Displaying publications 1 - 20 of 50 in total

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  1. Krishnan S, Abd Ghani N, Aminuddin NF, Quraishi KS, Razafindramangarafara BL, Baup S, et al.
    Ultrason Sonochem, 2021 Jun;74:105576.
    PMID: 33975186 DOI: 10.1016/j.ultsonch.2021.105576
    This study investigates the potential of using small amounts of ionic liquids (IL) to enhance ultrasound-assisted extraction of lipids content from green microalgae. Three imidazolium-based ILs (butyl, octyl and dodecyl), each of them with two anions (bromide and acetate) were tested as additives. Viscosity and surface tension of the ILs aqueous mixtures were analyzed to determine the influence of ILs' anions and alkyl chain length, whereas KI dosimetry experiments were used as an indicator of radicals formation. A key finding suggests that the small addition of ILs improves the ultrasonication either by enhancing the viscosity and reducing the water surface tension, leading to a more powerful acoustic cavitation process or by increasing HO° production likely to oxidize the microalgae cells membranes, and consequently disrupting them on a more efficient manner. KI dosimetry also revealed that long ILs alkyl chain is detrimental. This experimental observation is confirmed thus strengthened as the yield of extracted lipids from green microalgae has shown an incremental trend when the IL concentration also increased. These hypotheses are currently under investigation to spot detailed impact of ILs on cavitation process.
  2. Wong SC, Ooi MH, Abdullah AR, Wong SY, Krishnan S, Tio PH, et al.
    Trop Med Int Health, 2008 Jan;13(1):52-5.
    PMID: 18291002 DOI: 10.1111/j.1365-3156.2007.01967.x
    Japanese encephalitis virus (JEV) is an important encephalitis virus in Asia, but there are few data on Malaysia. A hospital-based surveillance system for Japanese encephalitis (JE) has been in operation in Sarawak, Malaysia, for the last 10 years. JEV is endemic in Sarawak, with cases occurring throughout the year and a seasonal peak in the last quarter (one-way anova, P < 0.0001). Ninety-two per cent of 133 cases were children aged 12 years or younger; the introduction of JE vaccination in July 2001 reduced the number of JE cases (84 in the four seasons prior to vs. 49 in the six seasons after, McNemar's test, P = 0.0001). After implementation of the programme, the mean age of infected children increased from 6.3 to 8.0 years (Student's t-test, P = 0.0037), suggesting the need for a catch-up programme.
  3. Zulkifli A, Ahmad RE, Krishnan S, Kong P, Nam HY, Kamarul T
    Tissue Cell, 2023 Jun;82:102075.
    PMID: 37004269 DOI: 10.1016/j.tice.2023.102075
    Tendon injuries account up to 50% of all musculoskeletal problems and remains a challenge to treat owing to the poor intrinsic reparative ability of tendon tissues. The natural course of tendon healing is very slow and often leads to fibrosis and disorganized tissues with inferior biomechanical properties. Mesenchymal stem cells (MSC) therapy is a promising alternative strategy to augment tendon repair due to its proliferative and multilineage differentiation potential. Hypoxic conditioning of MSC have been shown to enhance their tenogenic differentiation capacity. However, the mechanistic pathway by which this is achieved is yet to be fully defined. A key factor involved in this pathway is hypoxia-inducible factor-1-alpha (HIF-1α). This review aims to discuss the principal mechanism underlying the enhancement of MSC tenogenic differentiation by hypoxic conditioning, particularly the central role of HIF-1α in mediating activation of tenogenic pathways in the MSC. We focus on the interaction between HIF-1α with fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta 1 (TGF-β1) in regulating MSC tenogenic differentiation pathways in hypoxic conditions. Strategies to promote stabilization of HIF-1α either through direct manipulation of oxygen tension or the use of hypoxia mimicking agents are therefore beneficial in increasing the efficacy of MSC therapy for tendon repair.
  4. Zaied BK, Nasrullah M, Siddique MNI, Zularisam AW, Singh L, Krishnan S
    Sci Total Environ, 2020 Mar 01;706:136095.
    PMID: 31862587 DOI: 10.1016/j.scitotenv.2019.136095
    Lack of sufficient nitrogenous substrate and buffering potential have been acknowledged as impediments to the treatment of palm oil mill effluent through co-digestion processes. In this study, ammonium bicarbonate was used to provide the nitrogenous substrate and buffering potential. To regulate the impact of ammonium bicarbonate toxicity on the anaerobic co-digestion system, dosages from 0 to 40 mg/L were supplemented. The biogas yield was used to indicate the effects of NH4+ toxicity. In a solar-assisted bioreactor, solar radiation was first collected by a solar panel and converted into electricity, which was then used to heat a mixture of palm oil mill effluent and cattle manure to maintain the reactor in the mesophilic temperature range. This co-digestion operation was performed semi-continuously and was analyzed at a 50:50 mixing ratio of palm oil mill effluent and cattle manure. The results indicate that the additional dosing of ammonium bicarbonate can significantly enhance biogas production. Maximum cumulative biogas and methane productions of 2034.00 mL and 1430.51 mL, respectively, were obtained with the optimum addition of 10 mg/L ammonium bicarbonate; these values are 29.80% and 42.30% higher, respectively, than that obtained in the control co-digestion operation without addition of ammonium bicarbonate. Utilization of a mathematical equation (G = Gmk/t) to describe a kinetic analysis of the biogas yield also indicated that the optimum ammonium bicarbonate dose was 10 mg/L. The results of this study suggest that supplementation with ammonium bicarbonate doses of up to 40 mg/L can be used to provide nitrogenous substrates and buffering potential in anaerobic co-digestion processes. The determination of the optimal dose provides an alternative and efficient option for enhanced biogas production, which will have obvious economic advantages for feasible industrial applications.
