Browse publications by year: 2021

  1. Ariffin EY, Zakariah EI, Ruslin F, Kassim M, Yamin BM, Heng LY, et al.
    Sci Rep, 2021 Apr 12;11(1):7883.
    PMID: 33846405 DOI: 10.1038/s41598-021-86939-z
    Ferrocene or ferrocenium has been widely studied in the field of organometallic complexes because of its stable thermodynamic, kinetic and redox properties. Novel hexaferrocenium tri[hexa(isothiocyanato)iron(III)]trihydroxonium (HexaFc) complex was the product from the reaction of ferrocene, maleic acid and ammonium thiocyanate and was confirmed by elemental analysis CHNS, FTIR and single crystal X-ray crystallography. In this study, HexaFc was used for the first time as an electroactive indicator for porcine DNA biosensor. The UV-Vis DNA titrations with this compound showed hypochromism and redshift at 250 nm with increasing DNA concentrations. The binding constant (Kb) for HexaFc complex towards CT-DNA (calf-thymus DNA) was 3.1 × 104 M-1, indicated intercalator behaviour of the complex. To test the usefulness of this complex for DNA biosensor application, a porcine DNA biosensor was constructed. The recognition probes were covalently immobilised onto silica nanospheres (SiNSs) via glutaraldehyde linker on a screen-printed electrode (SPE). After intercalation with the HexaFc complex, the response of the biosensor to the complementary porcine DNA was measured using differential pulse voltammetry. The DNA biosensor demonstrated a linear response range to the complementary porcine DNA from 1 × 10-6 to 1 × 10-3 µM (R2 = 0.9642) with a limit detection of 4.83 × 10-8 µM and the response was stable up to 23 days of storage at 4 °C with 86% of its initial response. The results indicated that HexaFc complex is a feasible indicator for the DNA hybridisation without the use of a chemical label for the detection of porcine DNA.
    MeSH terms: Animals; DNA/analysis*; Electrodes; Iron/chemistry*; Swine; Biosensing Techniques/methods*; Metal Nanoparticles/chemistry; Electrochemical Techniques/methods*
  2. Lam SE, Mat Nawi SN, Abdul Sani SF, Khandaker MU, Bradley DA
    Sci Rep, 2021 04 12;11(1):7939.
    PMID: 33846448 DOI: 10.1038/s41598-021-86942-4
    Preliminary study has been made of black human hair, carbon concentration of some 53%, a model in examining the potential of hair of the human head in retrospective and emergency biodosimetry applications, also offering effective atomic number near to that of water. The hair samples were exposed to [Formula: see text]Co gamma rays, delivering doses from 0 to 200 Gy. Structural alterations were observed, use being made of Raman and photoluminescence (PL) spectroscopy. Most prominent among the features observed in the first-order Raman spectra are the D and G peaks, appearing at 1370 [Formula: see text] and 1589 [Formula: see text] respectively, the intensity ratio [Formula: see text] indicating dose-dependent defects generation and annealing of structural alterations. The wavelengths of the PL absorption and emission peaks are found to be centred at [Formula: see text] nm and [Formula: see text] nm, respectively. The hair samples mean band gap energy ([Formula: see text]) post-irradiation was found to be [Formula: see text] eV, of the order of a semiconductor and approximately two times the [Formula: see text] of other carbon-rich materials reported via the same methodology.
    MeSH terms: Elements; Female; Gamma Rays*; Hair/radiation effects*; Humans; Spectrometry, X-Ray Emission; Spectrum Analysis, Raman*; Luminescence*
  3. Jayaraj R, Shaw P, Shetty S, Kumaraswamy C, Gothandam KM, Ravishankar Ram M, et al.
    Br J Cancer, 2021 05;124(11):1891-1892.
    PMID: 33846522 DOI: 10.1038/s41416-021-01348-3
  4. Shahimi S, Elias A, Abd Mutalib S, Salami M, Fauzi F, Mohd Zaini NA, et al.
    Environ Sci Pollut Res Int, 2021 Aug;28(32):44002-44013.
    PMID: 33846919 DOI: 10.1007/s11356-021-13665-4
    A total of 24 strains of Vibrio alginolyticus were isolated from cockles (Anadara granosa) and identified for VibA and gyrB genes. All V. alginolyticus isolates were then tested against nine different antibiotics. In this study, the highest percentage of antibiotic resistance was obtained against penicillin (37.50%), followed by ampicillin, vancomycin (12.50%) and erythromycin (8.33%). All of V. alginolyticus isolates were susceptible against streptomycin, kanamycin, tetracycline, chloramphenicol and sulfamethoxazole. Polymerase chain reaction (PCR) assay has confirmed the presence of four antibiotic resistance genes of penicillin (pbp2a), ampicillin (blaOXA), erythromycin (ermB) and vancomycin (vanB). Out of 24 V. alginolyticus isolates, 2 isolates possessed the tdh-related hemolysin (trh) (strains VA15 and VA16) and none for the thermostable direct hemolysin (tdh) gene. Both strains of the tdh-related hemolysin (trh) were susceptible to all antibiotics tested. The multiple antibiotic resistance (MAR) index ranging between 0.2 and 0.3 with 5 antibiograms (A1-A5) was observed. Combination of enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and antibiotic resistance indicated 18 genome types which showed genetic heterogeneity of those V. alginolyticus isolates. The results demonstrated the presence of V. alginolyticus strain found in cockles can be a potential risk to consumers and can contribute to the deterioration of human health in the study area. Thus, it is essential for local authority to provide the preventive measures in ensuring the cockles are safe for consumption.
    MeSH terms: Animals; Anti-Bacterial Agents/pharmacology; Humans; Microbial Sensitivity Tests; Vibrio parahaemolyticus*; Drug Resistance, Bacterial/genetics; Vibrio alginolyticus/genetics; Cardiidae*; Arcidae*
  5. Muhamad A, Hayati F, Azizan N, Sahid Nik Lah NA, Andee DZ
    ANZ J Surg, 2021 04;91(4):763-764.
    PMID: 33847052 DOI: 10.1111/ans.16536
    MeSH terms: Humans; Colon, Descending
  6. Mansor E, Ahmad N, Raj D, Mohd Zulkefli NA, Mohd Shariff Z
    J Med Internet Res, 2021 04 13;23(4):e25219.
    PMID: 33847590 DOI: 10.2196/25219
    BACKGROUND: Globally, there is an increasing prevalence of excessive screen time exposure among young children, including in Malaysia. Parents are advised to limit this exposure, but there are barriers for many of them to follow this recommendation. To date, there is a lack of research on the factors that cause these parental barriers.

