to draft strategies for enhancement employee performance
Effect Of Motivational Music On Rating Of Perceived And Heart Rate Recovery In High Intensity Interval Training
No full textInterval training can induce physiological and health-related adaptations similar to those of traditional moderate-intensity continuous exercise, yet with reduced time commitment.
Music was proven to reduce the rating of perceived of exertion in moderate steady state of exercise but lack of data in high intensity interval training. It is important to investigate
how motivational music affect rating of perceived exertion and cardiorespiratory changes such as heart rate recovery to the body in high intensity interval training. This study aims
to investigate the effect of motivational music on cardiorespiratory response and rating of perceived exertion in high intensity interval training (HIIT). Eighteen (18) healthy
adults were recruited for the purpose of this study. The participants underwent HIIT protocol with music and non-music. The cardiorespiratory response and rating of perceived exertion were recorded after each HIIT session. Results showed that those underwent HIIT with music had lower rating of perceived exertion with mean 11.6 to 13.9 at end of test compared to non-music with mean 10.8 to 12.8 and the results were statistically significant (p<0.05). As for the heart rate recovery, lowest reading was recorded at 2min, followed by 1min and 0 min. Lower heart rates were also recorded with music compared to no music for all time interval. However, the results were not
statistically significant (p>0.05) for all readings. In conclusion, this study showed rating of perceived exertion during high intensity interval training can be reduced by motivational music played during the exercise
A TEMPLATE-BASED APPROACH TO WRITE COMPLETE SECURITY REQUIREMENTS FOR SOFTWARE DEVELOPMENT ENVIRONMENT
No full textWriting quality security requirements contributes to the success of secure software development. It has been a common practice to include security requirements in a software system after the system is defined. Thus, incorporating security requirements at a later stage of software development will increase the risks of security vulnerabilities in software development. However, the process of writing security requirements is tedious and complex. There are a few gaps found in the existing works, categorized into method-related and people-related issues. The method-related issues include the lack of checking on security requirements completeness, security requirements templates, security standards used as reference and automated tool for validation. While, the people-related issues consist of inexperienced requirements engineers, minimal involvement of technical team in defining security requirements and language barriers. Motivated from these gaps, the main objective of this study is to propose a template-based approach to write complete security requirements. This study proposes a new template-based approach to assist the requirements engineers and client-stakeholders for writing complete security requirements. For this, we integrate the template-based approach with security requirements density using probability ratio, syntax-based density using lexical density and security requirements completeness prioritization using numerical assignment. We also developed two new pattern libraries, SecLib and SRCLib to validate the syntax and the completeness of security requirements. Additionally, an automated tool support called SecureMEReq was also developed to realize the approach. Finally, a comprehensive evaluation of the approach, comprising the comparison study between manual and automated tool as well as usability test were conducted. In summary, the findings of the evaluations show that our approach can contribute to the body of knowledge of requirements engineering, especially in enhancing the completeness of writing security requirements. It is found that the approach is able to enhance the completeness level of security requirements compared to the manual approach and produce a complete generation of security requirements. The results of the usability tests show that the approach is useful and helpful in eliciting complete security requirements of software development and able to ease the security requirements elicitation process
HOLISTIC MULTI-METHODS APPROACH IN THE INVESTIGATION OF ENVIRONMENTAL AND RESTORATIVE FUNCTIONS OF COURTYARD GARDENS IN MALAYSIA PUBLIC HOSPITALS
No full textThe introduction of the hospital courtyard garden (HCG) in Malaysia can be traced as early as the 1970s. To date, it is still incorporated in the current planning of newly built hospitals.
However, their design quality is yet to be systematically evaluated and no specific framework or design guidelines or evaluation criteria exist to assess HCGs with a focus on the integration of the environmental and restorative functions. Therefore, this study aimed to investigate how the different types of courtyard gardens that have been included in the
planning of Malaysian hospitals after 1998 are currently performing in relation to the environmental and restorative functions and how they are used and perceived by the intended users (i.e. patients, staff and visitors). This study also explored how the HCG can be improved to achieve an optimal HCG design to enhance the users’ experiences in the hospital.
A representative sample of three different HCGs in three Malaysian public hospitals were selected to systematically evaluate them with a particular focus on users’ perceptions,
preferences, experiences and level of satisfaction with the overall HCG design concerning the environmental and restorative functions. To achieve the aim and research objectives, this study employed a mixed methods and case study approach through the intervention of a diagnostic post-occupancy evaluation (POE) which included multiple methods,
namely, i) field observation (site analysis and field measurement); ii) participant observation and behaviour mapping; iii) survey interview with the HCG users (n=120) and non-users (n=135); and iv) semi-structured interviews with the architects (n=2) and landscape architects (n=2).
Regarding the environmental performance of the HCG, the findings revealed that a proper consideration of both environmental and restorative functions resulted in improved thermal comfort in the HCG and adjacent spaces. The findings also showed that the air temperature in the HCG were found to be several degrees lower than the corresponding air temperature outside the hospital during the day. In terms of restorative functions, this study found that the HCG with a proper combination of landscape elements (a ratio of 70:30 for softscape and hardscape) received a higher restorative score compared to the HCG with a lower percentage of softscape (less than 40%). HCGs also has a significant influence on users’ well-being; the study revealed that over 75% of the 120 users perceived a positive mood change and felt more relaxed and less stressed whilst spending time there.
Additionally, based on a total of 48-hours of the video-based and direct observation on both a weekend and a weekday, this study found that all the three HCGs were most used by visitors (72% adult and 22% children), followed by staff (4%) and patients (2%). A Chi-square analysis on users’ satisfactions levels revealed the four most significant factors with the overall planning of the HCG: i) landscape elements (pc.OOO, C=.442); ii) wall conditions (p<.000, C=.429); iii) access from the main entrance (p<0.04, C=.393); and iv) visibility (p< 000, C=.382).
Based on the overall research findings gathered from difference source of data, this research has contributed to the establishment of a comprehensive HCG framework for a Malaysian climatically context which comprised of four interrelated components; i) physical; ii) environmental; iii) social; and iv) operational aspect. The study also has successfully provided recommendations for policy and practice related to the functional and spatial arrangement of HCGs to assist in reviewing and updating the planning and design requirements for optimal HCG design in future
MANAGING CO-PRODUCTION IN A SERVITIZATION CONTEXT AN ANALYSIS OF THE ROLES OF CONTRACTING
No full textThe essence of the transition process from a pure manufacturing firm towards servitization is the shift from selling the product alone to selling an integrated product and services package. This process entails significant co-production activities with the customer. To date, little empirical research has been conducted to examine how the servitized manufacturer manages the roles and responsibilities of the customer to enable effective service delivery through
contractual perspective. The objectives of this research are twofold: firstly, to understand and explain how contractual governance shape the specifications of customer's roles and
responsibilities in service delivery and secondly, to understand the process of co-production with the customer in service delivery after contract stipulation. As the nature of this research is exploratory, a multiple case study approach was deployed to
enable an in-depth investigation of the issues. This study draws on five case studies, representing the three types of servitization (product-oriented services, use oriented services
and result-oriented services). The analyses of how the contractual mechanism was used to shape the customer's roles and how the process of co-production activities in service delivery takes place after contract stipulation were based on 35 semi-structured interviews, a review of 493 documents including contracts and 277 email exchanges. The findings of the study show that contractual governance features mainly in shaping the specifications of customer's roles and responsibilities in service delivery. This research contributes to the literature by providing empirical evidence of the importance of contractual governance in shaping customer roles and responsibilities. Equally important, with the use of the Process Chain Network (PCN) diagram, this study provides insight into how servicedelivery in the servitization context is co-produced with the customer after contract stipulation. Therefore, it is argued that identifying the elements of co-production activities
that require significant interactions between service provider and customer is crucial when designing effective contract provision
A Modified Location Housing Affordability Index of Low and Middle Income Households Urban Areas Of Malaysia
