Browse publications by year: 2023

Energy balance and life cycle assessments in producing microalgae biodiesel via a continuous microalgal-bacterial photobioreactor loaded with wastewater

Leong WH, Lim JW, Rawindran H, Liew CS, Lam MK, Ho YC, et al.

Chemosphere, 2023 Nov;341:139953.
PMID: 37634592 DOI: 10.1016/j.chemosphere.2023.139953

Life cycle assessments of microalgal cultivation systems are often conducted to evaluate the sustainability and feasibility factors of the entire production chain. Unlike widely reported conventional microalgal cultivation systems, the present work adopted a microalgal-bacterial cultivation approach which was upscaled into a pilot-scale continuous photobioreactor for microalgal biomass production into biodiesel from wastewater resources. A multiple cradle-to-cradle system ranging from microalgal biomass-to-lipid-to-biodiesel was evaluated to provide insights into the energy demand of each processes making up the microalgae-to-biodiesel value chain system. Energy feasibility studies revealed positive NER values (4.95-8.38) for producing microalgal biomass but deficit values for microalgal-to-biodiesel (0.14-0.23), stemming from the high energy input requirements in the downstream processes for converting biomass into lipid and biodiesel accounting to 88-90% of the cumulative energy demand. Although the energy balance for microalgae-to-biodiesel is in the deficits, it is comparable with other reported biodiesel production case studies (0.12-0.40). Nevertheless, the approach to using microalgal-bacterial cultivation system has improved the overall energy efficiency especially in the upstream processes compared to conventional microalgal cultivation systems. Energy life cycle assessments with other microalgal based biofuel systems also proposed effective measures in increasing the energy feasibility either by utilizing the residual biomass and less energy demanding downstream extraction processes from microalgal biomass. The microalgal-bacterial cultivation system is anticipated to offer both environmental and economic prospects for upscaling by effectively exploiting the low-cost nutrients from wastewaters via bioconversion into valuable microalgal biomass and biodiesel.

MeSH terms: Animals; Life Cycle Stages; Lipids; Biomass; Biofuels; Microalgae*; Photobioreactors; Waste Water*
Sustainable valorization approaches on crustacean wastes for the extraction of chitin, bioactive compounds and their applications - A review

Azelee NIW, Dahiya D, Ayothiraman S, Noor NM, Rasid ZIA, Ramli ANM, et al.

Int J Biol Macromol, 2023 Dec 31;253(Pt 2):126492.
PMID: 37634772 DOI: 10.1016/j.ijbiomac.2023.126492

The unscientific disposal of the most abundant crustacean wastes, especially those derived from marine sources, affects both the economy and the environment. Strategic waste collection and management is the need of the hour. Sustainable valorization approaches have played a crucial role in solving those issues as well as generating wealth from waste. The shellfishery wastes are rich in valuable bioactive compounds such as chitin, chitosan, minerals, carotenoids, lipids, and other amino acid derivatives. These value-added components possessed pleiotropic applications in different sectors viz., food, nutraceutical, cosmeceutical, agro-industrial, healthcare, and pharmaceutical sectors. The manuscript covers the recent status, scope of shellfishery management, and different bioactive compounds obtained from crustacean wastes. In addition, both sustainable and conventional routes of valorization approaches were discussed with their merits and demerits along with their combinations. The utilization of nano and microtechnology was also included in the discussion, as they have become prominent research areas in recent years. More importantly, the future perspectives of crustacean waste management and other potential valorization approaches that can be implemented on a large scale.

