Anticorrosion potential of mangrove tannins on aluminium alloys AA6061 in NaCl solution has been studied using potentiodynamic polarisation method and scanning electron microscopy (SEM). The study was carried out in different pH of corrosive medium in the absence and presence of various concentrations of tannin. The corrosion inhibition behaviour of the mangrove tannin on AA6061 aluminium alloy corrosion was found to be dependant on the pH of NaCl solution. Our results showed that the inhibition efficiency increased with increasing tannins concentration in chloride solution at pH 6. Treatment of aluminium alloy 6061 with all concentrations of mangrove tannins reduced the current density, thus decreased the corrosion rate. Tannins behaved as mixed inhibitors at pH 6 and reduction in current density predominantly affected in cathodic reaction. Meanwhile, at pH 12, addition of tannins shifted the corrosion potential to more cathodic potentials and a passivating effect was observed in anodic potentials. SEM studies have shown that the addition of tannins in chloride solution at pH 12 reduced the surface degradation and the formation of pits.
Two new lanthanide coordination complexes with 2,2’-biquinoline-4,4’-dicarboxylic acid (H2bqda) and 1,10-phenanthroline (phen), [La2(Hbqda)2(bqda)2(phen)]n [1] and [Gd(bqda)1.5(phen)]n [2] were successfully synthesized and characterized. The complexes were obtained through hydrothermal method at 170oC for 3 days. The metal to acid to 1,10-phenanthroline ratio, 1:1:2 had been chosen to synthesize 1 and 2. The percentage yield for 1 and 2 was 68% and 75%, respectively calculated based on the starting lanthanide salt used. The yellow coloured complexes were found to be stable at room temperature and insoluble in organic solvents. The complexes obtained were characterized by elemental analysis (CHN), infrared spectroscopy (FTIR) and thermogravimetric (TGA) analysis. The FTIR spectra of these complexes confirm the complexation had taken place by the existence of COO- symmetric and asymmetric stretching peaks at 1385 and 1542-1532 cm-1, respectively.
The lysosomal aspartic proteinase cathepsin D is an acute phase protein involved in various physiological processes, including vitellogenesis, yolk processing and immune responses. In this study, we characterised the cathepsin D from the Asian seabass Lates calcarifer and examined its expression profile during infection. The complete coding sequence of L. calcarifer cathepsin D consists of 1191 nucleotides, encoding a 396 amino acid protein molecule that is made up of a putative signal peptide, a leader peptide and a mature peptide. Phylogenetic analyses showed that two types of cathepsin D are present in the teleost lineage i.e. cathepsin D1 and D2, whereas higher vertebrates possess only one type of cathepsin D. L. calcarifer cathepsin D was clustered together with cathepsin D1 from other teleosts. Compared to mammalian sequences, L. calcarifer cathepsin D lacks the β-hairpin loop that forms the double chain and is present as a single chain peptide with conserved aspartic active sites like other fish. Both multiple sequence alignment and phylogenetic analysis indicated that the L. calcarifer cathepsin D sequence codes for cathepsin D1 and suggested that it shares the same functions with cathepsin D from other fish. Expression profiling analysis of cathepsin D in L. calcarifer infected with Aeromonas hydrophila showed that it is up-regulated in immune-related tissues such as gills, spleen and liver, suggesting that cathepsin D plays an important role in the innate immune response of L. calcarifer against pathogens.
The HIV positive cases in Malaysia and the world are increasing from day to day among individuals of all races and ages. However, the issue of social support for HIV positive patients still needs to be discussed in detail as this issue will have an impact on the lives of HIV positive patients in Malaysia. The focus of this study is to examine social support among HIV positive people in Malaysia. This study used a full qualitative method to collect and analyze data. Five male informants with HIV positive were involved in this study. All informants were interviewed separately using semi structured interview methods. Among the topics discussed in this study were family acceptance, the type of social support they received and the social support resources. The findings showed that, four out of five informants were infected with the HIV viruses from sharing needle and one informant was infected from unprotected sex. The results showed that they received adequate social support in terms of emotions, information, instrumental and networking from various sources. Nevertheless, social support for HIV positive people in Malaysia still needs to be discussed and promoted to ensure their psychological well-being.
