Displaying publications 1 - 20 of 55 in total

Abstract:
Sort:
  1. Kamarozaman NS, Zainal N, Rosli AB, Zulkefle MA, Nik Him NR, Abdullah WFH, et al.
    Gels, 2022 Oct 26;8(11).
    PMID: 36354598 DOI: 10.3390/gels8110690
    A highly selective and sensitive EGFET-pH sensor based on composite TiO2-PANI had been developed in this work. A sol-gel titanium dioxide (TiO2) and the composite of TiO2 with semiconducting polyaniline (PANI) were deposited using a simple spin-coating method on an indium tin oxide (ITO) substrate. The films have been explored as a sensing electrode (SE) of extended gate field-effect transistor (EGFET) for pH applications in the range of pH 2 to 12. The pH sensitivities between TiO2, TiO2-PANI bilayer composite, and TiO2-PANI composite thin films were discussed. Among these, the TiO2-PANI composite thin film showed a super-Nernstian behavior with high sensitivity of 66.1 mV/pH and linearity of 0.9931; good repeatability with a standard deviation of 0.49%; a low hysteresis value of 3 mV; and drift rates of 4.96, 5.54, and 3.32 mV/h in pH 4, 7, and 10, respectively, for 6 h. Upon applying the TiO2-PANI composite as the SE for nitrate measurement, low sensitivity of 12.9 mV/dec was obtained, indicating that this film is a highly selective sensing electrode as a pH sensor. The surface morphology and crystallinity of the thin films were also discussed.
  2. Klionsky DJ, Abdelmohsen K, Abe A, Abedin MJ, Abeliovich H, Acevedo Arozena A, et al.
    Autophagy, 2016;12(1):1-222.
    PMID: 26799652 DOI: 10.1080/15548627.2015.1100356
  3. Gunjal S, Pateel DGS, Yang YH, Doss JG, Bilal S, Maling TH, et al.
    Subst Use Misuse, 2020;55(9):1533-1544.
    PMID: 32569533 DOI: 10.1080/10826084.2019.1657149
    Background: Areca nut (AN) and betel quid (BQ) chewing are ancient practices followed by an extensive proportion of the world's population. These practices are endemic in larger parts of South and Southeast Asia and selected Western Pacific countries. The prevalence of these habits varies across regions, age, gender, cultural practice, and socioeconomic status groups. Considerable variations exist between countries with respect to prevention/intervention programs, and policy guidelines of BQ usage. Objectives: (1) To provide an overview of the BQ chewing prevalence, practices, preventive interventions and policies in selected Asian and Western Pacific countries. (2) To explore the different terminologies associated with BQ use. Method: A narrative review of the current literature related to BQ, AN, and oral cancer was conducted by searching PUBMED, CINAHL, and GOOGLE databases. Results: The literature review revealed that the prevalence of BQ was found to be highest in Papua New Guinea, followed by Bangladesh, India, Pakistan, Myanmar and Sri Lanka. While, Cambodia, Malaysia, Indonesia and Taiwan had comparatively lower prevalence. Smokeless tobacco, BQ with tobacco, BQ without tobacco, AN were some of the terminologies used for BQ in various studies. Conclusions: The prevalence, and the interventional policies related to BQ and AN chewing habits varies widely among the selected countries. With the increasing awareness and association of BQ with oral cancer, there is a need to have better awareness, prevention and interventional strategies in place. We also found considerable variation in the use of terminologies associated with BQ.
  4. Klionsky DJ, Abdel-Aziz AK, Abdelfatah S, Abdellatif M, Abdoli A, Abel S, et al.
    Autophagy, 2021 Jan;17(1):1-382.
    PMID: 33634751 DOI: 10.1080/15548627.2020.1797280
    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
  5. Jotani MM, Gajera NN, Patel MC, Sung HH, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Oct 1;71(Pt 10):1121-4.
    PMID: 26594387 DOI: 10.1107/S2056989015016023
    The title compound, C17H15N3O2, is a monoclinic polymorph (P21/c with Z' = 1) of the previously reported triclinic (P-1 with Z' = 2) form [Gajera et al. (2013 ▸). Acta Cryst. E69, o736-o737]. The mol-ecule in the monoclinic polymorph features a central pyrazolyl ring with an N-bound p-tolyl group and a C-bound 1,3-benzodioxolyl fused-ring system on either side of the C atom bearing the amino group. The dihedral angles between the central ring and the N- and C-bound rings are 50.06 (5) and 27.27 (5)°, respectively. The angle between the pendent rings is 77.31 (4)°, indicating the mol-ecule has a twisted conformation. The five-membered dioxolyl ring has an envelope conformation with the methyl-ene C atom being the flap. The relative disposition of the amino and dioxolyl substituents is syn. One of the independent mol-ecules in the triclinic form has a similar syn disposition but the other has an anti arrangement of these substituents. In the crystal structure of the monoclinic form, mol-ecules assemble into supra-molecular helical chains via amino-pyrazolyl N-H⋯N hydrogen bonds. These are linked into layers via C-H⋯π inter-actions, and layers stack along the a axis with no specific inter-actions between them.
  6. Herman LS, Fornace K, Phelan J, Grigg MJ, Anstey NM, William T, et al.
    PLoS Negl Trop Dis, 2018 Jun;12(6):e0006457.
    PMID: 29902183 DOI: 10.1371/journal.pntd.0006457
    BACKGROUND: Plasmodium knowlesi is the most common cause of malaria in Malaysian Borneo, with reporting limited to clinical cases presenting to health facilities and scarce data on the true extent of transmission. Serological estimations of transmission have been used with other malaria species to garner information about epidemiological patterns. However, there are a distinct lack of suitable serosurveillance tools for this neglected disease.

