Faktor yang perlu diberi perhatian bagi bahan pemeka foto yang baik adalah keamatan serapan dan kedudukan serapan spektrum elektronik dalam julat cahaya nampak, keupayaan redoks dan kestabilan-fotonya. Kompleks molibdenum ditiolena dengan formula am [MoTp*(NO)(L)] dengan Tp* = tris(3,5-dimetilpirazolil)hidroborat dan L = toluena-3,4-ditiolat (L1); 1,2-benzenaditiolat (L2); 3,6-dikloro-1,2-benzenaditiolat (L3) didapati mempunyai sifat-sifat kimia dan fizik yang diperlukan untuk dijadikan sebagai anod pemeka-foto-elektron untuk sel foto-elektrokimia penguraian molekul air kepada hidrogen dan oksigen. Kompleks Mo-ditiolena yang disintesis daripada prekursor [MoTp*(NO)(I)2] dan sebatian ditiol dengan kehadiran Et3N sebagai agen penurunan dan penyahprotonan telah diciri dengan menggunakan kaedah analisis mikro unsur CHNS, spektroskopi IR, ultra-lembahyung dan cahaya nampak (UV-Vis), dan elektrokimia. Puncak penyerapan UV-Vis (λmax/ nm) dikesan pada 321-331, 369-372, 576-589 dan 736-741nm. Sifat keaktifan fotokimia dan foto-fizik turut dikaji bagi menentukan kesesuaiannya sebagai bahan pemeka foto bagi sel foto-elektrokimia. Ujian kestabilan-foto menunjukkan tiada berlaku penguraian terhadap ketiga-tiga kompleks tersebut selepas sinaran cahaya selama 24 jam.
Curcuma longa or turmeric has long been used in traditional medicine by the local population in Malaysia as an antiinflammatory agent. It has been proven to contain natural antiarthritic compound called curcumin. Joints abnormality and destruction have been implicated in the pathogenesis of rheumatoid arthritis (RA) due to inflammatory reactions. In this study, collagen-induced arthritis (CIA) model was utilized to study the effects of curcumin on joint inflammation in Sprague-Dawley rats. Body weight measurement, arthritis score assessment and radiology score assessment were carried out at specific intervals throughout this study. The results showed that the mean arthritis and radiology scores for animal groups designated as CIA CurcuminC and CIA CurcuminT were significantly lower compared with the negative control (CIA OV) group respectively. The mean arthritis scores for CIA CurcuminC group is significantly lower compared with CIA CurcuminT group but there is no significant difference in the mean radiology scores between the CIA CurcuminC and CIA CurcuminT groups. In conclusion, the oral supplementation of curcumin at the dose of 110 mg/mL/kg/day has a potential to delay and improve joint abnormality and injury in Sprague-Dawley rats with CIA.
Five compounds identified as friedelin 1, eupha-8, 24- diene 3-β-ol 2, stigmasterol 3, teraxerone 4 and teraxerol 5 have been isolated from Garcinia prainiana (Guttiferae) for the first time. There has been no previous report on the chemical constituents and biological activities of this plant. Compounds 1, 2 & 3 were isolated from the methanol extract of the twigs while compounds 4 & 5 were isolated from the methanol extract of the leaves. The structures for all the compounds were evaluated based on spectroscopic analysis and comparison with the published information in the literature.
There has been an increasing interest in the use of natural materials as drug delivery vehicles due to their biodegradability, biocompatibility and ready availability. These properties make bacterial cellulose (BC), from nata de coco, a promising biopolymer for drug delivery applications. The aim of this study was to investigate the film-coating and drug release properties of this biopolymer. Physicochemical, morphological and thermal properties of BC films were studied. Model tablets were film coated with BC, using a spray coating technique, and in vitro drug release studies of these tablets were investigated. It was found that BC exhibited excellent ability to form soft, flexible and foldable films without the addition
of any plasticizer. They were comparable to Aquacoat ECD (with plasticizer) in tensile strength, percentage elongation and elasticity modulus. Differential scanning calorimetry (DSC) BC showed a high Tg value indicating thermally stability of films. These results suggest that BC can be used as novel aqueous film-coating agent with lower cost and better film forming properties than existing film-coating agents.
A study was carried out to investigate the effects of different girdling techniques on the growth, development and quality of red wax apple fruits (Syzygium samarangense). Selected horticultural parameters were monitored at one week interval during the growth period from December 2008 to October 2010, using I, C, V shaped, 50%, and 100% girdling. Girdling was applied 2 weeks before flowering. The results showed that the C-shaped girdling technique produced the best results with regard to the fruit setting and chlorophyll content in comparison to the control and the other girdling
techniques employed. Furthermore, C-shaped girdling enhanced faster fruit growth producing the best final fruit length and diameter. In addition to significantly increased yield, juice percentage, leaf dry matter, biomass and TSS content of fruits. It was also observed that 50% girdling decreased fruit dropping. V-shaped girdling also increased the number of bud and reduced bud dropping compared to control. I-shaped girdle fruits produced the highest amount of K+ content in fruit juice compared to other treatments. The color development of the fruit peel in 100% girdling was also the highest among the treatments. From this study, it can be concluded that C-shaped girdling applied two weeks before flowering produced better fruit growth, yield and quality of red wax apple fruits under field conditions.
MeSH terms: Fruit and Vegetable Juices; Chlorophyll; Flavoring Agents; Food Additives; Fruit; Plant Leaves; Biomass; Syzygium; Malus
The leaf and fruit crude extracts of hexane, chloroform, methanol and water of Ardisia crispa were screened for their antioxidant activity using DPPH radical scavenging, ferric reducing power, and metal chelating antioxidant assay. The methanol crude extract of fruits showed higher antioxidant activity (90.16 ± 0.01%) than the methanol crude extract of leaves (82.24 ± 0.02%) in the DPPH radical scavenging assay. In the ferric reducing power assay methanol fruit extract showed the highest absorbance indicating high antioxidant activities than leaf extract. In the metal chelating antioxidant assay fruit methanol extract gave 40% antioxidant activities than the leaf. Thin Layer Chromatography of the fruit methanol crude extract showed that it contained phenolic compounds when it was detected with folin reagent. HPLC analysis revealed that the fruit methanol extract contained gallic acid. This indicated that the high antioxidant activities of the fruits were due to the presence of gallic acid in the fruits of Ardisia crispa.
Six varieties of Ficus deltoidea Jack (Moraceae) showed leaf morphological variations through quantitative measurement on different plant parts. There were significant differences among six varieties studied by plant parts. The varieties studied include var. deltoidea Corner, var. angustifolia (Miq.) Corner, var. trengganuensis Corner, var. bilobata Corner, var. intermedia Corner, and var. kunstleri (King) Corner. The upper, middle and lower plant parts showed morphological variations in terms of leaf length, leaf width, leaf area and petiole length. Qualitative parameters also showed trends in morphological variations in terms of leaf shape, leaf base, leaf apex and leaf attachment. However, some qualitative parameters were not the recommended parameters to differentiate among varieties. On the other hand, leaf heterophylly has occurred in F. deltoidea because foliage of the young plant was different from the mature plant. Leaf heterophylly was observed in leaf shape and leaf apex parameters, whereby leaves from the lower plant parts were different from the upper and middle parts. The heterophylly in leaf shape was detected in varieties angustifolia, bilobata, intermedia and trengganuensis, whilst six varieties of F. deltoidea showed leaf apex heterophylly
MeSH terms: Research; Plant Leaves; Ficus; Plant Development
Many researchers have developed various economic ordering quantity models by assuming an infinite time horizon and constant demand rate. However due to rapid technological advancement, shorter product life cycle and severe competition, those assumptions are no longer realistic. In this paper, we complement that shortcoming by considering an inventory model that satisfies a continuous time-varying demand rate for a finite time horizon when trade credit period and unit cash discount are allowed. The time horizon consists of n different cycles with equal or different cycles length. The trade credit period was assumed to be proportional to the cycle length. We developed mathematical models and presented a numerical example to support the effectiveness of these models.
MeSH terms: Financial Statements; Animals; Life Cycle Stages; Models, Theoretical; Economic Development
This paper describes the development of a two-point implicit code in the form of fifth order Block Backward Differentiation Formulas (BBDF(5)) for solving first order stiff Ordinary Differential Equations (ODEs). This method computes the approximate solutions at two points simultaneously within an equidistant block. Numerical results are presented to compare the efficiency of the developed BBDF(5) to the classical one-point Backward Differentiation Formulas (BDF). The results indicated that the BBDF(5) outperformed the BDF in terms of total number of steps, accuracy and computational time.
This research proposes a point forecasting method into Markov switching autoregressive model. In case of two regimes, we proved the probability that h periods later process will be in regime 1 or 2 is given by steady-state probabilities. Then, using the value of h-step-ahead forecast data at time t in each regime and using steady-state probabilities, we present an h-step-ahead point forecast of data. An empirical application of this forecasting technique for U.S. Dollar/ Euro exchange rate showed that Markov switching autoregressive model achieved superior forecasts relative to the random walk with drift. The results of out-of-sample forecast indicate that the fluctuations of U.S. Dollar/ Euro exchange rate from May 2011 to May 2013 will be rising.
MeSH terms: Forecasting; Probability; Research; United States; Walking
There are numerous parametric models for analyzing survival data such as exponential, Weibull, log-normal and gamma. One of such models is the Gompertz model which is widely used in biology and demography. Most of these models are extended to new forms for accommodating different types of censoring mechanisms and different types of covariates. In this paper the performance of the Gompertz model with time-dependent covariate in the presence of right censored data was studied. Moreover, the performance of the model was compared at different censoring proportions (CP) and sample sizes. Also, the model was compared with fixed covariate model. In addition, the effect of fitting a fixed covariate model wrongly to a data with time-dependent covariate was studied. Finally, two confidence interval estimation techniques, Wald and jackknife, were applied to the parameters of this model and the performance of the methods was compared.
The effect of composition on nickel cobaltites prepared by co-precipitation was investigated. Various compositions were synthesised under different heat treatment conditions. The formation mechanism, lattice parameter and crystallite size were determined by various techniques. X-ray diffraction (XRD) analysis revealed that the optimum condition for the formation of single phase nickel-cobalt oxide (NiCo2O4) can be obtained from solution containing Ni: Co ratio of 33.3 mol%: 66.7 mol% with heat treatment at 400 °C. The presence of pure phase NiCo2O4 with the particle size of approximately 34.10 nm was also observed in field emission scanning electron microscopy (FESEM). The crystallinity of the synthesized oxides was improved with the increment of Ni content.
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.
Culturing Macaca fascicularis bone marrow stem cells in fetal bovine serum (FBS) resulted in low proliferation and long period of incubation. Therefore, its potential uses are exhausted. Here we report the establishment of culturing the Macaca fascicularis bone marrow stem cells using the FBS in combination with autologous serum. Five percent autologous serum was added to the Minimum Essential Medium (MEM) alpha medium and 10% FBS while 0.2 mM acid ascorbic 2-phosphate, 10 mM β-glycerolphosphate, 10-8 molar dexamethasone were used for osteogenic induction. Following this combination, our results showed higher growth kinetic i.e. 1.41% growth rate higher compared to only 0.46% growth rates of the cells using FBS alone and shorter population doubling time (4 to 7 days) compared to the culture without the combination of FBS and autologous serum (30 days). Thus, the combination of the FBS and autologous serum permits fast cell growth and tissue construction.
In this study, the Hg levels in eight parts of Asystasia gangetica (L.) T. Anderson collected from 14 sites were determined using a Mercury Atomizer MA-1S and a Mercury Detector MD-1. It was found that the ranges for all the parts were 3.21-18.2 μg/kg dry weight for flowers, 1.29-11.2 μg/kg dry weight for stalks, 0.32- 29.4 μg/kg dry weight for seeds, 0.87-10.2 μg/kg dry weight for pericarps, 1.45-18.1 μg/kg dry weight for remainders, 11.8-68.2 μg/kg dry weight for leaves, 0.73-20.9 μg/kg dry weight for stems, and 3.40-33.1 μg/kg dry weight for roots. The overall Hg accumulation pattern in decreasing concentrations was leaf > root > flower > flower remains > stalk > stem > pericarp > seed. This study provided the background levels of Hg in this non-native invasive weed species in Malaysia. However, further studies are needed to confirm it as a biomonitors of Hg in this region.
In this study, heavy metal data (including four geochemical fractions) from offshore and intertidal sediments collected off the west coast of Peninsular Malaysia were analyzed using factor analysis. A similarity was found when comparing between offshore and intertidal sediments, where out of the 20 variables, five factors (resistant Cu, total Cu, resistant Pb, total Pb and total Zn) could be clearly selected on the basis of their high loadings as derived by factor analysis in both sediment sampling areas. However, the statistical outputs based on the present study using factor analysis cannot be practically acceptable mainly because the resistant fractions are not of anthropogenic origins and ecotoxicologists are more concern on the anthropogenic ones. Only a modification using a specific normalizing agent such as the nonresistant fraction, should be tested to show feasibility of the contribution of anthropogenic sources in the two sampling areas. However, a more comprehensive metal monitoring data should be compiled to complement the results obtainable from factor analysis, before a valid Malaysian Marine Sediment Pollution Index or Sediment Quality Guidelines, can be proposed to be established.
Given any semigroup presentation, we may obtain the diagram group. The purpose of this paper is to determine the graphs Γn(P), (n ∈ N), which are obtained from diagram group for the union of two semigroup presentations of integers with s and t different initial generators. The number of vertices and edges in these graphs will be computed.
Pengaruh rawatan haba terhadap mikrostruktur katod berliang Ag2O3-Bi2O3 di atas substrat keluli kalis karat telah dikaji. Komposit katod telah diendapkan ke atas substrat dengan menggunakan kaedah pengecatan sluri. Katod yang terhasil dirawat haba pada suhu 400, 500, 600, 700, 800 dan 830oC selama 1 jam dalam tekanan atmosfera. Analisis terma terhadap sluri kering telah dikaji untuk mendapatkan jadual pemanasan bagi penyingkiran komponen organik dengan menggunakan analisis termogravimetri (TGA) dan kalori imbasan kebezaan (DSC). Analisis TGA dan DSC mendapati penyingkiran komponen organik terjadi pada suhu di bawah 418oC dan fasa oksida komposit katod terbentuk pada suhu melebihi 600oC. Mikrostruktur katod terawat haba ditentukan dengan menggunakan mikroskop elektron imbasan (SEM) dan belauan sinar-X (XRD). Keputusan SEM menunjukkan yang saiz ira bagi katod meningkat dengan peningkatan suhu rawatan haba. Analisis pembelauan sinar-X mengesahkan kehadiran fasa δ-Bi2O3 di atas katod. Katod Ag2O3-Bi2O3 yang diendapkan di atas substrat keluli kalis karat dengan proses pengulangan salutan 1, 2, 3, dan 4 kali didapati masing-masing mempunyai keliangan 53%, 51%, 39% dan 28% setelah melalui proses rawatan haba pada suhu 800oC selama 1 jam.
Kajian ini dijalankan untuk membangunkan pandu gelombang optik menggunakan bahan fotopeka silika terdop fosforus. Teknik penyalutan mejam menggunakan sumber berbentuk cecair iaitu tetraetil ortosilikat, asid fosforik dan juga PBF untuk menghasilkan pandu gelombang fotopeka silika terdop fosforus dan boron. Pada ketebalan antara 1 μm hingga 8 μm, modulasi indeks biasan yang ditunjukkan di dalam bahan fotopeka silika terdop fosforon-boron adala 1×10-14 pada ketebalan 3 μm hingga 8 μm. Semua ujian dan rawatan fotopeka dilakukan dengan menggunakan sumber UV 366 nm, 0.369 mW/cm2 pada kadar denyutan 50 Hz. Semua sampel menunjukkan penurunan nilai indeks di bawah dedahan ini. Tempoh dedahan yang diperlukan dengan menggunakan kuasa UV yang berkenaan adalah kira-kira 10 minit. Dengan menggunakan penyurih laser ArF atau KrF yang berkuasa 10 mW misalnya, tempoh dedahan yang diperlukan adalah cuma 20 hingga 30 saat untuk mengubah indeks biasan pandu gelombang. Selain daripada itu, proses pemampasan juga dimasukkan yang bertujuan untuk memperbetulkan semula prestasi akibat daripada kesan toleransi semasa proses simulasi. Bagi memberikan kecekapan dalam pengukuran indeks biasan dan ketebalan lapisan BPSG, satu program antara muka penggunaan grafik dibangunkan untuk mempercepatkan dan meningkatkan kejituan bacaan yang diukur daripada pengganding prisma manual.
Kajian ini telah dijalankan untuk menyiasat kelakuan pasir penyambung turapan blok konkrit saling mengunci pada jarak sambungan dan kecerunan yang berbeza. Model di makmal yang berukuran 1.2×0.6 (m2) telah dibina dan blok konkrit daripada jenis quadpave yang bersaiz 200×100×60 (mm3) telah digunakan sebagai lapisan atas. Jarak sambungan yang digunakan adalah 2, 4 dan 6 mm dengan kecerunannya adalah 0, 5, 10 dan 15%. Uji kaji tarik keluar dijalankan untuk setiap keadaan. Hasil kajian menunjukkan jarak sambungan 2 mm adalah jarak sambungan yang paling sesuai untuk gunakan pada jalan yang bercerun. Semakin besar jarak sambungan, semakin menurun sifat penguncian antara blok konkrit. Ini berlaku di mana daya yang diperlukan untuk menarik blok keluar semakin mengecil apabila jarak sambungan semakin lebar. Kehadiran air dalam kuantiti yang sedikit menyebabkan pasir pengisi menjadi lebih mampat tetapi apabila air terlalu banyak, hakisan akan berlaku. Kajian ini mencadangkan kecerunan maksimum penggunaan turapan blok konkrit saling mengunci adalah sehingga 10% untuk mengelakkan hakisan pasir pada penyambung dan juga penurunan sifat penguncian antara blok konkrit.