Characterization of Injection Molded 17-4PH Stainless Steel Prepared with Waste Rubber Binder

This study is to investigate the sintering characteristics and to establish the best heating rate and soaking time used for sintering process, by determining the physical, mechanical, and microstructural properties of the injection molded 17-4PH stainless steel using waste rubber as a new developed binder system. By using the feedstock which having 65 vol.% of metal powder, the molding are injected into the tensile test bar and immediately processed with two stage debinding process that involves of solvent extraction and thermal pyrolisis to remove the binder. The specimens were sintered at 1360°C under vacuum atmosphere and tested for a critical property analysis of tensile test. Later, the observation on tensile testedspecimens fracture surface are done to understand the fracture behavior,distribution of grain and porosity and the significant correlation of fracture morphology to the mechanical properties. From this study, it is found that the combination of 50C/min heating rate and 60 minutes of soaking period resulted in higher density value, higher tensile strength, less porosity and homogenous grains distribution of the sintered specimens

An Intelligent Recognition Procedure for Trophozoite Stages of Plasmodium Knowlesi Malaria

Plasmodium (P.) Knowlesi is a fifth species of the malaria parasite in the world that caused a serious health problem. Current information suggests that P. Knowlesi is spread to people when an Anopheles mosquito infected by a monkey then bites and infects human (zoonotic transmission). Early identification of P. Knowlesi Malaria is an important step to an effective treatment. P. Knowlesi Malaria identification process is usually carried out with a 100x magnification of thin blood smear using microscope observation. However, this process is time-consuming and very tedious and strenuous for the human eyes. It also has a problem to differentiate between trophozoite, positive control (schizont and gametocyte) and negative control (white blood cell (WBC) and artefact). To overcome these situations, a computer-aided diagnosis system is developed to automatically identifying trophozoite stages of P. Knowlesi Malaria as early identification species, positive control and negative control. The processes involved starting from image acquisition, image processing and recognition. For image processing method, the most important part is the segmentation where the Otsu’s method is utilised to obtain the region of interest (ROI) of the infected cell. The features consist of the size of infected cell and size of the object. Finally, the recognition method using Multilayer Perceptron (MLP) is applied. The results show that the proposed automatic procedure is capable of recognising the trophozoite stage of P. Knowlesi Malaria with an accuracy of 98.70% for training and 97.67% for testing, using MLP trained by Lavernberg Marquardt (LM)

Genetic Divergence of Bermudagrass (Cynodon spp.) Population Using ISSR Markers

Bermudagrass is a widely distributed turf grasses use in Malaysia. Nevertheless, the genetic variation on molecular level of bermudagrass was insufficient. In this study, a sum of 15 cultivars were collected from different accessions in Malaysia and being analyzed using Inter-simple Sequence Repeat Markers (ISSR). A total of 172 fragments were generated from 15 selected ISSR primers. There are 164 polymorphic bands with 95.3% of polymorphism. Fragment size ranged from 120 to 1867bp. The cultivars were clustered into 5 major groups at coefficient level of 0.5 through arithmetic average (UPGMA) cluster analysis of Jaccard’s similarity coefficient. The genetic similarity coefficient was range from 0.25 to 0.61 with an average of 0.43. Satiri and Melaka cultivars were clustered separately from their own hybrid and common clusters, respectively. These findings indicated that ISSR marker is an effective molecular method use to study genetic variation of bermudagrass and could be used for varietal development program

Potential use of Acetylcholinesterase from Osteochilus hasselti in Monitoring Heavy Metal Pollution in Malaysia River

