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Fulltext Estimation of soil erodibility in Peninsular Malaysia: A case study using multiple linear regression and artificial neural networks

Rehman MA, Abd Rahman N, Ibrahim ANH, Kamal NA, Ahmad A

Heliyon, 2024 Apr 15;10(7):e28854.
PMID: 38576554 DOI: 10.1016/j.heliyon.2024.e28854

Soil erodibility (K) is an essential component in estimating soil loss indicating the soil's susceptibility to detach and transport. Data Computing and processing methods, such as artificial neural networks (ANNs) and multiple linear regression (MLR), have proven to be helpful in the development of predictive models for natural hazards. The present case study aims to assess the efficiency of MLR and ANN models to forecast soil erodibility in Peninsular Malaysia. A total of 103 samples were collected from various sites and K values were calculated using the Tew equation developed for Malaysian soil. From several extracted parameters, the outcomes of correlation and principal component analysis (PCA) revealed the influencing factors to be used in the development of ANN and MLR models. Based on the correlation and PCA results, two sets of influencing factors were employed to develop predictive models. Two MLR (MLR-1 and MLR-2) models and four neural networks (NN-1, NN-2, NN-3, and NN-4) optimized using Levenberg-Marquardt (LM) and scaled conjugate gradient (SCG) were developed and evaluated. The model performance validation was conducted using the coefficient of determination (R2), mean squared error (MSE), root mean squared error (RMSE), and Nash-Sutcliffe efficiency coefficient (NSE). The analysis showed that ANN models outperformed MLR models. The R2 values of 0.446 (MLR-1), 0.430 (MLR-2), 0.894 (NN-1), 0.855 (NN-2), 0.940 (NN-3), and 0.826 (NN-4); MSE values of 0.0000306 (MLR-1), 0.0000315 (MLR-2), 0.0000158 (NN-1), 0.0000261 (NN-2), 0.0000318 (NN-3), and 0.0000216 (NN-4) suggested the higher accuracy and lower modelling error of ANN models as compared with MLR. This study could provide an empirical basis and methodological support for K factor estimation in the region.
Fulltext Determining food safety in canned food using fuzzy logic based on sulphur dioxide, benzoic acid and sorbic acid concentration

Mavani NR, Mohd Ali J, Hussain MA, Abd Rahman N, Hashim H

Heliyon, 2024 Feb 29;10(4):e26273.
PMID: 38384537 DOI: 10.1016/j.heliyon.2024.e26273

Canned food market demand has arisen due to the higher need for instant and ready-to-eat food. Food preservatives are often added to canned and processed foods to prolong their shelf life and help to sustain the quality, taste, color, and food texture. However, excessive usage of such food preservatives can lead to various diseases and health issues including palpitations, allergies, and cancer. Therefore, food preservative detection in food samples is essential for safe consumption and health well-being. This paper proposed a fuzzy logic framework to determine the safety of food products based on the concentration of sulphur dioxide (SD), benzoic acid (BA), and sorbic acid (SA) in five different food categories as referred to the Food Acts 1983 and Food Regulations 1985 in Malaysia. The fuzzy logic framework comprises of Mamdani inference system design with 90 fuzzy rules, 15 and 5 membership functions for both the input and output parameters respectively. 50 random values and 10 lab analysis results based on the industrial samples were used to validate the developed algorithms in ensuring the safety of the food products. The membership functions generated for the three inputs (SD, BA, and SA) during the fuzzification steps are based on the maximum allowable limit from the food acts. The defuzzification of fuzzy logic gave an average output value of 0.1565, 0.1350, 0.1150, 0.1100, and 0.1550 for chicken curry with potatoes, satay sauce, sardine in tomato sauce, anchovies paste, and sardine spread accordingly. Results obtained from the fuzzy logic framework concluded that all the industrial samples are safe to be eaten and comply with the Sixth Schedule, Regulation 20 in both Acts.
Association between dietary 3-monochloropropane-1,2-diol esters (3-MCPDE) and renal cancer in Peninsular Malaysia: exposure assessment and matched case-control study

