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Fulltext Determinants of the willingness to participate in biobanking among Malaysian stakeholders in the Klang Valley

Amin L, Hashim H, Mahadi Z, Ismail K

BMC Med Res Methodol, 2018 12 05;18(1):163.
PMID: 30518344 DOI: 10.1186/s12874-018-0619-2

BACKGROUND: The demand in biobanking for the collection and maintenance of biological specimens and personal data from civilians to improve the prevention, diagnosis and treatment of diseases has increased notably. Despite the advancement, certain issues, specifically those related to privacy and data protection, have been critically discussed. The purposes of this study are to assess the willingness of stakeholders to participate in biobanking and to determine its predictors.

METHODS: A survey of 469 respondents from various stakeholder groups in the Klang Valley region of Malaysia was carried out. Based on previous research, a multi-dimensional instrument measuring willingness to participate in biobanking, and its predictors, was constructed and validated. A single step Structural Equation Modelling was performed to analyse the measurements and structural model using the International Business Machines Corporation Software Package for Social Sciences, Analysis of Moment Structures (IBM SPSS Amos) version 20 with a maximum likelihood function.

RESULTS: Malaysian stakeholders in the Klang Valley were found to be cautious of biobanks. Although they perceived the biobanks as moderately beneficial (mean score of 4.65) and were moderately willing to participate in biobanking (mean score of 4.10), they professed moderate concern about data and specimen protection issues (mean score of 4.33). Willingness to participate in biobanking was predominantly determined by four direct predictors: specific application-linked perceptions of their benefits (β = 0.35, p
Fulltext Protocol for a qualitative study exploring the perception of need, importance and acceptability of a digital diabetes prevention intervention for women with gestational diabetes mellitus during and after pregnancy in Malaysia (Explore-MYGODDESS)

Sobri NHM, Ismail IZ, Hassan F, Papachristou Nadal I, Forbes A, Ching SM, et al.

BMJ Open, 2021 08 26;11(8):e044878.
PMID: 34446477 DOI: 10.1136/bmjopen-2020-044878

INTRODUCTION: Women who develop gestational diabetes mellitus (GDM) have an increased risk of developing type 2 diabetes, and to reduce this risk the women have to adopt healthy behaviour changes. Although previous studies have explored the challenges and facilitators to initiate behaviour change among women with GDM, there is limited data from Malaysian women. Thus, this study will explore the factors affecting the uptake of healthy behaviour changes and the use of digital technology among women and their healthcare providers (HCPs) to support healthy behaviour changes in women with GDM.
METHODS AND ANALYSIS: The study will be modelled according to the Capability, Opportunity, Motivation and Behaviour and Behaviour Change Wheel techniques, and use the DoTTI framework to identify needs, solutions and testing of a preliminary mobile app, respectively. In phase 1 (design and development), a focus group discussion (FGDs) of 5-8 individuals will be conducted with an estimated 60 women with GDM and 40 HCPs (doctors, dietitians and nurses). Synthesised data from the FGDs will then be combined with content from an expert committee to inform the development of the mobile app. In phase 2 (testing of early iterations), a preview of the mobile app will undergo alpha testing among the team members and the app developers, and beta testing among 30 women with GDM or with a history of GDM, and 15 HCPs using semi-structured interviews. The outcome will enable us to optimise an intervention using the mobile app as a diabetes prevention intervention which will then be evaluated in a randomised controlled trial.
ETHICS AND DISSEMINATION: The project has been approved by the Malaysia Research Ethics Committee. Informed consent will be obtained from all participants. Outcomes will be presented at both local and international conferences and submitted for publications in peer-reviewed journals.
Combustion characteristics of Malaysian oil palm biomass, sub-bituminous coal and their respective blends via thermogravimetric analysis (TGA)

Idris SS, Rahman NA, Ismail K

Bioresour Technol, 2012 Nov;123:581-91.
PMID: 22944493 DOI: 10.1016/j.biortech.2012.07.065