MeSH terms: Animals; Chitin/chemistry; Crustacea/metabolism; Seafood; Waste Management*; Chitosan*
Fulltext ARNI Versus Perindopril for Remodeling in HFrEF. A Cohort Study

Bin Atan NMAS, Bin Hadi MF, Teoh VWY, Danaee M, Loch A

J Cardiovasc Pharmacol Ther, 2023;28:10742484231195019.
PMID: 37635324 DOI: 10.1177/10742484231195019

Introduction: Ventricular remodeling is a mal-adaptive process. Both angiotensin-converting enzyme inhibitors and sacubitril/valsartan have been shown to reverse remodeling in mostly uncontrolled observational studies. There is a lack of head-to-head studies. Methods: This cohort study compares the remodeling effects of angiotensin receptor blockers combined with a neprilysin inhibitor (ARNI) and perindopril in heart failure with reduced ejection fraction (HFrEF) patients between January 2017 and December 2020. Inclusion criteria: (i) age > 18 years, (ii) recent diagnosis of de-novo HFrEF (EF

MeSH terms: Valsartan/pharmacology; Adult; Drug Combinations; Heart Failure*; Humans; Middle Aged; Stroke Volume; Tetrazoles/pharmacology; Cohort Studies; Ventricular Function, Left; Treatment Outcome; Perindopril/adverse effects; Angiotensin Receptor Antagonists/pharmacology
Fulltext Climate Change and Aging Health in Developing Countries

Sarkar SM, Dhar BK, Fahlevi M, Ahmed S, Hossain MJ, Rahman MM, et al.

Glob Chall, 2023 Aug;7(8):2200246.
PMID: 37635700 DOI: 10.1002/gch2.202200246

The climate of the Earth has changed throughout history. Climate change negatively impacts human rights in a wide range of ways. The study aims to find out the impact of climate change on aging health in developing countries. The study found that public health will be devastated if climate change continues unabated. Countries that are least responsible for global warming are most susceptible to the effects of higher temperatures, such as death and disease. In low- and middle-income countries, disasters are more likely to happen to people aged 60 and over. Although climate change affects all of us, older people are especially at risk from it, as evidenced by a growing body of research. The study also offers countermeasures and suggestions to develop aging health in developing countries affected by climate change.
Fulltext Microplastics in Malaysia's Aquatic Environment: Current Overview and Future Perspectives

Sulaiman RNR, Bakar AA, Ngadi N, Kahar INS, Nordin AH, Ikram M, et al.

Glob Chall, 2023 Aug;7(8):2300047.
PMID: 37635702 DOI: 10.1002/gch2.202300047

Microplastic pollution has adversely affected the aquatic ecosystem, living creatures, and human health. Several studies in Malaysia have provided baseline information on the existence of microplastics in surface water, ingestion by marine life and sediment. Also, humans are exposed to microplastic due to consumption of contaminated abiotic and biotic products, such as processed seafood. Nonetheless, knowledge is still scarce among Malaysian on the potential remediation and pollution management of microplastics, which poses a significant challenge to preserve a good environmental status. Green technologies also other alternative to mitigate the contamination of microplastics for sustainable future. Hence, this review aims to provide an overview of microplastic's occurrence, fate, and implications in Malaysia's aquatic environment. Detection of microplastics from the water surface, ingestion by aquatics, and sediment samples are highlighted. Available different treatment processes toward microplastic remediation are also discussed. Additionally, the potential challenges, current perspective for plastic management in Malaysia, as well as green strategies for reducing microplastic contamination are also put forward. The goal of this work is to improve the understanding of the seriousness of microplastic contamination in aquatic environments, thus encouraging key concerns that need to be investigated further.
Recent developments in the role of protocatechuic acid in neurodegenerative disorders

Thapa R, Goyal A, Gupta G, Bhat AA, Singh SK, Subramaniyan V, et al.

EXCLI J, 2023;22:595-599.
PMID: 37636028 DOI: 10.17179/excli2023-5940
Challenges and Strategies for Improving Access to Cancer Drugs in Malaysia: Summary of Opinions Expressed at the 2nd MACR International Scientific Conference 2022

Tan SC, Poh WT, Yong ACH, Chua EW, Ooi J, Mahmud R, et al.

