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Streptomyces sp. MUM256: A Source for Apoptosis Inducing and Cell Cycle-Arresting Bioactive Compounds against Colon Cancer Cells
No full textNew and effective anticancer compounds are much needed as the incidence of cancer continues to rise. Microorganisms from a variety of environments are promising sources of new drugs; Streptomyces sp. MUM256, which was isolated from mangrove soil in Malaysia as part of our ongoing efforts to study mangrove resources, was shown to produce bioactive metabolites with chemopreventive potential. This present study is a continuation of our previous efforts and aimed to investigate the underlying mechanisms of the ethyl acetate fraction of MUM256 crude extract (MUM256 EA) in inhibiting the proliferation of HCT116 cells. Our data showed that MUM256 EA reduced proliferation of HCT116 cells via induction of cell-cycle arrest. Molecular studies revealed that MUM256 EA regulated the expression level of several important cell-cycle regulatory proteins. The results also demonstrated that MUM256 EA induced apoptosis in HCT116 cells mediated through the intrinsic pathway. Gas chromatography-mass spectrometry (GC-MS) analysis detected several chemical compounds present in MUM256 EA, including cyclic dipeptides which previous literature has reported to demonstrate various pharmacological properties. The cyclic dipeptides were further shown to inhibit HCT116 cells while exerting little to no toxicity on normal colon cells in this study. Taken together, the findings of this project highlight the important role of exploring the mangrove microorganisms as a bioresource which hold tremendous promise for the development of chemopreventive drugs against colorectal cancer. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Venomics of Trimeresurus (Popeia) nebularis, the Cameron Highlands Pit Viper from Malaysia: Insights into Venom Proteome, Toxicity and Neutralization of Antivenom
No full textTrimeresurus nebularis is a montane pit viper that causes bites and envenomation to various communities in the central highland region of Malaysia, in particular Cameron’s Highlands. To unravel the venom composition of this species, the venom proteins were digested by trypsin and subjected to nano-liquid chromatography-tandem mass spectrometry (LC-MS/MS) for proteomic profiling. Snake venom metalloproteinases (SVMP) dominated the venom proteome by 48.42% of total venom proteins, with a characteristic distribution of P-III: P-II classes in a ratio of 2:1, while P-I class was undetected. Snaclecs constituted the second most venomous protein family (19.43%), followed by snake venom serine proteases (SVSP, 14.27%), phospholipases A 2 (5.40%), disintegrins (5.26%) and minor proteins including cysteine-rich secretory proteins, L-amino acid oxidases, phosphodiesterases, 5 ′ -nucleotidases. The venomic profile correlates with local (painful progressive edema) and systemic (hemorrhage, coagulopathy, thrombocytopenia) manifestation of T. nebularis envenoming. As specific antivenom is unavailable for T. nebularis, the hetero-specific Thai Green Pit viper Monovalent Antivenom (GPVAV) was examined for immunological cross-reactivity. GPVAV exhibited good immunoreactivity to T. nebularis venom and the antivenom effectively cross-neutralized the hemotoxic and lethal effects of T. nebularis (lethality neutralizing potency = 1.6 mg venom per mL antivenom). The findings supported GPVAV use in treating T. nebularis envenoming. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
External Technology Acquisition and External Technology Exploitation: The Difference of Open Innovation Effects
No full textTo sustain in today's ever-changing and competitive landscape, firms must work within and outside of their organizations' boundaries. Open innovation (OI) strategies such as external technology acquisition (ETA), and external technology exploitation (ETE), can effectively improve the innovation performance of the organizations. Technologies like social media can help organizations to scout for appropriate technology, and source for ideas and knowledge from external sources to support their innovations. Moreover, digitalization can hasten business operations and enhance the innovation process of the firm. Focusing on open innovation (OI), this study takes an integrated approach towards investigating the impact of OI strategies, technology scouting through social media, and digitalization vision on innovation and firm performance. Data were drawn from 153 organizations in Malaysia, and the partial least squares (PLS) method was used to analyze data. The findings revealed that ETE, technology scouting through social media, and digitalization vision have a significant relationship with innovation performance. This, in turn, shows a positive relationship with firm performance. However, ETA does not have a significant relationship with innovation performance in the Malaysia context. This study extends the current literature on OI through the use of specific technology variables, such as technology scouting through social media and digitalization vision to support organizations' innovation. © 2019 by the authors
The Effectiveness of a Voice Care Program Among Primary School Teachers in Northeastern Malaysia