The combustion characteristics of Malaysia oil palm biomass (palm kernel shell (PKS), palm mesocarp fibre (PMF) and empty fruit bunches (EFB)), sub-bituminous coal (Mukah Balingian) and coal/biomass blends via thermogravimetric analysis (TGA) were investigated. Six weight ratios of coal/biomass blends were prepared and oxidised under dynamic conditions from temperature 25 to 1100°C at four heating rates. The thermogravimetric analysis demonstrated that the EFB and PKS evolved additional peak besides drying, devolatilisation and char oxidation steps during combustion. Ignition and burn out temperatures of blends were improved in comparison to coal. No interactions were observed between the coal and biomass during combustion. The apparent activation energy during this process was evaluated using iso-conversional model free kinetics which resulted in highest activation energy during combustion of PKS followed by PMF, EFB and MB coal. Blending oil palm biomass with coal reduces the apparent activation energy value.
Investigation on thermochemical behaviour of low rank Malaysian coal, oil palm biomass and their blends during pyrolysis via thermogravimetric analysis (TGA)

Idris SS, Abd Rahman N, Ismail K, Alias AB, Abd Rashid Z, Aris MJ

Bioresour Technol, 2010 Jun;101(12):4584-92.
PMID: 20153633 DOI: 10.1016/j.biortech.2010.01.059

This study aims to investigate the behaviour of Malaysian sub-bituminous coal (Mukah Balingian), oil palm biomass (empty fruit bunches (EFB), kernel shell (PKS) and mesocarp fibre (PMF)) and their respective blends during pyrolysis using thermogravimetric analysis (TGA). The coal/palm biomass blends were prepared at six different weight ratios and experiments were carried out under dynamic conditions using nitrogen as inert gas at various heating rates to ramp the temperature from 25 degrees C to 900 degrees C. The derivative thermogravimetric (DTG) results show that thermal decomposition of EFB, PMF and PKS exhibit one, two and three distinct evolution profiles, respectively. Apparently, the thermal profiles of the coal/oil palm biomass blends appear to correlate with the percentage of biomass added in the blends, thus, suggesting lack of interaction between the coal and palm biomass. First-order reaction model were used to determine the kinetics parameters for the pyrolysis of coal, palm biomass and their respective blends.
Ethanol fermentation in an immobilized cell reactor using Saccharomyces cerevisiae

Najafpour G, Younesi H, Syahidah Ku Ismail K

Bioresour Technol, 2004 May;92(3):251-60.
PMID: 14766158

Fermentation of sugar by Saccharomyces cerevisiae, for production of ethanol in an immobilized cell reactor (ICR) was successfully carried out to improve the performance of the fermentation process. The fermentation set-up was comprised of a column packed with beads of immobilized cells. The immobilization of S. cerevisiae was simply performed by the enriched cells cultured media harvested at exponential growth phase. The fixed cell loaded ICR was carried out at initial stage of operation and the cell was entrapped by calcium alginate. The production of ethanol was steady after 24 h of operation. The concentration of ethanol was affected by the media flow rates and residence time distribution from 2 to 7 h. In addition, batch fermentation was carried out with 50 g/l glucose concentration. Subsequently, the ethanol productions and the reactor productivities of batch fermentation and immobilized cells were compared. In batch fermentation, sugar consumption and ethanol production obtained were 99.6% and 12.5% v/v after 27 h while in the ICR, 88.2% and 16.7% v/v were obtained with 6 h retention time. Nearly 5% ethanol production was achieved with high glucose concentration (150 g/l) at 6 h retention time. A yield of 38% was obtained with 150 g/l glucose. The yield was improved approximately 27% on ICR and a 24 h fermentation time was reduced to 7 h. The cell growth rate was based on the Monod rate equation. The kinetic constants (K(s) and mu(m)) of batch fermentation were 2.3 g/l and 0.35 g/lh, respectively. The maximum yield of biomass on substrate (Y(X-S)) and the maximum yield of product on substrate (Y(P-S)) in batch fermentations were 50.8% and 31.2% respectively. Productivity of the ICR were 1.3, 2.3, and 2.8 g/lh for 25, 35, 50 g/l of glucose concentration, respectively. The productivity of ethanol in batch fermentation with 50 g/l glucose was calculated as 0.29 g/lh. Maximum production of ethanol in ICR when compared to batch reactor has shown to increase approximately 10-fold. The performance of the two reactors was compared and a respective rate model was proposed. The present research has shown that high sugar concentration (150 g/l) in the ICR column was successfully converted to ethanol. The achieved results in ICR with high substrate concentration are promising for scale up operation. The proposed model can be used to design a lager scale ICR column for production of high ethanol concentration.
Fulltext Determinants of stakeholders' attitudes towards biodiesel

Amin L, Hashim H, Mahadi Z, Ibrahim M, Ismail K

Biotechnol Biofuels, 2017;10:219.
PMID: 28932261 DOI: 10.1186/s13068-017-0908-8

BACKGROUND: Concern about the inevitable depletion of global energy resources is rising and many countries are shifting their focus to renewable energy. Biodiesel is one promising energy source that has garnered much public attention in recent years. Many believe that this alternative source of energy will be able to sustain the need for increased energy security while at the same time being friendly to the environment. Public opinion, as well as proactive measures by key players in industry, may play a decisive role in steering the direction of biodiesel development throughout the world. Past studies have suggested that public acceptance of biofuels could be shaped by critical consideration of the risk-benefit perceptions of the product, in addition to the impact on the economy and environment.
RESULTS: The purpose of this study was to identify the relevant factors influencing stakeholders' attitudes towards biodiesel derived from crops such as palm oil for vehicle use, as well as to analyse the interrelationships of these factors in an attitude model. A survey of 509 respondents, consisting of various stakeholder groups in the Klang Valley region of Malaysia, was undertaken. The results of the study have substantiated the premise that the most important direct predictor of attitude to biodiesel is the perceived benefits (β = 0.80, p
Influence of physico-chemical characteristics of rembau river, peninsular Malaysia, on congregating Pteroptyx fireflies

Abdullah NA, Asri LN, Husin SM, Shukor AM, Darbis NDA, Ismail K, et al.

Environ Monit Assess, 2021 Sep 07;193(10):634.
PMID: 34491451 DOI: 10.1007/s10661-021-09426-y

We studied the water quality of the riparian firefly sanctuary of Sungai Rembau, or Rembau River, in Negeri Sembilan, Malaysia, from January 2018 to November 2018 to determine the possible influence of the physico-chemical characteristics of the water on the firefly populations living within the sanctuary. We set up a total of five water quality sampling stations and 10 firefly sampling stations along the river. Dissolved oxygen (DO), temperature, pH and electrical conductivity (EC) were measured in situ, while chemical oxygen demand (COD), total suspended solids (TSS), biochemical oxygen demand (BOD) and ammonia-nitrogen (NH3-N) were analysed in the laboratory. Firefly samples were collected using a sweep net at both day and night for 1 min. Sungai Rembau was categorized as Class II on the Malaysian water quality index (WQI), which indicates slight pollution. Except for EC and DO, the water quality parameter values were not significantly different (p > 0.05) between the sampling stations. A total of 529 firefly individuals consisting of Pteroptyx tener (n = 525, 99.24%), P. malaccae (n = 3, 0.57%) and P. asymmetria (n = 1, 0.19%) were collected. There was significant correlation between firefly abundance and BOD (r = - 0.198, p
Fulltext Climate change considerations are fundamental to management of deep-sea resource extraction

Levin LA, Wei CL, Dunn DC, Amon DJ, Ashford OS, Cheung WWL, et al.

