Chlorella is one of the common microalgae found in a wide range of habitats, including Antarctica. Chlorella UMACC 234 is an interesting isolate in the collection of Antarctic microalgae in the University of Malaya algae culture collection (UMACC) as it grows well at temperatures much higher than the ambience. The alga was isolated from snow samples collected from Casey, Antarctica. This study investigates the influence of nitrogen source on the growth, biochemical composition and fatty acid profile of Chlorella UMACC 234. The cultures were grown in Bold’s Basal Medium with 3.0 mM NaNO3, NH4Cl or urea. The cultures grown on NaNO3 attained the highest specific growth rate (μ = 0.43 day–1) while the specific growth rates of those grown on NH4Cl and urea were not significantly different (p > 0.05). The urea-grown cells produced the highest amounts of lipids (25.7% dry weight) and proteins (52.5% dry weight) compared to those grown on other nitrogen sources. The cell numbers attained by the cultures grown at NaNO3 levels between 0.3 and 3.0 mM were similar but decreased markedly at 9.0 mM NaNO3. The fatty acids of Chlorella UMACC 234 were dominated by saturated fatty acids, especially 16:0 and 18:0. The percentage of polyunsaturated fatty acids was very low, especially in cells grown on urea (0.9% total fatty acids). Characterisation of the growth and biochemical composition of this Antarctic Chlorella is important to our studies on the relationship of Chorella isolates from tropical, temperate and polar regions, especially in terms of phylogeny and stress adaptation.
The consequence of postoperative infections associated with orthopaedic or biomaterial-associated implants is devastating to both the patients and the surgeons. Bacterial microcolonies adhere to the surface of implants, forming biofilms and then detaching part of itself into free-floating planktonic forms may be the cause of recurrent and persistent infections. These bacteria are very resistant towards antibiotics and require a higher drug concentration than usual in order to eradicate them. Quorem-sensing is regarded as one mechanism of communication or integration between these microorganisms in the biofilm and may even be in the transfer of resistant genes. Disruption of this pathway is regarded as one method of inhibiting its growth and formation. Implant design, technique and stability of fixation as well as the surface characteristics, the material and its biocompatibility may also influence bacterial adhesion. It has been suggested that multi-prong strategies such as prevention and disruption of biofilm formation, parenteral antibiotics, use of antibiotic-impregnated construction materials and altering the intrinsic properties of the implant surface may help to eradicate this menace.
Even though a lot of new advanced materials have been developed nowadays, steel remains a major material in construction, automobiles, appliances, industrial machinery as well as in the nuclear industry. Due to steel easily corroded, a proper surface protection is required to avoid any failures and extended the life cycle of the components. Surface coating is an efficient and economical method to obtain desirable material surfaces properties. Hot dip aluminizing technique was utilized in this study. Experiments have been conducted on the mild steel substrates with 12mm diameter. Prior to hot dipping process, observation on grain growth at three different temperatures had also been conducted to understand the behaviour of steel under application of heat. The substrates were heated at 700ºC, 800ºC and 900ºC for 1 hour and the microstructure was analyzed. The temperature of 800C was chosen for hot dipping. The substrates were dipped into the molten aluminum maintained at temperature 800ºC for 2,4,6,8,10,15 and 20 minutes. Optical microscopy and energy dispersive X-ray spectroscopy were used in this investigation. From the microstructure observation, it showed the appearance of intermetallic layer covered by the top layer of Al on the mild steel substrate increased with the increase in dipping time ranging from 36 to 282μm. The result of EDX analysis revealed the existence of Fe and Al in form of Fe2Al5 phase for all the dipping time.
An antimicrobial (AM) Active Packaging can be made by incorporating and immobilizing suitable AM agents into food package matrices and applying a bio switch concept. A starchbased film was prepared and incorporated with an antimicrobial agent, i.e. lysozyme with EDTA as a chelating agent. This film was then inoculated with the bacteria Escherichia coli and Bacillus subtilis to carry out the microbial contamination study. The inhibition of both E. coli and B. subtilis by the AM film was clearly observed as a clear zone formation in the culture agar test. The film appearance showed that lysozymes could give a better inhibition to the growth of E. coli and to B. subtilis, at a satisfying inhibition rate. From the broth test, the decreased in the optical densities were found to be 65.83% and 91.30%, suggesting an effective growth inhibition of E. coli and B. subtilis, respectively. Physically, the film which was incorporated with lysozymes was found to be slightly different from the control film. The moisture content of the film, with lysozymes, was found to be below 10.5%, as compared to the control, after 24 hours of formation in the storage at ambient temperature.