    METHODOLOGY/PRINCIPAL FINDINGS: Using in silico tools, we designed and expressed four novel P. knowlesi protein products to address the distinct lack of suitable serosurveillance tools: PkSERA3 antigens 1 and 2, PkSSP2/TRAP and PkTSERA2 antigen 1. Antibody prevalence to these antigens was determined by ELISA for three time-points post-treatment from a hospital-based clinical treatment trial in Sabah, East Malaysia (n = 97 individuals; 241 total samples for all time points). Higher responses were observed for the PkSERA3 antigen 2 (67%, 65/97) across all time-points (day 0: 36.9% 34/92; day 7: 63.8% 46/72; day 28: 58.4% 45/77) with significant differences between the clinical cases and controls (n = 55, mean plus 3 SD) (day 0 p<0.0001; day 7 p<0.0001; day 28 p<0.0001). Using boosted regression trees, we developed models to classify P. knowlesi exposure (cross-validated AUC 88.9%; IQR 86.1-91.3%) and identified the most predictive antibody responses.

    CONCLUSIONS/SIGNIFICANCE: The PkSERA3 antigen 2 had the highest relative variable importance in all models. Further validation of these antigens is underway to determine the specificity of these tools in the context of multi-species infections at the population level.

  7. Tan CS, Noni V, Melina WUHU, Abdorahman US, Bimbang JN, Malik NMA, et al.
    Sci Rep, 2022 09 19;12(1):15665.
    PMID: 36123431 DOI: 10.1038/s41598-022-19776-3
    Several vaccines have been fast-tracked through clinical trials to mitigate the progression of the SARS‑CoV‑2 pandemic. We analyzed sequential blood samples from 314 recipients of Comirnaty and CoronaVac in East Malaysia for the spike-binding IgG (IgG-S), nucleocapsid-binding IgG (IgG-N), spike-binding IgM (IgM-S) and serum vitamin D (VitD). A subset of samples was analyzed for the neutralizing antibodies (Ig-RBD). Results showed that IgG-S due to Comirnaty was significantly higher than CoronaVac. IgM-S was detected in 80.0% Comirnaty and 69.5% CoronaVac recipients, while IgG-N was detected in 58.1% CoronaVac but not in Comirnaty recipients. All IgG-S-positive vaccines possessed detectable Ig-RBD after the second dose but with a weak to moderate correlation. The serum VitD levels did not influence the antibody magnitude in both vaccines. In essence, SARS-CoV-2 vaccination is an IgG-S-dominant event, Comirnaty was more effective than CoronaVac in mounting IgG-S and Ig-RBD responses, independent of the patient's VitD level.
  8. Norliza Othman, Uzer Mohd Noor, Sukreen Hana Herman
    MyJurnal
    In this work, sensors were prepared by depositing the pH sensitive indicator (bromothymol blue)
    entrapped in polyaniline sol-gel onto the un-cladded middle potion of optical fiber. Polyaniline is sensitive
    to pH. However, it is important to study ways to increase sensitivity of the indicator by improving a
    combination of the materials used and pH sensor fabrication method. The fabrication and characterisation
    of optical fiber pH sensor on absorption intensity in arbitrary unit (a.u) were evaluated and optimised.
    The better sensitivity of the optical pH sensor was used to identify the optimum setting for number of
    layers deposited, coated length, and withdrawal rate. Thickness of the membrane film depends on the
    number of deposited layers and withdrawal speed which mainly affects sensitivity. The sensitivity of
    the optical pH sensor represents the slope (a.u/pH) of the absorbance intensities in pH 4, 5, 7, 9 and 10.
    Results obtained herein suggest that the optimised setting for bromothymol blue sol-gel coated optical
