Rice straw open burning: emissions, effects and multiple benefitsof non-burning alternatives

Rice is one of the most important staple foods not just to people in Asia, but around the world. To meet domestic and export demands, farmers in Southeast Asia (SEA) grow 2-3 crop cycles per year, which leaves only a short period for land preparation. Field open burning of rice straw has been widely practiced to quickly clear the surface biomass for the next crop planting. However, this uncontrolled open combustion of rice straw releases large amounts of toxic air pollutants including key conventional pollutants along with carcinogenic compounds like dioxins, polycyclic aromatic hydrocarbons, and benzene, as well as major climate forcing agents. Emissions from rice straw open burning (RSOB) have been shown to significantly elevate ambient levels of PM2.5 and surface ozone in adjacent urban areas. During the dry season, when stagnant meteorological conditions are prevalent, intensive open burning activities further intensify haze episodes. Rice straw, however, is a valuable resource that should be recovered and not disposed of by open burning. