Goniothalamin produced by the Malaysian medicinal plant, Goniothalamus andersonii J. Sinclair, strongly inhibits plant growth. However, its mode of action has not been characterized at the gene expression level. We conducted DNA microarray assay to analyze the changes in early gene responses of Arabidopsis thaliana seedlings. After a 6-h exposure to goniothalamin, we observed an upregulation of genes highly associated with heat response, and 22 heat shock protein (AtHSP) genes were upregulated more than 50 fold. Together with these genes, we observed upregulation of the genes related to oxidative stress and protein folding. Also, the genes related to cell wall modification and cell growth, expansin (AtEXPA) genes, were significantly downregulated. The results suggested that goniothalamin induces oxidative stresses and inhibits the expression of cell wall-associated proteins resulting in growth inhibition of Arabidopsis seedlings.
In this paper, ambient total suspended particulates (TSP) with a focus on humic-like substances (HULIS) are characterized based on intensive ground-based field samplings collected in Malaysia during non-haze and haze periods caused by peatland fires on the Indonesian island of Sumatra. Furthermore, concentrations of water-soluble organic carbon (WSOC) and carbon content of HULIS (HULIS-C) were determined, and fluorescence spectra of the HULIS samples were recorded by excitation emission matrix (EEM) fluorescence spectroscopy. The concentrations of WSOC and HULIS-C over the entire period ranged from 4.1 to 24 and 1.3 to 18 μgC m-3, respectively. The concentrations of WSOC and HULIS-C during the peatland fire-induced strong haze periods were over 4.3 and 6.1 times higher, respectively, than the average values recorded during the non-haze periods. Even during the light haze periods, the concentrations of WSOC and HULIS-C were significantly higher than their averages during the non-haze periods. These results indicate that peatland fires induce high concentrations of WSOC, particularly HULIS-C, in ambient TSP at receptor sites. EEM fluorescence spectra identified fulvic-like fluorophores at the highest intensity level in the EEM fluorescence spectra of the haze samples. A peak at excitation/emission (Ex/Em) ≈ (290-330)/(375-425) nm is also observed at high intensity, though this peak is normally associated with marine humic-like fluorophores. It is shown that a peak at Ex/Em ≈ (290-330)/(375-425) nm is not derived from marine sources only; furthermore, peatland fires are shown to be important contributors to HULIS around this peak.
This study was designed to evaluate efficacy and safety of aripiprazole once-monthly (AOM) by verifying non-inferiority of AOM to oral aripiprazole in Asian patients with schizophrenia.
It is essential to predict the mining-induced subsidence for sustainable mine management. The maximum observed subsidence having a noticeable areal extent due to Northern Upper Panels (NUP) and Southern Lower Panels (SLP) at the Barapukuria longwall coal mine is 5.8 m and 4.2 m, respectively, after the extraction of a 10 m thick coal seam. The mining-induced subsidence was simulated by the Displacement Discontinuity Method. The numerical model considered the effects of the ground surface, mining panels, faults, and the dyke. The predicted and the observed subsidence due to the mining of NUP and SLP were compared by varying Young's modulus, and the 0.10 GPa Young's modulus was found to be the best match in the geo-environmental condition. The effects of the faults and the dyke in the calculation were negligible. Future subsidence was predicted by considering 30 m extraction of the thick coal seam as 15.7-17.5 m in NUP and 8.7-10.5 m in SLP. The vulnerable areas demarcated considering the tilt angle and extensile strain might extend up to the coal mine office area and some villages.
Slope failures in Bangladesh's Chittagong division are a growing concern, with fatalities increasing from 19 in 2000 to 162 in 2017 and projected to rise further. This study aims to identify the most vulnerable rock formation and assess Carboxymethyl Cellulose (CMC) as a solution for enhancing shale strength and mitigating slope failures. The research began by evaluating weathering susceptibility and stability of different rock layers, revealing the high instability of shale in the Bhuban Formation. Slake durability tests measured cation concentration to understand shale instability mechanisms. Laboratory experiments, including immersion tests and grained-and-molded shale specimens, examined CMC's potential to improve shale stability. Results indicated that the shale of the Bhuban Formation had the highest hammer value variations, indicating increased weathering susceptibility. Shale instability was attributed to illite layer dissolution, releasing K+. Intact shale specimens treated with CMC showed enhanced penetration resistance, shear strength, and deformation behavior, suggesting CMC's potential in increasing shale stability. Grained-and-molded shale specimens treated with CMC demonstrated increased shear strength, critical shear displacement, and contraction deformational behavior. Optical microscopy and scanning electron microscopy revealed the formation of cross-links between shale grains, contributing to improved shale stability. Further research is needed to explore the application of CMC for enhancing in situ rock slope stability. This study emphasizes the importance of addressing slope failures in the Chittagong division and provides insights into mitigating the risks through CMC-based interventions.
A crude methanol extract of Goniothalamus andersonii J. Sinclair strongly inhibited elongation of lettuce (Lactuca sativa L.) radicles. We conducted bioassay-guided purification of G. andersonii bark extract and obtained goniothalamin as the major bioactive compound. Its EC50 values against elongation of lettuce radicles and hypocotyls were 50 and 125 micromol L(-1), respectively. Among the six species tested, timothy was the most sensitive to goniothalamin. Quantification of this compound in other Goniothalamus species suggested that the plant inhibitory activity of this genus is explainable by goniothalamin, with G. calcareus as an exception.
This study aimed to determine the distribution and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Kuala Lumpur during different monsoon seasons. The potential sources of PM2.5 were investigated using 16 priority PAHs with additional of biomass tracers namely levoglucosan (LV), mannosan (MN) and galactosan (GL). This study also investigated the cytotoxic potential of the extracted PAHs towards V79-4 cells. A high-volume air sampler (HVS) was used to collect PM2.5 samples for 24 h. PAHs were extracted using dichloromethane (DCM) while biomass tracers were extracted by a mixture of DCM/methanol (3:1) before analysis with gas chromatography-mass spectrometry (GC-MS). The cytotoxicity of the PAHs extract was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The results showed that the total mean ± SD concentrations of PAHs during the southwest (SW) and northeast (NE) monsoons were 2.51 ± 0.93 ng m-3 and 1.37 ± 0.09 ng m-3, respectively. Positive matrix factorization (PMF) using PAH and biomass tracer concentrations suggested four potential sources of PM2.5; gasoline emissions (29.1%), natural gas and coal burning (28.3%), biomass burning (22.3%), and diesel and heavy oil combustion (20.3%). Health risk assessment showed insignificant incremental lifetime cancer risk (ILCR) of 2.40E-07 for 70 years of exposure. MTT assay suggested that PAHs extracts collected during SW monsoon have cytotoxic effect towards V79-4 cell at the concentrations of 25 μg mL-1, 50 μg mL-1, 100 μg mL-1 whereas non-cytotoxic effect was observed on the PAHs sample collected during NE monsoon.