Muhamad Rosli SH, Lau MS, Khalid T, Maarof SK, Jeyabalan S, Sirdar Ali S, et al.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2023 Apr;40(4):475-492.
PMID: 36947708 DOI: 10.1080/19440049.2023.2183068

3-Monochloropropane-1,2-diol esters (3-MCPDE) are food contaminants commonly found in refined vegetable oils and fats, which have possible carcinogenic implications in humans. To investigate this clinically, we conducted an occurrence level analysis on eight categories of retail and cooked food commonly consumed in Malaysia. This was used to estimate the daily exposure level, through a questionnaire-based case-control study involving 77 subjects with renal cancer, with 80 matching controls. Adjusted Odds Ratio (AOR) was calculated using the multiple logistic regression model adjusted for confounding factors. A pooled estimate of total 3-MCPDE intake per day was compared between both groups, to assess exposure and disease outcome. Among the food categories analysed, vegetable fats and oils recorded the highest occurrence levels (mean: 1.91 ± 1.90 mg/kg), significantly more than all other food categories (p
Fulltext Measuring Pro-Environmental Behavior Triggered by Environmental Values

Ahmat Zainuri N, Abd-Rahman N, Halim L, Chan MY, Mohd Bazari NN

Int J Environ Res Public Health, 2022 Nov 30;19(23).
PMID: 36498088 DOI: 10.3390/ijerph192316013

Pro-environmental behavior in addressing climate change is influenced by multi-dimensional factors-knowledge, values, intention and sociodemographic background. Correlational studies between environmental values and environmental behaviors have not been able to determine values or behaviors that need to be given priority in future interventions. Therefore, this study firstly determined the environmental values and pro-environmental behavior that are easy or difficult to embrace by 152 respondents with low socioeconomic background. Secondly, we identified the extent pro-environmental behavior is triggered by environmental values. This survey study employs the Rasch analysis model. The respondents had difficulty in associating themselves with biospheric values however readily demonstrated consideration toward altruistic values, especially related to concerns for future generations. In terms of environmental conservation behavior, the respondents were not willing to relinquish comfort easily, such as giving up self-driving and taking public transportation or reducing usage of electricity. In addition, adults of low socioeconomic background find it difficult to endorse statements such as getting involved in campaigns related to environmental conservation. Thus, younger family members must be educated about conservation behaviors such as environmental campaigns commonly offered at schools, and these youngsters can be encouraged to extend their role by educating their parents.
Retrospective review of the prevalence and risk factors of anaemia among antenatal mothers attending health clinics in Alor Gajah, Melaka

Ali N, Nur Kalmi Z, Sanusi NS, Ahad A, Mohd Khairuddin NA, Rosman SR, et al.

Malays Fam Physician, 2022 Nov 30;17(3):137-143.
PMID: 36606167 DOI: 10.51866/oa.135

INTRODUCTION: Anaemia is common during pregnancy and can lead to miscarriage, intrauterine growth retardation, premature labour and antepartum haemorrhage. Anaemia in pregnancy is defined as a haemoglobin (Hb) level of <11 g/dL.
METHOD: This retrospective review included 407 antenatal mothers diagnosed with anaemia at 36±1 weeks of gestation at all 10 health clinics in Alor Gajah between January and December 2018.
RESULTS: According to the district annual returns, 2,407 antenatal mothers (36 weeks of gestation) were registered in the health clinics in Alor Gajah in 2018. Among them, the prevalence of anaemia was 18.6% (n=448). However, there were only 407 cards found. Most participants were Malays (89.4%), aged 20-40 years (93.6%) and married (96.3%). Almost all anaemia cases (96.5%) were mild (Hb level of 9-10.9 g/dL). Approximately 34.4% of the mothers were already anaemic at booking; 77.6% belonged to the B40 income group; and 31.6% had poor pregnancy spacing of <2 years. Iron deficiency anaemia was the most common type of anaemia (51.0%), followed by dilutional anaemia (34.0%), which did not normalise at 36 weeks of gestation. Anaemia was associated with lower educational (p<0.05) and Hb levels at booking (p<0.001).
CONCLUSION: Having normal maternal Hb levels in early pregnancy especially at booking is crucial, as it may reduce the possibility of anaemia during pregnancy. Early screening and supplementation of at-risk pregnancies may be applied as a preventive strategy. Suitable methods of iron treatment and investigation need further exploration.
Fulltext Evaluation of the current bacteriological profile and antibiotic sensitivity pattern in chronic suppurative otitis media