River pollution gave significant effects by declining the quality of freshwater sources, and cause a negative impact on the aquatic habitat and nearby aquaculture sector. Scheduled river monitoring was implemented to determine and investigate the pollution source in order to minimize the number of waste release into the river. Preliminary screening using biosensor tool considered as an effective method where capable to reduce the cost of implementation, easy to handle as well as rapid analysis. The potential use of acetylcholinesterase (AChE) purified from the brain tissue of Osteochilus hasselti as a biosensor tool for heavy metal pollution was investigated. Prior to the study, several water samples were collected from the selected state in Malaysia; Derhaka River (Penang), Perak River (Perak), Kuyuh River (Selangor), Melaka River (Malacca), Peta Waterfall (Endau-Rompin National Park, Johor), followed by filtered then brought to the laboratory immediately. AChE was extracted from the brain tissue of O. hasselti followed by affinity purification using procainamide-based chromatography. AChE was tested by incubated separately with the water samples. Based on the semi-quantitative assessment, all the sample from Derhaka River show higher inhibition towards AChE activity compared to the other river. DR01 capable of lowering almost half of the AChE activity to 56.8±2.8 % followed by DR03 (67.96 %) and DR02 (76.74%). Both Melaka river samples; MR1 and MR2 capable to inhibit AChE more than 10% while MR03 around 4 %. Sample from Kuyuh river; KR01, KR02 and KR03 significantly inhibiting the enzyme activity more than 10%. PR (PR01, PR02 and PR03) slightly affecting the AChE activity around 3 to 5 %. However, all the sample from Endau-Rompin National Park considered as unaffected. Secondary screening was done on each river samples using ICP-OEM for quantitative analysis. This can conclude that the inhibition level of AChE corresponds to the concentration of metal ion. From the study proves that O. hasselti AChE works as an alternative source of biosensor in monitoring the environmental pollution

Biodegradation of cyanide and evaluation of kinetic models by immobilized cells of Serratia marcescens strain AQ07

Immobilized form of Serratia marcescens strain AQ07 was experimented for cyanide biodegradation. Cyanide degradation (200 ppm) was achieved after 24-h incubation. Three parameters were optimized which included gellan gum concentration, beads size, and number of beads. In accordance with one-factor-at-a-time method, cyanide removal was optimum at 0.6% w/v gellan gum gel, 0.3-cm-diameter beads, and 50 beads number. It was able to withstand cyanide toxicity of 800 ppm, which makes it very suitable candidate in cyanide remediation. Beads reusability indicates one-cycle ability. The first cycle removed 96.3%, while the second removed 78.5%. Effects of heavy metals at 1.0 ppm demonstrated that mercury has a considerable effect on bacteria, inhibiting degradation to 61.6%, while other heavy metals have less effect, removing 97–98%. Maximum specific degradation rate of 0.9997 h−1 was observed at 200 ppm cyanide concentration. Gellan gum was used as the encapsulation matrix. ɤ-picoline-barbituric acid spectrophotometric analytical method was used to optimize the condition in buffer medium integrated with potassium cyanide via one-factor-at-a-time and response surface method. The range of cyanide concentrations used in this research, specific biodegradation rate was obtained to model the substrate inhibition kinetics. This rate fits to the kinetic models of Teisser, Aiba and Yano, which are utilized to elucidate substrate inhibition on degradation. One-factor-at-a-time approach parameters were adopted because it removes more cyanide compared to response surface methodology modules. The predicted biokinetic constant from this model suggests suitability of the bacteria for use in cyanide treatment of industrial waste effluents

Endosulfan Toxicity to Anabas testudineus and Histopathological Changes on Vital Organs

The toxicity of endosulfan, an organochlorine type insecticide to a commonly consumed freshwater fish species, A. testudineus (40.68±9.03 g; 13.49±0.99 cm), was investigated under static conditions. The nominal endosulfan concentrations ranging from 10 to 80 μg/L subjected to the fish population results in 96-hour median lethal concentration, LC50, of 35.2±3.99 μg/L. The toxicity is a function of both endosulfan concentration and exposure time (p>0.05). Histopathological analysis on vital organs exposed to sublethal concentrations indicates that structural changes started at sublethal dose and the effects aggravated with increasing endosulfan concentration. Gill was found to experience aneurism, hyperplasia in lamellar and autolysis of mast cell. Pyknotic nuclei and necrosis were observed in liver cell, while the lumen of renal tubule was found to narrow and haemorrhage was observed in cytoplasm cell. High LC50 compared to other fishes indicates that A. testudineus has high tolerant to endosulfan, however, endosulfan slowly alters the fish biochemistry and is potentially transferable to huma