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High incidence of Plasmodium knowlesi malaria compared to other human malaria species in several hospitals in Malaysia

Lai MY, Rafieqin N, Lee PYL, Amir Rawa MS, Dzul S, Yahaya N, et al.

Trop Biomed, 2021 Sep 01;38(3):248-253.
PMID: 34362867 DOI: 10.47665/tb.38.3.065

Through the regional control programme, Malaysia has been successfully reducing the incidence of Plasmodium falciparum and Plasmodium vivax infections. However, the incidence of zoonotic malaria Plasmodium knowlesi infection is increasing and now has been the major cause of malaria in Malaysia especially Malaysian Borneo. The emergence of knowlesi infection has threatened the malaria elimination programme which the government aims to reduce the overall malaria infections by 2020. Unlike other benign human Plasmodium spp., P. knowlesi can cause fatal infections. The aim of this study was to determine the incidence and distribution of five human malaria parasites including P. knowlesi in Peninsular Malaysia and Malaysian Borneo. A total of 112 blood samples were collected from seven states and district hospitals in Peninsular Malaysia and Malaysian Borneo from year 2015 to 2016. The samples were examined by microscopy and further confirmed by nested PCR assay targeting 18S rRNA gene of Plasmodium spp. Following the nested PCR assays, a total of 54 (48.2%) samples were positive for P. knowlesi infections, 12 (10.7%) cases were positive for P. vivax infections, followed by 7 (6.3%) cases of P. falciparum and 4 (3.5%) cases of P. malariae. There were 3 cases (2.7%) of mixed infections (P. knowlesi/P. vivax). However, no cases were identified as P. ovale. A total of 32 (28.6%) cases were found as negative infections. LoopMediated Isothermal Amplification Assay (LAMP) was performed to confirm inconclusive results produced by microscopy and nested PCR. P. knowlesi showed the highest prevalence in Sarawak (n= 30), Sabah (n=13), Pulau Pinang (n=5) and Pahang (n=6). PCR and LAMP was not able to detect a large number of microscopy positive samples due to DNA degradation during storage and shipping. Among all the states involved in this study, the highest prevalence of P. knowlesi infection was found in Sabah and Sarawak.
Fulltext Review of toxoplasmosis in Malaysia

Yahaya N

Southeast Asian J. Trop. Med. Public Health, 1991 Dec;22 Suppl:102-6.
PMID: 1822863

Various studies on toxoplasmosis in Malaysia have shown that specific antibodies to Toxoplasma gondii are common among Malaysians. Among the ethnic groups, the Malays have the highest prevalence rate followed by Indians, Orang Aslis (aborigines) and Chinese. Antibody is acquired early in life and increases with age. There is no significant difference in the prevalence rate between males and females. The disease is apparently more prevalent among rural dwellers and those in the lower socioeconomic group. It appears that the prevalence rate is also influenced by environmental conditions, occupation, diet and cultural habits. Studies with animals have shown the presence of antibody to T. gondii, but this does not seem to be the source of infection since Malaysians normally cook their meat well.
Clubroot Disease Stimulates Early Steps of Phloem Differentiation and Recruits SWEET Sucrose Transporters within Developing Galls

Walerowski P, Gündel A, Yahaya N, Truman W, Sobczak M, Olszak M, et al.

