Siti Khadijah Za'aba
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Preferred name
Siti Khadijah Za'aba
Official Name
Za'aba, Siti Khadijah
Alternative Name
SK Zaaba
Zaaba SK
Zaaba Siti Khadijah
Main Affiliation
Scopus Author ID
36151525400

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  • Publication
    Induction of Apoptosis of Melanoma Skin Cancer Cells by Atmospheric Plasma Jet
    ( 2023-01-01)
    Abdullah Z.
    ;
    Siti Khadijah Za'aba
    ;
    Mustaffa M.T.
    ;
    Saidin N.A.
    ;
    Mohtar J.A.
    The apoptotic effect is an important issue in cancer treatment. To achieve this goal, an atmospheric plasma jet (APJ) was set up for use on cultured cells in a temperature-controlled environment. Melanoma skin cancer and normal skin cells were targeted with this device. Following a 5 s plasma exposure, there was a 67% cell death in melanoma skin cancer cells compared with 5% in normal skin cells as measured after 24 h. When the treatment time was increased to 15, a 98% cell death was reported for melanoma skin cancer cells, which was 80% greater than the cell death in normal skin cells. Our observations further indicate that this preferential cell death is largely due to apoptosis. It shows that an APJ is a selective device in the induction of apoptosis in cancer and normal cells. APJ was shown to affect cells directly and indirectly through a plasma-activated medium (PAM). In direct treatment, cells were exposed to plasma while suspended in a culture medium, and in indirect treatment, cells were added to a culture medium previously acti-vated by plasma treatment. PAM was able to induce cell death 29% higher than direct treatment as measured after 48 h. The depth of the growth medium is also one of the factors in the induction of apoptosis of cancer cells. The growth medium protected the cells from plasma exposure. The result shows that the low level (0 mm) of growth medium will cause more cell death as compared with the high level (2 mm) of growth medium. Apoptotic behavior of skin cancer cells was de-duced from the fact that treated cells initially grew and died 12 h following the treatment, while untreated cells continued to grow and proliferate.
  • Publication
    Performance of Two Phase Anaerobic Digestion on Food Waste for Biogas Production
    ( 2022-01-01)
    Zakarya I.A.
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Hilmi N.A.M.
    ;
    Mohd Rashidi Che Beson
    ;
    Matei M.
    Every year, the total amount of solid waste generated in Peninsular Malaysia grew, according to the Malaysia government. The typical solid waste management system practiced in developing country brings many problems that can cause risks and hazards for living things and the environment in Malaysia if there are not managed properly. For example, illegal dumping cause groundwater and soil pollution. The methane gas produced from the landfill causes greenhouse effect. Food waste is categorized under household waste, where it is produced in residential areas, restaurants, cafeteria, markets and commercial areas. Therefore, anaerobic digestion process is introduced for organic waste with higher solids contents such as food waste as an alternative method. The effectiveness of anaerobic digestion process can be investigated through this process. In this study, two phase of anaerobic digesters was proposed. The reactor was operated at a temperature 35 °C, analyzed for biogas production, pH values and C/N ratio. The highest biogas production in this study is 50.4%. For a co-digestion containing more sludge can increase the pH value and biogas production.
  • Publication
    Improvement of cam performance curve using B-Spline curve
    (IOP Publishing, 2017-10-29)
    Shahriman Abu Bakar
    ;
    Mohamad Syafiq Abdul Khadir
    ;
    Wan K.
    ;
    Hashim M.S.M.
    ;
    Hazry Desa
    ;
    Cheng Ee Meng
    ;
    Ruslizam Daud
    ;
    Zuradzman Mohamad Razlan
    ;
    Siti Khadijah Za'aba
    ;
    Muhammad Azizi Azizan
    The mathematical modeling approach has been applied in order to increase the cam profile curve of Modenas CT115s performance by using MATLAB software as a programmed to calculate the mechanism of the cam profile. Cam is used inside the engine to push the rocker and consequently open and close the engine valve that allows the fuel-air mixture to be entered during the combustion process. The B-Spline curve was implemented in order to enhance the current performance of the cam profile. The calculation had been done by using manual and MATLAB software. The results obtained has been analyzed and interpreted in plotting the graphs. From the analysis, the profile that had the highest displacement factor, sk produced higher cam curve performance of the engine. Thus, it can be concluded that the increase of the displacement factor, sk can increase the engine performance as the valve displace further in which allow higher fuel-air mixture entrance during the combustion process.
      3  11
  • Publication
    Co-digestion of food waste with cow dung by anaerobic digestion for biogas production
    ( 2023-01-01)
    Hilmi N.A.M.