    OBJECTIVE: This study aimed to determine the parental barrier toward the reduction of excessive child screen time and its predictors among parents of children aged younger than 5 years in the Petaling District, Selangor, Malaysia.

    METHODS: A cross-sectional study was conducted from April 2019 to June 2020 among 789 parent-child dyads attending child health clinics in the Petaling District. Validated self-administered questionnaires were used to capture information on sociodemographic, parental, child-related, and environmental factors and parental barriers. Stratified sampling with probability proportionate to size was employed. Data were analyzed using SPSS Statistics version 25 (IBM Corp). Descriptive analysis and bivariable analysis were performed before multiple linear regression was used to identify predictors of parental barriers.

    RESULTS: The overall mean score of parental barriers was 3.51 (SD 0.83), indicating that the average numbers of barriers experienced by parents were more than 3. The multivariable analysis showed that the predictors of parental barriers included monthly household income (adjusted β=-.03, 95% CI -0.05 to -0.02), parents who worked in public sectors (adjusted β=.18, 95% CI 0.06 to 0.29), positive parental attitude on screens (adjusted β=.68, 95% CI 0.58 to 0.79), low parent self-efficacy to influence child's physical activity (adjusted β=-.32, 95% CI -0.43 to -0.20), and child screen time (adjusted β=.04, 95% CI 0.02 to 0.06).

    CONCLUSIONS: The strongest predictor of parental barriers to reduce excessive child screen time was the positive parental attitude on screen time which could contribute to their abilities to limit child screen time. Thus, future intervention strategies should aim to foster correct parental attitudes toward screen time activities among young children.