Cancer Manag Res, 2023;15:851-862.
PMID: 37636030 DOI: 10.2147/CMAR.S420890

Considerable progress has been made in cancer drug development in recent decades. However, for people in low- and middle-income countries, including Malaysia, many of these drugs are not readily available. During the 2nd Malaysian Association for Cancer Research (MACR) International Scientific Conference, a forum discussion was held to address these challenges and explore strategies to improve access to cancer medicines in the country. This paper presents the results of the said forum discussion. A few challenges to cancer drug access were highlighted, including lengthy approval and regulatory practices, cost of medicines, and manufacturing barriers. Besides, a few strategies for mitigating some of these challenges were proposed, such as mechanisms for cost reduction, uptake of biosimilars and generics, local manufacturing, public-private partnerships, strengthening the role of insurance companies, funding and regulation, and advocacy for fair pricing, by drawing examples from cancer medicines access initiatives in Malaysia and initiatives for different disease groups. Overall, this paper provides a comprehensive overview of the challenges and strategies for improving access to cancer medicines in Malaysia and provides valuable insights for policymakers, healthcare providers, the pharmaceutical industry, cancer patients, cancer support groups, and other stakeholders working on this important issue.
Fulltext Histopathology imagery dataset of Ph-negative myeloproliferative neoplasm

Mohamad Yusof UK, Mashohor S, Hanafi M, Md Noor S, Zainal N

Data Brief, 2023 Oct;50:109484.
PMID: 37636134 DOI: 10.1016/j.dib.2023.109484

Tumorous cancer has been a widely known and well-studied medical phenomenon; however, rare diseases like Myeloproliferative Neoplasm (MPN) have received less attention, leading to delayed diagnosis. Despite the availability of advanced technology in diagnostic tools that can boost the procedure, the morphological assessment of bone marrow trephine (BMT) images remains critical to confirm and differentiate MPN subtypes. This paper reports a histopathological imagery dataset that was created to focus on the most common MPN from the Philadelphia Chromosome (Ph)-negative type, namely Essential Thrombocythemia (ET), Polycythemia Vera (PV), and Primary Myelofibrosis (MF). The dataset consisted of 300 BMT images that can be used to enable computer vision applications, such as image segmentation, disease classification, and object recognition, in assisting the classification of the MPN disease. Ethical approval was obtained from the Ministry of Health, Malaysia and the bone marrow trephine images were captured using a digital microscope from the Olympus model (BX41 Dual head microscope) with x10, x20, and x40 lens types. The development of comprehensive tools deployed from this dataset can assist medical practitioners in diagnosing diseases, thus overcoming the current challenges.
Myoclonus-Ataxia Syndrome Associated with Hyperprolinemia Type I

Ong TL, Lau YH, Ngu LH, Hadi D, Lau KM, Mawardi AS

Mov Disord Clin Pract, 2023 Aug;10(Suppl 3):S38-S40.
PMID: 37636236 DOI: 10.1002/mdc3.13780
Fulltext Navigating the tourism digital landscape: The interrelationship of online travel sites' affordances, technology readiness, online purchase intentions, trust, and E-loyalty