    ;
    Irnis Azura Zakaria
    ;
    Ahmad Anas Nagoor Gunny
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Samah M.F.
    ;
    Daud Z.A.A.M.
    ;
    Beson M.R.C.
    Food waste is categorized under household waste which were produce in large amount every day and it can be a good potential to generate biogas production via anaerobic digestion. In this research, the characteristics of co-digestion process are measured to determine the biogas production between food waste and cow dung. The food waste is co-digest with two different type of cow dung are collected depends on their food consuming (grass:bran); 100% grass and 95% grass: 5% bran. The digester is maintained at 35°C of temperature for mesophilic condition. pH values and C/N ratio are noted until 35 days. The biogas production is analysed by using biogas analyzer. The highest biogas production in this study is 67.2% which are co- digest between food waste and cow dung (100%) compared cow dung (95%) is 53.9% on day 26. This shows that the cow dung (100%) produces more biogas than cow dung (95%). Anaerobic digestion process will best suits for biogas production and for the best utilization of food waste.
      1
  • Publication
    Induction of Apoptosis of Melanoma Skin Cancer Cells by Atmospheric Plasma Jet
    ( 2023-01-01)
    Abdullah Z.
    ;
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Saidin N.A.
    ;
    Johan Ariff Mohtar
    The apoptotic effect is an important issue in cancer treatment. To achieve this goal, an atmospheric plasma jet (APJ) was set up for use on cultured cells in a temperature-controlled environment. Melanoma skin cancer and normal skin cells were targeted with this device. Following a 5 s plasma exposure, there was a 67% cell death in melanoma skin cancer cells compared with 5% in normal skin cells as measured after 24 h. When the treatment time was increased to 15, a 98% cell death was reported for melanoma skin cancer cells, which was 80% greater than the cell death in normal skin cells. Our observations further indicate that this preferential cell death is largely due to apoptosis. It shows that an APJ is a selective device in the induction of apoptosis in cancer and normal cells. APJ was shown to affect cells directly and indirectly through a plasma-activated medium (PAM). In direct treatment, cells were exposed to plasma while suspended in a culture medium, and in indirect treatment, cells were added to a culture medium previously acti-vated by plasma treatment. PAM was able to induce cell death 29% higher than direct treatment as measured after 48 h. The depth of the growth medium is also one of the factors in the induction of apoptosis of cancer cells. The growth medium protected the cells from plasma exposure. The result shows that the low level (0 mm) of growth medium will cause more cell death as compared with the high level (2 mm) of growth medium. Apoptotic behavior of skin cancer cells was de-duced from the fact that treated cells initially grew and died 12 h following the treatment, while untreated cells continued to grow and proliferate.
      1  20
  • Publication
    Development of five port reflectometer for reflection based sensing system
    ( 2017-03-13)
    Setno Baharuddin
    ;
    Cheng Ee Meng
    ;
    Lee Kim Yee
    ;
    Siti Khadijah Za'aba
    ;
    Nurul Syahirah Khalid
    ;
    Zulkifly Abbas
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Mohd Afendi Rojan
    ;
    Zulkarnay Zakaria
    Five-Port Reflectometer is a microwave passivedevice where it implements the six-port algorithm to measure the complex reflection coefficient of material under test (MUT) through reflection on interface between MUT and microwave sensor. Initially, the Six-Port Reflectometer (SPR) was introduced by Engen in 1977 and major component used insix-port technique was designed in many types. When Riblet and Hanssonproposed ring junction with 5 ports only on 1981. Six ports ring junction has been reduced to five ports. In this paper, a dual frequency five ports ring junction circuit was designed, simulated and fabricated for reflection based sensing system. The fabricated five port ring junction is operating at frequencies of 0.64 GHz and 2.42 GHz. The measured result had good agreement with the simulated results for dual frequencies in terms of magnitude and phase.
      30  5
  • Publication
    Municipal solid waste characterization and quantification as a measure towards effective solid waste management in UniMAP
    ( 2020-12-29)
    Irnis Azura Zakaria
    ;
    Fazhil N.S.A.
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Jamaluddin M.N.F.
    The most common environmental problems in Malaysia is increasing in solid waste generation. Solid waste generation and composition knowledge is compulsory as a benchmark for the decision making in managing municipal solid waste management strategy. The objective of this study was to measure solid waste generation and compare solid waste composition at cafeterias of UniMAP. Three different cafeterias had been chosen as a sampling location. Waste was sorted out into several components such as food waste, plastic, papers, metal, glass, and other types of waste. There is significance difference in data collection between the three locations where the organic waste was the main component in waste composition. Solid waste sampling and laboratory analysis were carried out based on random sampling method by using American Standard Test Method (ASTM) standards for proximate analysis (moisture content, ash content, volatile matter and fixed carbon). Ultimate analysis which is C:N ratio was carried out. Results showed that total municipal solid waste generated during two weeks of collection at School of Manufacturing, Tuanku Tengku Fauziah Residential College (PFI 2) and Tan Sri Aisyah Ghani Residential College (KKTAG) were 459.9 kg (0.1452 kg/p/day), 709.0 kg (0.0292 kg/p/day) and 201.90 kg (0.0163 kg/p/day). Based on this information, a proper waste management can be introduced to treat organic waste such as food waste and paper including inorganic waste efficiently.