Wan Draman WNA, Md Daud MK, Mohamad H, Hassan SA, Abd Rahman N

Laryngoscope Investig Otolaryngol, 2021 Dec;6(6):1300-1306.
PMID: 34938866 DOI: 10.1002/lio2.682

OBJECTIVE: To determine the current microbiological profile of chronic suppurative otitis media (CSOM), their antimicrobial sensitivity, their resistance pattern to locally available antibiotics and the appropriate antibiotic against isolated microorganisms causing CSOM.
METHODS: This cross-sectional study involved 91 ear swab specimens obtained from patients clinically diagnosed with active CSOM. Swabs were cultured for microbial identification according to a standard protocol. We performed antibiotic susceptibility testing, using the modified Kirby-Bauer disc diffusion method, and the diameter of the inhibition zone was interpreted based Clinical Laboratory Standards Institute guidelines.
RESULTS: Microbial growth was seen in 85 (93.4%) samples, but 6 (6.6%) samples had no growth. Among the samples with growth, 63 (69.2%) were monomicrobial, 13 (14.3%) were polymicrobial, and 9 (9.9%) were of mixed growth with more than three microorganisms. The most common bacteria isolated was Pseudomonas aeruginosa (32.6%) followed by Staphylococcus aureus (16.9%) and Klebsiella spp. (5.6%). The most sensitive antibiotics against P aeruginosa were ceftazidime, meropenem, piperacillin-tazobactam, and cefepime. S aureus showed the highest sensitivity toward rifampin, cefoxitin, and fusidic acid.
CONCLUSIONS: The bacteriological profile of CSOM showed a high prevalence of P aeruginosa, followed by S aureus and Klebsiella spp. with different distributions in different age groups. We observed a declining pattern of their antibiotic sensitivity. It is important to be aware of the current trend of the bacteriological profiles and to revise the antibiotic regime according to both the sensitivity and age groups.Level of Evidence: NA.
Fulltext Extended high frequency hearing loss in tinnitus-positive chronic suppurative otitis media patient

Mohd Salehuddin NS, Md Daud MK, Nik Othman NA, Abd Rahman N

Laryngoscope Investig Otolaryngol, 2021 Oct;6(5):1137-1141.
PMID: 34667858 DOI: 10.1002/lio2.651

Objectives: To determine the association between extended high frequency hearing loss and tinnitus in normal cochlear function based on a conventional audiometry chronic suppurative otitis media (CSOM) patient.
Design and methods: A cross-sectional study was conducted on 220 ears diagnosed as having CSOM with an equal number of tinnitus and without tinnitus groups. Only those with normal cochlear function based on conventional pure tone audiometry (250 Hz to 8 kHz) were included. They were further tested for hearing at extended high frequencies of up to 16 kHz. The severity of tinnitus was tested using a tinnitus questionnaire.
Results: The prevalence of extended high frequency hearing loss in the normal cochlear function CSOM patients with tinnitus was 81.8% (95% CI 74.5%, 89.1%), whereas the prevalence in the tinnitus negative group was 30.0% (95% CI 21.3%, 38.7%). There was a significant association between extended high frequency hearing loss and tinnitus in CSOM patients (P
Halocarbon emissions by selected tropical seaweeds exposed to different temperatures

Keng FS, Phang SM, Abd Rahman N, Yeong HY, Malin G, Leedham Elvidge E, et al.

Phytochemistry, 2021 Oct;190:112869.
PMID: 34274551 DOI: 10.1016/j.phytochem.2021.112869

Four tropical seaweeds, Gracilaria manilaensis Yamamoto & Trono, Ulva reticulata Forsskål, Kappaphycus alvarezii (Doty) L.M.Liao and Turbinaria conoides (J.Agardh) Kützing, collected from various habitats throughout Malaysia, were subjected to temperatures of 40, 35, 30, 25 and 20 °C in the laboratory. An exposure range of 21-38 °C is reported for Malaysian waters. The effect of the temperature exposures on the halocarbon emissions of the seaweeds were determined 4 and 28 h after treatment. The emission rates for a suite of six halocarbons commonly emitted by seaweeds, bromoform (CHBr3), dibromomethane (CH2Br2), diiodomethane (CH2I2), iodomethane (CH3I), dibromochloromethane (CHBr2Cl) and dichlorobromomethane (CHBrCl2), were measured using a cryogenic purge-and-trap sample preparation system coupled to a gas chromatography-mass spectrometry. The emission rate of CHBr3 was the highest of the six halocarbons for all the seaweeds under all the temperatures tested, followed by CH2Br2, and CH2I2. The emission rates were affected by temperature change and exposure duration, but overall responses were unique to each seaweed species. Larger decreases in the emissions of CHBr3, CH2Br2, CH2I2 and CHBr2Cl were found for K. alvarezii and T. conoides after 4 h at 40 °C. In both cases there was a >90% (p
Fulltext Cell-based influenza vaccine: current production, halal status assessment, and recommendations towards Islamic-compliant manufacturing

Zulkarnain NN, Anuar N, Abd Rahman N, Sheikh Abdullah SR, Alias MN, Yaacob M, et al.

Hum Vaccin Immunother, 2021 07 03;17(7):2158-2168.
PMID: 33539195 DOI: 10.1080/21645515.2020.1865044

Influenza virus is a life-threatening pathogen that infects millions of people every year, with annual mortality in the hundreds of thousands. The scenario for controlling infection has worsened with increasing numbers of vaccine hesitancy cases reported worldwide due to objections on safety, religious and other grounds. Uses of haram (impermissible) and mashbooh (doubtful) ingredients in vaccine production has raised doubts among Muslim consumers and consequently stimulated serious vaccine hesitancy. To address this major problem, we have reviewed and recommended some alternatives appropriate for manufacturing cell-based influenza vaccine which comply with Islamic laws and consumers' needs. Intensive assessments of current influenza vaccine production in both scientific and Islamic views have led to the identification of four main ingredients deemed impermissible in novel sharia-compliant (approved by Islamic laws) vaccine manufacturing. Only some of these impermissible components could be replaced with halal (permissible) alternatives, while others remain impermissible due to unavailability and unsuitability.
REPLY TO THE LETTER TO THE EDITOR: EARLY DETECTION OF HIGH-FREQUENCY PRESBYCUSIS AMONG NORMAL HEARING INDIVIDUALS

Aziz A, Md Daud MK, Nik Othman NA, Abd Rahman N

Otol Neurotol, 2021 02 01;42(2):345-346.
PMID: 33273310 DOI: 10.1097/MAO.0000000000002908
Identification of Copy Number Variation Among Nonsyndromic Cleft Lip and or Without Cleft Palate With Hypodontia: A Genome-Wide Association Study

Ghazali N, Abd Rahman N, Ahmad A, Sulong S, Kannan TP

Front Physiol, 2021;12:637306.
PMID: 33732167 DOI: 10.3389/fphys.2021.637306

Nonsyndromic cleft lip and or without cleft palate (NSCL/P) with the hypodontia is a common developmental abnormality in humans and animals. This study identified the genetic aberration involved in both NSCL/P and hypodontia pathogenesis. A cross-sectional study using genome-wide study copy number variation-targeted CytoScan 750K array carried out on salivary samples from 61 NSCL/P and 20 noncleft with and without hypodontia Malay subjects aged 7-13 years old. Copy number variations (CNVs) of SKI and fragile histidine triad (FHIT) were identified in NSCL/P and noncleft children using quantitative polymerase chain reaction (qPCR) as a validation analysis. Copy number calculated (CNC) for each gene determined with Applied Biosystems CopyCaller Software v2.0. The six significant CNVs included gains (12q14.3, 15q26.3, 1p36.32, and 1p36.33) and losses (3p14.2 and 4q13.2) in NSCL/P with hypodontia patients compared with the NSCL/P only. The genes located in these regions encoded LEMD3, IGF1R, TP73, SKI, FHIT, and UGT2β15. There were a significant gain and loss of both SKI and FHIT copy number in NSCL/P with hypodontia compared with the noncleft group (p < 0.05). The results supported that CNVs significantly furnish to the development of NSCL/P with hypodontia.
Computational-aided design: minimal peptide sequence to block dengue virus transmission into cells

Arumugam AC, Agharbaoui FE, Khazali AS, Yusof R, Abd Rahman N, Ahmad Fuaad AAH

J Biomol Struct Dyn, 2020 Dec 31.
PMID: 33382015 DOI: 10.1080/07391102.2020.1866074

Dengue virus (DV) infection is one of the main public health concerns, affecting approximately 390 million people worldwide, as reported by the World Health Organization. Yet, there is no antiviral treatment for DV infection. Therefore, the development of potent and nontoxic anti-DV, as a complement for the existing treatment strategies, is urgently needed. Herein, we investigate a series of small peptides inhibitors of DV antiviral activity targeting the entry process as the promising strategy to block DV infection. The peptides were designed based on our previously reported peptide sequence, DN58opt (TWWCFYFCRRHHPFWFFYRHN), to identify minimal effective inhibitory sequence through molecular docking and dynamics studies. The in silico designed peptides were synthesized using conventional Fmoc solid-phase peptide synthesis chemistry, purified by RP-HPLC and characterized using LCMS. Later, they were screened for their antiviral activity. One of the peptides, AC 001, was able to reduce about 40% of DV plaque formation. This observation correlates well with the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) analysis - AC 001 showed the most favorable binding affinity through 60 ns simulations. Pairwise residue decomposition analysis has revealed four key residues that contributed to the binding of these peptides into the DV2 E protein pocket. This work identifies the minimal peptide sequence required to inhibit DV replication and explains the behavior observed on an atomic level using computational study.Communicated by Ramaswamy H. Sarma.
Early Detection of High-frequency Presbycusis Among Normal Hearing Individuals

Aziz A, Md Daud MK, Nik Othman NA, Abd Rahman N

Otol Neurotol, 2020 09;41(8):e989-e992.
PMID: 32472918 DOI: 10.1097/MAO.0000000000002725