    fiber with thickness of 285.4 nm is 4 deposited layers, 20mm/s withdrawal rate and 0.5 cm coated length.
  9. Walsh N, Zhang H, Hyland PL, Yang Q, Mocci E, Zhang M, et al.
    J Natl Cancer Inst, 2019 Jun 01;111(6):557-567.
    PMID: 30541042 DOI: 10.1093/jnci/djy155
    BACKGROUND: Genome-wide association studies (GWAS) identify associations of individual single-nucleotide polymorphisms (SNPs) with cancer risk but usually only explain a fraction of the inherited variability. Pathway analysis of genetic variants is a powerful tool to identify networks of susceptibility genes.

    METHODS: We conducted a large agnostic pathway-based meta-analysis of GWAS data using the summary-based adaptive rank truncated product method to identify gene sets and pathways associated with pancreatic ductal adenocarcinoma (PDAC) in 9040 cases and 12 496 controls. We performed expression quantitative trait loci (eQTL) analysis and functional annotation of the top SNPs in genes contributing to the top associated pathways and gene sets. All statistical tests were two-sided.

    RESULTS: We identified 14 pathways and gene sets associated with PDAC at a false discovery rate of less than 0.05. After Bonferroni correction (P ≤ 1.3 × 10-5), the strongest associations were detected in five pathways and gene sets, including maturity-onset diabetes of the young, regulation of beta-cell development, role of epidermal growth factor (EGF) receptor transactivation by G protein-coupled receptors in cardiac hypertrophy pathways, and the Nikolsky breast cancer chr17q11-q21 amplicon and Pujana ATM Pearson correlation coefficient (PCC) network gene sets. We identified and validated rs876493 and three correlating SNPs (PGAP3) and rs3124737 (CASP7) from the Pujana ATM PCC gene set as eQTLs in two normal derived pancreas tissue datasets.

    CONCLUSION: Our agnostic pathway and gene set analysis integrated with functional annotation and eQTL analysis provides insight into genes and pathways that may be biologically relevant for risk of PDAC, including those not previously identified.

  10. Saleem Z, Hassali MA, Versporten A, Godman B, Hashmi FK, Goossens H, et al.
    Expert Rev Anti Infect Ther, 2019 04;17(4):285-293.
    PMID: 30755077 DOI: 10.1080/14787210.2019.1581063
    OBJECTIVES: In line with the recent global action plan for antimicrobial resistance, this is the first time such a comprehensive antimicrobial point prevalence survey has been undertaken in Pakistan, the sixth most populous country.

    METHODS: This point prevalence survey (PPS) was conducted in 13 hospitals among 7 different cities of Pakistan. The survey included all inpatients receiving an antibiotic on the day of PPS. A web-based application was used for data entry, validation, and reporting as designed by the University of Antwerp (www.global-pps.com).

    RESULTS: Out of 1954 patients, 1516 (77.6%) were treated with antibiotics. The top three most reported indications for antibiotic use were prophylaxis for obstetrics or gynaecological indications (16.5%), gastrointestinal indications (12.6%) and lower respiratory tract infections (12.0%). The top three most commonly prescribed antibiotics were ceftriaxone (35.0%), metronidazole (16.0%) and ciprofloxacin (6.0%). Out of the total indications, 34.2% of antibiotics were prescribed for community-acquired infections (CAI), 5.9% for healthcare-associated infections (HAI), and 57.4% for either surgical or medical prophylaxis. Of the total use for surgical prophylaxis, 97.4% of antibiotics were given for more than one day.

    CONCLUSIONS: Unnecessary prophylactic antibiotic use is extremely high, and broad-spectrum prescribing is common among hospitals in Pakistan. There is an urgent need to work on the  national action plan of Pakistan on antibiotic resistance to address this.

  11. Budiman C, Lindang HU, Cheong BE, Rodrigues KF
    Protein J, 2018 06;37(3):270-279.
    PMID: 29761378 DOI: 10.1007/s10930-018-9772-z
    SIB1 FKBP22 is a peptidyl prolyl cis-trans isomerase (PPIase) member from a psychrotrophic bacterium, Shewanella sp. SIB1, consisting of N- and C-domains responsible for dimerization and catalytic PPIase activity, respectively. This protein was assumed to be involved in cold adaptation of SIB1 cells through its dual activity of PPIase activity and chaperone like-function. Nevertheless, the catalytic inhibition by FK506 and its substrate specificity remain unknown. Besides, ability of SIB1 FKBP22 to inhibit phosphatase activity of calcinuerin is also interesting to be studied since it may reflect wider cellular functions of SIB1 FKBP22. In this study, we found that wild type (WT) SIB1 FKBP22 bound to FK506 with IC50 of 77.55 nM. This value is comparable to that of monomeric mutants (NNC-FKBP22, C-domain+ and V37R/L41R mutants), yet significantly higher than that of active site mutant (R142A). In addition, WT SIB1 FKBP22 and monomeric variants were found to prefer hydrophobic residues preceding proline. Meanwhile, R142A mutant has wider preferences on bulkier hydrophobic residues due to increasing hydrophobicity and binding pocket space. Surprisingly, in the absence of FK506, SIB1 FKBP22 and its variants inhibited, with the exception of N-domain, calcineurin phosphatase activity, albeit low. The inhibition of SIB1 FKBP22 by FK506 is dramatically increased in the presence of FK506. Altogether, we proposed that local structure at substrate binding pocket of C-domain plays crucial role for the binding of FK506 and peptide substrate preferences. In addition, C-domain is essential for inhibition, while dimerization state is important for optimum inhibition through efficient binding to calcineurin.
  12. Tuminoh H, Hermawan H, Ramlee MH
    J Mech Behav Biomed Mater, 2022 Nov;135:105457.
    PMID: 36116340 DOI: 10.1016/j.jmbbm.2022.105457
    In the last decade, magnesium alloys have been considered as absorbable metals for biomedical applications, while some have reached their clinical use as temporary bone implants. However, their widespread use is still limited by its strength and degradability. One way of improvement can be done by reinforcing magnesium alloys with carbon nanofibres to form composites. This work aims at developing carbon nanofibre-reinforced magnesium-zinc (Mg-Zn/CNF) composites with optimum strength and degradability while ensuring their biocompatibility. A response surface method was used to determine their optimum process parameters (composition, compaction pressure, and sintering temperature), and analyse the resulting properties (elastic modulus, hardness, weight loss, and cytocompatibility). Results showed that the optimal parameters were reached at 1.8% of CNF, 425 MPa of compaction pressure, and 500 °C of sintering temperature, whereby it gave an elastic modulus of 5 GPa, hardness of 60 Hv, and a weight loss of 51% after three days immersion in PBS. The composites exhibited a hydrophobic surface that controlled the liberation of Mg2+ and Zn2+ ions, leading to more than 70% osteoblast cells viability up to seven days of incubation. This study can also serve as a starting point for future researchers interested in finding methods to fabricate Mg-Zn/CNF composites with high mechanical characteristics, corrosion resistance, and biocompatibility.
  13. Calleja N, AbdAllah A, Abad N, Ahmed N, Albarracin D, Altieri E, et al.
    JMIR Infodemiology, 2021 09 15;1(1):e30979.
    PMID: 34604708 DOI: 10.2196/30979
    Background: An infodemic is an overflow of information of varying quality that surges across digital and physical environments during an acute public health event. It leads to confusion, risk-taking, and behaviors that can harm health and lead to erosion of trust in health authorities and public health responses. Owing to the global scale and high stakes of the health emergency, responding to the infodemic related to the pandemic is particularly urgent. Building on diverse research disciplines and expanding the discipline of infodemiology, more evidence-based interventions are needed to design infodemic management interventions and tools and implement them by health emergency responders.

