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Fulltext Development of Nano-SiO2 and Bentonite-Based Mortars for Corrosion Protection of Reinforcing Steel

Karunarathne VK, Paul SC, Šavija B

Materials (Basel), 2019 Aug 17;12(16).
PMID: 31426501 DOI: 10.3390/ma12162622

In this study, the use of nano-silica (nano-SiO2) and bentonite as mortar additives for combating reinforcement corrosion is reported. More specifically, these materials were used as additives in ordinary Portland cement (OPC)/fly ash blended mortars in different amounts. The effects of nano-silica and bentonite addition on compressive strength of mortars at different ages was tested. Accelerated corrosion testing was used to assess the corrosion resistance of reinforced mortar specimens containing different amounts of nano-silica and bentonite. It was found that the specimens containing nano-SiO2 not only had higher compressive strength, but also showed lower steel mass loss due to corrosion compared to reference specimens. However, this was accompanied by a small reduction in workability (for a constant water to binder ratio). Mortar mixtures with 4% of nano-silica were found to have optimal performance in terms of compressive strength and corrosion resistance. Control specimens (OPC/fly ash mortars without any additives) showed low early age strength and low corrosion resistance compared to specimens containing nano-SiO2 and bentonite. In addition, samples from selected mixtures were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Finally, the influence of Ca/Si ratio of the calcium silicate hydrate (C-S-H) in different specimens on the compressive strength is discussed. In general, the study showed that the addition of nano-silica (and to a lesser extent bentonite) can result in higher strength and corrosion resistance compared to control specimens. Furthermore, the addition of nano-SiO2 can be used to offset the negative effect of fly ash on early age strength development.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Cell entry of a host-targeting protein of oomycetes requires gp96

Trusch F, Loebach L, Wawra S, Durward E, Wuensch A, Iberahim NA, et al.

Nat Commun, 2018 06 14;9(1):2347.
PMID: 29904064 DOI: 10.1038/s41467-018-04796-3

The animal-pathogenic oomycete Saprolegnia parasitica causes serious losses in aquaculture by infecting and killing freshwater fish. Like plant-pathogenic oomycetes, S. parasitica employs similar infection structures and secretes effector proteins that translocate into host cells to manipulate the host. Here, we show that the host-targeting protein SpHtp3 enters fish cells in a pathogen-independent manner. This uptake process is guided by a gp96-like receptor and can be inhibited by supramolecular tweezers. The C-terminus of SpHtp3 (containing the amino acid sequence YKARK), and not the N-terminal RxLR motif, is responsible for the uptake into host cells. Following translocation, SpHtp3 is released from vesicles into the cytoplasm by another host-targeting protein where it degrades nucleic acids. The effector translocation mechanism described here, is potentially also relevant for other pathogen-host interactions as gp96 is found in both animals and plants.

Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
Development of a novel model for the investigation of implant-soft tissue interface

Chai WL, Moharamzadeh K, Brook IM, Emanuelsson L, Palmquist A, van Noort R

J. Periodontol., 2010 Aug;81(8):1187-95.
PMID: 20450401 DOI: 10.1902/jop.2010.090648

In dental implant treatment, the long-term prognosis is dependent on the biologic seal formed by the soft tissue around the implant. The in vitro investigation of the implant-soft tissue interface is usually carried out using a monolayer cell-culture model that lacks a polarized-cell phenotype. This study developed a tissue-engineered three-dimensional oral mucosal model (3D OMM) to investigate the implant-soft tissue interface.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext THE EFFECTIVENESS OF ADSORBENT DERIVED FROM MORINGA OLEIFERA AS A WATER TREATMENT AGENT

Farasyahida A. Samad, Wan Salida Wan Mansor, idayatul Aini Zakaria

UMT Journal of Undergraduate Research, 2019;1(4):51-60.
MyJurnal

Clean, safe and readily available water is very crucial in everyday life, especially for health, hygiene, and the productivity of the community. Unfortunately, increase in contaminants in water supplies from human activities and industrialization is very worrying. Conventional wastewater treatment includes the usage of alum that will affect health with prolonged consumption. This research was carried out to focus on the development of wastewater treatment system using adsorbent from Moringa oleifera seeds. Adsorbent was successfully synthesized from the seeds of Moringa oleifera. Characterization of the sample was made using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), while the effectiveness of water treatment was analyzed using Turbidity Meter. Then, all samples were tested against kaolin wastewater. XRD results showed that all the adsorbent samples were amorphous in nature. FTIR results indicated that there were hydroxyl group and carboxylic group in the sample representing numerous oxygen-riddled functional groups on the surface. From SEM results, it was clearly shown that the pore structure and size of Moringa oleifera affected the capability of adsorption where the smaller the size, the more effective the sample. Turbidity test showed that the sample that worked best for wastewater treatment was adsorbent from Moringa oleifera seeds in size of 125µm that was heated for 4 hours with 93.76% turbidity removal. Therefore, this study proved that the adsorbent from Moringa oleifera seeds is very suitable for high turbidity wastewater treatment. Further studies investigating the combination of conventional activated carbon with adsorbent from Moringa oleifera seeds should be conducted before these samples are made available for further use so that we can compare which sample works best for wastewater treatment.

Matched MeSH terms: Microscopy, Electron, Scanning
Clostridium bifermentans serovar malaysia: sporulation, biogenesis of inclusion bodies and larvicidal effect on mosquito

Charles JF, Nicolas L, Sebald M, de Barjac H

Res. Microbiol., 1990 7 1;141(6):721-33.
PMID: 1980958

Sporulation of Clostridium bifermentans serovar malaysia, which has a larvicidal activity towards mosquitoes, was examined by electron microscopy. Parasporal inclusion bodies lacking a crystalline structure were first detected at t5 (5 h after the end of exponentional growth). Also, the presence of "brush-bottle"-like appendages appearing first at t5 was noted; these remained attached to the spores when released after sporangium lysis. Larvicidal activity assayed on Anopheles stephensi larvae appeared at t0 and increased rapidly to a maximum between t5 and t8. However, a decrease in bacterial toxicity occurred with sporangium lysis.

Matched MeSH terms: Microscopy, Electron
Biological treatment of produced water in a sequencing batch reactor by a consortium of isolated halophilic microorganisms

Pendashteh AR, Fakhru'l-Razi A, Chuah TG, Radiah AB, Madaeni SS, Zurina ZA

Environ Technol, 2010 Oct;31(11):1229-39.
PMID: 21046953 DOI: 10.1080/09593331003646612

Produced water or oilfield wastewater is the largest volume ofa waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m(-3) d(-1), 1.8 kg COD m(-3) d(-1) and 3.6 kg COD m(-3) d(-1)) and different total dissolved solids (TDS) concentration (35,000 mg L(-1), 100,000 mg L(-1), 150,000 mg L(-1), 200,000 mg L(-1) and 250,000 mg L(-1)). It was found that with an OLR of 0.9 kg COD m(-3) d(-1) and 1.8 kg COD m(-3) d(-1), average oil and grease (O&G) concentrations in the effluent were 7 mg L(-1) and 12 mg L(-1), respectively. At TDS concentration of 35,000 mg L(-1) and at an OLR of 1.8 kg COD m(-3)d(-1), COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L(-1), COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83%, and 85%, respectively.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Chronic low dose organic arsenic induced liver structural damage

Shahida S, Nor Zamzila A, Norlelawati AT, Jamalludin AR, Azliana AF, Zunariah Buyong