  5. Amalina F, Krishnan S, Zularisam AW, Nasrullah M
    Sci Total Environ, 2024 Mar 01;914:169608.
    PMID: 38157898 DOI: 10.1016/j.scitotenv.2023.169608
    Employing biomass for environmental conservation is regarded as a successful and environmentally friendly technique since they are cost-effective, renewable, and abundant. Biochar (BC), a thermochemically converted biomass, has a considerably lower production cost than the other conventional activated carbons. This material's distinctive properties, including a high carbon content, good electrical conductivity (EC), high stability, and a large surface area, can be utilized in various research fields. BC is feasible as a renewable source for potential applications that may achieve a comprehensive economic niche. Despite being an inexpensive and environmentally sustainable product, research has indicated that pristine BC possesses restricted properties that prevent it from fulfilling the intended remediation objectives. Consequently, modifications must be made to BC to strengthen its physicochemical properties and, thereby, its efficacy in decontaminating the environment. Modified BC, an enhanced iteration of BC, has garnered considerable interest within academia. Many modification techniques have been suggested to augment BC's functionality, including its adsorption and immobilization reliability. Modified BC is overviewed in its production, functionality, applications, and regeneration. This work provides a holistic review of the recent advances in synthesizing modified BC through physical, chemical, or biological methods to achieve enhanced performance in a specific application, which has generated considerable research interest. Surface chemistry modifications require the initiation of surface functional groups, which can be accomplished through various techniques. Therefore, the fundamental objective of these modification techniques is to improve the efficacy of BC contaminant removal, typically through adjustments in its physical or chemical characteristics, including surface area or functionality. In addition, this article summarized and discussed the applications and related mechanisms of modified BC in environmental decontamination, focusing on applying it as an ideal adsorbent, soil amendment, catalyst, electrochemical device, and anaerobic digestion (AD) promoter. Current research trends, future directions, and academic demands were available in this study.
  6. Ariffin H, Geikowski A, Chin TF, Chau D, Arshad A, Abu Bakar K, et al.
    Med J Malaysia, 2014 Aug;69(4):193-4.
    PMID: 25500851 MyJurnal
    We report a case of Griscelli Syndrome (GS). Our patient initially presented with a diagnosis of haemophagocytic lymphistiocytosis (HLH). Subsequent microscopic analysis of the patient's hair follicle revealed abnormal distribution of melanosomes in the shaft, which is a hallmark for GS. Analysis of RAB27A gene in this patient revealed a homozygous mutation in exon 6, c.550C>T, p.R184X . This nonsense mutation causes premature truncation of the protein resulting in a dysfunctional RAB27A. Recognition of GS allows appropriate institution of therapy namely chemotherapy for HLH and curative haemotopoeitic stem cell transplantation.
  7. Lum SH, How SJ, Ariffin H, Krishnan S
    Med J Malaysia, 2016 02;71(1):28-9.
    PMID: 27130741
    Immune thrombocytopenia is the most common diagnosis of isolated thrombocytopenia. The dilemma encountered by paediatricians is missing diagnosis of acute leukaemia in children with isolated thrombocytopenia. We demonstrated childhood ITP could be diagnosed using a four point clinical criteria without missing a diagnosis of acute leukaemia. Hence, bone marrow examination is not necessary in children with typical features compatible with ITP prior to steroid therapy. This can encourage paediatricians to choose steroid therapy, which is cheaper and non-blood product, as first line platelet elevating therapy in children with significant haemorrhage.
  8. Singh G, Krishnan S
    Med J Malaysia, 1978 Mar;32(3):232-5.
    PMID: 683048
  9. Krishnan S, Rohen JW, Lütjen-Drecoll E, Carmichael SW, Nicholson HD, Trotman P, et al.
    Surg Radiol Anat, 2009 Sep;31 Suppl 1:43-8.
    PMID: 27392490 DOI: 10.1007/BF03371484
  10. Lum SH, Choong SS, Krishnan S, Mohamed Z, Ariffin H
    Singapore Med J, 2016 Jun;57(6):320-4.
    PMID: 27353457 DOI: 10.11622/smedj.2016106
    INTRODUCTION: Children with Down syndrome (DS) are at increased risk of developing distinctive clonal myeloid disorders, including transient abnormal myelopoiesis (TAM) and myeloid leukaemia of DS (ML-DS). TAM connotes a spontaneously resolving congenital myeloproliferative state observed in 10%-20% of DS newborns. Following varying intervals of apparent remission, a proportion of children with TAM progress to develop ML-DS in early childhood. Therefore, TAM and ML-DS represent a biological continuum. Both disorders are characterised by recurring truncating somatic mutations of the GATA1 gene, which are considered key pathogenetic events.

