The microstructural evolution of Sn-40Pb/Cu joints has been investigated under 125 o C thermal exposure conditions using single shear lap joints. A scanning electron microscope (SEM) was used to observe the morphology of the phases and energy dispersive x-ray (EDX) was used to estimate the elemental compositions of the phases. A double layer of Cu6Sn5 and Cu3Sn were observed. The Cu6Sn5 developed with a scalloped morphology, while the Cu3Sn always grew as a somewhat undulated planar layer in phase with the Cu6Sn5. The Cu6Sn5 layer began to transform from scallop shape to planar type after aging for 375 hours due to reduction in the interfacial energy. The intermetallic layers showed a linear dependence on the square root of aging time. The growth rate constant of the intermetallic compounds are estimated as 15.2 x 10 - 14 and 0.152 x 10 -14 cm 2 /s for Cu6Sn5 and Cu3Sn intermetallic, respectively.
This paper presents investigations into the development of control schemes for end-point vibration
suppression and input tracking of a flexible manipulator. A constrained planar single-link flexible manipulator is considered and the dynamic model of the system is derived using the assumed mode method. To study the effectiveness of the controllers, a Linear Quadratic Regulator (LQR) was initially developed for control of rigid body motion. This is then extended to incorporate a noncollocated PID controller and a feedforward controller based on input shaping techniques to control vibration (flexible motion) of the system. For feedforward controller, positive and modified specified negative amplitude (SNA) input shapers are proposed and designed based on the properties of the system. Results from the simulation of the manipulator responses with the controllers are presented in time and frequency domains. The performances of the control schemes are assessed in terms of level of vibration reduction, input tracking capability and time response specifications. Finally, a comparative assessment of the control techniques is presented and discussed.
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.
The nuts consumption pattern of Malaysian adults were assessed by a set of food frequency questionnaire collected from June to December 2008 from 364 adults (129 men and 235 women) which were selected by stratified random sampling from five areas of Penang state. Average total nuts consumption of 0.77 g/day among Penang adults was found to be no gender-specific difference but was significantly different (P
This study aimed to detect the presence of enterococci in the root canals of untreated and treated teeth with periapical disease and to compare this to their presence in the saliva and in the immediate surgical environment during root canal treatment. Using an aseptic technique, 33 samples were obtained from 27 untreated and 6 previously treated teeth associated with apical periodontitis. Reduced Transport Fluid (RTF) was used as transport medium. Saliva samples and areas in the surgical environment were also sampled. These were performed prior to chemo-mechanical debrjdement and obturation for every case. The saliva was diluted to 10- J and was plated on Bile Aesculin Azide (BEA) agar whereas the rest of the samples were plated on Bile Aesculin (BE) agar. These plates were then incubated aerobically at 37°C for 48 hours. All the colony types that blackened the agar were sub-cultured to obtain pure isolates and tested on 6.5% sodium chloride (NaCI). Growth on this medium was Gram stained for further confirmation of cell morphology. Gram positive cocci isolated from previous positive test were identified as enterococci. Enterococci were recovered from untreated cases only; from 2 teeth (in 2 patients) prior to chemo-mechanical debridement, from 3 teeth (in 3 patients) prior to obturation and I from saliva sample. A 'total of 5 samples from 5 different patients were positive for enteroco•cci. Sampling in the immediate surgical environment revealed a low occurence in the range of3.0% (1/33) to 15_2% (5/33). In conclusion, the occurence of enterococci in patients and the immediate surgical environment was low number.
Oligodontia, although rare, may have significant impact on the quality of life of those affected with it. Provision of restorative treatment for these patients can be very challenging and demanding for clinicians, especially during the active growth phase. Nevertheless, the dental needs of these patients are real and should be addressed appropriately. The present case report described a restorative rehabilitative plan and execution of different restorative treatment modalities in a 14-year-old patient with oligodontia. The challenges faced in the provision of dental care were highlighted. The treatment outcome showed a positive psychological impact on the well-being of the patient based on parental observations.
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%.
