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Recombinant LipL32 Protein Developed Using a Synthetic Gene Detects Leptospira-specific Antibodies in Human Serum Samples

Yaakob Y, Rodrigues KF, Opook F, William T, John DV

Malays J Med Sci, 2017 Oct;24(5):44-51.
PMID: 29386971 DOI: 10.21315/mjms2017.24.5.5

Background: Synthetic biology is emerging as a viable alternative for the production of recombinant antigens for diagnostic applications. It offers a safe alternative for the synthesis of antigenic principles derived from organisms that pose a high biological risk.
Methods: Here, we describe an enzyme-linked immunosorbent assay (ELISA) using the synthetic recombinant LipL32 (rLipL32) protein expressed in Escherichia coli for the detection of Leptospira-specific antibodies in human serum samples. The rLipL32-based ELISA was compared with a microscopic agglutination test (MAT), which is currently used as the gold standard for the diagnosis of leptospirosis.
Results: Our results showed that all the MAT-positive serum samples were positive for Leptospira-specific IgG in an ELISA, while 65% (n = 13) of these samples were also positive for Leptospira-specific IgM. In the MAT-negative serum samples, 80% and 55% of the samples were detected as negative by an ELISA for Leptospira-specific IgM and IgG, respectively.
Conclusion: An ELISA using the synthetic rLipL32 antigen was able to distinguish Leptospira-specific IgM (sensitivity 65% and specificity 80%) and IgG (sensitivity 100% and specificity 55%) in human serum samples and has the potential to serve as a rapid diagnostic test for leptospirosis.
Fulltext Visualizing copper assisted graphene growth in nanoscale

Rosmi MS, Yusop MZ, Kalita G, Yaakob Y, Takahashi C, Tanemura M

Sci Rep, 2014;4:7563.
PMID: 25523645 DOI: 10.1038/srep07563

Control synthesis of high quality large-area graphene on transition metals (TMs) by chemical vapor deposition (CVD) is the most fascinating approach for practical device applications. Interaction of carbon atoms and TMs is quite critical to obtain graphene with precise layer number, crystal size and structure. Here, we reveal a solid phase reaction process to achieve Cu assisted graphene growth in nanoscale by in-situ transmission electron microscope (TEM). Significant structural transformation of amorphous carbon nanofiber (CNF) coated with Cu is observed with an applied potential in a two probe system. The coated Cu particle recrystallize and agglomerate toward the cathode with applied potential due to joule heating and large thermal gradient. Consequently, the amorphous carbon start crystallizing and forming sp(2) hybridized carbon to form graphene sheet from the tip of Cu surface. We observed structural deformation and breaking of the graphene nanoribbon with a higher applied potential, attributing to saturated current flow and induced Joule heating. The observed graphene formation in nanoscale by the in-situ TEM process can be significant to understand carbon atoms and Cu interaction.
Fulltext Development of a predictive model for estimating the specific heat capacity of metallic oxides/ethylene glycol-based nanofluids using support vector regression

Alade IO, Abd Rahman MA, Bagudu A, Abbas Z, Yaakob Y, Saleh TA

Heliyon, 2019 Jun;5(6):e01882.
PMID: 31304407 DOI: 10.1016/j.heliyon.2019.e01882

The specific heat capacity of nanofluids ( C P n f ) is a fundamental thermophysical property that measures the heat storage capacity of the nanofluids. C P n f is usually determined through experimental measurement. As it is known, experimental procedures are characterised with some complexities, which include, the challenge of preparing stable nanofluids and relatively long periods to conduct experiments. So far, two correlations have been developed to estimate the C P n f . The accuracies of these models are still subject to further improvement for many nanofluid compositions. This study presents a four-input support vector regression (SVR) model hybridized with a Bayesian algorithm to predict the specific heat capacity of metallic oxides/ethylene glycol-based nanofluids. The bayesian algorithm was used to obtain the optimum SVR hyperparameters. 189 experimental data collected from published literature was used for the model development. The proposed model exhibits low average absolute relative deviation (AARD) and a high correlation coefficient (r) of 0.40 and 99.53 %, respectively. In addition, we analysed the accuracies of the existing analytical models on the considered nanofluid compositions. The model based on the thermal equilibrium between the nanoparticles and base fluid (model II) show good agreement with experimental results while the model based on simple mixing rule (model I) overestimated the specific heat capacity of the nanofluids. To further validate the superiority of the proposed technique over the existing analytical models, we compared various statistical errors for the three models. The AARD for the BSVR, model II, and model I are 0.40, 0.82 and 4.97, respectively. This clearly shows that the model developed has much better prediction accuracy than existing models in predicting the specific heat capacity of metallic oxides/ethylene glycol-based nanofluids. We believe the presented model will be important in the design of nanofluid-based applications due to its improved accuracy.
Fulltext One-step and room-temperature fabrication of carbon nanocomposites including Ni nanoparticles for supercapacitor electrodes