    MeSH terms: Child, Preschool; Cross-Sectional Studies; Humans; Malaysia/epidemiology; Parent-Child Relations*; Parents; Surveys and Questionnaires
  7. Cho YH, Seo JB, Lee SM, Kim N, Yun J, Hwang JE, et al.
    Eur Radiol, 2021 Oct;31(10):7316-7324.
    PMID: 33847809 DOI: 10.1007/s00330-021-07747-7
    OBJECTIVES: To apply radiomics analysis for overall survival prediction in chronic obstructive pulmonary disease (COPD), and evaluate the performance of the radiomics signature (RS).

    METHODS: This study included 344 patients from the Korean Obstructive Lung Disease (KOLD) cohort. External validation was performed on a cohort of 112 patients. In total, 525 chest CT-based radiomics features were semi-automatically extracted. The five most useful features for survival prediction were selected by least absolute shrinkage and selection operation (LASSO) Cox regression analysis and used to generate a RS. The ability of the RS for classifying COPD patients into high or low mortality risk groups was evaluated with the Kaplan-Meier survival analysis and Cox proportional hazards regression analysis.

    RESULTS: The five features remaining after the LASSO analysis were %LAA-950, AWT_Pi10_6th, AWT_Pi10_heterogeneity, %WA_heterogeneity, and VA18mm. The RS demonstrated a C-index of 0.774 in the discovery group and 0.805 in the validation group. Patients with a RS greater than 1.053 were classified into the high-risk group and demonstrated worse overall survival than those in the low-risk group in both the discovery (log-rank test, < 0.001; hazard ratio [HR], 5.265) and validation groups (log-rank test, < 0.001; HR, 5.223). For both groups, RS was significantly associated with overall survival after adjustments for patient age and body mass index.

    CONCLUSIONS: A radiomics approach for survival prediction and risk stratification in COPD patients is feasible, and the constructed radiomics model demonstrated acceptable performance. The RS derived from chest CT data of COPD patients was able to effectively identify those at increased risk of mortality.

    KEY POINTS: • A total of 525 chest CT-based radiomics features were extracted and the five radiomics features of %LAA-950, AWT_Pi10_6th, AWT_Pi10_heterogeneity, %WA_heterogeneity, and VA18mm were selected to generate a radiomics model. • A radiomics model for predicting survival of COPD patients demonstrated reliable performance with a C-index of 0.774 in the discovery group and 0.805 in the validation group. • Radiomics approach was able to effectively identify COPD patients with an increased risk of mortality, and patients assigned to the high-risk group demonstrated worse overall survival in both the discovery and validation groups.

    MeSH terms: Humans; Thorax; Tomography, X-Ray Computed; Proportional Hazards Models; Kaplan-Meier Estimate
  8. Verdoia M, Suryapranata H, Damen S, Camaro C, Benit E, Barbieri L, et al.
    J Thromb Thrombolysis, 2021 Oct;52(3):797-807.
    PMID: 33847862 DOI: 10.1007/s11239-021-02439-x
    BACKGROUND: Gender differences in the thrombotic and bleeding risk have been suggested to condition the benefits of antithrombotic therapies in Acute Coronary Syndrome (ACS) patients, and mainly among those undergoing percutaneous coronary interventions with drug eluting stents (DES). The impact of gender on the optimal duration of dual antiplatelet therapy (DAPT) in ACS patients is still unexplored and was, therefore, the aim of the present sub-study.

    METHODS: REDUCE was a prospective, multicenter, randomized investigator-initiated study designed to enroll 1500 ACS patients after treatment with the COMBO Dual Stent Therapy, based on a noninferiority design. Patients were randomized in a 1:1 fashion to either 3 or 12 months of DAPT. Primary study endpoint was a composite of all-cause mortality, myocardial infarction, definite/probable stent thrombosis (ST), stroke, target-vessel revascularization (TVR) and bleedings (BARC II, III, V) at 12 months. Secondary endpoints were cardiovascular mortality and the individual components of the primary endpoint within 24 months.