In recent years, there has been considerable interest in simple sequence repeats (SSRs) particularly as molecular markers with applications in many different fields. We have carried out an effort to identify and analyse SSRs in the genome of the Asian seabass, Lates calcarifer by random sequencing. Genomic DNA was isolated from the muscle tissue of L. calcarifer, sheared by nebulisation and ligated into plasmid vector. Recombinant clones were selected randomly from the genomic libraries constructed. Subsequently, plasmid DNA was extracted and subjected to one-pass sequencing. A total of 4175 random sequences, also known as genome survey sequences (GSSs), with a total length of 1.7 Mb was generated. Screening of the whole L. calcarifer GSS data set allowed for the identification of a total of 151 perfect (100% similarity) SSRs. These SSR consensus patterns spread over a wide range of size (1 to 226 bp). The most frequent consensus pattern is dinucleotide, which represents 60% of all SSRs identified. The dinucleotides (AC)n, (AT)n and (AG)n were also found to occur frequently in the L. calcarifer genome. Sequence comparison between L. calcarifer and other fish species showed variation in repeat content, indicating the different ways in which repeats may evolve in the genome of these species. Data generated from this random sequencing of the L. calcarifer genome should serve as a valuable resource for further studies of this organism.
Sea bass (Lates calcarifer) is an economically important fish in Malaysia. In this study, a genomic library of L. calcarifer was constructed. Genomic DNA was isolated from the muscle tissue of sea bass, sheared by nebulisation, blunt-end repaired and ligated into the pCR®4Blunt- TOPO® plasmid vector. The ligation mixture was then transformed into Escherichia coli. In order to characterize the constructed genomic library, plasmid DNA was extracted from randomly selected recombinant clones. Gel electrophoresis showed that these recombinant clones contain inserts with a size range of 0.5 kb - 3.5 kb, with an average size of 1.7 kb. DNA sequencing was then carried out using the extracted DNA plasmid as template, and a total of 121 random sequences were generated from the L. calcarifer genomic library. Analysis of these sequences implies that the library is representative of L. calcarifer genome. Based on sequence similarity database searches, 17% of the random sequences were found to have significant BLAST hits, indicating that they represent L. calcarifer genes. Analysis using the Repeat Masker program reveals that 35% of the random sequences were identified as repeat elements. Initial characterization of this genomic library indicates that it is a potentially useful resource in the study of the L. calcarifer genome.
[Siakap (Lates calcarifer) merupakan spesies ikan yang penting dari segi ekonomi di Malaysia. Dalam kajian ini, satu perpustakaan genom L. calcarifer telah dibina. DNA genom telah dipencil daripada tisu otot L. calcarifer, diserpih secara nebulisasi, dibaiki hujung tumpul dan diligasi ke dalam vektor plasmid pCR®4Blunt-TOP®. Campuran ligasi seterusnya telah ditransformasikan ke dalam Escherichia coli. Bagi mencirikan perpustakaan genom yang terhasil, DNA plasmid telah diekstrak daripada klon-klon rekombinan yang dipilih secara rawak. Elektroforesis gel agaros menunjukkan klon-klon rekombinan ini membawa selitan DNA yang bersaiz di antara 0.5 kb - 3.5 kb, dengan purata saiz 1.7 kb. Seterusnya, penjujukan DNA telah dijalankan dengan menggunakan DNA plasmid yang diperoleh sebagai templat. Sebanyak 121 jujukan rawak telah dihasilkan daripada perpustakaan genom L. calcarifer ini. Analisis jujukan rawak memberikan implikasi yang perpustakaan ini adalah representatif bagi genom L. calcarifer. Berdasarkan persamaan dengan jujukan dalam pangkalan data, 17% jujukan rawak ini didapati mempunyai keputusan BLAST yang bermakna, yang menunjukkan mereka mewakili gen L. calcarifer. Analisis dengan menggunakan perisian RepeatMasker menunjukkan sebanyak 25% jujukan rawak ini dikenal pasti sebagai unsur berulang. Pencirian awal terhadap perpustakaan genom ini menunjukkan ia berpotensi sebagai sumber yang berguna dalam kajian genom L. calcarifer].