      1
  • Publication
    Carbon footprint assessment from purchased electricity consumption and campus commute in Universiti Malaysia Perlis (UniMAP): Pre- and during COVID-19 pandemic
    ( 2022-01-01)
    Nor Atiqa Baharom
    ;
    Sara Yasina Yusuf
    ;
    Siti Khadijah Za'aba
    ;
    Norazian Mohamed Noor
    ;
    Nor Ashikin Ahmad
    ;
    Wan Amiza Amneera Wan Ahmad
    ;
    Boboc M.
    Most institutions and organizations nowadays have been taking responsibility in reducing their carbon footprint (CF) to curtail the global warming impact to at least 20–25% reduction by 2030. Universities and higher learning institutions are starting to invest in becoming greener and carbon-free. Current COVID19 communicable disease has swayed the routine and concurrently influenced regular trends of greenhouse gases (GHG) emissions throughout the world. This study explored the possible GHG emissions (calculated as CO2e) from internal campus commute and purchased electricity consumption from the year 2018–2020 at Universiti Malaysia Perlis main campus to analyze the influence of COVID19 pandemic on its CO2e emission. The average amount of CO2e emitted during pre-COVID19 period (n = 26) was 1,518.8 tCO2e/year while during COVID19 period, it was 1,071.5 tCO2e/year (n = 10), marked as 29.5% reduction. Due to completeness and quality of data for contracted bus (monitoring period of years 2018, 2019 and 2020 as 12 months, 12 months, and 2 months, respectively), year 2019 was determined as the appropriate baseline year for setting the CO2e reduction target due to COVID19 pandemic precedented year. In comparison to pre-COVID19 pandemic, almost 95%/year and 7%/year reductions of CO2e were recorded for both Scope 1 and Scope 2, respectively. Comparing Scope 1 and 2, it was obviously observed that the purchased electricity consumption (Scope 2) was the predominant contributor to GHG emission at UniMAP campus by 78% despite of current pandemic influence and its reduction was indistinct (7%/year reduction). Thus, the reduction target in future should be venturing in energy savings and energy auditing in addition to carbon offsetting.
      1
  • Publication
    Microplasma effect on skin scaffold for melanoma cancer treatment
    ( 2017-03-30)
    Zulaika Abdullah
    ;
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Che Wan Sharifah Robiah Mohamad
    ;
    Ammar Zakaria
    An atmospheric plasma system using Helium gas was developed. The effect of helium plasma treatment on skin scaffold surface was studied by scanning electron microscopy (SEM). The changes of skin scaffold surfaces before and after helium plasma treatment was recorded. The surface of skin scaffold changed with the prolonged of helium plasma treatment time. The depth of helium plasma penetration was studied using methylene blue dye staining method. The methylene blue will detect the presence or absence of an oxygen that was induced from plasma excitation. The presence of the oxygen indicated on the depth of helium plasma penetration. Results showed plasma are able to penetrate 4mm of skin scaffold after 1200 seconds of exposure.
      1  21
  • Publication
    Study on the effect of atmospheric plasma processing using gas mixture on 3C-SiC
    ( 2017-03-30)
    Zulaika Abdullah
    ;
    Siti Khadijah Za'aba
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Mohammad Taufiq Mustaffa
    ;
    Mayvinne Arcena
    ;
    Ammar Zakaria
    Atmospheric plasma processing are widely used for improving surfaces properties. Cubic silicon carbide (3C-SiC) is one of the material used as biosensor for their biocompatibility properties. In this work, we present the results of atmospheric plasma processing treatments using gas mixture on 3C-SiC surface. The 3C-SiC samples were treated at different duration and flow rate. Helium/Nitrogen and Argon/Nitrogen gas mixtures were used as plasma treatments and its effect on the surface was investigated. A significant increment of surface wettability were observed after plasma exposition. Investigation by surface morphological measurements was performed by using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Contact angle measurement results showed a decreased in contact angle with increasing of treatment time and flow rate, and Argon/Nitrogen mixture promote more wettability compared to Helium/Nitrogen mixture.
      26  1