Tropical greenhouses require active evaporative cooling system such as pad-and-fan to ensure a suitable microclimate for crop production. Excess heat causes indoor temperature to become hotter than desired resulting in detrimental effects to crop growth and production. Solar radiation intensity and outside temperature affect temperature and relative humidity level inside a greenhouse, while wide gradients in temperature and relative humidity can cause problems related to crop growth and production uniformity. A 300 m2 greenhouse, equipped with evaporative pad and four exhaust fans at each end walls, was used in the study. Horizontal and vertical profiles of the temperature and relative humidity inside the greenhouse were investigated. Results showed that temperature increased from evaporative pad area to exhaust fans area in a horizontal plane, while relative humidity showed an inverse pattern from temperature. In the vertical plane, temperature increased, while relative humidity decreased from lower level to the upper level. ANOVA results showed that in overall, temperature and relative humidity inside the greenhouse were uniform as there was no significant difference at 95% confidence interval. Thus, it was concluded that greenhouse cooling system by evaporative pad and exhaust fans are suitable for application in a tropical country such as Malaysia.
This study evaluated lipid oxidation in refrigerated (±4ºC) duck meatballs treated with novel antioxidants over 21 days of storage. The duck meatballs were treated with a control substance, Cosmos caudatus (ulam raja) or Polygonum minus (kesum) extract, or BHT (butylated hydroxytoluene), and data was collected every three days. These results showed that Cosmos caudatus and Polygonum minus had better antioxidant effects on duck meatballs than BHT or the control. Folding and microbial potency test results were not significantly different among the three antioxidants tested but were better in antioxidant-treated samples than in control samples. However, Cosmos caudatus and Polygonum minus were slightly more effective in preventing microbial growth. This result suggests that Cosmos caudatus and Polygonum minus may be potentially useful natural resources for enhancing the shelf life of duck meatballs.
The emergence of research about the biological effects of electromagnetic field (EMF) have growing concern among
researchers. The aim of this study was to investigate the effects on the brain of rats periodically exposed to 0.1 mT EMF.
Total 24 adult male Sprague Dawley rats were subdivided randomly to 4 groups: 2 control groups (C1 6 hours: 6 h/
day for 5 days; C2 20 hours: 20 h/day for 5 days) and 2 treatment groups which exposed to 0.1 mT EMF (T1 6 hours:
6 h/day for 5 days; T2 20 hours: 20 h/day for 5 days). A significant decrease in the pyramidal cell number was higher
as the exposure duration to EMF was extended (T1, p
Helopeltis antonii is the major pest affecting cashew plants in Indonesia and causes potential damage to the plant. The development of the population was influenced by the fecundity and fertility of their eggs. The effect of mating on the eggs’ fecundity and the fertility of H. antonii was studied. Laboratory studies at Wonogiri Estate Service in Ngadirojo District, Wonogiri, Indonesia investigated the sexual maturity, the influence of female to male sex ratio on the females’ fecundity and longevity, and the influence of mating frequency to fecundity and the eggs hatchability of H. antonii. The study reveals that H. antonii females and males are ready to mate when they are two days old. The number of eggs laid and the longevity of the females’ lives were not significantly affected by the sex ratio; however, female to male sex ratios of 2:1 and 1:2 tended to produce a greater number of eggs. The fecundity of the female was not significantly influenced by the number of times the female mated. Unmated females laid fewer eggs than females paired with a mature male. The study shows that females need to mate to produce fertile eggs.
Mating studies were conducted on 78 isolates of Fusarium species section Liseola from rice, sugarcane and maize. From the crosses with tester strains of Gibberella fujikuroi species complex, 64.1% (50 out of 78 isolates) were cross-fertile with tester strains of mating populations A to E. The results of the mating studies showed that of the 50 isolates, 19 belonged to mating population A (Gibberella moniliformis), 18 to mating population B (Gibberella sacchari), 4 to mating population E (Gibberella subglutinans), 6 to mating population D (Gibberella intermedia) and 3 to mating population C (G. fujikuroi). Identification of several mating populations from rice,sugarcane and maize could be important biological entities under field conditions.
Vibrio parahaemolyticus is a gram negative bacterium and causes gastrointestinal illness in humans. In this study, twenty five out of fifty cockle samples from Padang, Indonesia produced purple colonies when they were grown on selective medium, CHROMagarTM Vibrio. Specific–PCR for toxR gene detection gave positive results in which a band with 368 base pairs size appeared on the gel for all the isolates that confirmed the presence of V. parahaemolyticus. In the virulence properties test, all the isolates showed negative results for tdh and trh genes detection. The results indicate that the isolates under this study do not contain virulence properties that correlate to the ability of infection and diseases, which means that they are nonpathogenic.