Akiyama T, Nakanishi S, Yaakob Y, Todankar B, Gupta VP, Asaka T, et al.

RSC Adv, 2022 Jul 21;12(33):21318-21331.
PMID: 35975049 DOI: 10.1039/d2ra02780a

With the increasing importance of power storage devices, demand for the development of supercapacitors possessing both rapid reversible chargeability and high energy density is accelerating. Here we propose a simple process for the room temperature fabrication of pseudocapacitor electrodes consisting of a faradaic redox reaction layer on a metallic electrode with an enhanced surface area. As a model metallic electrode, an Au foil was irradiated with Ar+ ions with a simultaneous supply of C and Ni at room temperature, resulting in fine metallic Ni nanoparticles dispersed in the carbon matrix with local graphitization on the ion-induced roughened Au surface. A carbon layer including fine Ni nanoparticles acted as an excellent faradaic redox reaction layer and the roughened surface contributed to an increase in surface area. The fabricated electrode, which included only 14 μg cm-2 of Ni, showed a stored charge ability three times as large as that of the bulky Ni foil. Thus, it is believed that a carbon layer including Ni nanoparticles fabricated on the charge collective electrode with an ion-irradiation method is promising for the development of supercapacitors from the viewpoints of the reduced use of rare metal and excellent supercapacitor performance.
Conventional versus Doxorubicin-Eluting Beads Transarterial Chemoembolization for Unresectable Hepatocellular Carcinoma: a Tertiary Medical Centre Experience in Malaysia

Rahman FA, Naidu J, Ngiu CS, Yaakob Y, Mohamed Z, Othman H, et al.

Asian Pac J Cancer Prev, 2016;17(8):4037-41.
PMID: 27644658

BACKGROUND: Hepatocellular carcinoma (HCC) is a common cancer that is frequently diagnosed at an advanced stage. Transarterial chemoembolisation (TACE) is an effective palliative treatment for patients who are not eligible for curative treatment. The two main methods for performing TACE are conventional (c-TACE) or with drug eluting beads (DEB-TACE). We sought to compare survival rates and tumour response between patients undergoing c-TACE and DEB-TACE at our centre.
MATERIALS AND METHODS: A retrospective cohort study of patients undergoing either treatment was carried out from January 2009 to December 2014. Tumour response to the procedures was evaluated according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Kaplan-Meier analysis was used to assess and compare the overall survival in the two groups.
RESULTS: A total of 79 patients were analysed (34 had c-TACE, 45 had DEB-TACE) with a median follow-up of 11.8 months. A total of 20 patients in the c-TACE group (80%) and 12 patients in the DEB-TACE group (44%) died during the follow up period. The median survival durations in the c-TACE and DEB-TACE groups were 4.9 ± 3.2 months and 8.3 ± 2.0 months respectively (p=0.008). There was no statistically significant difference noted among the two groups with respect to mRECIST criteria.
CONCLUSIONS: DEB-TACE demonstrated a significant improvement in overall survival rates for patients with unresectable HCC when compared to c-TACE. It is a safe and promising approach and should potentially be considered as a standard of care in the management of unresectable HCC.
Relationship between Serum Cytokeratin-18, Control Attenuation Parameter, NAFLD Fibrosis Score, and Liver Steatosis in Nonalcoholic Fatty Liver Disease

Kosasih S, Zhi Qin W, Abdul Rani R, Abd Hamid N, Chai Soon N, Azhar Shah S, et al.

