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Fulltext Deep Learning-Empowered Digital Twin Using Acoustic Signal for Welding Quality Inspection

Ji T, Mohamad Nor N

Sensors (Basel), 2023 Feb 28;23(5).
PMID: 36904847 DOI: 10.3390/s23052643

Weld site inspection is a research area of interest in the manufacturing industry. In this study, a digital twin system for welding robots to examine various weld flaws that might happen during welding using the acoustics of the weld site is presented. Additionally, a wavelet filtering technique is implemented to remove the acoustic signal originating from machine noise. Then, an SeCNN-LSTM model is applied to recognize and categorize weld acoustic signals according to the traits of strong acoustic signal time sequences. The model verification accuracy was found to be 91%. In addition, using numerous indicators, the model was compared with seven other models, namely, CNN-SVM, CNN-LSTM, CNN-GRU, BiLSTM, GRU, CNN-BiLSTM, and LSTM. A deep learning model, and acoustic signal filtering and preprocessing techniques are integrated into the proposed digital twin system. The goal of this work was to propose a systematic on-site weld flaw detection approach encompassing data processing, system modeling, and identification methods. In addition, our proposed method could serve as a resource for pertinent research.
Fulltext Progress of Enzymatic and Non-Enzymatic Electrochemical Glucose Biosensor Based on Nanomaterial-Modified Electrode

Mohamad Nor N, Ridhuan NS, Abdul Razak K

Biosensors (Basel), 2022 Dec 06;12(12).
PMID: 36551103 DOI: 10.3390/bios12121136

This review covers the progress of nanomaterial-modified electrodes for enzymatic and non-enzymatic glucose biosensors. Fundamental insights into glucose biosensor components and the crucial factors controlling the electrochemical performance of glucose biosensors are discussed in detail. The metal, metal oxide, and hybrid/composite nanomaterial fabrication strategies for the modification of electrodes, mechanism of detection, and significance of the nanomaterials toward the electrochemical performance of enzymatic and non-enzymatic glucose biosensors are compared and comprehensively reviewed. This review aims to provide readers with an overview and underlying concept of producing a reliable, stable, cost-effective, and excellent electrochemical performance of a glucose biosensor.
Fulltext Simultaneous Sensing of Cd(II), Pb(II), and Cu(II) Using Gold Nanoparticle-Modified APTES-Functionalized Indium Tin Oxide Electrode: Effect of APTES Concentration

Mohamad Nor N, Nasrul SN, Zakaria ND, Abdul Razak K

ACS Omega, 2023 May 16;8(19):16587-16599.
PMID: 37214679 DOI: 10.1021/acsomega.2c07085

In this work, indium tin oxide (ITO) electrodes were functionalized with varying 3-aminopropyltriethoxysilane (APTES) concentration percentages (0.5, 0.75, 1.0, and 2.0 wt %) to obtain the optimum conditions for the assembly of the as-synthesized gold nanoparticles (AuNPs). The AuNP coverage, wettability, and electrochemical performance of the modified electrodes were evaluated. The AuNP/0.75% APTES-ITO-modified electrode exhibited uniform coverage of AuNPs and high electrochemical performance for the simultaneous detection of Cd(II), Pb(II), and Cu(II) ions. Under the optimum conditions, the AuNP/0.75% APTES-ITO-modified electrode showed a linear detection range of 5-120 ppb and limit of detection of 0.73, 0.90, and 0.49 ppb for the simultaneous detection of Cd(II), Pb(II), and Cu(II) ions, respectively, via square wave anodic stripping voltammetry. The modified electrode demonstrated good anti-interference toward other heavy metal ions, good reproducibility, and suitability for application in environmental sample analysis.
Recent Advancement in Disposable Electrode Modified with Nanomaterials for Electrochemical Heavy Metal Sensors

Mohamad Nor N, Ramli NH, Poobalan H, Qi Tan K, Abdul Razak K

Crit Rev Anal Chem, 2023;53(2):253-288.
PMID: 34565248 DOI: 10.1080/10408347.2021.1950521

Heavy metal pollution has gained global attention due to its high toxicity and non-biodegradability, even at a low level of exposure. Therefore, the development of a disposable electrode that is sensitive, simple, portable, rapid, and cost-effective as the sensor platform in electrochemical heavy metal detection is vital. Disposable electrodes have been modified with nanomaterials so that excellent electrochemical properties can be obtained. This review highlights the recent progress in the development of numerous types of disposable electrodes modified with nanomaterials for electrochemical heavy metal detection. The disposable electrodes made from carbon-based, glass-based, and paper-based electrodes are reviewed. In particular, the analytical performance, fabrication technique, and integration design of disposable electrodes modified with metal (such as gold, tin and bismuth), carbon (such as carbon nanotube and graphene), and metal oxide (such as iron oxide and zinc oxide) nanomaterials are summarized. In addition, the role of the nanomaterials in improving the electrochemical performance of the modified disposable electrodes is discussed. Finally, the current challenges and future prospect of the disposable electrode modified with nanomaterials are summarized.
Fulltext Self-Assembled Iron Oxide Nanoparticle-Modified APTES-ITO Electrode for Simultaneous Stripping Analysis of Cd(II) and Pb(II) Ions