This study aims to determine the combined effects of hydrolysis time, temperature, pH and ratio of enzyme to substrate on the degree of hydrolysis (DH) of silver catfish frame using Response Surface Methodology. The proximate compositions of silver catfish frame and silver catfish hydrolysate powder were determined as well. The effects of independent factors were described using a three-level factors Face Centered Central Composite design. The suggested hydrolysis conditions for obtaining the optimum DH using Alcalase® were – temperature of 55oC, hydrolysis time of 163 min, pH of substrate at 9.45 and an enzyme concentration of 2.0%. The generated model showed a quadratic fit with experimental data. Proximate analyses revealed that silver catfish frame contained 25.02% protein, 68.21% fat and 7.08% ash. While silver catfish frame hydrolysate powder contained 65.05% protein, 32.92% fat and 0.86% ash. The protein recovery in silver catfish frame hydrolysate was as high as 71.6%.
This study aimed to determine the biofilm formation ability by Salmonella Typhi on cucumber, mango and guava surface, as well as to determine the relationship between time contact and biofilm formation. Crystal violet assay was performed to quantify the biofilm formation based on the value of optical density at 570 nm of the destaining crystal violet at the specific interval time. The result showed that the attachment of the bacterial cells on the fresh produce surface increased with the contact time. The readings of OD570at time 12 h for cucumber, mango and guava surfaces were 0.824, 0.683 and 0.598, respectively, indicating that the biofilm formation by Salmonella Typhi on different fresh produce surface varied with time. Since the result showed that Salmonella Typhi formed biofilm on fresh produce surfaces, hygienic practice from farm to fork including handling, processing, distribution and storage of the fresh produce should be of concern.
Tissue regeneration is a rapidly growing field providing a beacon of hope in the field of restorative and endodontics. Root canal treatment involves the removal of pulp tissue and replacement by an inorganic materials where as regenerative endodontics deals with replacement with healthy pulp to revitalize the teeth .Research in the field of tissue engineering and material science have lead to significant progress but still is plague with lots of drawbacks and failures, hence it is still not being adapted as routine clinical procedures .The purpose of this article is to review the advances made in regenerative endodontics and the future scopes.
Objective: This case report highlights on the challenges in the management of people with bipolar disorder. Method: We report a case of 36 year-old lady living with this disorder and her journey in a search for a meaningful life. Result: Adherence to treatment is a major determinant of outcome in bipolar patient like Ms WMY. Poor insight, negative attitudes towards treatment and poor understanding of medications and the illness can all lead to reduced adherence. Conclusion: This case demonstrates on how poverty of insight, poor social support, on-going stressors with significant life events and poor compliance to treatment create a series of stumbling blocks in recovery from bipolar disorder.
Silicon nanostructures have successfully been synthesized by thermal evaporation technique using nickel catalyst. Silicon powder served as starting source material was evaporated at high temperature (900-1100°C) in inert carrier gas. The grown silicon nanostructures were collected on (111) silicon substrate surface that positioned at varied location from source material. By controlling heating rate, gas flow rate, growth temperature and time, substrate position and location; to the optimum condition produced the best quality at silicon nanostructures. In this work, the best parameter to produce silicon nanostructures is system ramping up 1000°C at 20°C/min heating rate, N2 flow at 100ml/min; silicon needle-like one dimensional silicon nanostructures growth on vertically-positioned substrate located at 12cm from source material for 1 hour growth time. The effects of these parameters on the structures and physical of nanostructures were characterized by field emission scanning electron microscope and x-ray diffraction.
The objective of this research is recovery of squalene from palm fatty acid distillate (PFAD) using supercritical fluid extraction (SFE). The extraction process was performed by using the SFE and recovered squalene was analyzed from total lipid extracts using HPLC. A central composite design was used to study the effect of SFE variables namely pressure (X₁) from 200 to 400 bar and temperature (X₂) from 40 to 60⁰C on the total lipid extracts (Y₁) and squalene concentration (Y₂) and optimize the SFE conditions. The nonlinear regression equations were significantly (p < 0.05) fitted for both responses with high R₂ (> 0.965), which had no indication of lack of fit. The results indicated that a combined pressure (200 bar) and temperature (50⁰C) was predicted to provide the optimum region in terms of total lipid extracts (13.84 ± 0.52%) and squalene concentration (418.31 ± 18.40 ppm) studied.
Transition metals play an important role in the growth of carbon nanotubes (CNTs). Series of unsupported hybrid catalysts consisting of Ni:Cu, Ni:Cr, and Ni:Mn doped with Nd catalyst, respectively were synthesized by impregnation method. The catalytic performance of the catalyst for the production of CNTs was measured in the pyrolysis process of hydrocarbon source by catalytic chemical vapour deposition method. Acetylene gas was used as the source of carbon in the pyrolysis process. The decomposition of acetylene was carried out at 700ºC. The bulk properties of the catalysts were investigated by X-ray diffraction. Field emission scanning electron microscopy and thermal analysis were used to observe the morphology and thermal stability of the as-synthesized CNTs, respectively. Hybrid catalyst of Ni:Mn/Nd and Ni:Cr/Nd in 3:1 atomic ratio gave high percentage of carbon yield which was assigned for the high production of CNTs with the mass of yield 18 times greater than the initial mass of the catalyst used.
This study was performed to enumerate the total viable cell count of probiotic in five brands (A to E) of commercially cultured milk drinks that are available in the Malaysian market as well as to test their tolerance to various pH and bile concentrations by simulating the human gastrointestinal pH and bile concentration. The acid tolerance test was studied under pH 1.5 and 3.0 with 7.2 as control. The cell count for the acid tolerance test was obtained at an interval of 0, 1.5 and 3 hours respectively and was plated onto duplicate MRS agars to be incubated at 37°C for 48 hours. All cells recovered after 3 hours of pH treatment were selected for bile tolerance test in MRS broth containing bile concentrations of 0% (control), 0.3% and 2.0% and cell counts were recorded after 24 hours of incubation. The probiotic strains in products A, B, C & D met the suggested initial count of 106 CFU/ml with brand C recording the highest at 9.19 ± 0.14 log CFU/ml. Strains in product A, B & C showed good tolerance to pH 3.0 and 7.2 recording a count of >106 CFU/ml after 3 hours with a range of 6.60 – 9.04 log CFU/ml. The higher bile concentrations resulted in lower growth of strains in all the brands. Upon pH 1.5 treatment, only brand C recorded growth in all bile concentrations. After pH 3.0 treatment, all brands except brand E met the requirement of survival at 0.3% bile concentration. Results showed probiotics in product A, B & C met the initial count requirement, and exhibited good acid and bile tolerance therefore being a potentially good source of probiotic.
This research was carried out to determine the fructooligosaccharides content in local honey samples, namely the wild Malaysian Tualang honey and common wild honey obtained from Tapah, Perak and a commercial Tualang honey. Local wild honeys were found to contain a higher concentration of fructooligosaccharides (FOS) compared to the commercial Tualang honey. The FOS quantified from local wild honeys was inulobiose, kestose and nystose. Nystoses were found at a very low amount in the commercial Tualang honey. The effects of honey on the growth of Bifidobacterium longum BB 536 were investigated. Both wild and commercial honey samples including FOS standard were found to support the growth of B. longum. The pH value of the skim milk + honey inoculated with the probiotic strain decreases as expected. Addition of honey was found to support the growth of B. longum BB 536.
Raw goat milk is recognized as one kind of nutritious food owed to its originality and
medicinal values. This study aimed to evaluate the physico-chemical and microbiological
qualities of locally produced raw goat milk prior any processing steps during storage. Milk
samples passed organoleptic test and C.O.B. test were mostly (88.89 %) failed in alcohol test.
AOAC Official method of oven drying method, Kjeldahl method and Soxhlet method were
performed in physico-chemical analysis where results obtained were partially in lined with
reported literature due to subjective factors of breeds, geographical areas and feeds. The locally
produced raw goat milk’s compositions are high in water content and low in fat percentage.
Initial total plate count, coliform count and proteolytic count tested were 3.44 log cfu/ml, 1.87
log cfu/ml and 1.97 log cfu/ml, respectively. Storage time showed significant effect on the
bacterial counts (p>0.05) of milk samples. Shelf-life of milk samples were kept up to 12 hours
under ambient temperature (3.95 log cfu/ml) had not exceeded the standard limit. The shelflife
of the milk samples were extended up to 16 days storage under refrigerated temperature
of 4°C. The microbiological quality of the milk samples showed a significant bacteriological
growth upon prolonged storage and high initial coliform count indicates possible poor hygienic
practices at farm level.