Skin wound healing is a complex physiological event, involving many cellular and molecular components. The event of
wound healing is the coordinated overlap of a number of distinct phases, namely haemostasis, inflammatory, proliferative
and remodelling. The molecular events surrounding wound healing, particularly the reepithelialisation, has been reported
to be similar to the epithelial to mesenchymal transition (EMT). In this review, the mechanism between epithelialisation
and EMT were compared. Both are characterised by the loss of epithelial integrity and increased motility. In terms of
the signalling kinases, Smad and mitogen-activated protein kinase (MAPK) has been reported to be involved in both
reepithelialisation and EMT. At the transcriptional level, SLUG transcription factor has been reported to be important for
both reepithelialisation and EMT. Extracellular matrix proteins that have been associated with both events are collagen
and laminin. Lastly, both events required the interplay between matrix metalloproteinases (MMPs) and its inhibitor. As a
conclusion, both reepithelialisation and EMT shares similar signaling cascade and transcriptional regulation to exhibit
decreased epithelial traits and increased motility in keratinocytes.
Co-synthesis of In2O3 and ZnO nanowires (NWs) were grown on silicon and alumina substrates using vapour transport deposition method. Their morphological structures showed that the NWs were rather aligned on silicon substrate and randomly oriented on alumina substrate. The formation of NWs on silicon substrate was found to be dominated by the growth of ZnO NWs while that on alumina substrate was dominated by the growth of In2O3 NWs. The In2O3 and ZnO NWs were highly crystalline and have wurtzite structure.
Fusarium species is one of the common pathogens of post-harvest disease to cause rot on tomato and other perishable vegetable fruits. The objectives of this study were to determine the diversity of Fusarium isolated species from post-harvest diseases of tomato fruit, to identify the causal organisms by using phenotype characteristics and to verify the pathogens of Fusarium fruit of tomato based on pathogenicity test. Carnation leaf-piece agar (CLA) and potato dextrose agar (PDA) media were used for phenotype-based identification of the Fusarium isolates with emphasis for characterizations of the shapes and sizes of the macroconidia and microconidia, colony features, growth rates, conidiogenous cells and chlamydospores. A total of 180 Fusarium isolates were obtained from 13 locations throughout Selangor. Fusarium solani was most abundantly isolated (34%) followed by F. semitectum (31%) and F. oxysporum (31%), F. subglutinans (3%) while the least was F. equiseti (1%). Twenty seven isolates were tested for pathogenicity test by injecting 1 mL of the conidial suspension onto healthy tomatoes. All the tested Fusarium isolates were pathogenic on tomato with different severity levels. The non-inoculated controls showed no symptoms of fruit rot. The most virulent was F. oxysporum isolate B711T with DSI 93.75%, while the least were isolates of F. solani (B647T) and F. oxysporum (B727T) with DSI 37.5%. Majority of the isolated Fusarium species can potentially produce mycotoxins as their secondary metabolites. The potential production of mycotoxins by pathogenic isolates of Fusarium species in contaminated tomato fruits could pose health hazards when consumed.
Chemical structure of treated and untreated Aciplex membrane has been studied by X-ray Photoelectron Spectroscopy (XPS). Survey spectra showed that both membrane surfaces consist of Fluorine, Carbon, Oxygen, Sulphur and trace of Titanium. Binding energies for the elements are (C1s at 290.6 eV, F1s at 687.5 eV, O1s at 531.3 eV, S2P at 168.1 eV and Ti2P at 454.4 eV). Analysis of narrow scan XPS-spectra of each element demonstrate the presence of (-CF, -CF2, CF3, C-O-C and SO-3) groups, which are in agreement with the structural formula as disclosed by the manufacturer. There is no significant change in chemical states of untreated and treated membrane, which reflect its stability to treatment conditions.