    Objective: The World Health Organization organized the first global infodemiology conference, entirely online, during June and July 2020, with a follow-up process from August to October 2020, to review current multidisciplinary evidence, interventions, and practices that can be applied to the COVID-19 infodemic response. This resulted in the creation of a public health research agenda for managing infodemics.

    Methods: As part of the conference, a structured expert judgment synthesis method was used to formulate a public health research agenda. A total of 110 participants represented diverse scientific disciplines from over 35 countries and global public health implementing partners. The conference used a laddered discussion sprint methodology by rotating participant teams, and a managed follow-up process was used to assemble a research agenda based on the discussion and structured expert feedback. This resulted in a five-workstream frame of the research agenda for infodemic management and 166 suggested research questions. The participants then ranked the questions for feasibility and expected public health impact. The expert consensus was summarized in a public health research agenda that included a list of priority research questions.

    Results: The public health research agenda for infodemic management has five workstreams: (1) measuring and continuously monitoring the impact of infodemics during health emergencies; (2) detecting signals and understanding the spread and risk of infodemics; (3) responding and deploying interventions that mitigate and protect against infodemics and their harmful effects; (4) evaluating infodemic interventions and strengthening the resilience of individuals and communities to infodemics; and (5) promoting the development, adaptation, and application of interventions and toolkits for infodemic management. Each workstream identifies research questions and highlights 49 high priority research questions.

    Conclusions: Public health authorities need to develop, validate, implement, and adapt tools and interventions for managing infodemics in acute public health events in ways that are appropriate for their countries and contexts. Infodemiology provides a scientific foundation to make this possible. This research agenda proposes a structured framework for targeted investment for the scientific community, policy makers, implementing organizations, and other stakeholders to consider.

  14. Ayensu J, Annan R, Lutterodt H, Edusei A, Peng LS
    PLoS One, 2020;15(1):e0226026.
    PMID: 31978048 DOI: 10.1371/journal.pone.0226026
    BACKGROUND: Anaemia remains a major cause of morbidity and mortality among women and children worldwide. Because deficiencies in essential micronutrients such as iron, folate and vitamin B12 prior to and during gestation increase a woman's risk of being anaemic, adequate dietary intake of such nutrients is vital during this important phase in life. However, information on the dietary micronutrient intakes of pregnant women in Ghana, particularly of those resident in rural areas is scanty. Thus, this study aimed to assess anaemia prevalence and dietary micronutrient intakes in pregnant women in urban and rural areas in Ghana.

    METHODS: A comparative cross sectional study design involving 379 pregnant women was used to assess the prevalence of anaemia and low intake of dietary nutrients in pregnant women living in rural and urban areas in the Ashanti region of Ghana. Anaemia status and mid upper arm circumference (MUAC) were used as proxy for maternal nutritional status. Haemoglobin measurements were used to determine anaemia prevalence and the dietary diversity of the women were determined with a 24-hour dietary recall and a food frequency questionnaire.

    RESULTS: Overall, anaemia was present in 56.5% of the study population. Anaemia prevalence was higher among rural residents than urban dwellers. Majority of the respondents had inadequate intakes of iron, zinc, folate, calcium and vitamin A. The mean dietary diversity score (DDS) of the study population from the first 24-hour recall was 3.81 ± 0.7. Of the 379 women, 28.8% met the minimum dietary diversity for women (MDD-W). The independent predictors of haemoglobin concentration were, gestational age, maternal age and dietary diversity score. Such that respondents with low DDS were more likely to be anaemic than those with high DDS (OR = 1.795, p = 0.022, 95% CI: 1.086 to 2.967).

    CONCLUSIONS: A large percentage of pregnant women still have insufficient dietary intakes of essential nutrients required to support the nutritional demands during pregnancy. Particularly, pregnant women resident in rural areas require interventions such as nutrition education on the selection and preparation of diversified meals to mitigate the effects of undernutrition.