No full textGlobally, affordability is vital for the housing market. During the past few years, urban housing in Malaysia has inclined towards severely unaffordable prices. Housing affordability is to ensure that houses offered are affordable for every income groups, especially the low and middle-income households. If the location is included as part of housing affordability criteria, can house affordability be changed? When location is
taken into consideration, would housing affordability be different between two income households? The definition together with the quantifying of housing affordability uses household income, and housing expenditure has disregarded transportation expenditure which forms a substantial amount of household expenditure. There are needs to include location as part of the housing affordability. Location of housing project will ultimately influence transportation expenditure. This research aims to determine the housing affordability by applying a simplified Location Housing Affordability Index on low and middle income households in urban areas of Klang Valley. The scope and limitation of the research are within low and middle income households’ housing and transportation expenditure and relate the housing affordability to location. This research quantitatively
examines three urban areas within the Klang Valley which are Kerinchi, Subang Bestari and Putra Heights, selected based on their distances to Kuala Lumpur as an employment centre. By combining both housing and transportation affordability, a simplified Location Housing Affordability equation has been created to indicate the housing affordability of 434 respondents from low and middle-income households answering a questionnaire survey from the selected urban areas. Using PLS-SEM, this research has identified a relationship between the household income, housing expenditure and transportation expenditure with Location Housing Affordability Index. The findings suggest that the overall location of the urban areas in Malaysia for the low and middleincome households is very unaffordable. In the same time, the finding also suggest that an urban area near (Kerinchi) to employment centre is deemed to be affordable, for intermediate (Subang Bestari) and further (Putra Height) from employment centre are very unaffordable. The recommendation is to propose a simplified equation of the
Location Housing Affordability Index as a measuring tool to determine housing affordability in Malaysia. Furthermore, it recommends enhancing housing rental market close to employment centres in relation to location and transportation expenditure. Moreover, the impact of location on housing expenditure needs to be included in the calculation of affordable housing
Investigating the Functional Interaction between RhoGDI Family Proteins and Activated Cdc42 associated-kinase (ACK)
No full textACK is a non-receptor tyrosine kinase and an effector protein for Cdc42. ACK has been implicated in carcinogenesis events especially in promoting cell migration and invasion, indicating a need for a fuller understanding of the cellular roles of ACK both in normal and pathological conditions. A previous yeast-2-hybrid screen in the lab identified RhoGDI-3 as an interacting partner for ACK. RhoGDI-3 is a member of RhoGDI family of proteins, which are negative regulators that maintains Rho-family GTPases in the inactive GDP-bound state and sequesters them in the cytosol. RhoGDIs have also been found to become deregulated in cancer and it is possible therefore that they play
role in ACK-driven cancer progression. In this work, it is shown that ACK binds but does not phosphorylate the RhoGDIs in cells or in vitro. ACK was shown to shuttle between the cytoplasm and the nucleus. RhoGDI-1 and -2 have been found only in the cytoplasm, while RhoGDI-3 is localized to both cytoplasm and the nucleus, under the conditions tested. The interaction between RhoGDI-3 and ACK occurs predominantly in the nucleus and RhoGDI-3 levels were shown to decrease following co-expression with ACK, especially in the nucleus. Data generated here shows that ACK-mediates RhoGDI-3 proteasomal degradation potentially by regulating RhoGDI-3 ubiquitination. In order to determine the cellular effects of the interaction between ACK and the RhoGDIs, all possible Rho-family GTPases that interact with the RhoGDIs were determined in a systematic study. RhoGDI-1 and 2 were found to have relatively restricted activity, mainly binding members
of the Rho and Rac subfamilies. RhoGDI-3 displayed wider specificity interacting with several novel interacting partners within the Rho, Rac and Cdc42 subfamilies. Unexpectedly RhoGDI-3 was found to form complexes with the atypical Rho GTPases such as RhoD, Wrch2, Rnd2, Miro2 and RhoH which are not regulated by standard GDP/GTP cycling. The GTP levels of these target proteins were found to decrease following co-expression with RhoGDI-3, confirming its role as a negative regulator of these Rho GTPases. ACK was shown to regulate the activation of these target proteins, including RhoA, RhoB, Rac1 and RhoH, which are known to be involved in cell proliferation and migration. Aberrant activation of these target protein is frequently observed in cancer, suggesting a role for RhoGDI to drive ACK oncogenicity