Plant Cell, 2018 Nov 09.
PMID: 30413655 DOI: 10.1105/tpc.18.00283

Successful biotrophic plant pathogens can divert host nutrition towards infection sites. Here we describe how the protist Plasmodiophora brassicae establishes a long-term feeding relationship with its host by stimulating phloem differentiation and phloem-specific expression of sugar transporters within developing galls. Development of galls in infected Arabidopsis thaliana plants is accompanied by stimulation of host BREVIS RADIX (BRX), COTYLEDON VASCULAR PATTERN 2 (CVP2) and OCTOPUS (OPS) gene expression leading to an increase in phloem complexity. We characterised how the arrest of this developmental reprogramming influences both the host and the invading pathogen. Furthermore, we found that infection leads to phloem-specific accumulation of SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTERS (SWEET11 and SWEET12) facilitating local distribution of sugars towards the pathogen. Utilising Fourier-transform infrared (FTIR) microspectroscopy to monitor spatial distribution of carbohydrates, we found that infection leads to the formation of a strong physiological sink at the site of infection. High resolution metabolic and structural imaging of sucrose distributions revealed that sweet11 sweet12 double mutants are impaired in sugar transport towards the pathogen, delaying disease progression. This work highlights the importance of precise regulation of sugar partitioning for plant-pathogen interactions and the dependence of P. brassicae's performance on its capacity to induce a phloem sink at the feeding site.
Fulltext Species distribution and antifungal susceptibility patterns of Candida species: Is low susceptibility to itraconazole a trend in Malaysia?

Santhanam J, Yahaya N, Aziz MN

Med J Malaysia, 2013 Aug;68(4):343-7.
PMID: 24145264

Resistance to antifungal agents has increased in Candida spp., especially in non-albicans species. Recent findings reported a strikingly low susceptibility in Candida spp. towards itraconazole in Malaysia. In this study, a colorimetric broth dilution method was utilized to determine the susceptibility of Candida spp. isolated in Kuala Lumpur Hospital within a six month period. A total of 82 isolates from blood, peritoneal and other fluids were tested against 8 antifungal agents using the Sensititre Yeast One method. These comprised of 32 (39%) C. albicans, 17 (20.7%) C. glabrata, 15 (18.3%) C. tropicalis, 13 (15.9%) C. parapsilosis, two (2.4%) C. sake and 1 (1.2%) each of C. pelliculosa, C. rugosa and Pichia etchellsii/carsonii. Overall, susceptibility of all isolates to caspofungin was 98.8%, amphotericin B, 97.6%; 5-flucytosine, 97.6%; voriconazole, 97.6%; posaconazole, 87.8%; fluconazole, 82.9%; ketoconazole, 79.3%; and itraconazole, 56.1%. A total of 18 Candida spp. isolates (22 %) were resistant to at least one antifungal agent tested, and half of these were resistant to three or more antifungal agents. C. glabrata was the most frequently identified resistant species (10 isolates), followed by C. tropicalis (4 isolates), C. parapsilosis (3 isolates) and C. albicans (1 isolate). Resistance was highest against ketoconazole (20.9%), followed by itraconazole (13.4%). However, 30.5% of isolates were susceptible-dose dependent towards itraconazole. Long-term usage of itraconazole in Malaysia and a predominance of nonalbicans species may account for the results observed in this study. In conclusion, susceptibility to antifungal drugs is species-dependent among Candida spp.; reduced susceptibility to itraconazole is concomitant with the high number of non-albicans Candida species isolated in Malaysia.
Implementing primary eye care in private practises in Malaysia: the challenges faced by optometrists

Yahaya NA, Musa A, Azemin MZC, Rahman NAA

Med J Malaysia, 2023 May;78(3):357-363.
PMID: 37271846

OBJECTIVE: In Malaysia, optometrists' role in the private sector is limited compared to their counterparts elsewhere. Primary eye care (PEC) is still not widely offered in private practises despite its demand to reduce the public's eye morbidity. This study aims to explore the challenges perceived by the private sector optometrists in implementing PEC in Malaysia.
MATERIALS AND METHODS: In-depth interview using semistructured open-ended questions were designed to explore the challenges of implementing PEC. Fifteen private optometrists across Malaysian were interviewed via purposive sampling until the data were saturated. The interviews were audio-recorded, transcribed and analysed.
RESULTS: Four major themes emerged: working environment, support and recognition, self-sufficiency and customer influence. The first major theme identified a lack of time and equipment in the workplace as a barrier to PEC implementation. The second major theme acknowledges the lack of support and recognition for PEC practise from financial bodies, the government, Malaysian Optical Council (MOC) and other eye professionals. Meanwhile, some practising optometrists faced significant challenges due to their lack of self-sufficiency regarding skills, knowledge and confidence. The final major theme, customer influence, reflects the customer's role in shaping eye care delivery through their perception and acceptance of PEC.
CONCLUSION: Each of the issues identified played a significant impact in impeding PEC implementation in Malaysia. This study is the first step toward developing tailored interventions to improve eye care delivery in Malaysia.
Disease Expression and HLA Types in Early and Late Onset Disease of Malaysian Patients with Systemic Lupus Erythematosus

Radzi AM, Huan KS, Yahaya N, Shahera A, Kong N, Mohd Noah R

Malays J Med Sci, 2001 Jul;8(2):32-9.
PMID: 22893758

Age has been suggested to modify systemic lupus erythematosus expression. In this study we have attempted to study 13 patients with late onset (40 years and above) and 90 with early onset disease (below 40 years) to determine whether age-related differences in disease expression exist and whether the genetic make-up influences the age of disease onset. We found that patients with late onset disease initially presented with pericarditis (31% vs 3%, P<0.005) and a lower incidence of malar rash (31% vs 57%, p<0.05). During the disease course, there was a lower incidence of mucocutaneous symptoms especially malar rash (p<0.005) and psychosis (p<0.05) in the late onset group. Serological parameters were similar in both groups. There was a prevalence of HLA-DQA1*0103 in Chinese patients with late onset disease (pcorr=0.004). These findings suggest that a subgroup of late onset patients may experience milder disease and that the risk conferred by the HLA-DQA1*0103 may be significant among these patients.
Micellar electrokinetic chromatography method for the simultaneous determination of furanic compounds in honey and vegetable oils

Foo Wong Y, Makahleh A, Al Azzam KM, Yahaya N, Saad B, Sulaiman SA

Talanta, 2012 Aug 15;97:23-31.
PMID: 22841043 DOI: 10.1016/j.talanta.2012.03.056

A simple micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of 2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF), 5-hydroxymethylfurfural (5-HMF), 2-furoic acid (2-FA) and 3-furoic acid (3-FA) in honey and vegetable oils is described. Parameters affecting the separation such as pH, buffer and surfactant concentrations, applied voltage, capillary temperature, injection time and capillary length were studied and optimized. The separation was carried out in normal polarity mode at 20 °C, 22 kV and using hydrodynamic injection (17 s). The separation was achieved in a bare fused-silica capillary (46 cm × 50 μm i.d.) with a background electrolyte of 75 mM phosphoric acid (pH 7.3), containing 200 mM of sodium dodecyl sulphate (SDS). The detection wavelengths were at 200 nm (2-FA and 3-FA) and 280 nm (2-F, 3-F, 5-MF, 5-HMF). The furfurals were well separated in less than 20 min. The method was validated in terms of linearity, limit of detection and quantitation, precision and recoveries. Calibration curves of the six furfurals were well correlated (r(2)>0.991) within the range 1-25 μg mL(-1). Relative standard deviations of intra- and inter-day migration times and corrected peak areas ≤9.96% were achieved. The limit of detection (signal:noise, 3) was 0.33-0.70 μg mL(-1) whereas the limit of quantitation (signal:noise, 10) was 1.00-2.12 μg mL(-1). The method was applied to the determination of furanic compounds in honeys and vegetable oils (palm, walnut, grape seed and rapeseed). The effects of thermal treatment and gamma irradiation on the formation of the furanic compounds in honey were also investigated.
Evaluation of a magnetic activated charcoal modified with non-ionic silicone surfactant as a new magnetic solid phase extraction sorbent with triazine herbicides as model compounds in selected milk and rice samples

Mohd NI, Gopal K, Raoov M, Mohamad S, Yahaya N, Lim V, et al.

Talanta, 2019 May 01;196:217-225.
PMID: 30683354 DOI: 10.1016/j.talanta.2018.12.043

The non-ionic silicone surfactant (OFX 0309) has been applied in cloud point extraction for the extraction of triazine herbicides in food samples. Evidence has shown that the non-ionic silicone surfactant demonstrated a good performance as an extractor toward triazine herbicides. In this present study, OFX 0309 surfactant was combined with activated charcoal (AC) due to their valuable properties. Activated charcoal modified with non-ionic silicone surfactant coated with magnetic nanoparticles (AC-OFX MNPs) was synthesized and characterized by FT-IR, VSM, SEM, TEM and BET. This novel material was applied as a magnetic adsorbent for the pre-concentration and separation of triazine herbicides due to hydrophobic interaction between polysiloxane polyether of OFX 0309 surfactant and triazine herbicides. Under optimal conditions, the proposed magnetic solid phase extraction method using AC-OFX MNPs adsorbent was applied to extract triazine herbicides from selected milk and rice samples using high performance liquid chromatography coupled with diode array detector. The validation method revealed a good linearity (1 - 500 μg L-1) with the coefficient of determination (R2) in the range of 0.992-0.998 for the samples. The limits of detection (LOD) of the developed method were 0.04 - 0.05 µg L-1 (milk sample) and 0.02 - 0.05 µg L-1 (rice sample). The limits of quantification (LOQ) were 0.134 - 0.176 µg L-1 (milk sample) and 0.075 - 0.159 µg L-1 (rice sample). The recoveries of the triazine compounds ranged from 81% to 109% in spiked milk samples and from 81% to 111% in spiked rice samples, with relative standard deviations (RSD) values lower than 13.5% and 12.1% for milk and rice samples, respectively. To the best of our knowledge, this is the first study that have investigated the use of magnetic nanoparticles coated activated charcoal modified with OFX 0309 surfactant for pretreatment of triazine herbicides in food samples analysis for simultaneous separation of organic pollutants.
Molecularly imprinted silica gel incorporated with agarose polymer matrix as mixed matrix membrane for separation and preconcentration of sulfonamide antibiotics in water samples

Rozaini MNH, Semail NF, Saad B, Kamaruzaman S, Abdullah WN, Rahim NA, et al.

Talanta, 2019 Jul 01;199:522-531.
PMID: 30952293 DOI: 10.1016/j.talanta.2019.02.096

Molecularly imprinted silica gel (MISG) was incorporated through dispersion in agarose polymer matrix to form a mixed matrix membrane (MMM) and was applied for the determination of three sulfonamide antibiotic compounds (i.e. sulfamethoxazole (SMX), sulfamonomethoxine (SMM), and sulfadiazine (SDZ)) from environmental water samples. Several important microextraction conditions, such as type of desorption solvent, extraction time, amount of sorbent, sample volume, pH, and effect of desorption time, were comprehensively optimized. A preconcentration factors of ≥ 20 was achieved by the extraction of 12.5 mL of water samples using the developed method. This microextraction-HPLC method demonstrated good linearity (1-500 μg L-1) with a coefficient of determination (R2) of 0.9959-0.9999, low limits of detection (0.06-0.17 μg L-1) and limits of quantification (0.20-0.56 μg L-1), good analyte recoveries (80-96%), and acceptable relative standard deviations (< 10%) under the optimized conditions. The method is systematically compared to those reported in the literature.
Simultaneous preconcentration and determination of sulfonamide antibiotics in milk and yoghurt by dynamic pH junction focusing coupled with capillary electrophoresis

Semail NF, Abdul Keyon AS, Saad B, Kamaruzaman S, Mohamad Zain NN, Lim V, et al.

Talanta, 2022 Jan 01;236:122833.
PMID: 34635223 DOI: 10.1016/j.talanta.2021.122833

A dynamic pH junction was used in capillary electrophoresis (CE-DAD) to on-line preconcentrate, separate, and determine trace amounts of sulfonamide antibiotics (SAs) in milk and yoghurt samples in this study. A sample matrix with 0.15% acetic acid and 10% methanol (MeOH) at a pH of 4.0, and a background electrolyte (BGE) that contained 35 mM sodium citrate with 10% MeOH at a pH of 8.5, and an acidic barrage of 0.4% acetic acid with 10% MeOH at a pH of 2.5 were utilised to achieve a stacking effect for SAs through a dynamic pH junction. Under optimised conditions, the proposed preconcentration method showed good linearity (30-500 ng/mL, r2 ≥ 0.9940), low limits of detection (LODs) of 4.1-6.3 ng/mL, and acceptable analytes recovery (81.2-106.9%) with relative standard deviations (RSDs) within 5.3-13.7 (n = 9). The limits of quantification (LOQs) were below the maximum residue limit approved by the European Union (EU) in this type of matrices. Sensitivity enhancement factors of up to 129 were reached with the optimised dynamic pH junction using CE with a diode array detector (DAD). The method was used to determine SAs in fresh milk, low-fat milk, full-cream milk, and yoghurt samples.
Rapid ultrasound assisted emulsification micro-solid phase extraction based on molecularly imprinted polymer for HPLC-DAD determination of bisphenol A in aqueous matrices

Rozaini MNH, Yahaya N, Saad B, Kamaruzaman S, Hanapi NSM

Talanta, 2017 Aug 15;171:242-249.
PMID: 28551135 DOI: 10.1016/j.talanta.2017.05.006

Molecularly imprinted polymer (MIP) was employed as sorbent in ultrasound assisted emulsification molecularly imprinted polymer micro-solid phase extraction (USAE-MIP-µ-SPE) of bisphenol A (BPA) in water, beverages and the aqueous liquid in canned foods prior to high performance liquid chromatography-diode array detector (HPLC-DAD) analysis. Several effective variables, such as types of emulsification solvent and its volume, types of desorption solvent and its volume, salting out effect, pH of sample solution, mass of sorbent, extraction and desorption time, and sample volume, were optimized comprehensively. Under the optimized USAE-MIP-µ-SPE and HPLC-DAD conditions, the method demonstrated good linearity over the range of 0.5-700μgL-1with a coefficient determination of R2=0.9973, low limit of detection (0.07μgL-1), good analyte recoveries (82.2-118.9%) and acceptable RSDs (0.7-14.2%, n=3) with enrichment factor of 49. The method was applied to thirty samples of drinking water, mineral water, river water, lake water, as well as beverages and canned foods, the presence of BPA was identified in four samples. The proposed method showed good selectivity and reusability for extraction of BPA, and hence the USAE-MIP-µ-SPE is rapid, simple, cost effective and environmentally friendly.
Fulltext Primary thyroid lymphoma with elevated free thyroxine level

Yahaya N, Din SW, Ghazali MZ, Mustafa S

Singapore Med J, 2011 Sep;52(9):e173-6.
PMID: 21947158

Primary thyroid lymphoma (PTL) is a rare form of thyroid cancer that is known to be associated with Hashimoto thyroiditis. This association is supported by the presence of elevated titres of both antithyroglobulin and antimicrosomal antibodies in up to 95 percent of patients with PTL. Most patients with PTL present with a rapidly enlarging neck mass and compressive symptoms. The majority of thyroid cancer patients have normal levels of thyroid hormones; they are rarely hyperthyroid, with no obvious clinical features of thyrotoxicosis. We describe a patient who presented with minimal clinical features of thyrotoxicosis despite having markedly elevated serum free thyroxine and suppressed serum thyroid-stimulating hormone levels.
Autotransplantation of maxillary canine following removal of compound odontome: a case report

Zaman JQ, Yahaya N, Razali M, Ibrahim N, Nor GM, Ramli R

Singapore Dent J, 2007 Dec;29(1):41-5.
PMID: 18472529

Obstruction remains as an important cause of failure in the eruption of a tooth. In this article, a 15-year-old girl was presented with retained upper left primary canine (63) and first primary molar (64), while the contralateral permanent canine (13) and premolars (14 and 15) have erupted. Upon radiographic examination, a mass which was diagnosed later to be compound odontome was detected. The treatment consisted of surgical removal of the odontome, extraction of the primary canine (63) and left permanent canine (23), and transplantation of the permanent canine (23). The management of this case and the literature related to autotransplantation are discussed.
Fulltext Superhydrophilic graphene oxide/electrospun cellulose nanofibre for efficient adsorption of organophosphorus pesticides from environmental samples

Aris NIF, Rahman NA, Wahid MH, Yahaya N, Abdul Keyon AS, Kamaruzaman S

R Soc Open Sci, 2020 Mar;7(3):192050.
PMID: 32269813 DOI: 10.1098/rsos.192050

Superhydrophilic graphene oxide/electrospun cellulose nanofibre (GO/CNF) was synthesized, characterized and successfully used in a solid-phase membrane tip adsorption (SPMTA) as an adsorbent towards a simultaneous analysis of polar organophosphorus pesticides (OPPs) in several food and water samples. Separation, determination and quantification were achieved prior to ultra-performance liquid chromatography coupled with ultraviolet detector. The influence of several parameters such as sample pH, adsorption time, adsorbent dosage and initial concentration were investigated. SPMTA was linear in the range of 0.05 and 10 mg l-1 under the optimum adsorption conditions (sample pH 12; 5 mg of adsorbent dosage; 15 min of adsorption time) for methyl parathion, ethoprophos, sulfotepp and chlorpyrifos with excellent correlation coefficients of 0.994-0.999. Acceptable precision (RSDs) as achieved for intraday (0.06-5.44%, n = 3) and interday (0.17-7.76%, n = 3) analyses. Low limits of detection (0.01-0.05 mg l-1) and satisfactory consistency in adsorption (71.14-99.95%) were obtained for the spiked OPPs from Sungai Pahang, Tasik Cheras, cabbages and rice samples. The adsorption data were well followed the second-order kinetic model and fits the Freundlich adsorption model. The newly synthesized GO/CNF showed a great adsorbent potential for OPPs analysis.
Fulltext Magnetic nanoparticles assisted dispersive liquid-liquid microextraction of chloramphenicol in water samples

Saad SM, Aling NA, Miskam M, Saaid M, Mohamad Zain NN, Kamaruzaman S, et al.

R Soc Open Sci, 2020 Apr;7(4):200143.
PMID: 32431904 DOI: 10.1098/rsos.200143

This work describes the development of a new methodology based on magnetic nanoparticles assisted dispersive liquid-liquid microextraction (DLLME-MNPs) for preconcentration and extraction of chloramphenicol (CAP) antibiotic residues in water. The approach is based on the use of decanoic acid as the extraction solvent followed by the application of MNPs to magnetically retrieve the extraction solvent containing the extracted CAP. The coated MNPs were then desorbed with methanol, and the clean extract was analysed using ultraviolet-visible spectrophotometry. Several important parameters, such as the amount of decanoic acid, extraction time, stirring rate, amount of MNPs, type of desorption solvent, salt addition and sample pH, were evaluated and optimized. Optimum parameters were as follows: amount of decanoic acid: 200 mg; extraction time: 10 min; stirring rate: 800 rpm; amount of MNPs: 60 mg; desorption solvent: methanol; salt: 10%; and sample pH, 8. Under the optimum conditions, the method demonstrated acceptable linearity (R2 = 0.9933) over a concentration range of 50-1000 µg l-1. Limit of detection and limit of quantification were 16.5 and 50.0 µg l-1, respectively. Good analyte recovery (91-92.7%) and acceptable precision with good relative standard deviations (0.45-6.29%, n = 3) were obtained. The method was successfully applied to tap water and lake water samples. The proposed method is rapid, simple, reliable and environmentally friendly for the detection of CAP.
Fulltext Deep eutectic solvent-based emulsification liquid-liquid microextraction for the analysis of phenoxy acid herbicides in paddy field water samples

Mohamad Yusoff N'N, Rahim NY, Mohammad REA, Yahaya N, Miskam M

R Soc Open Sci, 2021 Mar 31;8(3):202061.
PMID: 34035939 DOI: 10.1098/rsos.202061

An emulsification liquid-liquid microextraction (ELLME) method was successfully developed using phenolic-based deep eutectic solvent (DES) as an extraction solvent for the determination of phenoxy acid herbicides, 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in environmental water samples. Five different phenolics-based DESs were successfully synthesized by using phenol (DES 1), 2-chlorophenol (DES 2), 3-chlorophenol (DES 3), 4-chlorophenol (DES 4) and 3,4-dichlorophenol (DES 6) as the hydrogen-bond donor (HBD) and choline chloride as the hydrogen-bond acceptor (HBA). The DESs were mixed at 1 : 2 ratio. A homogeneous solution (clear solution) was observed upon the completion of successful synthesis. The synthesized DESs were characterized by using Fourier transform infrared and nuclear magnetic resonance (NMR). Under optimum ELLME conditions (50 µl of DES 2 as extraction solvent; 100 µl of THF as emulsifier solvent; pH 2; extraction time 5 min), enrichment factor obtained for dicamba and MCPA were 43.1 and 59.7, respectively. The limit of detection and limit of quantification obtained for dicamba were 1.66 and 5.03 µg l-1, respectively, meanwhile for MCPA were 1.69 and 5.12 µg l-1, respectively. The developed ELLME-DES method was applied on paddy field water samples, with extraction recoveries in the range of 79-91% for dicamba and 82-96% for MCPA.
Fulltext A study on the removal of propyl, butyl, and benzyl parabens via newly synthesised ionic liquid loaded magnetically confined polymeric mesoporous adsorbent

Md Yusoff M, Yahaya N, Md Saleh N, Raoov M

RSC Adv, 2018 Jul 16;8(45):25617-25635.
PMID: 35539765 DOI: 10.1039/c8ra03408g

This study investigated the effectiveness of ionic liquids (ILs) loaded onto the surface of a polymeric adsorbent (βCD-TDI) grafted with modified magnetic nanoparticles (MNPs) via an analysis of water treatment, which resulted in high removal of selected endocrine-disrupting chemicals (parabens). The syntheses of MNPs, MNP-βCD-TDI, and IL-MNP-βCD-TDI were characterised and compared using Fourier transform infrared (FT-IR) spectroscopy, carbon-hydrogen-nitrogen (CHN) analysis, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results of SEM and TEM indicated that the pore size distribution exhibited mesoporous characteristics with a small surface area (BET analysis: 42.95 m2 g-1). Furthermore, a preliminary sorption experiment demonstrated the ability of IL-MNP-βCD-TDI to enhance not only the sorption capacity, but also the removal of propyl paraben (PP), butyl paraben (BP), and benzyl paraben (ArP). The adsorption process appeared to be pH-dependent, and hence the optimum pH of 6 was selected for a subsequent batch adsorption study of all the studied parabens with an equilibrium time of 80 min. Next, in an attempt to investigate the interactions that occur between the adsorbent and the adsorbates, adsorption kinetics and isotherm studies were performed. All the studied parabens were found to best fit pseudo-second-order kinetics and the Freundlich isotherm with R 2 > 0.98 at room temperature (298 K). The interaction of the host-guest inclusion complex and the π-π interaction between βCD and a selected paraben compound (ArP) were identified by performing 1H nuclear magnetic resonance (NMR), together with ultraviolet-visible (UV-vis) spectroscopic analysis. Finally, the adsorption efficiency of the developed material was practically tested on tap water, drain water, and industrial wastewater, which revealed a significant removal of parabens of up to 60-90% in comparison with a prior analysis.
Fulltext Moderating effect of Islamic religiosity on the relationship between chronic medical conditions and psychological well-being among elderly Malays

Abolfathi Momtaz Y, Hamid TA, Ibrahim R, Yahaya N, Abdullah SS

Psychogeriatrics, 2012 Mar;12(1):43-53.
PMID: 22416828 DOI: 10.1111/j.1479-8301.2011.00381.x

Research has found that physical health decline in later life is associated with poor psychological well-being. This study aimed to examine the possible moderating effect of Islamic religiosity on the relationship between chronic medical conditions and psychological well-being.
Fulltext Solid-Phase Extraction of Active Compounds from Natural Products by Molecularly Imprinted Polymers: Synthesis and Extraction Parameters

Kamaruzaman S, Nasir NM, Mohd Faudzi SM, Yahaya N, Mohamad Hanapi NS, Wan Ibrahim WN

Polymers (Basel), 2021 Oct 31;13(21).
PMID: 34771337 DOI: 10.3390/polym13213780

Molecularly imprinted polymers (MIPs) are synthetic polymers with a predetermined selectivity for a particular analyte or group of structurally related compounds, making them ideal materials for separation processes. Hence, in sample preparation, MIPs are chosen as an excellent material to provide selectivity. Moreover, its use in solid-phase extraction, also referred to as molecular imprinted solid phase extraction (MISPE), is well regarded. In recent years, many papers have been published addressing the utilization of MIPs or MISPE as sorbents in natural product applications, such as synthesis. This review describes the synthesis and characterization of MIPs as a tool in natural product applications.
Fulltext Sodium Alginate/β-Cyclodextrin Reinforced Carbon Nanotubes Hydrogel as Alternative Adsorbent for Nickel(II) Metal Ion Removal

Zakaria AF, Kamaruzaman S, Abdul Rahman N, Yahaya N

Polymers (Basel), 2022 Dec 16;14(24).
PMID: 36559892 DOI: 10.3390/polym14245524

Water pollution issues, particularly those caused by heavy metal ions, have been significantly growing. This paper combined biopolymers such as sodium alginate (SA) and β-cyclodextrin (β-CD) to improve adsorption performance with the help of calcium ion as the cross-linked agent. Moreover, the addition of carbon nanotubes (CNTs) into the hybrid hydrogel matrix was examined. The adsorption of nickel(II) was thoroughly compared between pristine sodium alginate/β-cyclodextrin (SA-β-CD) and sodium alginate/β-cyclodextrin immobilized carbon nanotubes (SA-β-CD/CNTs) hydrogel. Both hydrogels were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectral analysis, field emission scanning electron microscopy (FESEM), electron dispersive spectroscopy (EDX), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. The results showed SA-β-CD/CNTs hydrogel exhibits excellent thermal stability, high specific surface area and large porosity compared with SA-β-CD hydrogel. Batch experiments were performed to study the effect of several adsorptive variables such as initial concentration, pH, contact time and temperature. The adsorption performance of the prepared SA-β-CD/CNTs hydrogel was comprehensively reported with maximum percentage removal of up to 79.86% for SA-β-CD/CNTs and 69.54% for SA-β-CD. The optimum adsorption conditions were reported when the concentration of Ni(II) solution was maintained at 100 ppm, pH 5, 303 K, and contacted for 120 min with a 1000 mg dosage. The Freundlich isotherm and pseudo-second order kinetic model are the best fits to describe the adsorption behavior. A thermodynamic study was also performed. The probable interaction mechanisms that enable the successful binding of Ni(II) on hydrogels, including electrostatic attraction, ion exchange, surface complexation, coordination binding and host-guest interaction between the cationic sites of Ni(II) on both SA-β-CD and SA-β-CD/CNTs hydrogel during the adsorption process, were discussed. The regeneration study also revealed the high efficiency of SA-β-CD/CNTs hydrogel on four successive cycles compared with SA-β-CD hydrogel. Therefore, this work signifies SA-β-CD/CNTs hydrogel has great potential to remove Ni(II) from an aqueous environment compared with SA-β-CD hydrogel.

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