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Purification and identification of novel cytotoxic oligopeptides from soft coral Sarcophyton glaucum
No full textGlobally, peptide-based anticancer therapies have drawn much attention. Marine organisms are a reservoir of anticancer peptides that await discovery. In this study, we aimed to identify cytotoxic oligopeptides from Sarcophyton glaucum. Peptides were purified from among the S. glaucum hydrolysates produced by alcalase, chymotrypsin, papain, and trypsin, guided by a methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay on the human cervical cancer (HeLa) cell line for cytotoxicity evaluation. Purification techniques adopted were membrane ultrafiltration, gel filtration chromatography, solid phase extraction (SPE), and reversed-phase high-performance liquid chromatography (RP-HPLC). Purified peptides were identified by de novo peptide sequencing. From papain hydrolysate, three peptide sequences were identified: AGAPGG, AERQ, and RDTQ (428.45, 502.53, and 518.53 Da, respectively). Peptides synthesized from these sequences exhibited cytotoxicity on HeLa cells with median effect concentration (EC50) values of 8.6, 4.9, and 5.6 mmol/L, respectively, up to 5.8-fold stronger than the anticancer drug 5-fluorouracil. When tested at their respective EC50, AGAPGG, AERQ, and RDTQ showed only 16%, 25%, and 11% cytotoxicity to non-cancerous Hek293 cells, respectively. In conclusion, AERQ, AGAPGG, and RDTQ are promising candidates for future development as peptide-based anticancer drugs
Plasma synthesis of nanodiamonds in ethanol
No full textIn this work, we examined the characteristics of the plasma formed by fs laser filamentation in ethanol that affected the nanodiamonds formation by optical emission spectroscopy. Molecular and atomic C species were detected in the plasma as the precursors to the nanodiamonds formed; above the threshold laser energy of 360 μJ. Thus, the generation of homogeneous nanodiamonds was identified to be occurred within laser energy of 360–550 μJ where atomic C, ionized C and C2 clusters coexisted. The process of fs laser filamentation is monitored with in-situ absorbance measurement of ethanol. The intensity of the absorbance peak of the sample at ∼228 nm, corresponds to intrinsic absorbance of diamond (σ→ σ* transition) was observed to increase with irradiation time. The prepared samples are characterized by using Raman spectroscopy, XPS and TEM. Nanodiamonds of <5 nm in size were produced. Photoluminescence measurements show that the sample fluoresce at ∼490 nm, when excited by 266 nm, 355 nm, 368 nm and 406 nm laser while additional photoluminescence peak is detected at 329 nm when excited by 266 nm laser
The Relationship between Conversion Factors and Health: Evidence from the Ready-Made Garment Workers in Bangladesh
No full textThis study examined the association between health condition and conversion factors (i.e. environmental, individual and social) among workers in the ready-made garment (RMG) industry in Bangladesh. It used data gathered from a cross-sectional survey of 775 RMG workers in the Dhaka and Narayanganj districts. Using multiple logistic regression, the study found that: (1) achieving good health among RMG workers is hindered by various factors including high job-related demands, high noise levels, workplace crowding, heavy workloads, and low level of educational attainment; (2) job-related rewards and marital status have contributed to achieving good health; (3) health condition of workers is worse for women than for men; and (4) poor health condition is more prevalent among the oldest age group than in the lowest age category. The main contributions of this research: (1) this study develops a comprehensive framework to determine the factors affecting the health condition of manufacturing workers in general, and RMG workers in particular; and (2) it also examines the effects of both psychosocial and physical working conditions on the health of RMG workers
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
No full textThe 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
Aftermarket survey on end-of-life vehicle recovery in Malaysia: Key findings