    RESULTS: From June 2014 to May 2016 300 women and 1196 men were included in the study. Among them, 43.7% of females and 51.9% of males were assigned to the 3 months DAPT treatment. Baseline characteristics were well matched between the two arms, with the exception of a lower rate of TIMI flow 

  9. Dullah H, Malek MA, Omar H, Mangi SA, Hanafiah MM
    Environ Sci Pollut Res Int, 2021 Aug;28(32):44264-44276.
    PMID: 33847888 DOI: 10.1007/s11356-021-13833-6
    Deforestation and forest degradation are among the leading global concerns, as they could reduce the carbon sink and sequestration potential of the forest. The impoundment of Kenyir River, Hulu Terengganu, Malaysia, in 1985 due to the development of hydropower station has created a large area of water bodies following clearance of forested land. This study assessed the loss of forest carbon due to these activities within the period of 37 years, between 1972 and 2019. The study area consisted of Kenyir Lake catchment area, which consisted mainly of forests and the great Kenyir Lake. Remote sensing datasets have been used in this analysis. Satellite images from Landsat 1-5 MSS and Landsat 8 OLI/TRIS that were acquired between the years 1972 and 2019 were used to classify land uses in the entire landscape of Kenyir Lake catchment. Support vector machine (SVM) was adapted to generate the land-use classification map in the study area. The results show that the total study area includes 278,179 ha and forest covers dominated the area for before and after the impoundment of Kenyir Lake. The assessed loss of carbon between the years 1972 and 2019 was around 8.6 million Mg C with an annual rate of 0.36%. The main single cause attributing to the forest loss was due to clearing of forest for hydro-electric dam construction. However, the remaining forests surrounding the study area are still able to sequester carbon at a considerable rate and thus balance the carbon dynamics within the landscapes. The results highlight that carbon sequestration scenario in Kenyir Lake catchment area shows the potential of the carbon sink in the study area are acceptable with only 17% reduction of sequestration ability. The landscape of the study area is considered as highly vegetated area despite changes due to dam construction.
    MeSH terms: Conservation of Natural Resources; Malaysia; Rivers; Carbon Sequestration; Forests*
  10. Swarna Nantha Y, Chelliah AAP, Haque S, Md Zain AZ
    PLoS One, 2021;16(4):e0249620.
    PMID: 33848301 DOI: 10.1371/journal.pone.0249620
    BACKGROUND: A paradigm shift in the disease management of type 2 diabetes is urgently needed to stem the escalating trends seen worldwide. A "glucocentric" approach to diabetes management is no longer considered a viable option. Qualitative strategies have the potential to unearth the internal psychological attributes seen in people living with diabetes that are crucial to the sustenance of self-management behaviour. This study aims to identify and categorize the innate psychological dispositions seen in people with type 2 diabetes in relation to self-management behaviour.

    METHODS: We adopted a grounded theory approach to guide in-depth interviews of individuals with type 2 diabetes and healthcare professionals (HCP) at a regional primary care clinic in Malaysia. Twenty-four people with type 2 diabetes and 10 HCPs were recruited into the study to examine the inner narratives about disease management. Two focus group discussions (FGD) were also conducted for data triangulation.

    RESULTS: Participants' internal dialogue about the management of their disease is characterized by 2 major processes- 1) positive disposition and 2) negative disposition. Optimism, insight, and awareness are important positive values that influence T2D self-care practices. On the other hand, constructs such as stigma, worries, reservations, and pessimism connote negative dispositions that undermine the motivation to follow through disease management in individuals with type 2 diabetes.

    CONCLUSIONS: We identified a contrasting spectrum of both constructive and undesirable behavioural factors that influence the 'internal environment' of people with type 2 diabetes. These results coincide with the constructs presented in other well-established health belief theories that could lead to novel behavioural change interventions. Furthermore, these findings allow the implementation of psychosocial changes that are in line with cultural sensitivities and societal norms seen in a specific community.

    MeSH terms: Adult; Aged; Diabetes Mellitus, Type 2/epidemiology; Diabetes Mellitus, Type 2/psychology*; Diabetes Mellitus, Type 2/therapy; Female; Humans; Malaysia/epidemiology; Male; Middle Aged; Motivation; Self Care*; Health Behavior*; Qualitative Research; Grounded Theory*
  11. Alahmad B, Al-Hemoud A, Kang CM, Almarri F, Kommula V, Wolfson JM, et al.
    Environ Pollut, 2021 Aug 01;282:117016.
    PMID: 33848912 DOI: 10.1016/j.envpol.2021.117016
    BACKGROUND: Kuwait and the Gulf region have a desert, hyper-arid and hot climate that makes outdoor air sampling challenging. The region is also affected by intense dust storms. Monitoring challenges from the harsh climate have limited data needed to inform appropriate regulatory actions to address air pollution in the region.

    OBJECTIVES: To compare gravimetric measurements with existing networks that rely on beta-attenuation measurements in a desert climate; determine the annual levels of PM2.5 and PM10 over a two-year period in Kuwait; assess compliance with air quality standards; and identify and quantify PM2.5 sources.

    METHODS: We custom-designed particle samplers that can withstand large quantities of dust without their inlet becoming overloaded. The samplers were placed in two populated residential locations, one in Kuwait City and another near industrial and petrochemical facilities in Ali Sabah Al-Salem (ASAS) to collect PM2.5 and PM10 samples for mass and elemental analysis. We used positive matrix factorization to identify PM2.5 sources and apportion their contributions.

    RESULTS: We collected 2339 samples during the period October 2017 through October 2019. The beta-attenuation method in measuring PM2.5 consistently exceeded gravimetric measurements, especially during dust events. The annual levels for PM2.5 in Kuwait City and ASAS were 41.6 ± 29.0 and 47.5 ± 27.6 μg/m3, respectively. Annual PM2.5 levels in Kuwait were nearly four times higher than the U.S. National Ambient Air Quality Standard. Regional pollution was a major contributor to PM2.5 levels in both locations accounting for 44% in Kuwait City and 46% in ASAS. Dust storms and re-suspended road dust were the second and third largest contributors to PM2.5, respectively.

    CONCLUSIONS: The premise that frequent and extreme dust storms make air quality regulation futile is dubious. In this comprehensive particulate pollution analysis, we show that the sizeable regional anthropogenic particulate sources warrant national and regional mitigation strategies to ensure compliance with air quality standards.

    MeSH terms: Cities; Dust/analysis; Environmental Monitoring; Kuwait; Malaysia; Particulate Matter/analysis
  12. Li Z, Cui L, Zhao H, Du J, Gopinath SCB, Lakshmipriya T, et al.
    Dev Neurosci, 2021;43(1):53-62.
    PMID: 33849012 DOI: 10.1159/000515197
    OBJECTIVE: Brain-derived neurotrophic factor (BDNF) dysregulation is widely related with various psychiatric and neurological disorders, including schizophrenia, depression, Rett syndrome, and addiction, and the available evidence suggests that BDNF is also highly correlated with Parkinson's and Alzheimer's diseases.

    METHODS: The BDNF target sequence was detected on a capture probe attached on aluminum microcomb electrodes on the silicon wafer surface. A capture-target-reporter sandwich-type assay was performed to enhance the detection of the BDNF target.

    RESULTS: The limit of detection was noticed to be 100 aM. Input of a reporter sequence at concentrations >10 aM improved the detection of the target sequence by enhancing changes in the generated currents. Control experiments with noncomplementary and single- and triple-mismatches of target and reporter sequences did not elicit changes in current levels, indicating the selective detection of the BDNF gene sequence.

    CONCLUSION: The above detection strategy will be useful for the detection and quantification of BDNF, thereby aiding in the provision of suitable treatments for BDNF-related disorders.

    MeSH terms: Aluminum*; Electrodes; Genotype; Polymorphism, Genetic; Silicon; Polymorphism, Single Nucleotide
  13. Amy Suzana Abu Bakar, Norhafiza Razali, Mohammad Daniel Shafiq Hassan, Renu Agarwal
    MyJurnal
    Glaucoma is an optic neuropathy characterised by optic nerve degeneration associated with
    visual field defects. It remains the world’s number one cause of irreversible blindness and
    patients usually present at late stage of the disease since it is generally asymptomatic until
    severe. The disease is subdivided into primary and secondary with primary open-angle
    glaucoma (POAG) being the most common type. At present, lowering the intraocular pressure
    (IOP) remains the only proven efficient approach in delaying the onset or preventing the
    progression of the disease. Medical treatment with topical antiglaucoma agents is the
    treatment of choice in open angle glaucoma. The use of antiglaucoma drugs aims to reduce
    IOP by enhancing aqueous humour (AH) outflow, reducing AH production, or both. The choice
    to use any available treatment option should be carefully considered in an attempt to maximise
    benefits and reducing the risk of developing adverse drug reactions. This review highlights the
    six classes of ocular hypotensive agents currently in use for POAG treatment including
    prostaglandin analogues; -adrenergic receptor blockers; -2 adrenergic receptor stimulants;
    carbonic anhydrase inhibitors; muscarinic receptor stimulants; rho kinase inhibitors with
    regards to their mechanism/s of action and potential adverse drug reactions, and
    antiglaucoma fixed drug combinations.
    MeSH terms: Aqueous Humor; Blindness; Carbonic Anhydrase Inhibitors; Drug Combinations; Pharmaceutical Preparations; Glaucoma; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Nerve Degeneration; Optic Nerve Diseases; Prostaglandins, Synthetic; Receptors, Adrenergic; Receptors, Muscarinic; Visual Fields; Adrenergic Antagonists; rho-Associated Kinases; Drug-Related Side Effects and Adverse Reactions
  14. Tan TL, Zulkifli NA, Zaman ASK, Jusoh MB, Yaapar MN, Rashid SA
    Plant Physiol Biochem, 2021 May;162:737-751.
    PMID: 33799185 DOI: 10.1016/j.plaphy.2021.03.031
    Photosynthesis is one of the most fundamental biochemical processes on earth such that it is vital to the existence of most lives on this planet. In fact, unravelling the potentials in enhancing photosynthetic efficiency and electron transfer process, which are thought to improve plant growth is one of the emerging approaches in tackling modern agricultural shortcomings. In light of this, zero-dimensional carbon quantum dots (CQD) have emerged and garnered much interest in recent years which can enhance photosynthesis by modulating the associated electron transfer process. In this work, CQD was extracted from empty fruit bunch (EFB) biochar using a green acid-free microwave method. The resulting CQD was characterized using HRTEM, PL, UV-Vis and XPS. Typical rice (C3) and corn (C4) crops were selected in the present study in order to compare the significant effect of CQD on the two different photosynthetic pathways of crops. CQD was first introduced into crop via foliar spraying application instead of localised placement of CQD before seedling development. The influence of CQD on the photosynthetic efficiency of rice (C3) and corn (C4) leaves was determined by measuring both carbon dioxide conversion and the stomatal conductance of the leaf. As a result, the introduction of CQD greatly enhanced the photosynthesis in CQD-exposed crops. This is the first study focusing on phylogenetically constrained differences in photosynthetic responses between C3 and C4 crops upon CQD exposure, which gives a better insight into the understanding of photosynthesis process and shows considerable promise in nanomaterial research for sustainable agriculture practices.
    MeSH terms: Carbon Dioxide; Zea mays; Photosynthesis; Oryza*; Plant Leaves; Crops, Agricultural; Quantum Dots*
  15. Norrrahim MNF, Ariffin H, Yasim-Anuar TAT, Hassan MA, Ibrahim NA, Yunus WMZW, et al.
    Polymers (Basel), 2021 Mar 28;13(7).
    PMID: 33800573 DOI: 10.3390/polym13071064
    Residual hemicellulose could enhance cellulose nanofiber (CNF) processing as it impedes the agglomeration of the nanocellulose fibrils and contributes to complete nanofibrillation within a shorter period of time. Its effect on CNF performance as a reinforcement material is unclear, and hence this study seeks to evaluate the performance of CNF in the presence of amorphous hemicellulose as a reinforcement material in a polypropylene (PP) nanocomposite. Two types of CNF were prepared: SHS-CNF, which contained about 11% hemicellulose, and KOH-CNF, with complete hemicellulose removal. Mechanical properties of the PP/SHS-CNF and PP/KOH-CNF showed an almost similar increment in tensile strength (31% and 32%) and flexural strength (28% and 29%) when 3 wt.% of CNF was incorporated in PP, indicating that hemicellulose in SHS-CNF did not affect the mechanical properties of the PP nanocomposite. The crystallinity of both PP/SHS-CNF and PP/KOH-CNF nanocomposites showed an almost similar value at 55-56%. A slight decrement in thermal stability was seen, whereby the decomposition temperature at 10% weight loss (Td10%) of PP/SHS-CNF was 6 °C lower at 381 °C compared to 387 °C for PP/KOH-CNF, which can be explained by the degradation of thermally unstable hemicellulose. The results from this study showed that the presence of some portion of hemicellulose in CNF did not affect the CNF properties, suggesting that complete hemicellulose removal may not be necessary for the preparation of CNF to be used as a reinforcement material in nanocomposites. This will lead to less harsh pretreatment for CNF preparation and, hence, a more sustainable nanocomposite can be produced.
  16. Susilawati S, Prayogi S, Arif MF, Ismail NM, Bilad MR, Asy'ari M
    Polymers (Basel), 2021 Mar 28;13(7).
    PMID: 33800592 DOI: 10.3390/polym13071065
    This study assesses the optical properties and conductivity of PVA-H3PO4 (polyvinyl alcohol-phosphoric acid) polymer film blend irradiated by gamma (γ) rays. The PVA-H3PO4 polymer film blend was prepared by the solvent-casting method at H3PO4 concentrations of 75 v% and 85 v%, and then irradiated up to 25 kGy using γ-rays from the Cobalt-60 isotope source. The optical absorption spectrum was measured using an ultraviolet-visible spectrophotometer over a wavelength range of 200 to 700 nm. It was found that the absorption peaks are in three regions, namely two peaks in the ultraviolet region (310 and 350 nm) and one peak in the visible region (550 nm). The presence of an absorption peak after being exposed to hυ energy indicates a transition of electrons from HOMO to LUMO within the polymer chain. The study of optical absorption shows that the energy band gap (energy gap) depends on the radiation dose and the concentration of H3PO4 in the polymer film blend. The optical absorption, absorption edge, and energy gap decrease with increasing H3PO4 concentration and radiation dose. The interaction between PVA and H3PO4 blend led to an increase in the conductivity of the resulting polymer blend film.
    MeSH terms: Cobalt Radioisotopes; Electric Conductivity; Electrons; Phosphoric Acids; Polymers; Polyvinyl Alcohol; Radiation Dosage; Solvents; Physical Phenomena
  17. Wei Chong B, Othman R, Jaya RP, Shu Ing D, Li X, Wan Ibrahim MH, et al.
    Materials (Basel), 2021 Mar 28;14(7).
    PMID: 33800634 DOI: 10.3390/ma14071658
    Image analysis techniques are gaining popularity in the studies of civil engineering materials. However, the current established image analysis methods often require advanced machinery and strict image acquisition procedures which may be challenging in actual construction practices. In this study, we develop a simplified image analysis technique that uses images with only a digital camera and does not have a strict image acquisition regime. Mortar with 10%, 20%, 30%, and 40% pozzolanic material as cement replacement are prepared for the study. The properties of mortar are evaluated with flow table test, compressive strength test, water absorption test, and surface porosity based on the proposed image analysis technique. The experimental results show that mortar specimens with 20% processed spent bleaching earth (PSBE) achieve the highest 28-day compressive strength and lowest water absorption. The quantified image analysis results show accurate representation of mortar quality with 20% PSBE mortar having the lowest porosity. The regression analysis found strong correlations between all experimental data and the compressive strength. Hence, the developed technique is verified to be feasible as supplementary mortar properties for the study of mortar with pozzolanic material.
    MeSH terms: Bone Cements; Construction Materials; Glass Ionomer Cements; Regression Analysis; Water; Porosity; Compressive Strength; Physical Phenomena
  18. Alahnomi RA, Zakaria Z, Yussof ZM, Althuwayb AA, Alhegazi A, Alsariera H, et al.
    Sensors (Basel), 2021 Mar 24;21(7).
    PMID: 33804904 DOI: 10.3390/s21072267