    METHODS: We herein report, to our knowledge, the first observation on the frequency and nature of GATA1 gene mutations in a cohort of Malaysian children with DS-associated TAM (n = 9) and ML-DS (n = 24) encountered successively over a period of five years at a national referral centre.

    RESULTS: Of the 29 patients who underwent GATA1 analysis, GATA1 mutations were observed in 15 (51.7%) patients, including 6 (75.0%) out of 8 patients with TAM, and 9 (42.9%) of 21 patients with ML-DS. All identified mutations were located in exon 2 and the majority were sequence-terminating insertions or deletions (66.7%), including several hitherto unreported mutations (12 out of 15).

    CONCLUSION: The low frequency of GATA1 mutations in ML-DS patients is unusual and potentially indicates distinctive genomic events in our patient cohort.

  11. Tan KA, Lum SH, Yahya A, Krishnan S, Jalaludin MY, Lee WS
    Singapore Med J, 2019 Jun;60(6):303-308.
    PMID: 30556093 DOI: 10.11622/smedj.2018155
    INTRODUCTION: Endocrine dysfunction due to iron overload secondary to frequent blood transfusions is a common complication in children with transfusion-dependent thalassaemia (TDT). We ascertained the prevalence of endocrine dysfunction in children with TDT seen in a hospital setting in Malaysia.

    METHODS: We reviewed all patients with TDT who had ≥ 8 blood transfusions per year. Patients who had a history of stem cell transplantation, concurrent autoimmune diseases or were newly diagnosed to have TDT were excluded. Standard diagnostic criteria were used in the diagnosis of various endocrine dysfunctions.

    RESULTS: Of the 82 patients with TDT, 65% had at least one endocrine dysfunction. Short stature was the commonest (40.2%), followed by pubertal disorders (14.6%), hypoparathyroidism (12.3%), vitamin D deficiency (10.1%), hypocortisolism (7.3%), diabetes mellitus (5.2%) and overt hypothyroidism (4.9%). Subclinical hypothyroidism and pre-diabetes mellitus were seen in 13.4% and 8.6% of the patients, respectively. For children aged < 10 years, the prevalence of both thyroid dysfunction and hypoparathyroidism was 9.1%.

    CONCLUSION: Two-thirds of children with TDT experienced at least one endocrine dysfunction. Thyroid dysfunction and hypoparathyroidism may be missed if endocrine screening is only performed in children with TDT > 10 years of age. Close monitoring for endocrine dysfunction and hormonal therapy is essential to prevent long-term adverse outcomes.

  12. Jeon J, Krishnan S, Manirathinam T, Narayanamoorthy S, Nazir Ahmad M, Ferrara M, et al.
    Sci Rep, 2023 Jun 23;13(1):10206.
    PMID: 37353615 DOI: 10.1038/s41598-023-37200-2
    The probabilistic hesitant elements (PHFEs) are a beneficial augmentation to the hesitant fuzzy element (HFE), which is intended to give decision-makers more flexibility in expressing their biases while using hesitant fuzzy information. To extrapolate a more accurate interpretation of the decision documentation, it is sufficient to standardize the organization of the elements in PHFEs without introducing fictional elements. Several processes for unifying and arranging components in PHFEs have been proposed so far, but most of them result in various disadvantages that are critically explored in this paper. The primary objective of this research is to recommend a PHFE unification procedure that avoids the deficiencies of operational practices while maintaining the inherent properties of PHFE probabilities. The prevailing study advances the hypothesis of permutation on PHFEs by suggesting a new sort of PHFS division and subtraction compared with the existing unification procedure. Eventually, the proposed PHFE-unification process will be used in this study, an innovative PHFEs based on the Weighted Aggregated Sum Product Assessment Method-Analytic Hierarchy Process (WASPAS-AHP) perspective for selecting flexible packaging bags after the prohibition on single-use plastics. As a result, we have included the PHFEs-WASPAS in our selection of the most effective fuzzy environment for bio-plastic bags. The ranking results for the suggested PHFEs-MCDM techniques surpassed the existing AHP methods in the research study by providing the best solution. Our solutions offer the best bio-plastic bag alternative strategy for mitigating environmental impacts.
  13. Mazlan D, Krishnan S, Din MFM, Tokoro C, Khalid NHA, Ibrahim IS, et al.
    Sci Rep, 2020 04 14;10(1):6412.
    PMID: 32286486 DOI: 10.1038/s41598-020-63575-7
    This paper aims to examine the effect of cellulose nanocrystals (CNCs) derived from oil palm empty fruit bunch fiber (EFB) incorporating cement mortar on its structural performances. Cellulose nanocrystals (CNCs) were extracted from α-cellulose extracted from EFB using an acid hydrolysis process with a concentration of acid used was 64% w/v under the temperature of 45 °C for 60 minutes. The Cellulose nanocrystals (CNCs) were mixed into the cement mortar ranging from 0 to 0.8% w/w and its mechanical properties were determined. The developed CNCs mortar was characterized for their compressive and flexural properties as well as microstructure. The influence of CNCs concentration, curing method, dispersion of CNCs on mortar's mechanical performance was thoroughly examined to find out the optimum condition. Overall results revealed that an addition of 0.4% cellulose nanocrystals has shown to increase the compressive and flexural strength to 46% and 20%, respectively cured under the wrapping method. The hydration of cementitious composites also improved significantly with the addition of CNCs by the formation of highly crystalline of portlandite observed under the XRD test. This present work demonstrates the importance of palm oil empty fruit bunch waste as a sustainable resource of cellulose nanocrystals admixture to achieve structural strength of cement mortar and promotes green technologies in construction.
  14. Ariffin H, Hainaut P, Puzio-Kuter A, Choong SS, Chan AS, Tolkunov D, et al.
    Proc Natl Acad Sci U S A, 2014 Oct 28;111(43):15497-501.
    PMID: 25313051 DOI: 10.1073/pnas.1417322111
    The Li-Fraumeni syndrome (LFS) and its variant form (LFL) is a familial predisposition to multiple forms of childhood, adolescent, and adult cancers associated with germ-line mutation in the TP53 tumor suppressor gene. Individual disparities in tumor patterns are compounded by acceleration of cancer onset with successive generations. It has been suggested that this apparent anticipation pattern may result from germ-line genomic instability in TP53 mutation carriers, causing increased DNA copy-number variations (CNVs) with successive generations. To address the genetic basis of phenotypic disparities of LFS/LFL, we performed whole-genome sequencing (WGS) of 13 subjects from two generations of an LFS kindred. Neither de novo CNV nor significant difference in total CNV was detected in relation with successive generations or with age at cancer onset. These observations were consistent with an experimental mouse model system showing that trp53 deficiency in the germ line of father or mother did not increase CNV occurrence in the offspring. On the other hand, individual records on 1,771 TP53 mutation carriers from 294 pedigrees were compiled to assess genetic anticipation patterns (International Agency for Research on Cancer TP53 database). No strictly defined anticipation pattern was observed. Rather, in multigeneration families, cancer onset was delayed in older compared with recent generations. These observations support an alternative model for apparent anticipation in which rare variants from noncarrier parents may attenuate constitutive resistance to tumorigenesis in the offspring of TP53 mutation carriers with late cancer onset.
  15. Gopal Krishnan S, Fun WH, Ramadras MD, Yunus R, Lye YF, Sararaks S
    PLoS One, 2019;14(7):e0219534.
    PMID: 31291359 DOI: 10.1371/journal.pone.0219534
    BACKGROUND: Developing countries still struggle with late detection and mortality from pertussis. A review of clinical case definitions is necessary for early disease detection. This paper aimed to study possible clinical characteristics for earlier pertussis detection in a sporadic setting.