No full textThe National Automotive Policy was introduced in Malaysia in 2006, which includes end-of-life vehicle (ELV) recovery policies. However, there is limited information on the current state of ELV recovery in Malaysia, which hinders the fulfillment of these new requirements. For manufacturers, the lack of information will lead to difficulties in making strategic decisions in order to fulfill the ELV policies. In order to support design strategies for ELV recovery, it is crucial to identify the issues and factors of ELV recovery, which forms the objective of this study. A survey was carried out among the key stakeholders in the aftermarket chain and the results revealed that special tooling is needed to handle ELV components as well as design that will facilitate the separation of parts according to materials. These are among the main factors that contribute toward the effectiveness of ELV recovery. The following 5 factors (pre-production, health and environment, policy and worker, manufacturing process, and end-of-life value) are the factors that will enhance ELV recovery in Malaysia and it is believed that these factors are subject to dynamic changes in the aftermarket chain. It is believed that the results presented in this paper will be useful to academics and researchers in order to establish design strategies for ELV recovery in Malaysia. Moreover, stochastic techniques are required to cater the dynamic and complex behavior of the actual ELV recovery system in Malaysia
The ABA392/pET30a protein of Pasteurella multocida provoked mucosal immunity against HS disease in a rat model
No full textHaemorrhagic septicaemia (HS) is a well-known high fatality septicaemic disease happening among bovines. The disease is caused by the Pasteurella multocida serotype B:2 bacteria. P. multocida B:2 has high mortality and morbidity rates and is spread through the intranasal and oral routes in bovines. In this study, our aim was to investigate the efficacy of the recombinant protein vaccine, ABA392/pET30a via intranasal inoculation by targeting the mucosal immunity. The constructed recombinant protein vaccine ABA392/pET30a was subjected to an animal study using Sprague Dawley rats. The study was divided into two parts: active and passive immunization studies. Both studies were carried out through the determination of immunogenicity (using Total White Blood Cell (TWBC) Count with Indirect ELISA) and histopathogenicity, analyzing (Bronchus Associated Lymphoid Tissue (BALT) formation) in lungs. As a result, the IgA and IgG development of both tested groups: group 1 (50μg/mL protein vaccine) and group 2 (100μg/mL protein vaccine) showed equivalent with the positive control group 4 (formalin-killed P. multocida B:2). However, there was a significant difference when compared with the negative control group 3 (normal saline). These results demonstrate that both the protein vaccine at the concentration 50μg/mL and 100μg/mL have the same efficacy as the commercially available positive control vaccine. From the studies, higher concentration of protein vaccine at 100μg/mL showed higher development of both IgA and IgG compared to 50μg/mL protein vaccine. Higher and rapid development of IgA compared to IgG showed that mucosal immunity has been induced through the intranasal administration of the protein vaccine. In addition, leucocytosis was observed at each dose of vaccination showed that the protein vaccine is capable to induce the immune responses of the host. Histopathogenicity studies of the vaccinated groups showed more BALT formation and no severe lesions after challenge compared to the negative control group. Besides, no inflammatory onsite or anaphylactic responses were observed after the intranasal inoculation which proved to be safer and provided longer lasting immunity. Therefore, recombinant protein vaccine ABA392/pET30a could be a potential candidate for intranasal administration which can provoke mucosal immunity against HS disease
Torrefaction of de-oiled Jatropha seed kernel biomass for solid fuel production
No full textNon-edible Jatropha seed used for biodiesel production has increased due to its high-oil contents in kernel and potential to reduce greenhouse gas emission. High demand for biodiesel generates a large volume of waste. In this study, de-oiled Jatropha seed kernel was torrefied at 200 °C, 250 °C and 300 °C, holding time of 15, 30, 45 and 60 min and particle sizes of 0.5–1.0 and 1.0–2.0 mm to produce solid fuel. Torrefaction performance was highly affected by torrefaction temperature compared with holding time. The enhancement factor of HHV increased up to 1.243 after torrefaction at 300 °C and 60 min with particle size of 0.5–1.0 mm. The large particle size reduces the diffusion rate of torrefaction vapour through internal pores, thereby producing high solid yield and low enhancement in HHV. The analysis of torrefaction severity index shows that HHV increase is highly dependent on the weight loss, thereby directly decreasing the total energy in biochar. Scanning electron microscopy image clearly illustrated that the microparticles on the surface were destroyed to increase the porous structure of the biochar with increasing torrefaction temperature. Severe torrefaction with particle size of 0.5–1.0 mm was an effective approach to increase the energy content of biochar
Numerical and outdoor real time experimental investigation of performance of PCM based PVT system