Int J Hepatol, 2018;2018:9252536.
PMID: 30363686 DOI: 10.1155/2018/9252536

Backgrounds: The aim of this study was to appraise the relationship between serum fragmented cytokeratin-18(CK-18), controlled attenuation parameter (CAP), and liver steatosis assessed by ultrasound (US) in nonalcoholic fatty liver disease (NAFLD) patients.
Methods: Patients who underwent abdominal US were recruited, followed with measurement of CAP using Fibroscan® and serum fragmented CK-18 using enzyme-linked immunosorbent assay. The degree of liver steatosis assessed by US was categorized into mild (S1), moderate (S2), and severe (S3).
Results: A total of 109 patients were included in our study. CAP and fragmented CK-18 level were significantly correlated with liver steatosis grade with rs = 0.56 and 0.68, p=0.001, respectively. NAFLD Fibrosis Score was poorly correlated with liver steatosis grade (rs=-0.096, p=0.318). Using fragmented CK-18 level, area under receiver operating characteristic (AUROC) curves for S≥2 and S≥3 were excellent (0.82 and 0.84, respectively). Using CAP, AUROC curves for detection of S≥2 and S≥3 were good (0.76, 0.77, respectively). We also proposed cut-off value of CAP to detect S≥2 and S≥3 to be 263 and 319db/m, respectively, and fragmented CK-18 level to detect S≥2 and S≥3 (194 and 294 U/L, respectively).
Conclusions: Both the fragmented CK-18 level and the CAP, but not NAFLD Fibrosis Score, were well correlated with hepatic steatosis grade as assessed by US.
Waste NR Latex Based-Precursors as Carbon Source for CNTs Eco-Fabrications

Hazan MA, Chan KF, Jofri KA, Mamat MS, Endot NA, Liza S, et al.

Polymers (Basel), 2021 Oct 04;13(19).
PMID: 34641224 DOI: 10.3390/polym13193409

In this work, the potential of utilizing a waste latex-based precursor (i.e., natural rubber glove (NRG)) as a carbon source for carbon nanotube (CNT) fabrication via chemical vapor deposition has been demonstrated. Gas chromatography-mass spectroscopy (GC-MS) analysis reveals that the separation of the lightweight hydrocarbon chain from the heavier long chain differs in hydrocarbon contents in the NRG fraction (NRG-L). Both solid NRG (NRG-S) and NRG-L samples contain >63% carbon, <0.6% sulfur and <0.08% nitrogen content, respectively, as per carbon-nitrogen-sulfur (CNS) analysis. Growth of CNTs on the samples was confirmed by Raman spectra, SEM and TEM images, whereby it was shown that NRG-S is better than NRG-L in terms of synthesized CNTs yield percentage with similar quality. The optimum vaporization and reaction temperatures were 350 and 800 °C, respectively, considering the balance of good yield percentage (26.7%) and quality of CNTs (ID/IG = 0.84 ± 0.08, diameter ≈ 122 nm) produced. Thus, utilization of waste NRG as a candidate for carbon feedstock to produce value-added CNTs products could be a significant approach for eco-technology.
Fulltext Transfer free graphene growth on SiO2 substrate at 250 °C

Vishwakarma R, Rosmi MS, Takahashi K, Wakamatsu Y, Yaakob Y, Araby MI, et al.

Sci Rep, 2017 03 02;7:43756.
PMID: 28251997 DOI: 10.1038/srep43756

Low-temperature growth, as well as the transfer free growth on substrates, is the major concern of graphene research for its practical applications. Here we propose a simple method to achieve the transfer free graphene growth on SiO2 covered Si (SiO2/Si) substrate at 250 °C based on a solid-liquid-solid reaction. The key to this approach is the catalyst metal, which is not popular for graphene growth by chemical vapor deposition. A catalyst metal film of 500 nm thick was deposited onto an amorphous C (50 nm thick) coated SiO2/Si substrate. The sample was then annealed at 250 °C under vacuum condition. Raman spectra measured after the removal of the catalyst by chemical etching showed intense G and 2D peaks together with a small D and intense SiO2 related peaks, confirming the transfer free growth of multilayer graphene on SiO2/Si. The domain size of the graphene confirmed by optical microscope and atomic force microscope was about 5 μm in an average. Thus, this approach will open up a new route for transfer free graphene growth at low temperatures.