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
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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
    A Study on the effectiveness of atmospheric air plasma in sterilization on indium tin oxide
    (Springer, 2024-12)
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Nurzahira Ahmad Zabidi
    Atmospheric air plasma is a cold plasma and its application is enhanced nowadays as an alternative to a sterile surface that cannot withstand high temperatures and chemical material. For instance, the consumption of smartphones among health workers in hospitals was said to be a cause that can spread pathogens to patients widely in the wards. Moreover, the smartphone consists of components that are sensitive to high temperatures and chemical materials that would give corrosion effects. The aims are to investigate the surface changes of indium tin oxide (ITO) after exposure to air plasma and to investigate the effectiveness of atmospheric air plasma by inactivating Escherichia coli (E-coli). The morphological test was conducted to study the surface changes of ITO using SEM. The microbiological test was conducted to examine the validity of the atmospheric air plasma in inactivating E-coli. The result revealed that 24V, 1L/min, 1.0mm copper thickness was capable of inactivating E-coli within 30 s without changing the ITO surface. However, more studies still need to be conducted in the future work for improving and get an accurate result in air plasma set-up for sterilization.
  • Publication
    Review on the development of plasma discharge in liquid solution
    ( 2017-03-30)
    Nur Arina Hasmimi Ramli
    ;
    Siti Khadijah Za'aba
    ;
    Mohammad Taufiq Mustaffa
    ;
    Ammar Zakaria
    ;
    Shahriman Abu Bakar
    Review papers on the basic principles and applications of plasma discharge in liquid have been reported. However, the development of plasma discharge in liquid is not widely reviewed. The aim of this paper is to review on the elements involved in developing plasma discharge in liquid. An overview will be given of the various types of existing power source, working gas, dielectric barrier, electrode material used to produce plasma, and reactive species production inside plasma discharge.
      2  32
  • 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
    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
    Image de-noising based on WMF technique for electrical trees structure in high voltage cable insulation
    (Semarak Ilmu Publishing, 2025-11)
    Siti Khadijah Za'aba
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Baharuddin Ismail
    ;
    Afifah Shuhada Rosmi
    Electrical treeing is a common problem during the pre-breakdown phenomenon in solid insulations due to the damage caused by Partial Discharge (PD) that progresses through stressed insulation via chemical degradation, which resembles the shape of a tree root. This resulted in a decrease in performance through degrading the insulation, which became a serious problem while dealing with electrical equipment. Hence, a deep understanding of electrical tree structure is vital to improving the quality of solid insulations. Ergo, optical microscopy is primarily used to examine tree structures, shapes, and fractal dimensions to reconstruct electrical tree structures for morphological study. However, optical microscopy images are frequently degraded by noise from readout procedures or image data acquisition systems, noise caused by occlusion, illumination, non-uniform intensity, destroying potential tree pixels, and a critical loss of information about the electrical tree structures. Therefore, this research proposed the Wiener Median Fusion (WMF) filter for electrical tree study. The performance of the WMF de-noising technique improves the image quality for the precise portrayal of the electrical tree structure based on thresholding segmentation algorithm analysis in terms of accuracy, sensitivity, and false positive rate. Based on the analysis of the thresholding segmentation algorithm, Otsu's thresholding exhibits the highest result compared to Niblack. The Otsu's overall percentage in terms of accuracy is 80.2934%, the sensitivity is 99.1513%, and the false positive rate is 82.6265%.
      1  2
  • Publication
    Performance of two phase anaerobic digestion on food waste for biogas production
    ( 2022-01-01)
    Irnis Azura Zakaria
    ;
    Mohammad Rizam Che Beson
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Siti Khadijah Za'aba
    ;
    Monica Matei
    ;
    Nur Adlina Mohd Hilmi
    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.
      7  6
  • Publication
    Life cycle assessment of expanded polystyrene
    ( 2021-01-26)
    Lim Y.S.
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Irnis Azura Zakaria
    ;
    Sara Yasina Yusuf
    ;
    Siti Khadijah Za'aba
    ;
    Mohamad M.A.
    Expanded polystyrene (EPS) is one of the most common materials used in packaging. In Malaysia, EPS is a type of plastic which is not in the recycling category. Usually, EPS wastes will end up in landfill and incinerator, leading to severe environmental impacts. Therefore, a cradle-to-grave life cycle assessment (LCA) study of EPS was carried out to investigate the potential environmental impacts of EPS. The most significant potential environmental impact will also be identified. Both will be identified under 2 different scenarios. The study was analyzed using GaBi Education Software with the method of TRACI 2.1 to the environmental indicators of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and ozone depletion potential (ODP). In scenario 1, the emission percentage for GWP, AP, EP, and ODP are 99.73 %, 0.21 %, 0.06 %, and 3x10-6 %, respectively. As for scenario 2, all the 3 conditions show similar trend with scenario 1. The LCA study of EPS is particularly focused on the manufacturing, distribution, and the end-of-lifetime treatments, with the introduction of recycling into the system. The findings show that manufacturing of EPS is the major contributor of the environmental impacts and GWP contributes to the most significant potential environmental impacts. Overall, recycling was found to have the least impact to the environment, which possibly be used as the new end-of-lifetime treatment of EPS in Malaysia.
      13  4
  • 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  38