No full textPhotovoltaic power generation is a suitable option to counter depleting and environmentally hazardous fossil fuels. However, increased cell temperature of the photovoltaic module reduces the electrical performance. Therefore, for enhancing the electrical performance as well as to obtain the useful thermal, a combined photovoltaic thermal system is suitable technology. Furthermore, the addition of phase change materials into photovoltaic thermal systems adds more dual benefits in terms of cooling of PV cell as well as heat storage. Hence, there are still issues to transfer heat from the system efficiently, which cause lower performance of PVT and PVT-PCM systems. In this paper, the aluminium material of thermal collector is used by introducing a novel design to enhance heat transfer performance, which is assembled in PVT and PVT-PCM systems. Experimental validation is carried out for the 3D FEM-based numerical analysis with COMSOL Multiphysics® at 200 W/m2 to 1000 W/m2 varying irradiation levels while keeping mass flow rate fixed at 0.5LPM and inlet water temperature at 32 °C. The experiment is carried out at outdoor free weather conditions with passive cooling of the module by an overhead water tank scheme. A good agreement in numerical and experimental results is achieved through experimental validation. Cell temperature reduction of 12.6 °C and 10.3 °C is achieved from the PV module in case of the PVT-PCM system. The highest value of the electrical efficiency achieved is 13.72 13.56% for PV and 13.85 and 13.74% for PVT numerically and experimentally respectively. Similarly, for PVT-PCM, electrical efficiency is achieved as 13.98 and 13.87% numerically and experimentally respectively. In the case of the PVT system, electrical performance is improved as 6.2 and 4.8% and for PVT-PCM, it is improved as 7.2 and 7.6% for numerically and experimentally respectively
Pyrus pyrifolia fruit peel as sustainable source for spherical and porous network based nanocellulose synthesis via one-pot hydrolysis system
No full textIn the present study, we attempted revalorization of pear (Pyrus pyrifolia L.) peel residue into high value-added nanomaterials. A green and facile one-pot isolation procedure was designed to simplify the isolation process of nanocellulose directly from pear peel residue. The one-pot approach employed in this work is interesting as the reaction involved less harmful chemicals usage and non-multiple steps. The reaction was carried out by adding hydrogen peroxide as an oxidant and chromium (III) nitrate as catalyst in the acidic medium under mild process conditions. FTIR spectroscopy proved that the pear peel derived nanocellulose was purely cellulose phases without the presence of non-cellulosic layer. XRD study indicated that the isolated nanocellulose possessed of cellulose I polymorph with high crystallinity index of 85.7%. FESEM analysis clearly revealed that the considerable size reduction during one-pot process. Remarkably, TEM analysis revealed that the isolated nanocellulose consisted of network-liked nature and spherical shaped morphologies with high aspect ratio of 24.6. TGA showed nanocellulose has lower thermal stability compared to pear peel residue. This study provided a cost-effective method and straightforward one-pot process for fabrication of nanocellulose from pear peel residue. This is the first investigation on the nanocellulose extraction from pear fruit
Kesan penuaan sesuhu terhadap sifat mikro kekerasan pempaterian Sn-Ag-Cu/cnt/cu menggunakan pelekukan nano (Effect of isothermal aging on microhardness properties of Sn-Ag-Cu/CNT/Cu using nanoindentation)
No full textEffect of thermal aging towards hardness properties of Sn-3.0Ag-0.5Cu (SAC305) solder joint added with carbon nanotube (CNT) particles was investigated. Hardness properties indicate the strength of solder was determined by nanoindentation approach. SAC solder alloy was added with 0.03% weight percent of CNT to form SAC305-CNT solder paste. Printed solder paste on printed circuit board (PCB) with copper (Cu) surface finish underwent reflow soldering at peak temperature 260°C to form SAC305 and SAC305-CNT solder joint. Then, SAC305 and SAC305-CNT were exposed to thermal aging via high temperature storage test (HTS) at constant temperature 150°C for about 200, 400, 600, 800 and 1000 h. Solder joint samples after reflow and thermal aging were analysed using nanoindentation method to determine hardness properties. For microstructure analysis, samples were etched and images were captured via optical microscope. The results showed microhardness values decrease with increasing of aging time for both investigated solder joints. However, hardness values for SAC305-CNT solder joint was higher (~10-26%) compared to SAC305 solder joint without CNT. From nanoindentation test, localized microhardness properties of solder joint under isothermal aging have been attained. Trend of microhardness values obtained was parallel with the trend gained by using conventional hardness test. © 2019 Penerbit Universiti Kebangsaan Malaysia. All rights reserved