  15. Strobl C, Churchill Cihlar J, Lagacé R, Wootton S, Roth C, Huber N, et al.
    Forensic Sci Int Genet, 2019 09;42:244-251.
    PMID: 31382159 DOI: 10.1016/j.fsigen.2019.07.013
    The emergence of Massively Parallel Sequencing technologies enabled the analysis of full mitochondrial (mt)DNA sequences from forensically relevant samples that have, so far, only been typed in the control region or its hypervariable segments. In this study, we evaluated the performance of a commercially available multiplex-PCR-based assay, the Precision ID mtDNA Whole Genome Panel (Thermo Fisher Scientific), for the amplification and sequencing of the entire mitochondrial genome (mitogenome) from even degraded forensic specimens. For this purpose, more than 500 samples from 24 different populations were selected to cover the vast majority of established superhaplogroups. These are known to harbor different signature sequence motifs corresponding to their phylogenetic background that could have an effect on primer binding and, thus, could limit a broad application of this molecular genetic tool. The selected samples derived from various forensically relevant tissue sources and were DNA extracted using different methods. We evaluated sequence concordance and heteroplasmy detection and compared the findings to conventional Sanger sequencing as well as an orthogonal MPS platform. We discuss advantages and limitations of this approach with respect to forensic genetic workflow and analytical requirements.
  16. Thompson AM, Smit HGJ, Witte JC, Stauffer RM, Johnson BJ, Morris G, et al.
    Bull Am Meteorol Soc, 2019 Jan;100(1):155-171.
    PMID: 33005057 DOI: 10.1175/bams-d-17-0311.1
    The ozonesonde is a small balloon-borne instrument that is attached to a standard radiosonde to measure profiles of ozone from the surface to 35 km with ~100-m vertical resolution. Ozonesonde data constitute a mainstay of satellite calibration and are used for climatologies and analysis of trends, especially in the lower stratosphere where satellites are most uncertain. The electrochemical-concentration cell (ECC) ozonesonde has been deployed at ~100 stations worldwide since the 1960s, with changes over time in manufacture and procedures, including details of the cell chemical solution and data processing. As a consequence, there are biases among different stations and discontinuities in profile time-series from individual site records. For 22 years the Jülich [Germany] Ozone Sonde Intercomparison Experiment (JOSIE) has periodically tested ozonesondes in a simulation chamber designated the World Calibration Centre for Ozonesondes (WCCOS) by WMO. In October-November 2017 a JOSIE campaign evaluated the sondes and procedures used in SHADOZ (Southern Hemisphere Additional Ozonesondes), a 14-station sonde network operating in the tropics and subtropics. A distinctive feature of the 2017 JOSIE was that the tests were conducted by operators from eight SHADOZ stations. Experimental protocols for the SHADOZ sonde configurations, which represent most of those in use today, are described, along with preliminary results. SHADOZ stations that follow WMO-recommended protocols record total ozone within 3% of the JOSIE reference instrument. These results and prior JOSIEs demonstrate that regular testing is essential to maintain best practices in ozonesonde operations and to ensure high-quality data for the satellite and ozone assessment communities.
  17. Burgess AJ, Retkute R, Herman T, Murchie EH
    Front Plant Sci, 2017;8:734.
    PMID: 28567045 DOI: 10.3389/fpls.2017.00734
    The arrangement of leaf material is critical in determining the light environment, and subsequently the photosynthetic productivity of complex crop canopies. However, links between specific canopy architectural traits and photosynthetic productivity across a wide genetic background are poorly understood for field grown crops. The architecture of five genetically diverse rice varieties-four parental founders of a multi-parent advanced generation intercross (MAGIC) population plus a high yielding Philippine variety (IR64)-was captured at two different growth stages using a method for digital plant reconstruction based on stereocameras. Ray tracing was employed to explore the effects of canopy architecture on the resulting light environment in high-resolution, whilst gas exchange measurements were combined with an empirical model of photosynthesis to calculate an estimated carbon gain and total light interception. To further test the impact of different dynamic light patterns on photosynthetic properties, an empirical model of photosynthetic acclimation was employed to predict the optimal light-saturated photosynthesis rate (Pmax ) throughout canopy depth, hypothesizing that light is the sole determinant of productivity in these conditions. First, we show that a plant type with steeper leaf angles allows more efficient penetration of light into lower canopy layers and this, in turn, leads to a greater photosynthetic potential. Second the predicted optimal Pmax responds in a manner that is consistent with fractional interception and leaf area index across this germplasm. However, measured Pmax , especially in lower layers, was consistently higher than the optimal Pmax indicating factors other than light determine photosynthesis profiles. Lastly, varieties with more upright architecture exhibit higher maximum quantum yield of photosynthesis indicating a canopy-level impact on photosynthetic efficiency.