Mohamad Nor N, Arivalakan S, Zakaria ND, Nilamani N, Lockman Z, Abdul Razak K

ACS Omega, 2022 Feb 01;7(4):3823-3833.
PMID: 35128290 DOI: 10.1021/acsomega.1c07158

Carboxyl (-COOH)-stabilized iron oxide nanoparticles (IONPs) synthesized through co-precipitation were used to modify an indium tin oxide (ITO) electrode, which was chemically functionalized with 3-aminopropyltriethoxysilane (APTES) for heavy metal detection. The effect of soaking time (30, 60, 90, and 120 min) of IONP-COOH self-assembled on an APTES-ITO electrode was studied. Cyclic voltammetry and scanning electron microscopy were applied to analyze the electrochemical properties and morphologies of IONP-COOH/APTES-ITO modified electrode. The modified electrodes were then employed for the simultaneous detection of Cd(II) and Pb(II) by using square wave anodic stripping voltammetry. At 90 min of soaking time, excellent electrochemical performance and larger effective surface area (A e) were obtained. The linear range for the simultaneous detection of Cd(II) and Pb(II) ions using the modified electrode was 10-100 ppb with limits of detection of 0.90 and 0.60 ppb, respectively. The interference study revealed a low interference effect from Cr(III), Hg(II), Zn(II), Cu(II), Mg(II), Na(I), and K(I) toward the simultaneous detection of Cd(II) and Pb(II). Finally, the IONP-COOH/APTES-ITO-modified electrode was applied to analyze seawater samples and was able to simultaneously detect Cd(II) and Pb(II) ions.
Functional and structural analyses of an expansin-like protein from the antarctic yeast Glaciozyma antarctica PI12 reveal strategies of nutrient scavenging in the sea ice environment

Mohamad Nor N, Hashim NHF, Quay DHX, Mahadi NM, Illias RM, Abu Bakar FD, et al.

Int J Biol Macromol, 2020 Feb 01;144:231-241.
PMID: 31843615 DOI: 10.1016/j.ijbiomac.2019.12.099

Genome data mining of the Antarctic yeast, Glaciozyma antarctica PI12 revealed an expansin-like protein encoding sequence (GaEXLX1). The GaEXLX1 protein is 24.8 kDa with a high alkaline pI of 9.81. Homology modeling of GaEXLX1 showed complete D1 and D2 domains of a conventional expansin. The protein exhibited 36% sequence similarity to Clavibacter michiganensis EXLX1 (PDB: 4JCW). Subsequently, a recombinant GaEXLX1 protein was produced using Escherichia coli expression system. Incubation with Avicel, filter paper and cotton fiber showed that the protein can disrupt the surface of crystalline and pure cellulose, suggesting a cell wall modification activity usually exhibited by expansin-like proteins. Binding assays displayed that GaEXLX1 can bind to polymeric substrates, including those postulated to be present in the sea ice ecosystem such as crab chitin and moss lichenan. GaEXLX1 may assist in the recognition and loosening of these substrates in the sea ice prior to hydrolysis by other extracellular enzymes. Similar loosening mechanism to classical expansin-like protein has been postulated for this psychrophilic protein based on several conserved residues of GaEXLX1 involved in binding interaction identified by docking analyses.
Fulltext Translation of the Revised Dyadic Adjustment Scale (RDAS) into the Malay Language and Its Psychometric Qualities among Healthy Married Malay Women

Hamid N, Muhamad R, Kueh YC, Zahari Z, Mohamad Nor N, Abdullah N, et al.

J Pharm Bioallied Sci, 2020 10 08;12(4):444-448.
PMID: 33679091 DOI: 10.4103/jpbs.JPBS_265_19

Background: In Malaysia, the problem of marital distress is fast becoming an important public health concern. A major shortcoming is inadequate marital evaluation. There are, however, very few localized instruments for married women in Malaysia. The objective of this study was to translate the original version of the Revised Dyadic Adjustment Scale (RDAS) and to evaluate for its psychometric properties. Multiple aspects of validity and reliability were also assessed.
Materials and Methods: The questionnaire was first translated into the Malay language (RDAS-M). In this cross-sectional study, healthy married Malay women in Kota Bharu, Kelantan, were recruited from January to April 2018. Participants were asked to complete the RDAS-M that consists of three domains, that is, dyadic consensus, dyadic satisfaction, and dyadic cohesion with a total of 14 items. The concept, content, and construct validity using exploratory factor analysis (EFA) and reliability of the RDAS-M were assessed.
Results: Of the 164 recruited participants, 150 consented to participate. The mean age of the participants was 34.1 years (standard deviation [SD], 9.5 years), ranging from 20 to 57 years. All 14 items were considered comprehensible by more than 95% of the subjects. Based on EFA, total variance extracted was 69.08%, and the original three factors were retained. The Malay version of the RDAS was valid based on factor loadings for dyadic consensus, dyadic satisfaction, and dyadic cohesion, which ranged from 0.64 to 0.80, 0.79 to 0.98, and 0.37 to 0.78, respectively. The internal consistency was good with coefficient α of 0.87 for dyadic consensus, 0.93 for dyadic satisfaction, and 0.78 for dyadic cohesion.
Conclusions: The Malay version of the RDAS is easy to understand, and is a reliable and valid instrument for married women. It is also comparable with the original version of the RDAS in terms of structure and psychometric properties.
Fulltext Validity and Reliability of the Malay Versions of Bloating Severity (BSQ-M) and Quality of Life (BLQoL-M) Questionnaires