BACKGROUND: Presbycusis is an age-related sensorineural hearing loss and it may reduce quality of life. We conducted a study to establish the prevalence of high-frequency presbycusis in normal hearing individuals and to validate the role of extended high-frequency distortion product otoacoustic emission (DPOAE) in the screening.
METHOD: A cross-sectional study was conducted among 205 normal hearing adult participants with an age range between 25 and 54 years old. Hearing analysis with extended high-frequency pure-tone audiometry (PTA) and high-frequency DPOAE was carried out for all eligible participants. High-frequency presbycusis was considered to be present when the impairment of more than 25 dB occurs at higher than 8 kHz frequencies on both ears.
RESULTS: Prevalence of high-frequency presbycusis using extended PTA was 31.7 (95% CI: 25.3, 38.1) and using high-frequency DPOAE was 57.4 (95% CI: 50.7, 64.4). The sensitivity and specificity of high-frequency DPOAE in detecting high-frequency presbycusis were 72.3 and 49.3% respectively with positive predictive value of 39.8% and negative predictive value of 79.3%. The association between age and high-frequency presbycusis was significant based on high-frequency DPOAE (p = 0.029).
CONCLUSIONS: The prevalence of high-frequency hearing loss is higher with increasing in age. High-frequency DPOAE may be used as a screening tool followed by confirmation using extended PTA. The early detection of presbycusis is important so that measures can be taken to prevent more severe problems developing.
Fulltext The antibacterial efficacy of silver diamine fluoride (SDF) is not modulated by potassium iodide (KI) supplements: A study on in-situ plaque biofilms using viability real-time PCR with propidium monoazide

Abdullah N, Al Marzooq F, Mohamad S, Abd Rahman N, Rani KGA, Chi Ngo H, et al.

PLoS One, 2020;15(11):e0241519.
PMID: 33141868 DOI: 10.1371/journal.pone.0241519

Silver diamine fluoride (SDF) is commonly used to arrest caries lesions, especially in early childhood caries. Recently, it was suggested that SDF can be combined with potassium iodide (KI) to minimize the discoloration of demineralized dentine associated with SDF application. However, the antibacterial efficacy of SDF alone or combined with KI on in-situ biofilm is unknown. Hence, we compared the anti-plaque biofilm efficacy of two different commercially available SDF solutions, with or without KI, using an in-situ biofilm, analysed using viability real-time PCR with propidium monoazide (PMA). Appliance-borne in-situ biofilm samples (n = 90) were grown for a period of 6 h in five healthy subjects who repeated the experiment on three separate occasions, using a validated, novel, intraoral device. The relative anti-biofilm efficacy of two SDF formulations; 38.0% Topamine (SDFT) and 31.3%, Riva Star (SDFR), KI alone, and KI in combination with SDFR (SDFR+KI) was compared. The experiments were performed by applying an optimized volume of the agents onto the biofilm for 1min, mimicking the standard clinical procedure. Afterwards the viability of the residual biofilm bacteria was quantified using viability real-time PCR with PMA, then the percentage of viable from total bacteria was calculated. Both SDF formulations (SDFT and SDFR) exhibited potent antibacterial activities against the in-situ biofilm; however, there was non-significant difference in their efficacy. KI alone did not demonstrate any antibacterial effect, and there was non-significant difference in the antibacterial efficacy of SDF alone compared to SDF with KI, (SDFT v SDFR/KI). Thus, we conclude that the antibacterial efficacy of SDF against plaque biofilms is not modulated by KI supplements. Viability real-time PCR with PMA was successfully used to analyze the viability of naturally grown oral biofilm; thus, the same method can be used to test the antimicrobial effect of other agents on oral biofilms in future research.
In vitro functional evaluation of isolaureline, dicentrine and glaucine enantiomers at 5-HT2 and α1 receptors

Heng HL, Chee CF, Thy CK, Tee JT, Chin SP, Herr DR, et al.

Chem Biol Drug Des, 2019 02;93(2):132-138.
PMID: 30216681 DOI: 10.1111/cbdd.13390

Compounds with activity at serotonin (5-hydroxytryptamine) 5-HT2 and α1 adrenergic receptors have potential for the treatment of central nervous system disorders, drug addiction or overdose. Isolaureline, dicentrine and glaucine enantiomers were synthesized, and their in vitro functional activities at human 5-HT2 and adrenergic α1 receptor subtypes were evaluated. The enantiomers of isolaureline and dicentrine acted as antagonists at 5-HT2 and α1 receptors with (R)-isolaureline showing the greatest potency (pKb = 8.14 at the 5-HT2C receptor). Both (R)- and (S)-glaucine also antagonized α1 receptors, but they behaved very differently to the other compounds at 5-HT2 receptors: (S)-glaucine acted as a partial agonist at all three 5-HT2 receptor subtypes, whereas (R)-glaucine appeared to act as a positive allosteric modulator at the 5-HT2A receptor.
Fulltext Tropospheric Ozone Formation Estimation in Urban City, Bangi, Using Artificial Neural Network (ANN)

