MyMedR

Stressful life events and depressive symptoms among adolescents in Malaysia: the mediating role of maladaptive cognitive schema

Wong YS, Zulkefly NS, Tan KA

Int J Adolesc Med Health, 2020 Jun 08;33(6):493-500.

PMID: 32549164 DOI: 10.1515/ijamh-2019-0228

OBJECTIVES: The present study aimed to examine the mediational role of maladaptive cognitive schema in the association between stressful life events, which are operationalised as major (i. e. negative life events) and minor (i. e. daily hassles) life stressors, and depressive symptoms among adolescents.

METHODS: A cross-sectional correlational study was conducted to recruit participants across four selected states of Kedah, Kelantan, Melaka and Selangor in Peninsular Malaysia. This study involved a total of 1,032 adolescents from 25 government secondary schools, identified using probability proportional to size cluster sampling technique. Data were collected through a self-report questionnaire.

RESULTS: Using structural equation modelling analyses, findings revealed a full mediation effect of maladaptive cognitive schema between negative life events and depressive symptoms, and a partial mediation effect between daily hassles and depressive symptoms.

CONCLUSIONS: This study provided valuable insights about the significance of maladaptive cognitive schema as a mediator in the stress-depression association and advanced the understanding of mechanism underlying development of depressive symptoms among adolescents in Malaysia. Findings also benefit the clinical practice in the development of targeted depression prevention and intervention programs.

A three-dimensional exoscope system for bilateral simultaneous cochlear implant surgery: how I do it

Tan SH, Kulasegarah J, Prepageran N

J Laryngol Otol, 2022 Jan 07.

PMID: 34991738 DOI: 10.1017/S002221512100431X

Author reply: The relationship between alcohol intake and falls

Myint PK, Tan MP, Khaw KT

Geriatr Gerontol Int, 2022 01;22(1):91-92.

PMID: 34755445 DOI: 10.1111/ggi.14308

Optical enzymatic formaldehyde biosensor based on alcohol oxidase and pH-sensitive methacrylic-acrylic optode membrane

Nurlely, Ahmad M, Heng LY, Tan LL

Spectrochim Acta A Mol Biomol Spectrosc, 2022 Feb 15;267(Pt 2):120535.

PMID: 34749257 DOI: 10.1016/j.saa.2021.120535

Optical biosensor for the detection of formaldehyde has been developed based on the transparent enzymatic stacked membranes system on the glass substrate, and employing optical absorption transducer with H+ ion-selective Nile Blue chromoionophore (NBCM) dye-doped methacrylic acrylic (MB28) copolymer membrane as the optode membrane. Alcohol oxidase (AOx) enzymes were entrapped within the biocompatible sol-gel matrix and deposited on top of the pH optode membrane. As the uppermost catalytic membrane catalyzes the oxidative conversion of formaldehyde to formic acid and hydrogen peroxide, the immobilized NBCM undergoes protonation reaction and forms HNBCM+, the dark blue ion-chromoionophore complex via H+ ion transfer reaction within the soft and flexible MB28 polymeric membrane. This rendered the enzymatic optode membrane absorbed a high yellow light intensity from the light source and exhibited maximum absorption peaks at 610 and 660 nm. Optical evaluation of formaldehyde by means on UV-vis absorption transduction of the enzymatic stacked membranes demonstrated rapid response time of 10 min with high sensitivity, good linearity and high reproducibility across a wide formaldehyde concentration range of 1 × 10-3-1 × 103 mM (R2 = 0.9913), and limit of detection (LOD) at 1 × 10-3 mM, which could be useful for formaldehyde assay in industrial, agricultural, environmental, food and beverages as well as medical samples. The formaldehyde concentration in snapper fish, pomfret fish and threadfin fish samples determined by the proposed optical enzymatic biosensor were very much close to the formaldehyde concentration values determined by the UV-vis spectrophotometric NASH standard method based on the statistical t-test. This suggests that the optical biosensor can be used as a reliable method for quantitative determination of formaldehyde levels in food samples.

Fulltext Longitudinally Extensive Transverse Myelitis in Highly Active Relapsing-remitting Multiple Sclerosis

Ng CF, Remli R, Tan HJ

Neurol India, 2021 11 9;69(5):1412-1413.

PMID: 34747827 DOI: 10.4103/0028-3886.329533

Transverse myelitis in multiple sclerosis is typically a short cord lesion with patchy distribution. Rarely, longitudinally extensive transverse myelitis can be seen in those with highly active disease or frequent relapses. The recognition of this uncommon phenotype in multiple sclerosis is important as the treatment is largely different from other demyelinating diseases. We describe a patient with highly active relapsing-remitting multiple sclerosis on interferon beta-1a who developed LETM after multiple relapses.

Fulltext Elderly's intention to use technologies: A systematic literature review

Yap YY, Tan SH, Choon SW

Heliyon, 2022 Jan;8(1):e08765.

PMID: 35128090 DOI: 10.1016/j.heliyon.2022.e08765

The population aging and an increased life expectancy are widely recognized social changes. Technologies are believed to improve the elderly's daily lives and maintain their health efficiently. Despite the advantage of adopting technologies, the elderly are slower to adopt new technologies compared to younger adults. This paper presents a Systematic Literature Review (SLR) to identify the different antecedents prevailing in the literature on elderly technology adoption. The SLR classifies and analyzes 26 relevant articles on elderly's technology adoption. Our findings revealed that quantitative approach and cross-sectional studies predominate in this field, building fundamentally upon the technology-driven theories. We identify seven categories of antecedents influencing elderly's use of technology, namely, technology, psychological, social, personal, cost, behavior, and environment antecedents. A conceptual framework for elderly's technology adoption and recommendations were presented. Particular attention is given to the need for in depth study for the antecedents, development of new measurement scales and investigation on the effectiveness of the proposed benefits after technology adoption.

Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET

Tan ML, Lentaris G, Amaratunga Aj G

Nanoscale Res Lett, 2012;7(1):467.

PMID: 22901374

The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio (Ion/Ioff), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency.

Horseshoe crab, Tachypleus gigas (Müller, 1785) spawning population at Balok Beach, Kuantan, Pahang, Malaysia

Tan AN, Christianus A, Shakibazadeh S, Hajeb P

Pak J Biol Sci, 2012 Jul 01;15(13):610-20.

PMID: 24218930

Local and regional decline of Asian horseshoe crabs has spurred a study on its spawning population at Balok Beach, Kuantan, Pahang, Malaysia. This location was identified as spawning site due to the occurrence of horseshoe crab spawning pairs and nests. Size-frequency, length-weight relationships, sex ratio and epibiont infestation of Tachypleus gigas were studied. Instar stage was estimated based on prosomal width. Condition of the horseshoe crab carapace was reported. Visual search technique of horseshoe crab was conducted during high tide of new and full moons. Prosomal, opisthosomal and telson length and weight of each horseshoe crab were measured. Largest female was recorded with mean prosomal length and width of 154.4 and 246.9 mm, respectively. About 69.8% of the males belonged to size group of 151-200 mm and 53.3% of females were grouped into 201-250 mm. All individuals were of fourteenth to sixteenth instar stages. Sex ratio varied from 0.313 to 2.5 and attributed to commercial harvest and monsoon season. Sand sediment of study site showed 93% of fine sands with grain size ranged from 120 to 250 microm. Acorn and pedunculate barnacle, conical and flat slipper shells were found on the carapace of the specimens. Most males had damaged eyes and carapaces while females with broken telsons. Body damages of about 19.9% on the specimens were likely due to nearby fishing activities. Lack of satellite male indicated low spawning population. The finding of this study showed that the species is extremely threatened by human activities and coastal development.

Quality of life of patients with epilepsy in Malaysia

Mohamed S, Gill JS, Tan CT

Asia Pac Psychiatry, 2014 Mar;6(1):105-9.

PMID: 23857866 DOI: 10.1111/j.1758-5872.2012.00192.x

To determine the quality of life of patients with epilepsy and its relationship with depression, and the clinical and sociodemographic variables.

Fulltext Pelvic aneurysmal bone cyst

Sharifah M, Nurhazla H, Suraya A, Tan S

Biomed Imaging Interv J, 2011 Oct;7(4):e24.

PMID: 22279501 MyJurnal DOI: 10.2349/biij.7.4.24

This paper describes an extremely rare case of a huge aneurysmal bone cyst (ABC) in the pelvis, occurring in the patient's 5(th) decade of life. The patient presented with a history of painless huge pelvic mass for 10 years. Plain radiograph and computed tomography showed huge expansile lytic lesion arising from the right iliac bone. A biopsy was performed and histology confirmed diagnosis of aneurysmal bone cyst. Unfortunately, the patient succumbed to profuse bleeding from the tumour.

Compression neuropathy of the common peroneal nerve secondary to a ganglion cyst

Yazid Bajuri M, Tan BC, Das S, Hassan S, Subanesh S

Clin Ter, 2011;162(6):549-52.

PMID: 22262327

There are various causes of the common peroneal nerve palsy. However, common peroneal nerve palsy caused by ganglia are uncommon. We hereby present a case of a 55-year-old man with a 1 week history of foot drop and swelling in the region of the right leg. Physical examination and nerve conduction study studies confirmed a diagnosis of common peroneal nerve palsy. Magnetic resonance imaging (MRI) revealed a lobulated, elongated cystic-appearing mass anterior to the head of fibula. Surgical decompression of the nerve with removal of the mass was performed. Surgical pathology reports confirmed the diagnosis of a ganglion cyst. Findings on physical examination, nerve conduction study and MRI results of this interesting case are being discussed. We wish to highlight that even a tumour which is benign and within the nerve sheath can cause compression.

Fulltext Neonatal rash - a case study

Kwa SK, Sinniah D, Tan KK

Aust Fam Physician, 2012 Sep;41(9):707-9.

PMID: 22962649

An infant, aged 48 days, is brought in by her mother to her doctor because of a rash that started during the neonatal period.

Fulltext Determination of ammonium ion using a reagentless amperometric biosensor based on immobilized alanine dehydrogenase

Tan LL, Musa A, Lee YH

Sensors (Basel), 2011;11(10):9344-60.

PMID: 22163699 DOI: 10.3390/s111009344

The use of the enzyme alanine dehydrogenase (AlaDH) for the determination of ammonium ion (NH(4)(+)) usually requires the addition of pyruvate substrate and reduced nicotinamide adenine dinucleotide (NADH) simultaneously to effect the reaction. This addition of reagents is inconvenient when an enzyme biosensor based on AlaDH is used. To resolve the problem, a novel reagentless amperometric biosensor using a stacked methacrylic membrane system coated onto a screen-printed carbon paste electrode (SPE) for NH(4)(+) ion determination is described. A mixture of pyruvate and NADH was immobilized in low molecular weight poly(2-hydroxyethyl methacrylate) (pHEMA) membrane, which was then deposited over a photocured pHEMA membrane (photoHEMA) containing alanine dehydrogenase (AlaDH) enzyme. Due to the enzymatic reaction of AlaDH and the pyruvate substrate, NH(4)(+) was consumed in the process and thus the signal from the electrocatalytic oxidation of NADH at an applied potential of +0.55 V was proportional to the NH(4)(+) ion concentration under optimal conditions. The stacked methacrylate membranes responded rapidly and linearly to changes in NH(4)(+) ion concentrations between 10-100 mM, with a detection limit of 0.18 mM NH(4)(+) ion. The reproducibility of the amperometrical NH(4)(+) biosensor yielded low relative standard deviations between 1.4-4.9%. The stacked membrane biosensor has been successfully applied to the determination of NH(4)(+) ion in spiked river water samples without pretreatment. A good correlation was found between the analytical results for NH(4)(+) obtained from the biosensor and the Nessler spectrophotometric method.

Fulltext Wernicke's Encephalopathy in a Patient with Nasopharyngeal Carcinoma: Magnetic Resonance Imaging Findings

Law HL, Tan S, Sedi R

Malays J Med Sci, 2011 Jul;18(3):71-4.

PMID: 22135604

We report a case of Wernicke's encephalopathy in a patient with nasopharyngeal carcinoma with a 3-month history of poor oral intake related to nausea and vomiting due to chemotherapy. The patient later developed deep coma while receiving in-patient therapy. Magnetic resonance imaging of the brain revealed typical findings of Wernicke's encephalopathy. The patient was treated with thiamine injections, which resulted in subsequent partial recovery of neurological function. This paper stresses the importance of magnetic resonance imaging for prompt diagnosis of Wernicke's encephalopathy.

Fulltext A cohort study of risk factors and clinical outcome predictors for patients presenting with unstable angina and non ST segment elevation myorardial infraction undergoing coronary intervention

Chong E, Shen L, Tan HC, Poh KK

Med J Malaysia, 2011 Aug;66(3):249-52.

PMID: 22111450

Thrombolysis in Myocardial Infarction (TIMI) score has been used to predict outcomes in patients presenting with unstable angina (UA) and non-ST elevation myocardial infarction (NSTEMI). Our study assessed other clinical predictors for patients with UA/NSTEMI undergoing early percutaneous coronary intervention (PCI).

Fulltext Genetic polymorphisms of human platelet antigens-1 to -6, and -15 in the Malaysian population

Tan JY, Lian LH, Nadarajan VS

Blood Transfus, 2012 Jul;10(3):368-76.

PMID: 22682339 DOI: 10.2450/2012.0095-11

Human platelet antigens (HPA) are determinant in several platelet-specific alloimmune disorders, such as neonatal alloimmune thrombocytopenia, post-transfusion purpura and platelet transfusion refractoriness. The distribution of HPA systems in the Malaysian population is not known. Defining the patterns of HPA systems provides a basis for risk assessment and management of the above complications.

Fulltext Silencing quorum sensing through extracts of Melicope lunu-ankenda

Tan LY, Yin WF, Chan KG

Sensors (Basel), 2012;12(4):4339-51.

PMID: 22666033 DOI: 10.3390/s120404339

Quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. In this work, we screened edible, endemic plants in Malaysia for anti-quorum sensing properties. Extracts from Melicope lunu-ankenda (Gaertn.) T. G. Hartley, a Malay garden salad, inhibited response of Chromobacterium violaceum CV026 to N-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of E. coli [pSB401], disrupted pyocyanin synthesis, swarming motility and expression of lecA::lux of Pseudomonas aeruginosa PAO1. Although the chemical nature of the anti-QS compounds from M. lunu-ankenda is currently unknown, this study proves that endemic Malaysian plants could serve as leads in the search for anti-quorum sensing compounds.

Fulltext Circulatory microRNA-145 expression is increased in cerebral ischemia

Gan CS, Wang CW, Tan KS

Genet. Mol. Res., 2012;11(1):147-52.

PMID: 22370881 DOI: 10.4238/2012.January.27.1

Cerebral ischemia or ischemic stroke is mainly attributed to vascular and circulation disorders. Among protein biomarkers, RNA profiles have also been identified as markers of ischemic stroke. MicroRNA-145 expression is ostensibly recognized as marker and modulator of vascular smooth muscle cell phenotype; however, expression levels in ischemic stroke had not been investigated. Employing real-time quantitative PCR, we examined the expression profile of circulatory microRNA-145 in healthy control subjects (N = 14) and ischemic stroke patients (N = 32). Circulatory microRNA-145 expression was significantly higher in ischemic stroke patients than in control subjects. This demonstrates that hemostatic mechanisms are affected by ischemic stroke. We conclude that circulating microRNA-145 has potential as a biomarker for ischemic stroke.

Pretreatment of oil palm frond using hot compressed water: an evaluation of compositional changes and pulp digestibility using severity factors

Goh CS, Tan HT, Lee KT

Bioresour Technol, 2012 Apr;110:662-9.

PMID: 22326327 DOI: 10.1016/j.biortech.2012.01.083

The influence of reaction temperature (160-200°C), residence time (45-90min), and liquid-solid ratio (8-16v/w) on oil palm frond (OPF) pre-treated with hot compressed water (HCW) was evaluated using severity factors. Effect of the process parameters studied on pulps composition and digestibility were found to be complex. The results revealed that digestibility could not be predicted merely according to composition. Severity factor was correlated with compositional changes and digestibility with good R-squared values at varied liquid-solid ratios (8-16v/w), but not with overall glucose yield. HCW pretreatment significantly improved the overall glucose yield up to 83.72% with severity of 3.31 and liquid-solid ratio of 8.0 compared to untreated raw OPF which only recorded an overall glucose yield of 30.97%. HCW is therefore an effective method for pretreatment of OPF for glucose recovery.

A rapid and cost effective method in purifying small RNA

Citartan M, Tan SC, Tang TH

World J Microbiol Biotechnol, 2012 Jan;28(1):105-11.

PMID: 22806785 DOI: 10.1007/s11274-011-0797-0

Purification of RNA fragments from a complex mixture is a very common technique, and requires consideration of the time, cost, purity and yield of the purified RNA fragments. This study describes the fastest method of purifying small RNA with the lowest cost possible, without compromizing the yield and purity. The technique describes the purification of small RNA from polyacrylamide gel, resulting in a good yield of small RNA with minimum experimental steps in avoiding degradation of the RNA, obviating the use of ethidium bromide and phenol-chloroform extraction, as well as siliconized glass wools to remove the polyacrylamide gel particles. The purified small RNA is suitable for a wide variety of applications such as ligation, end labelling with radio isotope, RT-PCR (Reverse Transcriptase-PCR), Northern blotting, experimental RNomics study and also Systematic Evolution of Ligands by Exponential Enrichment (SELEX).

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