    Recent developments in the field of microwave planar sensors have led to a renewed interest in industrial, chemical, biological and medical applications that are capable of performing real-time and non-invasive measurement of material properties. Among the plausible advantages of microwave planar sensors is that they have a compact size, a low cost and the ease of fabrication and integration compared to prevailing sensors. However, some of their main drawbacks can be considered that restrict their usage and limit the range of applications such as their sensitivity and selectivity. The development of high-sensitivity microwave planar sensors is required for highly accurate complex permittivity measurements to monitor the small variations among different material samples. Therefore, the purpose of this paper is to review recent research on the development of microwave planar sensors and further challenges of their sensitivity and selectivity. Furthermore, the techniques of the complex permittivity extraction (real and imaginary parts) are discussed based on the different approaches of mathematical models. The outcomes of this review may facilitate improvements of and an alternative solution for the enhancement of microwave planar sensors' normalized sensitivity for material characterization, especially in biochemical and beverage industry applications.
    MeSH terms: Beverages; Data Collection; Industry; Microwaves; Models, Theoretical; Monitoring, Physiologic; Refractive Surgical Procedures
  19. Wu XH, Liew YK, Mai CW, Then YY
    Int J Mol Sci, 2021 Mar 24;22(7).
    PMID: 33805207 DOI: 10.3390/ijms22073341
    Medical devices are indispensable in the healthcare setting, ranging from diagnostic tools to therapeutic instruments, and even supporting equipment. However, these medical devices may be associated with life-threatening complications when exposed to blood. To date, medical device-related infections have been a major drawback causing high mortality. Device-induced hemolysis, albeit often neglected, results in negative impacts, including thrombotic events. Various strategies have been approached to overcome these issues, but the outcomes are yet to be considered as successful. Recently, superhydrophobic materials or coatings have been brought to attention in various fields. Superhydrophobic surfaces are proposed to be ideal blood-compatible biomaterials attributed to their beneficial characteristics. Reports have substantiated the blood repellence of a superhydrophobic surface, which helps to prevent damage on blood cells upon cell-surface interaction, thereby alleviating subsequent complications. The anti-biofouling effect of superhydrophobic surfaces is also desired in medical devices as it resists the adhesion of organic substances, such as blood cells and microorganisms. In this review, we will focus on the discussion about the potential contribution of superhydrophobic surfaces on enhancing the hemocompatibility of blood-contacting medical devices.
    MeSH terms: Bacterial Adhesion/drug effects; Biocompatible Materials/pharmacology; Biocompatible Materials/chemistry*; Biotechnology; Blood*; Disinfection/methods*; Equipment Contamination/prevention & control*; Fibrinolytic Agents/pharmacology; Hemolysis; Humans; Surface Properties; Wettability*; Biofilms/drug effects; Nanoparticles; Biofouling/prevention & control*; Hydrophobic and Hydrophilic Interactions*
  20. Rizal S, H P S AK, Oyekanmi AA, Gideon ON, Abdullah CK, Yahya EB, et al.
    Polymers (Basel), 2021 Mar 24;13(7).
    PMID: 33805242 DOI: 10.3390/polym13071006
    The exponential increase in textile cotton wastes generation and the ineffective processing mechanism to mitigate its environmental impact by developing functional materials with unique properties for geotechnical applications, wastewater, packaging, and biomedical engineering have become emerging global concerns among researchers. A comprehensive study of a processed cotton fibres isolation technique and their applications are highlighted in this review. Surface modification of cotton wastes fibre increases the adsorption of dyes and heavy metals removal from wastewater. Cotton wastes fibres have demonstrated high adsorption capacity for the removal of recalcitrant pollutants in wastewater. Cotton wastes fibres have found remarkable application in slope amendments, reinforcement of expansive soils and building materials, and a proven source for isolation of cellulose nanocrystals (CNCs). Several research work on the use of cotton waste for functional application rather than disposal has been done. However, no review study has discussed the potentials of cotton wastes from source (Micro-Nano) to application. This review critically analyses novel isolation techniques of CNC from cotton wastes with an in-depth study of a parameter variation effect on their yield. Different pretreatment techniques and efficiency were discussed. From the analysis, chemical pretreatment is considered the most efficient extraction of CNCs from cotton wastes. The pretreatment strategies can suffer variation in process conditions, resulting in distortion in the extracted cellulose's crystallinity. Acid hydrolysis using sulfuric acid is the most used extraction process for cotton wastes-based CNC. A combined pretreatment process, such as sonication and hydrolysis, increases the crystallinity of cotton-based CNCs. The improvement of the reinforced matrix interface of textile fibres is required for improved packaging and biomedical applications for the sustainability of cotton-based CNCs.
External Links