    METHODS: We conducted a retrospective review of medical and laboratory records in a general paediatric ward of a district hospital in a developing country. Inclusion criteria were all children hospitalised with nasopharyngeal swab taken for Bordetella pertussis. We compared sensitivity and specificity of World Health Organization diagnostic criteria with other clinical characteristics. Polymerase chain reaction Bordetella pertussis was the gold standard used.

    RESULTS: Out of 207 eligible admissions, the study retrieved 128 complete records. Approximately half of the children were less than 3 months old. The World Health Organization diagnostic criteria had a low sensitivity (15%), but high specificity (92%). In comparison, combinations that included paroxysmal cough, ill contact and facial congestion had higher sensitivity. Increasing cough duration improved specificity while compromising sensitivity.

    CONCLUSION: Several clinical characteristics such as paroxysmal cough, facial congestion and a history of ill contact have potential for early clinical detection. Conventional emphasis on cough duration may hamper early detection.

  16. Venugopal V, Krishnan S, Palanimuthu VR, Sankarankutty S, Kalaimani JK, Karupiah S, et al.
    PLoS One, 2018;13(11):e0206109.
    PMID: 30408068 DOI: 10.1371/journal.pone.0206109
    The aim of the present study is to analyze the viability of anti-EGFR anchored immunonanoparticle (INP) bearing Paclitaxel (PTX) to specifically bind the EGFR protein on the TNBC cells. The NP was prepared by nanoprecipitation and characterized the particle size, charge, entrapment of drug and release of it. The anti-EGFR anchored and the integrity was confirmed by SDS-PAGE. Cytotoxicity and NPs cellular uptake was analyzed with MDA-MB-468 type cancer cells and the EGFR expression was confirmed by PCR, qualitatively and quantitatively. The in-vivo antitumor activity of INP was determined by using athymic mice model and targeting efficiency was measured by calculating the PTX accumulation in the tumor plasma. The prepared INP with the size of 336.3 nm and the charge of -3.48 mV showed sustained drug release upto 48 h. The INP showed significant reduction of cancer cell viability of 10.6% for 48 h with 93 fold higher PTX accumulation in the tumor plasma compared with NPs. Based on these reports, we recommend that anti-EGFR anchored PTX loaded NP may have the ability to target the TNBC cells and improve the therapeutic action and subsidize the side effects of PTX for the treatment of TNBC.
  17. Abisha S, Mutawa AM, Murugappan M, Krishnan S
    PLoS One, 2023;18(4):e0284021.
    PMID: 37018344 DOI: 10.1371/journal.pone.0284021
    Different diseases are observed in vegetables, fruits, cereals, and commercial crops by farmers and agricultural experts. Nonetheless, this evaluation process is time-consuming, and initial symptoms are primarily visible at microscopic levels, limiting the possibility of an accurate diagnosis. This paper proposes an innovative method for identifying and classifying infected brinjal leaves using Deep Convolutional Neural Networks (DCNN) and Radial Basis Feed Forward Neural Networks (RBFNN). We collected 1100 images of brinjal leaf disease that were caused by five different species (Pseudomonas solanacearum, Cercospora solani, Alternaria melongenea, Pythium aphanidermatum, and Tobacco Mosaic Virus) and 400 images of healthy leaves from India's agricultural form. First, the original plant leaf is preprocessed by a Gaussian filter to reduce