No full textObjectives: We sought to determine the effectiveness of a voice care program among primary school teachers in a northeastern district in Malaysia. Methods: We conducted a randomized community trial in eight primary schools in a northeastern district in Malaysia. The self-administered and validated Malay-Voice Handicap Index-10 (M-VHI-10) questionnaire was used to assess overall voice handicap scores preintervention and eight weeks post-intervention. Teachers with a score of five or more (n = 86) were randomized into intervention (n = 41) and control groups (n = 45). The intervention group received portable voice amplifiers and vocal hygiene instruction, which was delivered by lectures and a booklet. The control group was not prescribed any intervention. Results: The sociodemographic, lifestyle, and occupational characteristics of the teachers (except maximum number of students per class) were similar between both groups. The baseline M-VHI-10 scores between both groups were also comparable. After the intervention phase, there was a significant effect observed in the total M-VHI-10 scores (p = 0.021, F-stat (df): 5.33 (1,79)) between both groups after controlling for the maximum number of students per class. Conclusions: Our results support the use of voice amplification in adjunct with vocal hygiene instruction as a prevention and treatment modality to reduce voice handicap among teachers. Our study demonstrated encouraging evidence on the low-cost voice care program as well as the success of group and workplace-based approaches in the school setting. © 2019, Oman Medical Specialty Board. All rights reserved
Mechanical properties of superplastic thin boronised duplex stainless steel (DSS)
No full textA thin 'dog-bone' shape plate of thermo-mechanically treated duplex stainless steel (DSS) was superplastically boronised in compression for 1 and 6 h in a specially designed clamp at 1223 K. Specimens were characterized with XRD, SEM, FESEM, hardness test and tensile test. Substrate microstructures were fine and equiaxed with average grain sizes of 2.996 ±m 0.888 μm and 3.616 ±m 0.855 μm for 1 and 6 h SPB DSS, respectively obeying superplastic characteristics. Two thick and uniform sides of the boronised layer with a thickness range of 26 to 51 μm obtained having a surface hardness of 1768 and 2209 HV after being boronised for 1 and 6 h. The ultimate tensile strength (UTS) values declined from 688 to 427 MPa as boronising time increased, while the toughness and fracture strain values also followed the same trend. Meanwhile, a fracture surface analysis carried out to understand the basis of the UTS, toughness and fracture strain values reduction, revealed that boronising affected the mode of fracture from ductile-dimple to mix ductile and brittle-transgranular and intergranular. An increase in the boronising time and boronised layer thickness led to a decline in the UTS, toughness, and fracture strain values of boronised DSS. In addition, destruction on the opposite side of the boronised layer also contributed to the decline in tensile strength. In order to achieve good mechanical properties in the tensile direction (UTS, fracture toughness, and fracture strain), the thickness of the boronised layer must be kept low. On the other hand, for good mechanical properties in compressive direction (surface hardness) can be achieved with a thick boronised layer. SPB thin DSS shall be stand-alone lightweight materials or combined with other materials through diffusion bonding or cladding for multifunctional properties. © 2019 IOP Publishing Ltd
Teachers’ perspectives of assessment and alternative assessment in the classroom
No full textThis study aims to explore teachers’ perspectives of the elements in assessment, choice of the types of assessment and perspectives of alternative assessment. The study was a case study involving seven in-service secondary school teachers who were interviewed. The findings indicate that respondents develop questions based on bloom’s taxonomy and higher order thinking. Formative and summative assessment are used to create a more comprehensive classroom assessment. Also, the respondents view alternative assessment as consisting of various techniques. © BEIESP
Significance of Surface Eco-Protection Techniques for Cohesive Soils Slope in Selangor, Malaysia
No full textRapid infrastructure development in Malaysia especially in Selangor causes drastic change in landscape and clearing of more vegetated areas. This has gradually lead to slope instability problems that causes enormous loss affecting human lives, destruction of property and environment. Thus, conservation practices by incorporating vegetation to enhance slope stability is much needed alternative to the conventional technique of stabilization. Limited studies had been done in discovering the effectiveness of vegetative covers in relation to slope and soil parameters. Hence, in this paper, a parametric study is carried out to discover the relationship between some of the various vegetation species and different soil types as well as slope angles. Conventional limit equilibrium methods are applied in the analysis considering the soil shear strength parameters, unit weight of soil, as well as slope geometry. Typical scenarios of cut-slope along highways in Selangor are simulated in order to obtain comparable results from the stability assessment by means of calculating the factor of safety. The modelling showed that shallow slip failure can be prevented when sufficient number of roots of a certain tensile force interact with the slip plane, increasing the overall factor of safety of the slope. The percentage of FOS increased due to the vegetation effects can reach up to 43% with slope angles ranging between 15° and 25°. Moreover, based on the parametric study, silty soils showed more significance in contributing to the increase in FOS when incorporating vegetation. © 2018, Springer Nature Switzerland AG