IIUM Medical Journal Malaysia, 2020;19(1):37-44.
MyJurnal

Introduction: Over the decades, organic arsenic has been thought to be less toxic than inorganic arsenic.
Monosodium methylarsonate (MSMA) is a potent organoarsenical herbicide that is still being used in most
Asian countries. Reported studies on the effects of organic arsenic are mainly to the gastrointestinal system,
however there are limited research on its impacts to the liver. Therefore, this study aimed to investigate the
effect of MSMA exposure on hepatocytes and liver sinusoidal endothelial cells (LSEC). Materials and Methods:
Fourteen Sprague Dawley rats (n=14) were divided equally into arsenic-exposed (n=7) and control (n=7)
groups. The rats in arsenic-exposed group were given MSMA at 63.20 mg/kg daily for 6 months through oral
gavage. While the rats in control group were given distilled water ad libitum. At the end of the duration,
they were euthanized and underwent liver perfusion for tissue preservation. Liver tissues were harvested and
processed for light microscopy, scanning and transmission electron microscopy. The findings were analysed
descriptively. Results: MSMA had caused necrotic and apoptotic changes to the liver. Normal organelles
morphology were loss in the hepatocytes while LSEC revealed defenestration. Conclusion: In this study,
chronic low dose organic arsenic exposure showed evidence of toxicity to hepatocytes. Interestingly, LSEC
demonstrated capillarization changes.

Matched MeSH terms: Microscopy, Electron, Transmission
Effects of kenaf loading and alkaline treatment on properties of kenaf filled natural rubber latex foam

Ahmad Fikri Abdul Karim, Hanafi Ismail, Zulkifli Mohamad Ariff

Sains Malaysiana, 2018;47:2163-2169.

This research was carried out to study the effects of kenaf loading and alkaline treatment on tensile properties, density,
thermal and morphological properties of kenaf filled natural rubber latex foam (NRLF). Samples were prepared using a
Dunlop method. From the results, increasing loading of kenaf reduced the tensile strength and elongation at break for
both samples, treated and untreated kenaf filled NRLF. Meanwhile, modulus at 100% elongation and density increased
with an increased in kenaf loading. Samples with treated kenaf showed higher tensile strength, modulus at 100%
elongation and density but low in elongation at break as compared with samples with untreated kenaf. Thermal study
by using thermogravimetric analysis (TGA) showed that thermal stability reduced with increased in kenaf loading for
both samples. Samples with treated kenaf have higher thermal stability compared with samples of untreated kenaf. The
filler-matrix interaction and the pores size variation of both samples was clearly seen in the micrograph images by using
scanning electron microscope (SEM).

Matched MeSH terms: Microscopy, Electron, Scanning
Potential of using multiscale corn husk fiber as reinforcing filler in cornstarch-based biocomposites

Ibrahim MIJ, Sapuan SM, Zainudin ES, Zuhri MYM

Int J Biol Macromol, 2019 Oct 15;139:596-604.
PMID: 31381916 DOI: 10.1016/j.ijbiomac.2019.08.015

In this study, biodegradable composite films were prepared by using thermoplastic cornstarch matrix and corn husk fiber as a reinforcing filler. The composite films were manufactured via a casting technique using different concentrations of husk fiber (0-8%), and fructose as a plasticizer at a fixed amount of 25% for starch weight. The Physical, thermal, morphological, and tensile characteristics of composite films were investigated. The findings indicated that the incorporation of husk fiber, in general, enhanced the performance of the composite films. There was a noticeable reduction in the density and moisture content of the films, and soil burial assessment showed less resistance to biodegradation. The morphological images presented a consistent structure and excellent compatibility between matrix and reinforcement, which reflected on the improved tensile strength and young modulus as well as the crystallinity index. The thermal stability of composite films has also been enhanced, as evidenced by the increased onset decomposition temperature of the reinforced films compared to neat film. Fourier transform infrared analysis revealed increasing in intermolecular hydrogen bonding following fiber loading. The composite materials prepared using corn husk residues as reinforcement responded to community demand for agricultural and polymeric waste disposal and added more value to waste management.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Scanning electron micrographs of two species of Sturnophagoides (Acari: Astigmata: Pyroglyphidae) mites in Malaysia

Mariana A, Santana Raj AS, Ho TM, Tan SN, Zuhaizam H

Trop Biomed, 2008 Dec;25(3):217-24.
PMID: 19287360

Scanning electron microscope (SEM) images of two dust mites, Sturnophagoides brasiliensis and Sturnophagoides halterophilus, are presented to provide an improved visualization of the taxonomic characters of these mites. Sturnophagoides halterophilus can be differentiated from S. brasiliensis by their expanded genu and femur of leg I. The differences in morphology of male and female S. brasiliensis are also discussed.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Characterization and safety assessment of bioengineered limbal epithelium