Mior Shariffuddin NS, Azinuddin M, Yahya NE, Hanafiah MH

Heliyon, 2023 Aug;9(8):e19135.
PMID: 37636344 DOI: 10.1016/j.heliyon.2023.e19135

This study investigates the relationship between online travel sites' affordances (OTSA), technology readiness (TR), and their impact on tourists' online purchase intentions (OPI), as well as the moderating role of trust on OPI and e-loyalty. The survey was conducted online from September 2022 until November 2022 on 306 participants who were selected purposively. The collected data was analyzed using Partial Least Squares-Structural Equation Analysis (PLS-SEM). The findings indicated that OTSA has a greater influence on OPI in comparison to TR. Specifically, OTSA's level of interactivity and stickiness had a noteworthy impact on OPI, while only the innovativeness of TR had a positive effect on OPI. The results of the moderating role of trust indicated that OPI negatively affects e-loyalty in the presence of trust. The research conducted in this study has yielded valuable insights that hold theoretical and practical significance, particularly for local governments and tourism agencies operating in the realm of online travel sites. A key finding of the study emphasizes the importance of improving technology adoption and user experience to facilitate greater comfort and confidence among tourists in using these platforms. Establishing trust between tourists and online travel sites emerges as a critical factor in shaping the success of the tourism industry. By prioritizing trust and transparency, tourism agencies and online travel sites can forge robust relationships with their customers and promote the growth of the tourism industry toward digitalization.
Fulltext A call to action: Unpacking the challenges to implementing social sustainability initiatives in a developing country city

Razia S, Abu Bakar Ah SH

Heliyon, 2023 Aug;9(8):e19085.
PMID: 37636356 DOI: 10.1016/j.heliyon.2023.e19085

With cities sprawling and populations booming in developing regions, ensuring social sustainability in urban areas has become more urgent. This study investigates the challenges of implementing social sustainability initiatives for cities in developing countries, focusing on Dhaka as a representative city. A mixed-method approach involving structured questionnaire surveys and key informant interviews was used to collect quantitative and qualitative data. The study identified eighteen challenges to implementing social sustainability initiatives in Dhaka city, including a lack of poor urban governance, an inefficient city management system, a lack of political stability, a long delay in the planning approval process, etc. Additionally, experts identified additional challenges that require attention. The study offers empirical evidence to assist government officials, policymakers, and urban planners overcome these challenges and implement social sustainability effectively. To address the identified challenges, the study recommends revisiting the Structure Plan, Urban Area Plan, Detailed Area Plan, and Urban Sector Policy-2011. It highlights the crucial role of community social workers in mitigating specific issues in socially sustainable urban development. Eventually, the study will contribute to the implementation of SDG-11 in the 2030 Agenda for Sustainable Development by bridging the gap between urbanization and socially sustainable cities.
Fulltext Mobile technology features and technostress in mandatory online teaching during the COVID-19 crisis

Khlaif ZN, Sanmugam M, Hattab MK, Bensalem E, Ayyoub A, Sharma RC, et al.

Heliyon, 2023 Aug;9(8):e19069.
PMID: 37636397 DOI: 10.1016/j.heliyon.2023.e19069

Technostress is defined as any unhealthy condition caused by dealing with modern technology in various harmful ways; examples of technostress include addiction and stress. Even though technostress has been extensively studied in the literature, little attention has been paid to investigating technostress among academics who work in exceptional circumstances, such as crises, and who might be experiencing different psychological states due to those circumstances. To fill the gap, this study aims to explore the factors influencing technostress among school teachers. The study examined technostress's level and factor graphics structure among 692 academics from different Arab countries during COVID-19. The technostress factors and their stories were explored and measured using sequential mixed methods and confirmatory and exploratory factor analysis. The study discusses various factors' direct and indirect effects on mobile technology integration in education and the theoretical and practical implications of managing technostress in online classes. A model of techno-stressors among Arab academics was found to include: schedule overload, complexity, uncertainty, uselessness, invasion, and compulsion. The direct effect of various factors on mobile technology integration in education is mainly positive, while indirect effects are more varied. The theoretical and practical implications of managing technostress in online classes include: considering the psychological and physiological impact of technostress on students' learning performance, decreasing overall satisfaction with the learning experience, and improving the overall quality of online courses. As a result of this study's findings, a new perspective is provided on how academics in particular circumstances (in this study, the occupation of Palestine) may behave and feel toward technology in teaching.
Fulltext A novel online multi-task learning for COVID-19 multi-output spatio-temporal prediction