Abdul Aziz FAB, Abd Rahman N, Mohd Ali J

Comput Intell Neurosci, 2019;2019:6252983.
PMID: 31239836 DOI: 10.1155/2019/6252983

Due to the rapid development of economy and society around the world, the most urban city is experiencing tropospheric ozone or commonly known as ground-level air pollutants. The concentration of air pollutants must be identified as an early precaution step by the local environmental or health agencies. This work aims to apply the artificial neural network (ANN) in estimating the ozone concentration forecast in Bangi. It consists of input variables such as temperature, relative humidity, concentration of nitrogen dioxide, time, UVA and UVB rays obtained from routine monitoring, and data recorded. Ten hidden layer is utilized to obtain the optimized ozone concentration, which is the output layer of the ANN framework. The finding showed that the meteorology condition and emission patterns play an important part in influencing the ozone concentration. However, a single network is sufficient enough to estimate the concentration despite any circumstances. Thus, it can be concluded that ANN is able to give reliable and satisfactory estimations of ozone concentration for the following day.
Intraoral appliances for in situ oral biofilm growth: a systematic review

Abdullah N, Al-Marzooq F, Mohamad S, Abd Rahman N, Chi Ngo H, Perera Samaranayake L

J Oral Microbiol, 2019;11(1):1647757.
PMID: 31489127 DOI: 10.1080/20002297.2019.1647757

Background: Oral biofilms are the root cause of major oral diseases. As in vitro biofilms are not representative of the intraoral milieu, various devices have been manufactured over the years to develop Appliance Grown Oral Biofilm (AGOB). Objective: To review various intraoral appliances used to develop AGOB for microbiological analysis, and to judge the optimal means for such analyses. Design: Four databases (PubMed, Science Direct, Scopus and Medline) were searched by two independent reviewers, and articles featuring the key words 'device' OR 'splint' OR 'appliance'; 'Oral biofilm' OR 'dental plaque'; 'in vivo' OR 'in situ'; 'Microbiology' OR 'Bacteria' OR 'microbiome'; were included. The standard Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) were adopted for data gathering. Results: Of the 517 articles which met the initial inclusion criteria, 24 were deemed eligible for review. The age of the AGOB, sampled at various intervals, ranged from 30 min to 28 days. The most commonly used microbiome analytical methods were fluorescence microscopy, total cell count using conventional, and molecular tools including Next Generation Sequencing (NGS) platforms. Conclusions: No uniformly superior method for collecting AGOB could be discerned. NGS platforms are preferable for AGOB analyses.
Fulltext Thioguanine-based DENV-2 NS2B/NS3 protease inhibitors: Virtual screening, synthesis, biological evaluation and molecular modelling

Hariono M, Choi SB, Roslim RF, Nawi MS, Tan ML, Kamarulzaman EE, et al.

PLoS One, 2019;14(1):e0210869.
PMID: 30677071 DOI: 10.1371/journal.pone.0210869

Dengue virus Type 2 (DENV-2) is predominant serotype causing major dengue epidemics. There are a number of studies carried out to find its effective antiviral, however to date, there is still no molecule either from peptide or small molecules released as a drug. The present study aims to identify small molecules inhibitor from National Cancer Institute database through virtual screening. One of the hits, D0713 (IC50 = 62 μM) bearing thioguanine scaffold was derivatised into 21 compounds and evaluated for DENV-2 NS2B/NS3 protease inhibitory activity. Compounds 18 and 21 demonstrated the most potent activity with IC50 of 0.38 μM and 16 μM, respectively. Molecular dynamics and MM/PBSA free energy of binding calculation were conducted to study the interaction mechanism of these compounds with the protease. The free energy of binding of 18 calculated by MM/PBSA is -16.10 kcal/mol compared to the known inhibitor, panduratin A (-11.27 kcal/mol), which corroborates well with the experimental observation. Results from molecular dynamics simulations also showed that both 18 and 21 bind in the active site and stabilised by the formation of hydrogen bonds with Asn174.
Effect of irradiance on the emission of short-lived halocarbons from three common tropical marine microalgae

Lim YK, Keng FS, Phang SM, Sturges WT, Malin G, Abd Rahman N

PeerJ, 2019;7:e6758.
PMID: 31041152 DOI: 10.7717/peerj.6758

Marine algae have been reported as important sources of biogenic volatile halocarbons that are emitted into the atmosphere. These compounds are linked to destruction of the ozone layer, thus contributing to climate change. There may be mutual interactions between the halocarbon emission and the environment. In this study, the effect of irradiance on the emission of halocarbons from selected microalgae was investigated. Using controlled laboratory experiments, three tropical marine microalgae cultures, Synechococcus sp. UMACC 371 (cyanophyte), Parachlorella sp. UMACC 245 (chlorophyte) and Amphora sp. UMACC 370 (diatom) were exposed to irradiance of 0, 40 and 120 µmol photons m-2s-1. Stress in the microalgal cultures was indicated by the photosynthetic performance (Fv/Fm, maximum quantum yield). An increase in halocarbon emissions was observed at 120 µmol photons m-2s-1, together with a decrease in Fv/Fm. This was most evident in the release of CH3I by Amphora sp. Synechococcus sp. was observed to be the most affected by irradiance as shown by the increase in emissions of most halocarbons except for CHBr3 and CHBr2Cl. High positive correlation between Fv/Fm and halocarbon emission rates was observed in Synechococcus sp. for CH2Br2. No clear trends in correlation could be observed for the other halocarbons in the other two microalgal species. This suggests that other mechanisms like mitochondria respiration may contribute to halocarbon production, in addition to photosynthetic performance.
Fulltext Optimisation of stabiliser combinations in instant ice cream mix powder formulation via mixture design methodology

Abdul Razak, S. Z., Abd. Rahman, N. A., Baharuddin, A. S., Mohd Amin, N. A., Mat Johari, A., Mohammad Parid, D.

International Food Research Journal, 2019;26(6):1689-1698.
MyJurnal

The present work aimed at obtaining the optimum combination of stabilisers used in an
instant ice cream formulation. Instant ice cream mixes were formulated using milk protein,
fat, sucrose, stabilisers, emulsifiers and water. A basic formulation for ice cream mix was
prepared according to the process flow of instant ice cream. Three different stabilisers
mixtures, which were carboxymethyl cellulose (CMC), carrageenan, and sodium alginate
used in 14 formulations were studied using mixture design methodology. Physical analyses on
meltdown rate, hardness, melted ice cream viscosity, and overrun were performed. The results
were compared with those of commercial instant ice cream to determine the acceptability and
quality of the final products. From the optimisation study, the recommended combination of
stabilisers was found to be 0.151% CMC and 0.149% sodium alginate. The optimised sample
had a higher viscosity of 0.17 Pa.s than the commercial one (0.16 Pa.s), which corresponded to
higher hardness thus indicating slower melting rate, which is a good texture for ice cream. The
overrun of the optimised sample was 108.33%, which is considered high. The high amount of
air, viscosity, and hardness resulted in a low melting rate of 0.22 g/min, which is desirable for
ice cream consumption. Based on sensory evaluation, the optimised instant ice cream was the
most preferred by panellists as compared to commercial sample.

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