The aim of this study was to investigate the effects of a two week reduction in training load on selected physiological and performance among junior cyclist. Twenty seven male junior cyclists (age= 16.6±0.7 years, height=165.6±6.1 cm, weight= 54.1±8.1 kg) were matched into either the control group (n=13) or the experimental group (n=14) using their initial VO2max values. Both groups followed a 12-week progressive endurance training program and subsequently, the experimental group (EXP) engaged in a two week tapering (recovery via a reduction in training loads) phase. The control group continued with their normal training routine. A simulated 20 km time trials performance and a graded exercise test on cycle ergometer were performed before and after endurance training and after the two week tapering protocol. Following the conclusion of the two week intervention or no intervention program both groups undertook a TT20km. Results showed no significant difference in the TT20km performance. Compared to the CON group, the EXP group showed significant changes in all the selected physiological variables tested, p
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.
This study aimed to analyze consumers’ perceptions and acceptance toward ‘belacan’. Results
showed internal reliability of above 0.7 for sections analyzed. Factor analysis found two underlying factors in the section designed to examine consumers’ perceptions. The overall consumers’ perception had a positive and moderate correlation with their acceptance and was significant at .01. Results also showed that ‘belacan’ consumption level was relatively frequent and well accepted by all races in Malaysia. The findings of the study would be noteworthy to the fishery industry and the small and medium industry (SME) in Malaysia in meeting consumers’ needs.
The Malaysian skincare industry is growing rapidly with a vast number of new sunscreens being produced annually. Inadequate skincare regulations and lack of enforcement have resulted in the overrating of sunscreens’ quality. The objectives of this study were to evaluate the efficacy and safety of the local and international sunscreens and to determine the effects of adding concentrated antioxidants into them. Three local and three internationally manufactured sunscreens were tested for the in vitro Ultraviolet A protection factor (UVAPF), Sun Protection Factor (SPF) and photostability. The creams were spread onto roughened polymethylmethacrylate plates where the absorbance was measured using a spectrophotometer before and after two hours of sunlight irradiation. The procedure was repeated combining available concentrated vitamin C and E creams. International sunscreens were found to have more accurate SPF labels (p=0.009) while local sunscreens were found to be more photostable (p=0.003). However, both sunscreens had inadequate UVAPF (p=0.471). Vitamin C enhanced the SPF values (p= 0.04) of both groups of sunscreens while vitamin E enhanced their photostability (p=0.000). Interestingly, combining vitamins C and E rich creams with the sunscreens had no effect on the SPF and UVAPF values as compared to the use of a single vitamin. More importantly, the combination of vitamins decreased the photostability (p=0.002) of sunscreens as compared to the addition of vitamin E alone. In conclusion, photoprotection is best achieved when sunscreens are used together with creams containing either vitamin C or E alone.
Liberica coffee is the most important coffee species grown in Malaysia. However, there is little or no research at all conducted on coffee berries and green coffee beans since the plant itself is a low income crop in Malaysia. Therefore, research on Malaysian Liberica coffee can help to increase the knowledge of coffee farmers and coffee manufacturers in the processing and handling of the coffee. Physical properties of Liberica coffee berries and beans were investigated the current study. The properties investigated include the size, mass, density, coefficient of friction, angle of repose, fracture force and colour. In comparison to Arabica and Robusta coffee, Liberica coffee has the biggest size, mass, true density and fracture force values but were lower in bulk density in both berries and beans. The Liberica berries and beans were found to be orange-ish and yellowish colour respectively. Angle of repose was low and approximately similar in berries and beans while jute fibre gave the highest friction to both Liberica berries and beans.
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.
A longitudinal study was conducted to relate basal metabolic rate (BMR) with growth during adolescence. Subjects comprise 70 boys and 69 girls aged between ten and thirteen years at the time of recruitment. Parameters studied include anthropometric measurements and BMR, which was measured by indirect calorimetry using the Deltatrac metabolic monitor. Measurements were carried out serially once every six months, with a total of 713 BMR data points collected over three years. Mean BMR of boys aged 11, 12, 13 and 14 years were 4.96 ± 0.63 MJ/day, 5.28 ± 0.71 MJ/day, 5.73 ± 0.68 MJ/day and 5.92 ± 0.63 MJ/day, respectively; while mean BMR of girls in the 10, 11, 12 and 13 year age groups were 4.96 ± 0.63 MJ/day, 4.85 ± 0.63 MJ/day, 5.05 ± 0.55 MJ/day and 4.94 ± 0.51 MJ/day, respectively. Comparison of measured BMR with BMR values predicted from the FAO/WHO/UNU (1985) equations shows that the predictive equations overestimated the BMR of Malaysian boys by 3% and that of girls by 5%. The Henry & Rees (1991) equations for populations in the tropics underestimated BMR of boys and girls by 1% and 2%, respectively. Linear regression equations to predict BMR based on body weight were derived according to sex and age groups. It is recommended that these predictive equations be used for the estimation of BMR of Malaysian adolescents.