Wu Z, Loo CK, Obaidellah U, Pasupa K

Heliyon, 2023 Aug;9(8):e18771.
PMID: 37636411 DOI: 10.1016/j.heliyon.2023.e18771

In light of the ongoing COVID-19 pandemic, predicting its trend would significantly impact decision-making. However, this is not a straightforward task due to three main difficulties: temporal autocorrelation, spatial dependency, and concept drift caused by virus mutations and lockdown policies. Although machine learning has been extensively used in related work, no previous research has successfully addressed all three challenges simultaneously. To overcome this challenge, we developed a novel online multi-task regression algorithm that incorporates a chain structure to capture spatial dependency, the ADWIN drift detector to adapt to concept drift, and the lag time series feature to capture temporal autocorrelation. We conducted several comparative experiments based on the number of daily confirmed cases in 20 areas in California and affiliated cities. The results from our experiments demonstrate that our proposed model is superior in adapting to concept drift in COVID-19 data and capturing spatial dependencies across various regions. This leads to a significant improvement in prediction accuracy when compared to existing state-of-the-art batch machine learning methods, such as N-Beats, DeepAR, TCN, and LSTM.
Fulltext Unlocking the secrets of exchange rate determination in Malaysia: A Game-Changing hybrid model

Butt S, Ramzan M, Wong WK, Chohan MA, Ramakrishnan S

Heliyon, 2023 Aug;9(8):e19140.
PMID: 37636448 DOI: 10.1016/j.heliyon.2023.e19140

Nominal exchange rate determination is a puzzling phenomenon throughout the literature. Thus, the study aims to analyze the nominal exchange rate determination with a hybrid approach of macroeconomic and microstructure determinants, i.e., interest rate differential, oil price, order flow, and bid-ask spread over the long- and short-run horizons in the context of Malaysia. The dataset consists of high-frequency daily data from 2010 to 2017, employing a nonlinear ARDL approach. The results indicate that the bid-ask spread and interest rate differential were found to be key determinants of exchange rate dynamics in the long and short run. The findings show strong evidence of long-run asymmetry in the interest rate differential, while short-run asymmetry effects exist between microstructure determinants and the exchange rate. In addition, it indicates that the bid-ask spread holds informative content to explain the dynamics of the exchange rate in Malaysia. Additionally, the negative changes in the oil price could potentially act as macroeconomic news announcements and the bid-ask spread as liquidity determinants in Malaysia, which play a significant role in exchange rate determination. The study concluded that the prominent short-run asymmetry effects captured in cumulative order flow and bid-ask spread While a long-run asymmetry exists between the oil price and exchange rate in Malaysia. The empirical results allow for long-run and short-run asymmetric pricing impacts of a hybrid approach on the nominal exchange rate in Malaysia. This study is helpful in providing policy direction and practical implications for monetary authorities and market dealers. The bid-ask spread and oil price could be considered influential exchange rate determinants in the short run in Malaysia.
Fulltext Elevating athletic performance: Maximizing strength and power in long jumpers through combined low-intensity blood flow restriction and high-intensity resistance training

Sarfabadi P, Rizvi MR, Sharma A, Sami W, Sajid MR, Arora S, et al.

Heliyon, 2023 Aug;9(8):e19068.
PMID: 37636460 DOI: 10.1016/j.heliyon.2023.e19068

PURPOSE: This study aimed to evaluate the effects of low-intensity blood flow restriction (BFR) training and high-intensity resistance training (HI-RT) on the leaping performance of long-jumpers.
MATERIALS AND METHODS: Long jump players were divided into two groups; one group (group A) receiving HI-RT (n = 8) and the other group (group B) receiving combined low-intensity BFR training plus HI-RT (n = 8). Muscle power and knee muscle strength was assessed at baseline, 3 weeks and 6 weeks of intervention.
RESULTS: 1-RM was found to be significantly different between Group A and Group B at 3 and 6 weeks. Further, IKDQR, IKDHR and IKDQL was significantly improved in group B as compared to group A both at 3 and 6 weeks. There was significant time effect, group effect and time-group interaction in the strength of quadriceps and hamstring of both left and right leg measured through isokinetic device. Post-hoc analysis for 1-RM in group B showed a significant improvement at baseline and 6 weeks and the broad jump was significant at baseline and 3 weeks and at baseline and 6 weeks.
CONCLUSION: The combined effects of low-intensity BFR training and HI-RT is effective in improving the muscle strength and power of lower limbs in long jumpers.
A Rare Case of Complicated Sinonasal Meliodosis Mimicking Sinonasal Lymphoproliferative Disease

Cheah Y, Jumastapha H, Tang IP

Indian J Otolaryngol Head Neck Surg, 2023 Sep;75(3):2564-2567.
PMID: 37636706 DOI: 10.1007/s12070-023-03792-4

Unilateral nasal obstruction with purulent nasal discharge is one of the presentations for sinonasal melioidosis. However, it may mimic nasal NK/T cell lymphoma. Both causing tissue destruction involving nasal septum, lateral nasal wall and palate. Here, we report a case of disseminated melioidosis involving sinonasal mimicking nasal lymphoma in a 32-year-old immunocompetent lady. She presented with prolonged fever, unilateral nasal blockage, painful facial swelling and knee pain. Clinical findings revealed extensive necrotic tissue and crusting involving right lateral wall of nasal cavity. Tissue and blood culture and sensitivity (C + S) grew Burkholderia pseudomallei. Recovery was complete after surgery and antibiotics.
A Rare Cause of Acute Dyspnoea: Reinke Oedema

Cheah SC, Yee LW, Kok WL, Nazri Zamri FI, Baki MM

Indian J Otolaryngol Head Neck Surg, 2023 Sep;75(3):2420-2422.
PMID: 37636736 DOI: 10.1007/s12070-023-03714-4

Reinke oedema is a benign condition due to fluid collection within subepithelial space of the true vocal fold. This phenomenon is predisposed by chronic smoking, alcohol consumption and contribution of laryngopharyngeal reflux. Although benign, it may be life threatening when bilateral vocal folds are affected causing airway obstruction. In this report, awake tracheostomy was performed for a 65- year- old lady with stridor secondary to severe Reinke oedema. The importance of establishing a definitive airway is highlighted here in securing a difficult airway.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12070-023-03714-4.
Primary Lymphoepithelial Carcinoma of the Submandibular Gland in A Young Patient: A Case Report

Ishak AI, Kong LS, Yunus MRM, Bakar MZA

Indian J Otolaryngol Head Neck Surg, 2023 Sep;75(3):2577-2580.
PMID: 37636741 DOI: 10.1007/s12070-023-03663-y

Lymphoepithelial carcinoma (LEC) is a rare entity of malignancy. It has been associated with Epstein-Barr virus (EBV), and in regions where it is endemic, such as Southeast Asia, EBV is typically associated with nasopharyngeal carcinoma. The incidence of such malignancies in the young population is unusual. Here we report a 17-year-old with a 5-year history of a painless right submandibular mass presenting with a sudden increase in size for one month before surgery. Neck examination revealed a firm right submandibular gland measuring five by five cm, with an irregular surface, non-tender with normal overlying skin. We performed a fine needle aspiration cytology (FNAC), and he underwent computed tomography (CT) scan of the neck. He underwent a right submandibulectomy. Lymph nodes from levels I and II were also removed. The final histopathology was reported as LEC. Following this tissue diagnosis, another follow-up surgery, a modified radical neck dissection, was carried out for locoregional clearance. Postoperatively, he completed chemoradiotherapy treatment and is now on regular follow-up.
Fulltext Cooling of a PVT System Using an Underground Heat Exchanger: An Experimental Study

Majeed SH, Abdul-Zahra AS, Mutasher DG, Dhahd HA, Fayad MA, Al-Waeli AHA, et al.