Lim MN, Umapathy T, Baharuddin PJ, Zubaidah Z

Med J Malaysia, 2011 Oct;66(4):335-41.
PMID: 22299553 MyJurnal

Transplantation of cultivated limbal epithelium on substrates such as amniotic membrane is an established treatment for severe ocular surface disease with limbal stem cell deficiency. In this study, we adapted an established method to generate sheets of limbal epithelium on amniotic membrane and characterized the cells contained in these sheets and tested them for safety with regard to microbial contamination. Human limbal biopsies were cultivated on denuded amniotic membranes. After three weeks of culture, the phenotypes of cultivated cells were analyzed by immunohistochemistry and real-time RT-PCR for the expression of a panel of specific markers. Cultivated limbal epithelial cell sheets were also analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Sterility tests and mycoplasma assays were conducted for the safety of product. A confluent layer of polygonal cells was formed in 2 weeks and 1-3 stratified layer of cells were observed after three weeks of culture. Cultivated cells were positive for p63, K3, K19, and involucrin but negative for K14, integrin alpha9 and ABCG2 when analyzed by immunohistochemistry. Expression of molecular markers was detectable with real-time RT-PCR. SEM showed multilayer of flat squamous polygonal epithelial cells. Desmosomal and hemidesmosomal attachments were evident. Our study showed that cultivated limbal epithelium consists of limbal progenitors as well as differentiated corneal epithelial cells. SEM and TEM analysis showed cultivated cells demonstrated typical features of corneal epithelium. The risk of contamination is low and can be prevented by culturing the cells in a clean room facility complying to Good Manufacturing Practice standard.

Matched MeSH terms: Microscopy, Electron, Scanning; Microscopy, Electron, Transmission
Fulltext Interfaces between hexagonal and cubic oxides and their structure alternatives

Zhou H, Wu L, Wang HQ, Zheng JC, Zhang L, Kisslinger K, et al.

Nat Commun, 2017 11 14;8(1):1474.
PMID: 29133800 DOI: 10.1038/s41467-017-01655-5

Multi-layer structure of functional materials often involves the integration of different crystalline phases. The film growth orientation thus frequently exhibits a transformation, owing to multiple possibilities caused by incompatible in-plane structural symmetry. Nevertheless, the detailed mechanism of the transformation has not yet been fully explored. Here we thoroughly probe the heteroepitaxially grown hexagonal zinc oxide (ZnO) films on cubic (001)-magnesium oxide (MgO) substrates using advanced scanning transition electron microscopy, X-ray diffraction and first principles calculations, revealing two distinct interface models of (001) ZnO/(001) MgO and (100) ZnO/(001) MgO. We have found that the structure alternatives are controlled thermodynamically by the nucleation, while kinetically by the enhanced Zn adsorption and O diffusion upon the phase transformation. This work not only provides a guideline for the interface fabrication with distinct crystalline phases but also shows how polar and non-polar hexagonal ZnO films might be manipulated on the same cubic substrate.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Application of Biochar Derived From Pyrolysis of Waste Fiberboard on Tetracycline Adsorption in Aqueous Solution

Xu D, Gao Y, Lin Z, Gao W, Zhang H, Karnowo K, et al.

Front Chem, 2019;7:943.
PMID: 32117859 DOI: 10.3389/fchem.2019.00943

In this study, biochars derived from waste fiberboard biomass were applied in tetracycline (TC) removal in aqueous solution. Biochar samples were prepared by slow pyrolysis at 300, 500, and 800°C, and were characterized by ultimate analysis, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), etc. The effects of ionic strength (0-1.0 mol/L of NaCl), initial TC concentration (2.5-60 ppm), biochar dosage (1.5-2.5 g/L), and initial pH (2-10) were systemically determined. The results present that biochar prepared at 800°C (BC800) generally possesses the highest aromatization degree and surface area with abundant pyridinic N (N-6) and accordingly shows a better removal efficiency (68.6%) than the other two biochar samples. Adsorption isotherm data were better fitted by the Freundlich model (R2 is 0.94) than the Langmuir model (R2 is 0.85). Thermodynamic study showed that the adsorption process is endothermic and mainly physical in nature with the values of ΔH0 being 48.0 kJ/mol, ΔS0 being 157.1 J/mol/K, and ΔG0 varying from 1.02 to -2.14 kJ/mol. The graphite-like structure in biochar enables the π-π interactions with a ring structure in the TC molecule, which, together with the N-6 acting as electron donor, is the main driving force of the adsorption process.

Matched MeSH terms: Microscopy, Electron, Scanning
Dendrimer-like nanoparticles based β-galactosidase assembly for enhancing its selectivity toward transgalactosylation

Misson M, Du X, Jin B, Zhang H

Enzyme Microb Technol, 2016 Mar;84:68-77.
PMID: 26827776 DOI: 10.1016/j.enzmictec.2015.12.008

Functional nanomaterials have been pursued to assemble nanobiocatalysts since they can provide unique hierarchical nanostructures and localized nanoenvironments for enhancing enzyme specificity, stability and selectivity. Functionalized dendrimer-like hierarchically porous silica nanoparticles (HPSNs) was fabricated for assembling β-galactosidase nanobiocatalysts for bioconversion of lactose to galacto-oligosaccharides (GOS). The nanocarrier was functionalized with amino (NH2) and carboxyl (COOH) groups to facilitate enzyme binding, benchmarking with non-functionalized HPSNs. Successful conjugation of the functional groups was confirmed by FTIR, TGA and zeta potential analysis. HPSNs-NH2 showed 1.8-fold and 1.1-fold higher β-galactosidase adsorption than HPSNs-COOH and HPSNs carriers, respectively, with the highest enzyme adsorption capacity of 328mg/g nanocarrier at an initial enzyme concentration of 8mg/ml. The HPSNs-NH2 and β-galactosidase assembly (HPSNs-NH2-Gal) demonstrated to maintain the highest activity at all tested enzyme concentrations and exhibited activity up to 10 continuous cycles. Importantly, HPSNs-NH2-Gal was simply recycled through centrifugation, overcoming the challenging problems of separating the nanocarrier from the reaction medium. HPSNs-NH2-Gal had distinguished catalytic reaction profiles by favoring transgalactosylation, enhancing GOS production of up to 122g/l in comparison with 56g/l by free β-galactosidase. Furthermore, it generated up to 46g/l GOS at a lower initial lactose concentration while the free counterpart had negligible GOS production as hydrolysis was overwhelmingly dominant in the reaction system. Our research findings show the amino-functionalized HPSNs can selectively promote the enzyme activity of β-galactosidase for transgalactosylation, which is beneficial for GOS production.

Matched MeSH terms: Microscopy, Electron, Scanning
Encapsulation of Ethylene Gas into Granular Cold-Water-Soluble Starch: Structure and Release Kinetics

Shi L, Fu X, Tan CP, Huang Q, Zhang B

J Agric Food Chem, 2017 Mar 15;65(10):2189-2197.
PMID: 28215072 DOI: 10.1021/acs.jafc.6b05749

Ethylene gas was introduced into granular cold-water-soluble (GCWS) starches using a solid encapsulation method. The morphological and structural properties of the novel inclusion complexes (ICs) were characterized using scanning electron microscopy, X-ray diffractometry, and Raman spectroscopy. The V-type single helix of GCWS starches was formed through controlled gelatinization and ethanol precipitation and was approved to host ethylene gas. The controlled release characteristics of ICs were also investigated at various temperature and relative humidity conditions. Avrami's equation was fitted to understand the release kinetics and showed that the release of ethylene from the ICs was accelerated by increasing temperature or RH and was decelerated by increased degree of amylose polymerization. The IC of Hylon-7 had the highest ethylene concentration (31.8%, w/w) among the five starches, and the IC of normal potato starch showed the best controlled release characteristics. As a renewable and inexpensive material, GCWS starch is a desirable solid encapsulation matrix with potential in agricultural and food applications.

Matched MeSH terms: Microscopy, Electron, Scanning
Fulltext Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

Shameli K, Ahmad MB, Zamanian A, Sangpour P, Shabanzadeh P, Abdollahi Y, et al.

Int J Nanomedicine, 2012;7:5603-10.
PMID: 23341739 DOI: 10.2147/IJN.S36786

Green synthesis of noble metal nanoparticles is a vastly developing area of research. Metallic nanoparticles have received great attention from chemists, physicists, biologists, and engineers who wish to use them for the development of a new-generation of nanodevices. In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant and stabilizer simultaneously. Characterizations of nanoparticles were done using different methods, which included ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier-transform infrared spectroscopy. The ultraviolet-visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 415 nm. Transmission electron microscopy showed that mean diameter and standard deviation for the formation of silver nanoparticles was 6.30 ± 2.64 nm. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The most needed outcome of this work will be the development of value-added products from C. longa for biomedical and nanotechnology-based industries.

Matched MeSH terms: Microscopy, Electron, Transmission
Characterization of a novel rat cytomegalovirus (RCMV) infecting placenta-uterus of Rattus rattus diardii

Loh HS, Mohd-Azmi ML, Lai KY, Sheikh-Omar AR, Zamri-Saad M

Arch Virol, 2003 Dec;148(12):2353-67.
PMID: 14648291

A new rat cytomegalovirus (RCMV) isolated from the placenta/uterus of a house rat (Rattus rattus diardii) was found to productively infect rat embryo fibroblast (REF) cells. The virus produced typical herpesvirus-like cytopathic effects characterized by a lytic infection. The well-known herpesvirus morphology was confirmed by electron microscopy. Its slow growth in cell culture indicated that the virus is belonging to subfamily Betaherpesvirinae. Electron microscopy techniques and immunohistochemistry confirmed the presence of herpesviral inclusion bodies and virus related particles in the cytoplasm and nucleus of infected cells. Hyperimmune serum against the Maastricht strain of RCMV revealed the virus identity in neutralization test, immunoperoxidase and immunofluorescence techniques. Despite typical characteristics of CMV, the viral genome is significantly different from that of Maastricht, English, UPM/Sg and UPM/Kn strains. The dissimilarities, which have not been reported before, had been confirmed by mean of restriction endonuclease analysis. The new RCMV strain, a virus that infects placenta and uterus of rats, has been named as ALL-03.

Matched MeSH terms: Microscopy, Electron
Fulltext Ultrastructural changes in endothelial cells of buffaloes following in-vitro exposure to Pasteurella multocida B:2

Puspitasari Y, Salleh A, Zamri-Saad M

BMC Vet Res, 2020 Jun 09;16(1):186.
PMID: 32517749 DOI: 10.1186/s12917-020-02415-2

BACKGROUND: Pasteurella multocida B:2 causes haemorrhagic septicaemia in cattle and buffaloes. However, buffaloes are found to be more susceptible to the infection than cattle. Upon infection, the pathogen rapidly spread from the respiratory tract to the blood circulation within 16-72 h, causing septicaemia. So far, limited study has been conducted to evaluate the response of endothelial cells of buffalo towards P. multocida B:2 and its lipopolysaccharide (LPS). This study aimed to evaluate the ultrastructural changes in the aortic endothelium of buffaloes (BAEC) following exposure to P. multocida B:2 and its endotoxin. The endothelial cells were harvested from the aorta of healthy buffaloes and were prepared as monolayer cell cultures. The cultures were divided into 3 groups before Group 1 was inoculated with 107 cfu/ml of whole cell P. multocida B:2, Group 2 with LPS, which was extracted earlier from 107 cfu/ml of P. multocida B:2 and Group 3 with sterile cell culture medium. The cells were harvested at 0, 6, 12, 18, 24, 36, and 48 h post-inoculation for assessment of cellular changes using transmission electron microscopy.
RESULTS: The BAEC of Groups 1 and 2 demonstrated moderate to severe endothelial lysis, suggestive of acute cellular injury. In general, severity of the ultrastructural changes increased with the time of incubation but no significant difference (p > 0.05) in the severity of the cellular changes between Groups 1 and 2 was observed in the first 18 h. The severity of lesions became significant (p