To evaluate the effectiveness of core stability training and dynamic stretching on thoracolumbar range of motion (ROM), pain level and functional disability among chronic low back pain patients. Forty-three participants aged from 19-67 years old with the primary complaint of low back pain of more than 12 weeks’ duration were assigned to three groups: core stability (CS) (n=17), dynamic stretching (DS) (n=16) and control (n=12). All participants received regular thermotherapy and electrotherapy from the hospital rehabilitation unit. The CS group and DS groups were assigned with additional training, namely core stability training and dynamic stretching training programs for the respective groups. No additional training was given to the control group. The participants’ thoracolumbar range of motion (ROM), pain level and functional disability were tested over four different testing periods (pre, acute, ongoing, post). The current study shows both the CS group and DS group show significant improvement (p
Increasing demands for stingless bee honey in Malaysia have prompted alternative method using plastic cups as artificial
honey pots within beehives to enhance yield. However, honey’s acidity may lead to migration of plastic additives, affecting
body’s physiological responses on prolonged consumption. This study was performed to determine the presence of dibutyl
phthalate (DBP) and oleamide in stingless bee honey collected from plastic cups. A method for simultaneous extraction
and detection of both analytes by solvent terminated dispersive liquid-liquid microextraction (ST-DLLME) coupled with high
performance liquid chromatography (HPLC) was developed. Good linearity was observed with coefficient of determination
R2
≥ 0.97 in the concentration range of 0.5-50 and 10-250 µg/g for DBP and oleamide, respectively. The limit of detection
for DBP was 0.15 µg/g; while oleamide was 4 µg/g. The limit of quantitation for DBP and oleamide was 0.5 and 11 µg/g,
respectively. DBP and oleamide were not detected in all the honey samples collected.
This study provides predictable flow behavior of a hybrid biocomposites made from kenaf/coir reinforced unsaturated polyester using the Moldflow software. A medium size electrical part has been chosen as a mold having multi-wall thicknesses and complex surfaces. Three different shapes of charges of the bulk molding materials were used and compressed into the mold part. The shapes of charges would be rectangular, cubic and cylindrical shapes. The results showed that rectangular charge took 0.2 seconds to fill up the part while the cubic and the cylindrical charges took 1.911 and 2.898 seconds respectively. After 70 seconds the conversion at nodes was more than 98% for all charges. On the other hand, the final densities were 1.88 ± 0.08 g/cm3 for all charges. The cubic charges showed a better temperatures distribution at flow front followed by rectangular, the last being the cylindrical charge, and the average shrinkage was 5-7% for the charges. The cubic shape showed good fibers orientation to the flow direction of the bulk materials followed by cylindrical charge while the rectangular charge showed poor orientation of fibers affected on the deflections, weld lines and air traps in the internal part. For the rectangular, the charge showed more critical weld lines and more air traps especially on the surface of the molded part and more deflections on the corner edges. But, the cubic charge showed the lowest deflections rate, air traps and weld lines defects.
Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.
Agricultural expansion and deforestation are spatial processes of land transformation that impact on landscape pattern. In peninsular Malaysia, the conversion of forested areas into two major cash crops--rubber and oil palm plantations--has been identified as driving significant environmental change. To date, there has been insufficient literature studying the link between changes in landscape patterns and land-related development policies. Therefore, this paper examines: (i) the links between development policies and changes in land use/land cover and landscape pattern and (ii) the significance and implications of these links for future development policies. The objective is to generate insights on the changing process of land use/land cover and landscape pattern as a functional response to development policies and their consequences for environmental conditions. Over the last century, the development of cash crops has changed the country from one dominated by natural landscapes to one dominated by agricultural landscapes. But the last decade of the century saw urbanization beginning to impact significantly. This process aligned with the establishment of various development policies, from land development for agriculture between the mid 1950s and the 1970s to an emphasis on manufacturing from the 1980s onward. Based on a case study in Selangor, peninsular Malaysia, a model of landscape pattern change is presented. It contains three stages according to the relative importance of rubber (first stage: 1900--1950s), oil palm (second stage: 1960s--1970s), and urban (third stage: 1980s--1990s) development that influenced landscape fragmentation and heterogeneity. The environmental consequences of this change have been depicted through loss of biodiversity, geohazard incidences, and the spread of vector-borne diseases. The spatial ecological information can be useful to development policy formulation, allowing diagnosis of the country's "health" and sustainability. The final section outlines the usefulness of landscape analysis in the policy-making process to prevent further fragmentation of the landscape and forest loss in Malaysia in the face of rapid economic development.
Hospital-acquired vancomycin-resistant enterococci (VRE) were first reported in the late 1980s and have since been an increasing problem worldwide. Kuala Lumpur Hospital thus far, to the best of our knowledge has been spared from this pathogen. We describe the first confirmed case of Enterococcus faecium exhibiting the van A phenotype in our hospital, in a patient with chronic renal failure who was successfully treated with linezolid. The microbiology laboratory plays an important role in the identification and detection of VRE.
The faecal egg count reduction test (FECRT) was conducted on 39 sheep farms and 9 goat farms located in Peninsular Malaysia. The anthelmintic groups used in these tests were the benzimidazoles, levamisole, the benzimidazole/levamisole combination, macrocyclic lactones and closantel. Results indicated that the prevalence of resistance to the benzimidazole group was high, with approximately 50% of the sheep farms and 75% of the goat farms having resistant nematode parasite populations present. Resistance to levamisole, closantel and ivermectin was also detected. Differentiation of the infective larvae derived from faecal cultures indicated that by far the most predominant parasite species was Haemonchus contortus.
Acute kidney injury (AKI) is a common problem in hospitals and many end up requiring dialysis. The aim was to identify the associated factors of dialysis-dependent of AKI patients admitted to the intensive care units (ICUs). A retrospective cohort study was conducted where a list of 121 AKI patients admitted to ICU in Hospital Universiti Sains Malaysia was retrospectively reviewed. AKI patients aged below 18 years old, had kidney transplantation or chronic dialysis before ICU admission and had incomplete medical record were excluded from the study. Simple and multiple logistic regression analysis were used. The mean [standard deviation (SD)] age of patients was 56 (17.15) years. Majority of patients were males (63.2%) and Malay ethnic (54.1%). 49.3% of patients were in stage I, 48.3% in stage II and 76.2% in stage III. The mean (SD) duration of patients stayed in ICU was 7 days (6.92) for non-dialysis dependent and 12 days (8.37) for dialysis-dependent. The associated factors were male gender [adjusted odds ratio (OR): 3.68; 95% confidence interval [CI]: 1.53, 8.86; P = 0.004], AKI Stage III (adjusted OR: 4.51; 95% CI: 1.28, 15.91; P = 0.019), admitted in ICU (adjusted OR: 3.05; 95% CI: 1.28, 7.29; P = 0.012), and longer length of stay (adjusted OR: 1.10; 95% CI: 1.03, 1.18; P = 0.003). The factors influence of dialysis-requiring AKI were observed to be dependent on the male male gender, suffer from the advanced stage (Stage III), admitted to the ICU and had a longer length of stay in ICU. Therefore, it is important for physicians to identify patients who are at high risk of developing AKI and implement preventive strategies.
Acute kidney injury (AKI) was frequently encountered complication among intensive care unit (ICU) patients and recognized as a major public health problem. The present study aimed to determine the basic features of AKI patients admitted to ICU. A retrospective cohort study was conducted among 106 AKI patients admitted to ICU, Hospital Universiti Sains Malaysia from January 1, 2007 until the end of December 2013. The AKI patients ranged from 18 to 80 years old with the mean (standard deviation) of 58.93 (15.76) years, 60.4% were male and 91.5% were Malay ethnicity. Hypertension and diabetes were in 38.1% and 28.8%, respectively. The median (interquartile range) length of ICU stay was 4.50 (9.00) days. Eighty-two patients (79.6%) were classified as the Acute Kidney Injury Network (AKIN)-I, 12 (11.7%) as AKIN-II, and nine (8.7%) as AKIN-III. Sepsis was the common etiology among AKI patients (74.3%). Twenty-four patients (22.9%) required dialysis and 90.5% were mechanically ventilated. In conclusion, AKI developed more in male patients, Malay ethnicity, presented with comorbid, caused by sepsis, admitted to ICU, required mechanical ventilation, and need for renal replacement therapy.
Chronic kidney disease (CKD) represents a major public health issue, which then progresses to end-stage renal disease (ESRD) sooner or later. This retrospective cohort study aimed to determine the renal survival time of CKD patients. In total, 247 CKD patients in one of the tertiary referral hospitals in Malaysia between January 2005 and December 2015 were enrolled. All CKD patients were included if they were dependent on dialysis. Patients who were transferred out and those with incomplete records were excluded from the study. The renal survival time was calculated from the time of the first diagnosis of CKD to a confirmed ESRD diagnosis or the use of dialysis. In total, 193 (78.1%) CKD patients progressed to ESRD. The mean age of the ESRD patients was 53 years old. The majority of ESRD patients were male (57.0%) and of Malay ethnicity (89.6%). The most common comorbidities among ESRD patients were hypertension (92.2%) and diabetes mellitus (85.5%). The majority of patients were in Stage IV and V (97.9%). The overall renal survival time of CKD patients who develop ESRD was 26 months (95% confidence interval: 20.41, 31.59). Patients who smoked (P = 0.001), had hyperlipidemia (P <0.001) and consumed lipid-lowering agents (P = 0.004) had a significant P-value in the log-rank test. The progression of CKD from diagnosis to ESRD was within 2 years. Therefore, early recognition of CKD is important to improve patients' outcomes and prolong their renal survival time.
Ferritin is a highly-conserved iron-storage protein that has also been identified as an acute phase protein within the innate immune system. The iron-storage function is mediated through complementary roles played by heavy (H)-chain subunit as well as the light (L) in mammals or middle (M)-chain in teleosts, respectively. In this study, we report the identification of five ferritin subunits (H1, H2, M1, M2, M3) in the Atlantic salmon that were supported by the presence of iron-regulatory regions, gene structure, conserved domains and phylogenetic analysis. Tissue distribution analysis across eight different tissues showed that each of these isoforms is differentially expressed. We also examined the expression of the ferritin isoforms in the liver and kidney of juvenile Atlantic salmon that was challenged with Aeromonas salmonicida as well as in muscle cell culture stimulated with interleukin-1β. We found that each isoform displayed unique expression profiles, and in certain conditions the expressions between the isoforms were completely diametrical to each other. Our study is the first report of multiple ferritin isoforms from both the H- and M-chains in a vertebrate species, as well as ferritin isoforms that showed decreased expression in response to infection. Taken together, the results of our study suggest the possibility of functional differences between the H- and M-chain isoforms in terms of tissue localisation, transcriptional response to bacterial exposure and stimulation by specific immune factors.
For the past 20 years, many authors have focused their investigations on wireless sensor networks. Various issues related to wireless sensor networks such as energy minimization (optimization), compression schemes, self-organizing network algorithms, routing protocols, quality of service management, security, energy harvesting, etc., have been extensively explored. The three most important issues among these are energy efficiency, quality of service and security management. To get the best possible results in one or more of these issues in wireless sensor networks optimization is necessary. Furthermore, in number of applications (e.g., body area sensor networks, vehicular ad hoc networks) these issues might conflict and require a trade-off amongst them. Due to the high energy consumption and data processing requirements, the use of classical algorithms has historically been disregarded. In this context contemporary researchers started using bio-mimetic strategy-based optimization techniques in the field of wireless sensor networks. These techniques are diverse and involve many different optimization algorithms. As far as we know, most existing works tend to focus only on optimization of one specific issue of the three mentioned above. It is high time that these individual efforts are put into perspective and a more holistic view is taken. In this paper we take a step in that direction by presenting a survey of the literature in the area of wireless sensor network optimization concentrating especially on the three most widely used bio-mimetic algorithms, namely, particle swarm optimization, ant colony optimization and genetic algorithm. In addition, to stimulate new research and development interests in this field, open research issues, challenges and future research directions are highlighted.
The aeration strategy ranging from intermittent to continuous aeration in the REACT period of moving bed sequencing batch reactor (MBSBR) was evaluated for simultaneous removal of 4-chlorophenol (4-CP) and nitrogen. The results show that the removal rates of 4-CP and ammonium nitrogen (NH(4)(+)-N) increased with the increase of continuous aeration period. In the presence of 4-CP, NH(4)(+)-N removal was mainly by the assimilation process. The removal of NH(4)(+)-N to oxidized nitrogen via oxidation was only observed after 4-CP was completely degraded with sufficient aeration period provided indicating the inhibitory effect of 4-CP on nitrification. As the intermittent aeration strategy would lead to slower 4-CP degradation resulting in the delay of nitrification process, continuous aeration would be the preferred strategy in the simultaneous removal of 4-CP and nitrogen in the MBSBR system.