ACS Omega, 2023 Aug 22;8(33):29926-29938.
PMID: 37636923 DOI: 10.1021/acsomega.2c07900

In the recent decades, the researchers have been focused on the use of photovoltaic thermal (PVT) systems that provide the best performance and cooling for the photovoltaic panels. In this study, a PVT system consisting of a monocrystalline PV panel and a spiral heat exchanger was connected to an underground heat exchanger that is buried at a depth of 4 m below the surface of the earth. The procedure of the current study can be considered the first of its kind in the Middle East and North Africa region (based on the researchers' knowledge). The study was carried out on agricultural land in Baghdad-Iraq during months of July and August-2022, which are considered the harshest weather conditions for this city. The heat exchanger consists of a copper tube with a length of 21 m and formed in the shape of 3U, and it was buried in the earth and connected with a PVT system. The results of the study showed that the site chosen to bury the heat exchanger (4 m deep) has a stable soil temperature at 22.5 °C. From various volumetric flow rates, a flow rate of 0.18 l/s was selected which is considered the highest flow rate that can show vibration in the PVT system which may harm the system. The practical measurements showed that the largest difference in the surface temperatures of standalone PV and PVT was around 20 °C in favor of the latter. The electrical efficiency of the studied PVT system also increased to outperform the standalone PV system by 127.3%. By comparing the results of the current study with studies of water-cooled PVT systems from the literature, it is clear that the proposed system is feasible and has an acceptable efficiency in such harsh weather conditions tested during the experiment.
Fulltext Implications of Organic Matter Input, Sedimentary Environmental Conditions, and Gas Generation Potential of the Organic-Rich Shale in the Onshore Jiza-Qamar Basin, Yemen

Hakimi MH, Kahal A, Rahim A, Naseem W, Alsomid W, Al-Buraihi A, et al.

ACS Omega, 2023 Aug 22;8(33):30483-30499.
PMID: 37636926 DOI: 10.1021/acsomega.3c03691

The Jiza-Qamar Basin is one of the most important exploration sedimentary basins in Yemen. For over a decade, the exploration of hydrocarbons has been occurring in this basin. Late Cretaceous age rocks are the most occurring organic-rich sediments in this basin, including coals, coaly shales, and shales. The studied organic-rich shale beds are from the Late Cretaceous Mukalla Formation and associated with coal seams. These organic-rich shales can serve as source rocks for hydrocarbon generation potential. The current study investigates the geochemical characteristics, including assessing the organic matter (OM) input, sedimentary environmental conditions, and hydrocarbon generation potential of the organic-rich shale within the Mukalla Formation from three well locations in the onshore Jiza-Qamar Basin using organic geochemistry, biomarker, and carbon isotope measurements. The studied shale samples have high OM content with total organic carbon values between 0.74 and 19.48 wt %. Furthermore, they contain mainly hydrogen-poor Types III and IV kerogen, indicating the presence of the gas-prone source rock. The presence of these types of kerogen indicates the abundance of vitrinite and inertinite macerals, as established by microscopic investigation. However, the studied organic-rich shales had biomarker features, including high Ph/Ph ratio between 3.82 and 7.46, high Tm/Ts ratio of more than 7, and high C29 regular steranes compared to C27 and C28 regular steranes. Apart from the biomarker results, the studied Mukalla shales are characterized by the abundance of land-derived OM that deposited in fluvial to fluvial deltaic environments under highly oxic conditions. The finding of the considerable concentration of terrigenous OM is probably confirmed by the bulk carbon isotope and maceral composition data. The maturity indicators show that the examined organic-rich shale samples in the studied wells exhibit low VR values of up to 0.71%, and thereby, they have not been yet reached the high maturity for gas generation. This low maturity level in the studied wells is probably attributed to shallow burial depth, exhibiting depth of up to 2835 m. Therefore, the substantial gas exploration operations from the organic-rich shale source rock system of the Late Cretaceous Mukalla Formation can be recommended in the deeper stratigraphic succession in the offshore Jiza-Qamar Basin.

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