Glob Chang Biol, 2020 09;26(9):4664-4678.
PMID: 32531093 DOI: 10.1111/gcb.15223

Climate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to affect most deep-ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep-sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep-seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full-cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth-System Model projections of climate-change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep-seabed mining. Models that combine climate-induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep-seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral-related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep-ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.
Do staff capacity and performance-based budgeting improve organisational performance? Empirical evidence from Chinese public universities

He L, Ismail K

Humanit Soc Sci Commun, 2023;10(1):29.
PMID: 36712594 DOI: 10.1057/s41599-023-01523-2

The COVID-19 pandemic has raised many issues for higher education institutions, one of which is the continued decline in funding and an increased emphasis on effectiveness and efficiency. Performance-based budgeting is being adopted in organisations to allocate resources more efficiently, and Chinese public universities are no exception. The present study explicitly aimed to examine the relationship among staff capacity, performance-based budgeting, and organisational performance in Chinese public universities. It also investigated the role of top management support as a moderator. A purposive sampling method was used to select a total of 271 participants who agreed to participate in an online survey. A multimethod approach combining partial least squares-structural equation modelling (PLS-SEM), the PROCESS macro and necessary condition analysis (NCA) was adopted. The PLS-SEM results indicated that performance-based budgeting had a positive relationship with university performance and served as a mediator between staff capacity and university performance. The moderated mediation results showed that top management moderated the relationship among the selected variables. The NCA results suggested that both staff capacity and performance-based budgeting are meaningful and significant necessary conditions for university performance. The combined results indicated how researchers and practitioners can identify the factors that are critical for university performance and result in the best possible outcomes. This is possibly the first study to use this multimethod approach in accounting research. Overall, this study offers valuable insights into performance-based budgeting implementation in higher education institutions and may serve as a guideline for public universities to improve the efficiency of funding, reduce costs and increase revenues.
Fulltext Demographics characteristics and analysis of malocclusions of orthodontic patients seen at IIUM Dental Specialist Clinic, Kuantan, Pahang

Ismail, K., Ghazali@Suhaimi, S.S., Abu Bakar, N., Mokhtar, K.I., Kharuddin, A.F.

International Medical Journal Malaysia, 2017;16(2):107-111.
MyJurnal

Introduction: Malocclusion is one of the most common dental problems observed. Limited data is currently
available regarding the demographics of malocclusion observed locally.

Materials And Methods: This is a
retrospective study where 770 patients were recruited from May 2009 till December 2014. 560 orthodontic
study models that met the inclusion criteria were examined and the malocclusions were classified according
to the British Standard Institute (BSI) incisor classification. Demographic pattern and their relationship were
analysed by structural equation modelling using SPSS (version 23.0).

Results: From 560 study models
analysed, 72% were female. The age of the patients ranges from 7-12 years old (17.1%), 13-17 years old
(55.9%) and >18 years old (27.0%). Majority of the patients were Malay followed by Chinese (5.7%), Indian
(1.8%) and other races (1.8%) Treatments received were fixed appliances (FA) (60.0%), removable appliances
(RA) (12.5%), functional appliances (FnA) (1.1%), combination of RA and FA (16.1%), combination of FnA and
FA (2.1%) and consultation (8.2%). Types of malocclusions observed were Class I (25.7%), Class II/1(32.7%),
Class II/2 (7.5%) and Class III (34.1%). There was significant association (p
New magnetic Schiff's base-chitosan-glyoxal/fly ash/Fe3O4 biocomposite for the removal of anionic azo dye: An optimized process

Malek NNA, Jawad AH, Abdulhameed AS, Ismail K, Hameed BH

Int J Biol Macromol, 2020 Mar 01;146:530-539.
PMID: 31917215 DOI: 10.1016/j.ijbiomac.2020.01.020

In this study, a new magnetic Schiff's base-chitosan-glyoxal/fly ash/Fe3O4 biocomposite (Chi-Gly/FA/Fe3O4) was successfully synthesized by direct compositing of magnetic chitosan (Chi) with fly ash (FA) powder particles, and followed by Schiff's base formation via cross-linking reaction with glyoxal (Gly). Various techniques such as BET, XRD, FTIR, and SEM-EDX were utilized to characterize of Chi-Gly/FA/Fe3O4 biocomposite. The effectiveness of Chi-Gly/FA/Fe3O4 as an adsorbent was evaluated for the removal anionic azo dye such as reactive orange 16 (RO16) from aqueous environment. The effect of adsorption process parameters namely adsorbent dose (A: 0.02-0.1 g), solution pH (B: 4-10), temperature (C: 30-50 °C), and contact time (D: 5-20 min) were optimized via Box-Behnken design (BBD) in response surface methodology (RSM). The adsorption process followed the pseudo-second order (PSO) kinetic, and Freundlich isotherm models. The maximum adsorption capacity of Chi-Gly/FA/Fe3O4 biocomposite for RO16 dye was recorded to be 112.5 mg/g at 40 °C. The RO16 dye adsorption mechanism was attributed to various interactions such as electrostatic, n-π, H-bonding, and Yoshida H-bonding. Furthermore, the Chi-Gly/FA/Fe3O4 biocomposite exhibited a high ability to separate from the aqueous solution after adsorption process by external magnetic field.
Chitosan-glyoxal film as a superior adsorbent for two structurally different reactive and acid dyes: Adsorption and mechanism study

Jawad AH, Norrahma SSA, Hameed BH, Ismail K

Int J Biol Macromol, 2019 Aug 15;135:569-581.
PMID: 31150675 DOI: 10.1016/j.ijbiomac.2019.05.127

In this work, chitosan (Chi) was cross-linked with glyoxal (Gly) and deposited onto glass plate to be a superior adsorbent film for two structurally different reactive orange 16 (RO-16) and methyl orange (MO) dyes by using non-conventional adsorption system without filtration process. The characterizations indicate that the cross-linked chitosan-glyoxal (Chi-Gly) film has a low swelling index, high adherence strength on glass plate, amine group (NH2) content was 32.52%, and pHpzc of ∼6.0 indicating a negative surface charge occurs above pHpzc. The adsorption isotherm data of RO-16 and MO by Chi-Gly film were in agreement with Langmuir isotherm, with maximum adsorption capacities of 1554.3 mg/g and 1451.9 mg/g, respectively. The pseudo-first-order kinetic model best described the kinetic data. The adsorption process was spontaneous and exothermic in nature at Chi-Gly film thickness of 8.55 μm, and pH ~3. The mechanism of adsorption included mainly electrostatic attractions, dipole-dipole hydrogen bonding interactions, n-π stacking attractions, and Yoshida H-bonding. This study reveals that immobilized Chi-Gly film as a good candidate for adsorption of reactive and acid dyes as it does not require any filtration process and adsorbent recovery during and post-adsorption process.
Fly ash modified magnetic chitosan-polyvinyl alcohol blend for reactive orange 16 dye removal: Adsorption parametric optimization

Malek NNA, Jawad AH, Ismail K, Razuan R, ALOthman ZA

Int J Biol Macromol, 2021 Oct 31;189:464-476.
PMID: 34450144 DOI: 10.1016/j.ijbiomac.2021.08.160

A magnetic biocomposite blend of chitosan-polyvinyl alcohol/fly ash (m-Cs-PVA/FA) was developed by adding fly ash (FA) microparticles into the polymeric matrix of magnetic chitosan-polyvinyl alcohol (m-Cs-PVA). The effectiveness of m-Cs-PVA/FA as an adsorbent to remove textile dye (reactive orange 16, RO16) from aquatic environment was evaluated. The optimum adsorption key parameters and their significant interactions were determined by Box-Behnken Design (BBD). The analysis of variance (ANOVA) indicates the significant interactions can be observed between m-Cs-PVA/FA dose with solution pH, and m-Cs-PVA/FA dose with working temperature. Considering these significant interactions, the highest removal of RO16 (%) was found 90.3% at m-Cs-PVA/FA dose (0.06 g), solution pH (4), working temperature (30 °C), and contact time (17.5 min). The results of adsorption kinetics revealed that the RO16 adsorption was better described by the pseudo-second-order model. The results of adsorption isotherm indicated a multilayer adsorption process as well described by Freundlich model with maximum adsorption capacity of 123.8 mg/g at 30 °C. An external magnetic field can be easily applied to recover the adsorbent (m-Cs-PVA/FA). The results supported that the synthesized m-Cs-PVA/FA presents itself as an effective and promising adsorbent for textile dye with preferable adsorption capacity and separation ability during and after the adsorption process.
Fulltext Human facial neural activities and gesture recognition for machine-interfacing applications

Hamedi M, Salleh ShH, Tan TS, Ismail K, Ali J, Dee-Uam C, et al.

Int J Nanomedicine, 2011;6:3461-72.
PMID: 22267930 DOI: 10.2147/IJN.S26619

The authors present a new method of recognizing different human facial gestures through their neural activities and muscle movements, which can be used in machine-interfacing applications. Human-machine interface (HMI) technology utilizes human neural activities as input controllers for the machine. Recently, much work has been done on the specific application of facial electromyography (EMG)-based HMI, which have used limited and fixed numbers of facial gestures. In this work, a multipurpose interface is suggested that can support 2-11 control commands that can be applied to various HMI systems. The significance of this work is finding the most accurate facial gestures for any application with a maximum of eleven control commands. Eleven facial gesture EMGs are recorded from ten volunteers. Detected EMGs are passed through a band-pass filter and root mean square features are extracted. Various combinations of gestures with a different number of gestures in each group are made from the existing facial gestures. Finally, all combinations are trained and classified by a Fuzzy c-means classifier. In conclusion, combinations with the highest recognition accuracy in each group are chosen. An average accuracy >90% of chosen combinations proved their ability to be used as command controllers.
Fulltext A Mobile Phone App for the Prevention of Type 2 Diabetes in Malaysian Women With Gestational Diabetes Mellitus: Protocol for a Feasibility Randomized Controlled Trial

Benton M, Iman I, Goldsmith K, Forbes A, Ching SM, Papachristou Nadal I, et al.

JMIR Res Protoc, 2022 Sep 08;11(9):e37288.
PMID: 36074545 DOI: 10.2196/37288

BACKGROUND: Over 50% of women with a history of gestational diabetes mellitus (GDM) will develop type 2 diabetes (T2D) in later life. Asian women experience a disproportionate risk of both GDM and T2D compared to women from other ethnic backgrounds. Lifestyle interventions and behavior change can delay or even prevent the onset of T2D. We have developed a digitalized diabetes prevention intervention for the prevention of T2D in Malaysian women with GDM.
OBJECTIVE: The protocol describes a randomized controlled trial (RCT) to test the feasibility of undertaking a definitive trial of a diabetes prevention intervention, including a smartphone app and group support. Secondary aims are to summarize anthropometric, biomedical, psychological, and lifestyle outcomes overall and by allocation group, and to undertake a process evaluation.
METHODS: This is a two-arm parallel feasibility RCT. A total of 60 Malaysian women with GDM will be randomized in the antenatal period to receive the intervention or standard care until 12 months post partum. The intervention is a diabetes prevention intervention delivered via a smartphone app developed based on the Information-Motivation-Behavioral Skills model of behavior change and group support using motivational interviewing. The intervention provides women with tailored information and support to encourage weight loss through adapted dietary intake and physical activity. Women in the control arm will receive standard care. The Malaysian Ministry of Health's Medical Research and Ethics Committee has approved the trial (NMRR-21-1667-60212).
RESULTS: Recruitment and enrollment began in February 2022. Future outcomes will be published in peer-reviewed health-related research journals and presented at national, regional, or state professional meetings and conferences. This publication is based on protocol version 2, January 19, 2022.
CONCLUSIONS: To our knowledge, this will be the first study in Malaysia that aims to determine the feasibility of a digital intervention in T2D prevention among women with GDM. Findings from this feasibility study will inform the design of a full-scale RCT in the future.
TRIAL REGISTRATION: ClinicalTrials.gov NCT05204706; https://clinicaltrials.gov/ct2/show/NCT05204706.
INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/37288.
The prevalence of oral tori in Malaysians