Mahd-Ab Lah N, Kueh YC, Kuan G, Yahaya FH, Wong MS, Abd Samat NA, et al.

Int J Environ Res Public Health, 2021 Mar 03;18(5).
PMID: 33802426 DOI: 10.3390/ijerph18052487

Abdominal bloating (AB) is a prevalent and bothersome symptom, but there are no specific measures for severity and quality of life (QoL) other than the Bloating Severity Questionnaire (BSQ) and Bloating Quality of Life (BLQoL). We aimed to translate the BSQ and BLQoL into the Malay language and to validate them using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) approaches. The 12-item BSQ has two components, seven-item severity in general (SevGen) and five-item severity in the past 24 h (Sev24), and BLQOL has five items. Translation to the Malay language (BSQ-M and BLQoL-M) was performed using standard forward and backward processes. EFA followed by CFA were performed in participants with AB due to functional bowel disorders, with the purpose of examining the validity and reliability of the questionnaires translated into Malay. After EFA with 152 participants, all the items of BSQ-M remained in the model. Total variance extracted was 53.26% for BSQ-M and 58.79% for BLQoL-M. The internal consistency based on Cronbach's alpha values was 0.52 for SevGen, 0.86 for Sev24, and 0.81 for BLQoL-M. After performing CFA with another 323 participants, the final measurement model for BSQ-M and BLQoL-M fit the data well in terms of several fit indices (BSQ-M: root mean square error of approximation (RMSEA) = 0.050, Comparative Fit Index (CFI) = 0.966, Tucker-Lewis Fit Index (TLI) = 0.956, and standardized root mean squared residual (SRMR) = 0.051; BLQoL-M: RMSEA = 0.071, CFI = 0.985, TLI = 0.962, SRMR = 0.021). The composite reliability for BSQ-M and BLQoL-M were satisfactory (SevGen = 0.83, Sev24 = 0.89, BLQoL = 0.80). The intraclass correlation (ICC) results showed excellent stability for BSQ-M and BLQoL-M, ranging from 0.74 to 0.93. The Malay language versions of BSQ-M and BLQoL-M are valid and reliable instruments for measuring the severity and QoL of AB for the Asian population with functional bowel disorders.
Placenta microRNA profile of patient with Obstetric Antiphospholipid Syndrome

Mohamad MA, Ahmad Asnawi AW, Suhiman MS, Sathar J, Hayati AR, Abdul Rahim NS, et al.

Malays J Pathol, 2023 Dec;45(3):425-440.
PMID: 38155384

The onset of obstetric antiphospholipid syndrome (APS) occurs when antiphospholipid antibodies act upon the placenta. During pregnancy, APS exhibits traits such as vascular thrombosis, inflammation, and hindered trophoblast implantation. The involvement of microRNA expression has been proposed as a genetic factor contributing to the syndrome's development. MicroRNAs play a role in regulating gene expression in various cellular processes, including the formation of placental tissue. Therefore, additional research is needed to explore the control of placental miRNA in APS. In this study, we aimed to profile miRNA expressions from placenta tissue of patients with APS. Differentially expressed miRNAs were determined for its targeted genes and pathways. Agilent microarray platform was used to measure placental microRNA expressions between normal placental tissue and those obtained from patients with APS. Differentially expressed miRNAs were detected using GeneSpring GX software 14.2 and sequences were mapped using TargetScan software to generate the predicted target genes. Pathway analysis for the genes was then performed on PANTHER and REACTOME software. Selected miRNAs and their associated genes of interest were validated using qPCR. Microarray findings revealed, 9 downregulated and 21 upregulated miRNAs expressed in placenta of patients with APS. Quantitative expressions of 3 selected miRNAs were in agreement with the microarray findings, however only miR-525-5p expression was statistically significant. Pathway analysis revealed that the targeted genes of differentially expressed miRNAs were involved in several hypothesised signalling pathways such as the vascular endothelial (VE) growth factor (VEGF) and inflammatory pathways. VE-cadherin, ras homolog member A (RHOA) and tyrosine kinase receptor (KIT) showed significant downregulation while Retinoblastoma gene (RET), Dual specificity protein phosphatase 10 (DUSP10) and B-lymphocyte kinase (BLK) genes were significantly upregulated. These preliminary findings suggest the involvement of miRNAs and identified novel associated genes involvement in the mechanism of obstetric APS, particularly through the alteration of vascular-associated regulators and the inflammatory signalling cascade.