Matched MeSH terms: Microscopy, Electron, Transmission
Use of Fe₃O₄ Nanoparticles for Enhancement of Biosensor Response to the Herbicide 2,4-Dichlorophenoxyacetic Acid

Loh KS, Lee YH, Musa A, Salmah AA, Zamri I

Sensors (Basel), 2008 Sep 18;8(9):5775-5791.
PMID: 27873839

Magnetic nanoparticles of Fe₃O₄ were synthesized and characterized using transmission electron microscopy and X-ray diffraction. The Fe₃O₄ nanoparticles were found to have an average diameter of 5.48 ±1.37 nm. An electrochemical biosensor based on immobilized alkaline phosphatase (ALP) and Fe₃O₄ nanoparticles was studied. The amperometric biosensor was based on the reaction of ALP with the substrate ascorbic acid 2-phosphate (AA2P). The incorporation of the Fe₃O₄ nanoparticles together with ALP into a sol gel/chitosan biosensor membrane has led to the enhancement of the biosensor response, with an improved linear response range to the substrate AA2P (5-120 μM) and increased sensitivity. Using the inhibition property of the ALP, the biosensor was applied to the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The use of Fe₃O₄ nanoparticles gives a two-fold improvement in the sensitivity towards 2,4-D, with a linear response range of 0.5-30 μgL-1. Exposure of the biosensor to other toxicants such as heavy metals demonstrated only slight interference from metals such as Hg2+, Cu2+, Ag2+ and Pb2+. The biosensor was shown to be useful for the determination of the herbicide 2, 4-D because good recovery of 95-100 percent was obtained, even though the analysis was performed in water samples with a complex matrix. Furthermore, the results from the analysis of 2,4-D in water samples using the biosensor correlated well with a HPLC method.

Matched MeSH terms: Microscopy, Electron, Transmission
Production of biodiesel from palm fatty acid distillate by microwave-assisted sulfonated glucose acid catalyst

Nur Nazlina Saimon, Heng Khuan Eu, Anwar Johari, Norzita Ngadi, Mazura Jusoh, Zaki Yamani Zakaria

Sains Malaysiana, 2018;47:109-115.

Biodiesel, one of the renewable energy sources has gained attention for decades as the alternative fuel due to its remarkable properties. However, there are several drawbacks from the industrial production of biodiesel such as the spike in the production cost, environmental issues related to the usage of homogeneous catalyst and profitability in long term. One of the solutions to eliminate the problem is by utilizing low cost starting material such as palm fatty acid distillate (PFAD). PFAD is a byproduct from the refining of crude palm oil and abundantly available. Esterification of PFAD to biodiesel will be much easier with the presence of heterogeneous acid catalyst. Most of acid catalyst preparation involves series of heating process using conventional method. In this study, microwave was utilized in catalyst preparation, significantly reducing the reaction time from conventional heating method. The catalyst produced was characterized using X-Ray Diffraction (XRD), Brunauer Emmet and Teller (BET), Scanning Electron Microscopy (SEM), Temperature-Programmed Desorption - Ammonia (TPD-NH3) and Fourier Transform Infrared (FTIR) while percentage yield and conversion of the PFAD were analysed by gas chromatography - flame ionization detector (GC-FID) and acid-base titration, respectively. It has been demonstrated that the percentage yield of biodiesel from the PFAD by employing sulfonated glucose acid catalyst (SGAC) reached 98.23% under the following conditions: molar ratio of methanol to PFAD of 10:1, catalyst loading of 2.5% and reaction temperature of 70oC. The microwave-assisted SGAC showed its potential to replace the SGAC produced via conventional heating method.

Matched MeSH terms: Microscopy, Electron, Scanning

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