  18. Nitanan Koshy Matthew, Ahmad Shuib, Sridar Ramachandran, Syamsul Herman Mohammad Afandi, Zaiton Samdin, Ismail Muhammad, et al.
    Sains Malaysiana, 2018;47:447-455.
    Forest degradation and deforestation are some of the major global concerns as they can reduce the forest carbon stock
    and sequestration capacity. However, the carbon stock and sequestration potential in a mixed dipterocarp tropical forest
    remains unclear due to a lack of information. This study was carried out on the carbon stock and estimated its economic
    value to justify its conservation. Six plots were established in the Endau Rompin National Park, Johor and subplots
    measuring 50 × 20 m were established in each plot. All trees greater than 15 cm DBH (diameter at breast height) were
    identified and the parameters measured included tree height and diameter. The aboveground carbon (AGC) content was
    about 222 Mg(C) ha-1, belowground carbon (BGC) was 53 Mg (C) ha-1 and it was 6 Mg (C) ha-1 for other components.
    In total, the carbon stock amounted to 281 Mg (C) ha-1. On the other hand, the total CO2 sequestrated in the mixed
    dipterocarp forest amounted to 1,040 t CO2
    ha-1. The carbon value was estimated at RM32,240 t CO2
    ha-1 or $7,280 t CO2
    ha-1. Therefore, the study found that the dipterocarp forest should be preserved to mitigate greenhouse gas emissions.
  19. Muhammad Al Kahfi Edrus, Muhammad Sallehuddin Mohd Azman, Herman Tuminoh, Ahmad Kafrawi Nasution, Muhammad Hanif Ramlee
    MyJurnal
    Introduction: Biodegradable materials, such as Mg-based, Fe-based, and Zn-based, bring as much attention as bone-implant materials due to its biocompatibility and biodegradability characteristics. Among them, the Mg is the most abundant elements in human body and primarily found in the bones. However, the Mg has a lower mechanical properties and resistances to fracture compared to the other biodegradable and non-biodegradable metals. Therefore, the aim of this study was to develop a possible biodegradable material made of Mg-Zn alloys reinforced with carbon nano fiber (CNF) and later tested with several testing procedures. Methods: The powder metallurgy method (PM) was utilized to fabricate a total of 24 samples of Mg-Zn alloys reinforced with 1.0%wt, 1.2%wt, 1.4%wt, 1.6%wt, 1.8%wt and 2.0%wt of CNF. The PM method was involved with the process of grinding using ball milling, compaction under 400MPa pressure and sintered under 400 °C. Compression testing was done to measure the mechanical strength meanwhile scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) was used to identify the microstructural of samples. Results: From this study, it was found that Mg-Zn alloys with 1.6 wt% of CNF produce the highest Young's modulus (2687.91MPa) with acceptable yield strength (84.91MPa). For microstructural analysis, the results showed a compact surface for 1.2, 1.4 and 1.6 wt% of CNF and non-homogeneous structure of all the samples. Conclusion: In conclusion, this study has successfully shown the promising use of Mg-Zn-CNF composite as new materials for implant in terms of suitable strength and structure.
  20. Wan Mahmud WM, Awang A, Herman I, Mohamed MN
    Malays J Med Sci, 2004 Jul;11(2):19-25.
    PMID: 22973123
    Increased international collaboration in clinical trials has created a need for cross culturally valid instruments to assess the quality of life and behavioural disorders. Cross cultural studies of depressive symptomatology, in particular, must be preceded by an exhaustive study of the psychometric properties of the instruments to ensure the validity of the comparison. In this article, we examined the validity, reliability and factor structure of the Malay version of the Beck Depression Inventory II (BDI-II) among Malay postpartum women attending selected health centres in Kedah, North West of Peninsular Malaysia. Our findings indicated that the current version of the BDI-II is psychometrically strong and appropriate for use in assessing depressive symptomatology among this group of women.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links