Struktur kimia Aciplex membran yang sudah dibersihkan dan yang belum dibersihkan telah dikaji menggunakan Spektroskopi Fotoelektron Sinaran-X (XPS). Spektra yang telah ditinjau menunjukkan bahawa kedua-dua permukaan membran mengandungi Florin, Karbon, Oksigen, Sulfur dan sedikit Titanium. Tenaga ikatan bagi unsur-unsur tersebut adalah (C1s pada 290.6 eV, F1s pada 687.5 eV. O1s pada 531.3 eV, S2P pada 168.2 eV dan Ti2P pada 454.4 eV). Analisis imbasan kecil spektra-xps bagi setiap unsur menunjukkan kehadiran kilmpulan (-CF, - CF2, CF3, C-O-C dan SO-3) yang bertepatan dengan formula struktur dari pihak pembekal. Tiada terdapat perubahan nyata berhubung dengan keadaan kimia membran yang sudah dibersihkan dan yang belum dibersihkan yang menggambarkan kestabilannya terhadap keadaan pembersihan.
The aim of this study was to investigate the genotoxicity effect of Cd and Zn and their binary mixtures in tilapia fish Oreochromis niloticus using the micronucleus test. Two cytogenetic end points were considered; the frequencies of micronucleated cells and nuclear abnormalities. Fishes were exposed to 4.63 mg/L Cd, 7.50 mg/L Zn and 4.63 mg/L Cd + 7.50 mg/L Zn mixture for the period of 24, 48, 72 and 96 h. The results showed that the frequencies of micronuclei and nuclear abnormalities in the erythrocyte were significantly increased in all groups of treatments when compared with the control group (0 exposures). In addition, the highest frequencies of micronucleated and nuclear abnormalities were obtained after 48 h exposure in almost all cases (except in the mixture of Cd+Zn) and decreased after 72 and 96 h exposure. Frequencies of micronuclei and erythrocytes with nuclear abnormalities exposed to a mixture of Cd+Zn in O. niloticus were always lower at all-time points (after 24, 48, 72 and 96 h) than that of a single Cd and Zn exposure. Therefore, the study demonstrated that the genotoxic potential of these metal compounds and the simultaneous treatment of Cd and Zn suggest the presence of antagonistic interactions.
Lipase from a newly isolated strain of Rhizopus rhizopodifonnis was partially purified and characterized. By acetone fractionation, the enzyme was purified to about 2.8 fold, with 62.5% recovery and with specific activity of 3.2 U/mg. By gel filtration through Sephadex G-100, the enzyme was further purified to 9.7 fold and had a specific activity of 11.1 U/mg. By polyacrylamide gel electrophoresis, five protein bands were observed after acetone fractionation, white two protein bands were observed after the preparation was passed through Sephadex G-100. It has a pH optimum at 6.0 and a temperature optimum at 45°C. The enzyme is most stable at pH 7.0 and temperature of 50°C. The enzyme has a preference for short chain triglycerides and can also hydrolyse some methyl esters. The lipase is specific for 1,3 positions.
Lipase daripada satu stren Rhizopus rhizopodifonnis yang baru dipencilkan telah diseparatulen dan diciri. Melalui fraksi asiton, enzim telah ditulen lebih kurang 2.8 ganda, dengan pengutipan 62.5% dan aktiviti spesifik 3.2 U/mg. Dengan penurasan gel melalui Sephadex G-l00, enzim ditulenkan lagi hingga 9.7 ganda dengan aktiviti spesifik mencapai 11.1 U/mg. Dengan elektroforesis gel poliakritamida, 5 jalur protein didapati selepas fraksi asetone, sementara 2 jalur protein dilihati selepas penurasan gel Sephadex G-10. Enzim ini mempunyai pH optimum pada pH 6.0 dan suhu optimumnya ialah 45°C Enzim ini paling stabit pada pH 7.0 dan suhu 50°C Enzim mempunyai kepilihan pada trigliserida rantai pendek dan dapat menghidrolisiskan beberapa ester metit. Lipase ini spesifik pada posisi 1,3.
Ultrafine, cemented tungsten carbide (WC) possesses exceptional hardness, wear resistance and high strength in various applications. In this study, WC was produced through micro powder injection molding (μPIM), which is also applicable for metals and ceramics in producing complex parts with high-dimensional accuracy. Different inhibitors, such as VC, Cr2C3, NbC, or TaC, were added to improve the mechanical properties of WC and control its grain growth. The effects of a grain growth inhibitor were investigated by adding VC in WC–10%Co–nVC, where n = 0 to 1.2 wt. %. The mechanical properties of the sintered part, such as hardness and flexural strength, were determined. The morphology and elemental distribution of the samples were studied by field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. X-ray diffraction was employed to study the phases of the obtained samples. The results showed that the sample with 0.4 wt. % VC (optimal amount) sintered at 1410°C exhibited the highest theoretical density, hardness and flexural strength of 95.2%, 1973±31 HV and 2586±172 MPa, respectively. The average grain size measured was 519±27 nm. VC acted as a grain growth inhibitor during sintering, thereby improving the mechanical properties.
Silicon nanomaterial was prepared using the peroxide/acid/salt technique in which an aqueous silicon-based salt solution was added to H2O2/HF etchants. In order to optimize the experimental conditions for silicon nanomaterial production, the amount of nanomaterial produced was studied as a function of the volume of the silicon salt solution used in the synthesis. A set of samples was prepared using: 0, 5, 10, 15, and 20 mL of an aqueous 1 mg/L metasilicate solution. The area under the corresponding peaks in the infrared (ir) absorption spectra was used as a qualitative indicator to the amount of the nanomaterial present. The results indicated that using 10 mL of the metasilicate solution produced the highest amount of nanomaterial. Furthermore, the results demonstrated that the peroxide/acid/salt technique results in the enhancement of the production yield of silicon nanomaterial at a reduced power demand and with a higher material to void ratio. A model in which the silicon salt forms a secondary source of silicon nanomaterial is proposed. The auxiliary nanomaterial is deposited into the porous network causing an increase in the amount of nanomaterial produced and a reduction in the voids present. Thus a reduction in the resistance of the porous layer, and consequently reduction in the power required, are expected.
In this research we introduce an analyzing procedure using the Kullback-Leibler information criteria (KLIC) as a statistical tool to evaluate and compare the predictive abilities of possibly misspecified density forecast models. The main advantage of this statistical tool is that we use the censored likelihood functions to compute the tail minimum of the KLIC, to compare the performance of a density forecast models in the tails. Use of KLIC is practically attractive as well as convenient, given its equivalent of the widely used LR test. We include an illustrative simulation to compare a set of distributions, including symmetric and asymmetric distribution, and a family of GARCH volatility models. Our results on simulated data show that the choice of the conditional distribution appears to be a more dominant factor in determining the adequacy and accuracy (quality) of density forecasts than the choice of volatility model.
This paper analyzes the asymmetric long memory volatility dependency of the interday prices of Composite Index (CI) at Bursa Malaysia by using GARCH family models. The GARCH type models are used with the assumption that the innovations series follow either one of the following distributions: Gaussian, Student -t and skewed Student -t. The stock returns' long memory dependency is determined using the Hurst parameter. The long memory and asymmetric volatility are modelled by fractionally integrated GARCH models. It is found that the asymmetric and long memory GARCH models with skewed student-t distribution give better predictive ability on the volatility of the Kuala Lumpur Composite Index (KLCI).
The main purpose of this article is to introduce the technique of panel data analysis in econometrics modeling. The elasticity of labour, capital and economic of scale for twenty two food manufacturing firms covering from 1989 to 1993 is estimated using the Cobb-Douglas model. The three main techniques of panel data analysis discussed are least square dummy variables (LSDV), analysis of covariance (ANCOVA) and generalized least square (GLS). Ordinary Least Square (OLS) method is included as the basis of comparison.
The main objective of this paper is to explore the varying volatility dynamic of inflation rate in Malaysia for the period from January 1980 to December 2004. The GARCH, GARCH-Mean, EGARCH and EGARCH-Mean models are used to capture the stochastic variation and asymmetries in the economic instruments. Results show that the EGARCH model gives better estimates of sub-periods volatility. Further analysis using Granger causality test show that there is sufficient empirical evidence that higher inflation rate level will result in higher future inflation uncertainty and higher level of inflation uncertainty will lead to lower future inflation rate.
The increase in the amount of extracted silicon nanostructures resulting from the incorporation of sodium metasilicon salt in the etching solution was investigated. Silicon nanostructures were prepared in the form of thin fluorescent films via anodisation etching of silicon wafers in aqueous HF/H2O2 solution in the presence of the silicon-based salt. The quality of the fluorescent films was assessed using several nondestructive analytical techniques. The nanostructures produced were then extracted. The harvested nanostuctures were examined for quantitative elemental analysis using atomic absorption spectrophotometry. This investigation was limited to silicon nanostructures with size ≤ 200 nm. The results indicate that the incorporation of the silicate increased the yield of silicon nanostructures production significantly.
The volume flux pinning force density of MgxB2 (x = 0.8, 1.0 and 1.2) materials was calculated for grains boundary and point pinning potentials. Stoichiometric Mg0.8, MgB2, and Mg1.2B2 samples were prepared by the conventional solid state reaction method. Three pellets were annealed at temperature range of 650-800°C. Structural analysis revealed large values for FWHM at (hkl) (110)(°) which indicates distortion in the boron plane of these specimens. The a and c – axis lattice parameters showed respective contraction and elongation with the increase in processing temperature. The low crystallinity found in Mg0.8B2 and Mg1.2B2 specimens was concluded to be due to structural defects, which act as flux pinning centres. Experimental anisotropic factor and the minimum fraction for current path, obtained from the framework of current percolation theory were used to explain the strong field dependence of the critical current density, Jc in the specimens. The summit of the maximum pinning force density was shifted to lower magnetic field position with the increase of anisotropy. The scaling laws were employed in a Kramer– like field in order to identify the dominant pinning mechanism correspondence to the summit of maximum pinning. For MgB2 specimens however, a renormalization field based on the current percolation exposition is considered for the identification of their dominant pinning since it is very difficult to account for the flat behaviour of the pinning force in the weakened current region of these specimens.
Using the Microtox bioassay toxicity was determined in 16 areas located in eight sites: In contaminated areas, in areas
with natural recovery, after bioremediation and phytoremediation projects and in control areas (uncontaminated). These
areas correspond to the following ecosystems: mangrove, fresh water swamp (Pachira aquatica), marsh and pasture (in
the coastal plain and Pliocene-Pleistocene terraces). A significant toxicity was detected in uncontaminated organic
soils (22.2-49.1 toxicity units (TU)) which were comparable to levels found in hydrocarbon contaminated areas (22.3-
42.0 TU). Generally, the toxicity in organic soils was much higher than that found in mineral soils (which was from
below quantification levels to 9.3 TU). In an area restored by phytoremediation, the simple method used by Petróleos
Mexicanos achieved recovery and superficial detoxification in the treated plot, exhibiting a toxicity reduction of 2.4 times
with respect to untreated soil and a toxicity even slightly lower than the uncontaminated control in the same ecosystem
(22.2 TU). Likewise, a bioremediation project in pasture resulted in a toxicity reduction down to levels comparable to
uncontaminated soil (from below quantification levels to 7.9 TU). A tendency to decrease toxicity in organic soils during
the rainy season was observed, toxicity drop in 80% of the areas sampled. Based on these findings, recommendations
are presented for use of this test method in regional diagnostic studies.
Biomass burning is one of the main sources of air pollution in South East Asia, predominantly during the dry period between June and October each year. Sumatra and Kalimantan, Indonesia, have been identified as the regions connected to biomass burning due to their involvement in agricultural activities. In Sumatra, the Province of Riau has always been found to have had the highest number of hotspots during haze episodes. This study aims to determine the concentration of five major pollutants (PM10, SO2, NO2, CO and O3) in Riau, Indonesia, for 2006 and 2007. It will also correlate the level of air pollutants to the number of hotspots recorded, using the hotspot information system introduced by the Malaysian Centre for Remote Sensing (MACRES). Overall, the concentration of air pollutants recorded was found to increase with the number of hotspots. Nevertheless, only the concentration of PM10 during a haze episode is significantly different when compared to its concentration in non-haze conditions. In fact, in August 2006, when the highest number of hotspots was recorded the concentration of PM10 was found to increase by more than 20% from its normal concentration. The dispersion pattern, as simulated by the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT), showed that the distribution of PM10 was greatly influenced by the wind direction. Furthermore, the particles had the capacity to reach the Peninsular Malaysia within 42 hours of emission from the point sources as a consequence of the South West monsoon.
Vermicomposting using Lumbricus rubellus was conducted in two different durations, 10 and 30 weeks in the same plots. Three different of treatments combination were prepared with eight replicates for each treatment namely cow dung : kitchen waste in 30:70 ratio (T1), cow dung : coffee grounds in 30:70 ratio (T2), and cow dung : kitchen waste : coffee grounds in 30:35:35 ratio (T3). Macronutrients elements in the vermicompost from each treatment were measured in the tenth and thirtieth week. Comparatively longer duration of vermicomposting by using Lumbricus rubellus enhanced the quality of vermicompost by the increase of the macronutrient elements while reducing the heavy metal concentration and C/N ratio.
Vermicomposting for 140 days by using Lumbricus rubellus was conducted after 21 days of natural pre-composting. Five treatments in different ratio of goat manure: spent mushroom substrate were prepared as feed materials with four replicates for each treatment namely; 20:80 (TA), 40:60 (TB), 50:50 (TC), 60:40 (TD) and 80:20 (TE). As for control, each treatment without earthworm was prepared. On the basis of nutrient elements, goat manure and spent mushroom substrate can be decomposed through both methods of vermicomposting and natural composting. Findings of this study indicated that the higher usage of goat manure with longer duration resulted in the production of improved organic fertilizer.
In this study, Bacterial cellulose (BC) grafted with Acrylic acid (AA) was prepared using Co60 γ-rays source (30 KGy).
Although many samples were prepared, BC: AA with ratio of 1:1 labelled as A1 and 2:1 labelled as A2 gave the most
significant results. Hence these particular ratios have been selected and further investigated. AA was proven grafted onto
BC by using ATR-FTIR due to the absent of C-O stretching (1040 cm-1) in both hydrogels. The SEM image of both hydrogels
samples showed highly porosity networks structure have been produced. The physical properties of the hydrogels such
as equilibrium water content (%) and swelling ratio (%) in different pH buffer solution were measured. It was found
that the equilibrium water content (%) of A1 was 93.10% while A2 was 74.83%, respectively. The results indicated that
the equilibrium water content (%) increased by gaining the AA concentration. At pH10, the A2 swelling ratio (%) was
two folded with 3350% in comparison with the A1. For the removal of methylene blue (MB) from aqueous solution, the
results from the UV-VIS spectroscopy demonstrated that the A2 sample hydrogel was also an effective absorbent material
Currently, fetal bovine serum (FBS) have been widely use in culture media to promote human cell proliferation. However,
the usage of FBS for cell therapy in clinical application was associated with the risk of viral and prion transmission as
well as immune rejection. To provide an option for this risk, this study was conducted to determine the effect of adipose
derived stem cells (ADSCs) co-culture with chondrocyte in promoting cell proliferation and chondrogenesis toward
FBS free condition. ADSCs co-cultured with chondrocyte at the ratio of 1:1, 2:1 and 1:2 were tested. Cell morphology
changes, cell proliferation and gene expression level of stemness (Oct4, FGF-4, Nanog) and chondrogenic (Collagen
Type II, ACP) were assessed. The results showed ADSCs in all co-culture groups changed morphology from fibroblastic
spindle to polygonal shape which resembled chondrocytes. The morphological changes were accompanied with increased
expression of chondrogenic genes; denoted chondrogenesis process. While maintaining expression of stemness genes
indicated continuation of cell proliferation. From the three co-culture groups tested; ADSCs and chondrocytes (1:1 ratio)
have been shown to exert better effects in promoting cell proliferation and chondrogenesis. In conclusion, ADSCs could
replace FBS to grow sufficient number of chondrogenic cells to repair cartilage injury in the near future. Further in vivo
study should be performed to test the effectiveness of this co-culture technique in cartilage injury repair.