Evaluation and Comparison of the Morphological and Histopathological changes induced by ER:YAG Laser and burs on Enamel, Dentin and Pulp Tissue

The cavity preparation between the convent ion al methods and lasers were compared in 18 patients with 40 samples. • The patient acceptance was good with the laser procedures like that of the conventional methods. • The time required to prepare the cavity with laser was (6.50±1.63 minutes) slight longer than the conventional methods (4.65±0.93 minutes). • On the Scanning Electron Microscope analysis the surface of lased cavity was irregular in appearance with absence of smear layer. • The ground sect ions of the teeth in both methods showed no differences. • The histopathological study of the decalcified sect ions showed that there was no demonstrable pulpal hyperaemia and inflammation in both the methods. In conclusion, there were no significant difference s in the ground sect ion and decalcified sect ion with respect to laser and bur. • However with Scanning Electron Microscope there were significant surface changes between the groups with the laser showing a surface that is beneficial for adhesive restoration and features which suggest that they could reduce the post operative hypersensitivity

Haematology of the Malaysian jungle fowl (Gallus gallus spadiceus)

Haemotological values and total plasma protein concentration were determined from blood samples obtained from seven adult male jungle fowls (Gallus gallus spadiceus) trapped in the secondary forests of west Malaysia. The mean values for total RBC count, Rb concentration and PCV were 2.7 X 106/μl, 11.4 g/dl and 43.3% respectively. The mean values for MCV, MCR and MCRC were 159.4 μ3, 42.0 pg and 26.4% respectively. The mean of total WBC count was 27.5 X 103/μl. The mean differential and absolute counts for WBC were: heterophils, 51.3% and 14.0 X 103/μl; lymphocytes, 31.3% and 8.6 X 103/μl; monocytes, 8.6% and 2.5 X 103/μl; oesinophils, 4.3% and 1.2 X 10 3/f.Ll; and basophils, 4.6% and 1.2 X 103/μl. The mean total plasma protein concentration was 4.2 g/di This study shows that the jungle fowl has a higher,percentage of heterophils and lower percentage of lymphocytes than the domestic chicken

New host records of parasites in the Malayan red jungle fowl, Gallus gallus spadiceus

Thirty species of parasites were recovered from seven adult male Malayan red jungle fowls Gallus gallus spadiceus from Ulu Langat, Selangor, Malaysia. Fifteen species of the parasites are newly recorded for this host; they are Pseudolynchia canariensis, Eimeria sp., Trichomonas gallinarum, Ascaridia galli, Capillaria annulata, Capillaria contorta, Cardiofilaria nilesi, Dispharynx spiralis, Gongylonema sp., Heterakis gallinarum, Tetrameres fissispina, Hymenolepis cantaniana, Raillietina cesticillus, Raillietina tetragona and Postharmostomum gallinum. The most common parasites are the nematode species of Heterakis and Capillaria

Electrical Discharge Machining of Beryllium Copper Alloys Using Graphite Electrode

Electrical Discharge Machining (EDM) is commonly used to produce molds and dies, to drill small, burr-free holes and to make prototype quantities of contacts for the aerospace and electronics markets. Most of EDM machines are manufactured and equipped with built-in ‘machining technology’ for steels. Apart from steel, beryllium copper alloys are amongst essential material for mould and die making. Therefore, the present study elucidates the die-sinking EDM characteristics of beryllium copper alloys with graphite as an electrode. Experiments were conducted on EDM Die Sinking Charmilles Robofom 35P. The output responses investigated were Material Removal Rate (MRR) and Surface Roughness (Ra). Full factorial and Linear Regression analysis of Design of Experiment (DOE) module in Minitab was employed as a principal methodology to examine the effects of current, polarity, pulse duration and voltage over output responses. The significant and optimum machining parameters for each output responses was also identified and established. Experiment results indicate that the Material Removal Rate (MRR) was mainly affected by current, pulse duration, voltage and interaction between current*pulse duration. For the Surface Roughness (Ra), the significant factors were current, voltage and pulse duration. Confirmation tests were carried out and used to compare results obtained by theoretical predication with those experimentally. It was found that the error margin of factors influenced between the predicted and actual results is 5% for Material Removal Rate (MRR) and 4.2% for Surface Roughness (Ra)

Piezoelectric actuators for delamination control in composite plates subjected to low velocity impact

The potential of MFC actuator as a tool for reducing low velocity impact induced delamination has been investigated using LS-DYNA explicit code. For this purpose, three different piezoelectric actuation models were implemented through its user defined material subroutine, namely, the linear strain model, electric field dependent model and induced strain model. The induced strain model was found to provide the best match with experimental results for actuation strain prediction, hence used in impact investigations. In predicting the delamination, a newly formulated damage model was used as it was found that the existing damage models in LS-DYNA are simplistic and rate sensitive. An independent three-dimensional piezoelectric finite element code was developed and used to study the effects of design and actuation parameters on the actuation characteristics of the MFC. The parametric study was meant to determine a laminate-actuator system that would allow sufficient presence of the piezoelectric effects in it. A selected laminate-actuator system was later used to investigate the effects of piezoelectric control actions on the impact force and displacement for purely elastic impact cases. For simply supported laminate it was found that the peak impact force and displacement could be reduced by applying a counter moment to the incoming impact load, whereas for clamped laminate the same was achieved by regulating the laminate stiffness at the impact point. The technique of impact force reduction confirmed that delamination could be reduced. However, this concept could not be experimentally verified as the design requirements could not be practically implemented. The actuator required voltages beyond its operating range to reduce delamination even in the case of very low energy impact. This is something not achievable with the existing piezoelectric materials. Assuming powerful piezoelectric actuators are not impossible in near future, this study could provide useful information for an attempt to validate this concept

Thermochemical Conversion of Biomass: Acid Catalysed Pathways and Kinetics of Cellulose Pyrolysis

Ph.DDOCTOR OF PHILOSOPH

The Proficiency Levels Of Bahasa Melayu Writing Skills In Malaysian Primary Schools.

The 1996 Education Act affirms the status of Bahasa Melayu as a language of knowledge and as a medium of instruction in national schools in Malaysia (Education Act, 1996; Sharifah Maimunah, 2004). Correspondingly, by the end of their primary education pupils are expected to acquire a certain level of Bahasa Melayu proficiency that will enable them to grasp lessons conducted in Bahasa Melayu at the secondary school and tertiary levels

Shape control of composite plates with piezoelectric actuators

In this paper, shape control of composite plates using piezoelectric actuators is being investigated. The goal of this study was to see how composite plates behave when they are integrated with piezoelectric actuators. Modelling and simulation were done using COMSOL Multiphysics software and results were validated using previously published studies. Parametric investigations were carried out to inves-tigate the effect of patch locations and stacking sequences with respect to suppression of deflection. The obtained results showed that for uniformly distributed load considered in this work the patches worked effectively when they were placed at the center of the composite plate

Ecology of Haemaphysalis wellingtoni in Red Junglefowl

The ecology of the parasitic stages of Haemaphysalis wellingtoni was studied in 30 Red Junglefowls in a farm in Jenderam Hulu, Sepang, Selangor, Malaysia. The free ranging Red Junglefowls are trapped using leg traps and individual bird was carefully examined for tick infestations. The ticks were collected from the neck, comb, and outer ear canal, counted and preserved in 70% ethanol. The identification of the tick species and their stages at each site was done through examination using a stereomicroscope and keys to tick identification. Tissue biopsies with ticks attached were also obtained to determine the pathology of tick-feeding sites. The comb tissues were processed with the standard histological technique and stained with hematoxylin and eosin to observe the cellular changes initiated by the ticks. Only one species of the tick was identified, which was Haemaphysalis wellingtoni. The mean of tick numbers in the outer ear canal was the highest (1.77± 0.193), followed by the dorsal aspect of the neck (1.32± 0.329) and the comb (0.72± 0.190). In this study, there are significant differences in stage of the ticks at different infestation sites suggesting that they have preferential site for different stages of their life-cycle. Generally, the mean count for tick stages (adult, nymph and larval) were almost similar on the dorsal part of neck and the outer ear canal. The mean numbers of nymph and larval stages in the neck and outer ear canal were similar, except for the adult stage which was 3.63 on neck and 3.33 in the outer ear canal. However, adult stage was absent on the comb while the mean of nymph stage was 0.16. The larval stage was lower in number in the comb (0.87) compared to the neck and outer ear canal (both 2.2). The cellular changes observed at tick feeding sites consisted of eosinophil and very high lymphocyte infiltrations which indicated chronic inflammation. The congestion, hyperkeratosis and detachment of the keratin layer were also observed at tick feeding sites