Yaacob H, Tirmzi H, Ismail K

J Oral Med, 1983 Jan-Mar;38(1):40-2.
PMID: 6573459
Fulltext Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films

Raship NA, Tawil SNM, Nayan N, Ismail K, Bakri AS, Azman Z, et al.

Materials (Basel), 2022 Nov 14;15(22).
PMID: 36431511 DOI: 10.3390/ma15228025

Undoped ZnO, Gd-doped ZnO with various doping concentration (1, 3, 5, and 7 at%), and 3 at% (Gd, Al) co-doped ZnO films were prepared on a glass substrate using the co-reactive sputtering method. The influence of the doping and co-doping process on the films was characterized using X-ray diffraction, FESEM, EDX, MFM, VSM, UV-VIS spectroscopy, and the Hall Effect measurement at room temperature. XRD study confirmed that the Gd and Al ions are incorporated into a ZnO lattice. EDX analysis confirmed the existence of Zn, O, Al, and Gd elements in the prepared Gd-doped ZnO and (Gd, Al) co-doped ZnO films, which suggests the successful doping procedure. All the deposited films obtained maximum optical transmittance above 80%, showing a high transparency of the films in the visible region. The optical band gap was found red-shifted from 3.11 to 3.21 eV with the increase in Gd doping concentration. The increase in band gap energy from 3.14 eV to 3.16 eV was obtained for 3 at% Gd and 3 at% (Gd, Al) co-doped ZnO films. The MFM measurement proved the existence of room-temperature ferromagnetism and spin polarization in Gd and (Gd, Al) co-doped ZnO films. By co-doping with Al, the result obtained from MFM shows the enhancement of magnetic properties, as it exhibited a smaller domain size with a shorter magnetic correlation length L, a larger phase shift Φrms, and the highest value of δfrms compared to the sample with 3 at% Gd incorporated into ZnO. The carrier concentration and electrical conductivity increased with the increase in Gd concentration, whereas the electrical resistivity and hall mobility showed a reverse trend. The similar trend of results obtained for 3 at% (Gd, Al) co-doped ZnO as compared to 3 at% Gd-doped ZnO also indicates greater electrical properties after a shallow donor such as aluminum was incorporated into Gd-doped ZnO thin films. In conclusion, for future applications, one should consider the possible influence of other types of shallow donor incorporation in an attempt to enhance the properties of new types of diluted magnetic semiconductors (DMSs).
Fulltext Effect of Al Concentration on Structural, Optical and Electrical Properties of (Gd, Al) Co-Doped ZnO and Its n-ZnO/p-Si (1 0 0) Heterojunction Structures Prepared via Co-Sputtering Method

Raship NA, Tawil SNM, Nayan N, Ismail K

Materials (Basel), 2023 Mar 16;16(6).
PMID: 36984272 DOI: 10.3390/ma16062392

Heterojunction structures of n-ZnO/p-Si were prepared through the growth of undoped ZnO and (Gd, Al) co-doped ZnO films onto p-type Si (1 0 0) substrates, using a co-sputtering method. The structural and optical properties of the Gd-doped ZnO films were studied as a function of different Al doping concentrations. The X-ray diffraction profiles indicated that the films had a nanocrystalline structure of ZnO with a (0 0 2) preferential orientation. An increase in the Al doping concentration deteriorated the (0 0 2) diffraction peak intensity. The transmittance measurements in the UV-Vis wavelength range indicated that the film's optical gap increased with increase in Al doping concentration. The heterojunction parameters were evaluated using the current-voltage (I-V) characterization carried out of the fabricated n-ZnO/p-Si heterostructure, in dark conditions at room temperature. From these measurements, the n-ZnO-based DMS/p-Si heterojunction diode with the use of (Gd, Al) co-doped ZnO film showed the lowest leakage current of 1.28 × 10-8 A and an ideality factor η of 1.11, close to the ideal diode behavior of η = 1, compared to the n-Gd-doped ZnO/p-Si and n-undoped ZnO/p-Si heterojunction diodes.
Fulltext The Accuracy of the Patient Health Questionnaire-9 Algorithm for Screening to Detect Major Depression: An Individual Participant Data Meta-Analysis

He C, Levis B, Riehm KE, Saadat N, Levis AW, Azar M, et al.

Psychother Psychosom, 2020;89(1):25-37.
PMID: 31593971 DOI: 10.1159/000502294

BACKGROUND: Screening for major depression with the Patient Health Questionnaire-9 (PHQ-9) can be done using a cutoff or the PHQ-9 diagnostic algorithm. Many primary studies publish results for only one approach, and previous meta-analyses of the algorithm approach included only a subset of primary studies that collected data and could have published results.
OBJECTIVE: To use an individual participant data meta-analysis to evaluate the accuracy of two PHQ-9 diagnostic algorithms for detecting major depression and compare accuracy between the algorithms and the standard PHQ-9 cutoff score of ≥10.
METHODS: Medline, Medline In-Process and Other Non-Indexed Citations, PsycINFO, Web of Science (January 1, 2000, to February 7, 2015). Eligible studies that classified current major depression status using a validated diagnostic interview.
RESULTS: Data were included for 54 of 72 identified eligible studies (n participants = 16,688, n cases = 2,091). Among studies that used a semi-structured interview, pooled sensitivity and specificity (95% confidence interval) were 0.57 (0.49, 0.64) and 0.95 (0.94, 0.97) for the original algorithm and 0.61 (0.54, 0.68) and 0.95 (0.93, 0.96) for a modified algorithm. Algorithm sensitivity was 0.22-0.24 lower compared to fully structured interviews and 0.06-0.07 lower compared to the Mini International Neuropsychiatric Interview. Specificity was similar across reference standards. For PHQ-9 cutoff of ≥10 compared to semi-structured interviews, sensitivity and specificity (95% confidence interval) were 0.88 (0.82-0.92) and 0.86 (0.82-0.88).
CONCLUSIONS: The cutoff score approach appears to be a better option than a PHQ-9 algorithm for detecting major depression.
Fulltext Marine electrical imaging reveals novel freshwater transport mechanism in Hawai'i

Attias E, Thomas D, Sherman D, Ismail K, Constable S

Sci Adv, 2020 Nov;6(48).
PMID: 33239299 DOI: 10.1126/sciadv.abd4866

Conventional hydrogeologic framework models used to compute ocean island sustainable yields and aquifer storage neglect the complexity of the nearshore and offshore submarine environment. However, the onshore aquifer at the island of Hawai'i exhibits a notable volumetric discrepancy between high-elevation freshwater recharge and coastal discharge. In this study, we present a novel transport mechanism of freshwater moving from onshore to offshore through a multilayer formation of water-saturated layered basalts with interbedded low-permeability layers of ash/soil. Marine electromagnetic imaging reveals ∼35 km of laterally continuous resistive layers that extend to at least 4 km from west of Hawai'i's coastline, containing about 3.5 km3 of freshened water. We propose that this newly found transport mechanism of fresh groundwater may be the governing mechanism in other volcanic islands. In such a scenario, volcanic islands worldwide can use these renewable offshore reservoirs, considered more resilient to climate change-driven droughts, as new water resources.

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