Insight into the origin of chikungunya virus in Malaysian non-human primates via sequence analysis
No full textChikungunya virus (CHIKV) is maintained in the sylvatic cycle in West Africa and is transmitted by Aedes mosquito species to monkeys. In 2006, four verified CHIKV isolates were obtained during a survey of arboviruses in monkeys (Macaca fascicularis) in Pahang state, Peninsular Malaysia. RNA was extracted from the CHIKV isolates and used in reverse transcription polymerase chain reactions (RT-PCR) to amplify PCR fragments for sequencing. Nucleic acid primers were designed to generate overlapping PCR fragments that covered the whole viral sequence. A total of 11,238 base pairs (bp) corresponding to open reading frames (ORFs) from our isolates and 47 other registered isolates in the National Center for Biotechnology Information (NCBI) were used to elucidate sequences, amino acids, and phylogenetic relationships and to estimate divergence times by using MEGA 7.0 and the Bayesian Markov chain Monte Carlo method. Phylogenetic analysis revealed that all CHIKV isolates could be classified into the Asian genotype and clustered with Bagan Panchor clades, which are associated with the chikungunya outbreak reported in 2006, with sequence and amino acid similarities of 99.9% and 99.7%, respectively. Minor amino acid differences were found between human and non-human primate isolates. Amino acid analysis showed a unique amino acid at position 221 in the nsP1region, at which a glycine (G) was found only in monkey isolates, whereas arginine (R) was found at the same position only in human isolates. The time to the most recent common ancestor (MRCA) estimation indicated that CHIKV probably started to diverge from human to non-human primates in approximately 2004 in Malaysia. The results suggested that CHIKV in non-human primates probably resulted from the spillover of the virus from humans. The study will be helpful in understanding the movement and evolution of CHIKV in Malaysia and globally. © 2019 The Author(s
Untangling electronic, optical and bonding properties of hexagonal bismuth borate SrBi2B2O7 crystal for ultraviolet opto-electronic applications: An ab initio study
No full textTo realize the efficient frequency conversion, the nonlinear ultraviolet crystal must exhibit strong second harmonic generation and possible phase-matching condition. The current first principles calculations predict that SrBi2B2O7 represents potentially a new class of materials with such characteristics. For this aim, we present the first analysis of dynamical, bonding, linear and nonlinear optical properties of the SrBi2B2O7 single crystal. To untangle such properties, both density functional theory calculation and topological analysis were used. It is found that the compound exhibits a wide indirect band gap and an interesting bonding motif. In particular, the distortion caused by the stereochemically active lone pair of the s-state in the Bi3+ unit favors the enhancement of local dipole moment. In addition, the refraction index, absorption spectrum, phase matching and second harmonic properties were calculated and analyzed. According to the results, SrBi2B2O7 has a large d33 s-order susceptibility component which makes it a very promising UV nonlinear optical material. © 2019 Elsevier B.V
Optimal Electrospun TiO 2 Nanofiber Photocatalytic Performance via Synergistic Morphology and Particle Crystallinity with Anatase/Rutile Phase Tuning
No full textTiO2 nanofiber photocatalysts offer a highly efficient and stable method of dye degradation through photogenerated radicals. Through electrospinning, the synthesis of the nanofibers with high surface area (i.e., low fiber diameter) and particle crystallinity (e.g., crystallite size and crystal phases) is highly desired to yield the best degradation performance. In this study, it is demonstrated that a synergistic combination of low fiber diameter, high crystallite size, and mixed anatase/rutile ratio is obtained to yield an optimal methylene blue degradation rate constant of 0.04100 min−1. The optimization is conducted with the aid of response surface analysis of electrospinning parameters (flow rate, applied voltage, and tip-to-collector distance (TCD)) toward the obtained fiber diameter response. The nanofiber diameter is observed to be from 177.3 to 310.4 nm across the studied range of parameters. The change in nanofiber diameter exhibits linear relationship with the applied voltage while quadratic relationships are observed for both solution flow rate and TCD. Through selective comparison, the lowering of fiber diameter has an adverse effect on the crystallinity and phase transformation (anatase-rutile) of TiO2 particles. This relationship is shown to have a significant effect on the photocatalytic performance of the TiO2 nanofibers. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei