6 research outputs found
The seasonal cycle and variability of sea level in the South China Sea
The spatial and temporal characteristics of the seasonal sea level cycle in the South China Sea (SCS) and its forcing mechanisms are investigated using tide gauge records and satellite altimetry observations along with steric and meteorological data. The coastal mean annual amplitude of the seasonal cycle varies between zero and 24 cm, reaching a maximum between July and January. The maximum mean semiannual amplitude is 7 cm, peaking between March and June. Along the coast, the seasonal cycle accounts for up to 92% of the mean monthly sea level variability. Atmospheric pressure explains a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by the local wind shows annual amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with the maximum annual amplitudes reaching 15 cm. Significant variability in the seasonal cycle is found on a year-to-year basis. The annual and semiannual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 66% of the temporal variability of the annual cycle. The zonal wind was found to exert considerable influence in the Malacca Strait
Development of an immunochromatographic lateral flow dipstick for the detection of Mycobacterium tuberculosis 16 kDa antigen (Mtb-strip)
Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that causes tuberculosis (TB). This contagious disease remains a severe health problem in the world. The disease is transmitted via inhalation of airborne droplets carrying Mtb from TB patients. Early detection of the disease is vital to prevent transmission of the infection to people in close contact with the patients. To date, there is a need of a simple, rapid, sensitive and specific diagnostic test for TB. Previous studies showed the potential of Mtb 16 kDa antigen (Ag16) in TB diagnosis. In this study, lateral flow immunoassay, also called simple strip immunoassay or immunochromatographic test (ICT) for detection of Ag16 was developed (Mtb-strip) and assessed as a potential rapid TB diagnosis method. A monoclonal antibody against Ag16 was optimized as the capturing and detection antibody on the Mtb-strip. Parameters affecting the performance of the Mtb-strip were also optimized before a complete prototype was developed. Analytical sensitivity showed that Mtb-strip was capable to detect as low as 125 ng of purified Ag16. The analytical sensitivity of Mtb-strip suggests its potential usefulness in different clinical applications
Composition of Plecoptera (Insecta) fauna in rivers at different altitudes of high mountain in Peninsular Malaysia
The composition of Plecoptera species in rivers at different altitudes in Malaysia is not well understood. Therefore, a study
on the diversity of stonefly (Plecoptera) was carried out at Gunung Jerai, Kedah, and Gunung Ledang, Johor. The data were
collected from three streams for each Gunung Ledang and Gunung Jerai making a total of six streams; Tupah, Bt Hampar,
and Teroi rivers from Gunung Jerai while, Ulu Jementah, Jeram Tinggi, and Anak Air Puteh rivers from Gunung Ledang.
Plecoptera nymphs were collected using the kick-net sampling technique. All rivers from both mountains recorded five genera
out of three families but Kamimuria was found only in Gunung Jerai while Phanoperla was found in a river at Gunung
Ledang. Anak Air Puteh River (975 m a.s.l.) recorded the greatest diversity of plecopterans genus (4) while Tupah River
(200 m a.s.l.), reported the most diverse plecopterans at Gunung Jerai (4). Based on correlation analysis, the plecopterans
composition is influenced by water temperature, pH, altitudes, COD, and BOD (p<0.05). Low pH values (acidic) at the
highest region for both mountains (Teroi and Anak Air Puteh rivers) allowed an acid-tolerant plecopterans (Nemouridae) to
thrive in those rivers. The decreasing diversity of Plecoptera taxa from low to high altitudes were affected by the water
physicochemical parameters that vary in altitudes, and probably due to the type of vegetative structures
Selective in vitro cytotoxic effects of piroxicam and mefenamic acid on several cancer cells lines.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) are heterogenous group of compounds used to cure and prevent inflammation. It was demonstrated that NSAIDs has the ability to inhibit the viability of colon cancer cells in vitro. We investigated the effects of Piroxicam and mefenamic acid on the viability of 4 cancer cell lines in which 2 of them are colon cancer cell lines (HCT 116 and CaCo-2). Cell viability was determined using MTT assay. Both NSAIDs was observed to markedly decrease the cell viability of both cell lines (HCT 116 and CaCo-2). Piroxicam was statistically more cytotoxic towards the cancer cell lines when compared to mefenamic acid. However, the cytotoxic effect of NSAIDs was less potent on breast cancer cells (MCF-7) and liver cancer cells (Hep G2). In conclusion, piroxicam and mefenamic acid showed selective cytotoxic effects against colon cancer cells but not against liver or breast cancer cells
Evaluation of the antinociceptive activity of Ficus deltoidea aqueous extract.
The aqueous extract of Ficus deltoidea leaves was evaluated for possible antinociceptive activity in three models of nociception, namely, acetic acid-induced abdominal writhing, formalin and hot plate test. The results of the present study showed that intraperitoneal administration of the F. deltoidea leaves aqueous extract at the dose of 1, 50 and 100 mg/kg, 30 min prior to pain induction produced significant dose-dependent antinociceptive effect in all the models used, which indicating the presence of both central and peripherally mediated activities. Furthermore, the antinociceptive effect of the extract in the formalin and hot plate test was reversed by the non-selective opioid receptor antagonist naloxone suggesting that the endogenous opioid system is involved in its analgesic mechanism of action. Thus, the present results demonstrated that F. deltoidea leaves aqueous extract contains pharmacologically active constituents which possess antinociceptive activity justifying its popular therapeutic use in treating conditions associated with the painful conditions