the noise and improve the quality of the image through image enhancement. A segmentation method based on expectation and maximization (EM) is then utilized to segment the leaf's-diseased regions. Next, the discrete Shearlet transform is used to extract the main features of the images such as texture, color, and structure, which are then merged to produce vectors. Lastly, DCNN and RBFNN are used to classify brinjal leaves based on their disease types. The DCNN achieved a mean accuracy of 93.30% (with fusion) and 76.70% (without fusion) compared to the RBFNN (82%-without fusion, 87%-with fusion) in classifying leaf diseases.
  18. Masanam HB, Perumal G, Krishnan S, Singh SK, Jha NK, Chellappan DK, et al.
    Nanomedicine (Lond), 2022 Oct;17(25):1981-2005.
    PMID: 36695290 DOI: 10.2217/nnm-2021-0427
    The development of rapid, noninvasive diagnostics to detect lung diseases is a great need after the COVID-2019 outbreak. The nanotechnology-based approach has improved imaging and facilitates the early diagnosis of inflammatory lung diseases. The multifunctional properties of nanoprobes enable better spatial-temporal resolution and a high signal-to-noise ratio in imaging. Targeted nanoimaging agents have been used to bind specific tissues in inflammatory lungs for early-stage diagnosis. However, nanobased imaging approaches for inflammatory lung diseases are still in their infancy. This review provides a solution-focused approach to exploring medical imaging technologies and nanoprobes for the detection of inflammatory lung diseases. Prospects for the development of contrast agents for lung disease detection are also discussed.
  19. Harilal M, G Krishnan S, Pal B, Reddy MV, Ab Rahim MH, Yusoff MM, et al.
    Langmuir, 2018 02 06;34(5):1873-1882.
    PMID: 29345940 DOI: 10.1021/acs.langmuir.7b03576
    This article reports the synthesis of cuprous oxide (Cu2O) and cupric oxide (CuO) nanowires by controlling the calcination environment of electrospun polymeric nanowires and their charge storage properties. The Cu2O nanowires showed higher surface area (86 m2 g-1) and pore size than the CuO nanowires (36 m2 g-1). Electrochemical analysis was carried out in 6 M KOH, and both the electrodes showed battery-type charge storage mechanism. The electrospun Cu2O electrodes delivered high discharge capacity (126 mA h g-1) than CuO (72 mA h g-1) at a current density of 2.4 mA cm-2. Electrochemical impedance spectroscopy measurements show almost similar charge-transfer resistance in Cu2O (1.2 Ω) and CuO (1.6 Ω); however, Cu2O showed an order of magnitude higher ion diffusion. The difference in charge storage between these electrodes is attributed to the difference in surface properties and charge kinetics at the electrode. The electrode also shows superior cyclic stability (98%) and Coulombic efficiency (98%) after 5000 cycles. Therefore, these materials could be acceptable choices as a battery-type or pseudocapacitive electrode in asymmetric supercapacitors.
  20. Cardosa MJ, Krishnan S, Tio PH, Perera D, Wong SC
    Lancet, 1999 Sep 18;354(9183):987-91.
    PMID: 10501361
    In mid-1997, several children died in Sarawak, Malaysia, during an epidemic of enterovirus-71 (EV71) hand, foot, and mouth disease. The children who died had a febrile illness that rapidly progressed to cardiopulmonary failure and the cause was not satisfactorily resolved. We describe the isolation and identification of a subgenus B adenovirus from the children who died.
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