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.
Bacillus cereus is a soil inhabitant gram positive bacterium, and is known to cause severe food poisoning. The objective of this study was to isolate and identify the presence of Bacillus cereus s.l. from selected ready to eat cereals purchased randomly from local supermarkets in Kuching and Kota Samarahan, Sarawak. The result showed that four of the 30 food samples were detected to be contaminated by B. cereus s.l. . Our findings suggested that it is important for the public to be aware of the safety of RTE cereals consumption, as it is possible that B. cereus s.l. may be present in high count number and pose hazardous health effects to the consumers.
Mental health is a growing concern in the field of occupational health globally due to its social, health, and economic implications on the individual and the community at large. As universities in Malaysia are advancing towards becoming world-class research universities, academicians are now faced with more pressures, making them more vulnerable to burnout. A cross sectional study was conducted among 194 randomly sampled academicians from a faculty of a public university. Data was collected using a self-administered questionnaire to assess the sociodemographic characteristics, occupational characteristics and burnout. Analysis was done using SPSS version 21. The response rate was 87.1%. The overall prevalence of burnout was 10.7% with significant associations between gender (χ2 = 4.61; p = 0.03), teaching experience (χ2 = 0.83; p = 0.02), job satisfaction (χ2 = 11.33; p = 0.001). Female academicians have a higher prevalence of burnout (14.3%). Academicians who have fewer years of teaching experience (
Background: The World Health Organization recommends the practice of exclusive breastfeeding of infants for the first 6 months after birth. The objective of present study was to estimate the prevalence and the factors influencing exclusive breastfeeding. The perceptions of mothers about breastfeeding in an urban slum area of Western India were also enquired.
Methods: This cross sectional study was conducted over six months amongst 200 mothers of children in the age group of 6 – 12 months attending the growth and development clinic in one of the urban health centres. Data was collected using a pre-tested, structured questionnaire on breastfeeding practices. Factors related to exclusive breastfeeding were analysed using bivariate and multivariate analysis.
Results: Prevalence of exclusive breastfeeding reported by the participants was 61.5%. Having a male child, maternal age < 30 years, level of education of mother parity, receiving infant feeding advice, initiation of breastfeeding within one hour of birth and administration of colostrum to the baby were associated with exclusive breastfeeding (p
The production of ethanol, from glucose in batch and fed batch culture, was investigated. In the fed batch culture, the glucose feeding was added into the culture at 16th hour of fermentation. The effects of different glucose concentration feeding rates on ethanol fermentation were investigated for fed batch culture. The 2gL-1hr-1 glucose concentration feeding rate was found to give higher ethanol yield (2.47 g ethanol g glucose-1), with respect to substrate consumed as compared to 8 gL-1hr-1 (0.23 g ethanol g glucose-1) and 4 gL-1hr-1 (0.20 g ethanol g glucose-1). The ethanol yield with respect to substrate consumed obtained in batch culture was 0.81 g ethanol g glucose-1. The fed batch culture at 2 gL-1hr-1 glucose concentration feeding rate was proven to be a better fermentation system than the batch culture. The specific growth rate, specific glucose consumption rate and specific ethanol production rate for the fed batch fermentation, at 2 gL-1hr-1 glucose concentration feeding rate, were 0.065 hr-1, 1.20 hr-1 and 0.0009 hr-1, respectively.
Neck abscess is still common in developing countries. Often the presentation is late especially when the pain becomes intolerable or the airway is compromised. Intramuscular abscess in the neck is very rarely encountered. We report a case of an abscess of the right sternocleidomastoid. The culture grew Proteus mirabilis. The outline of management is discussed.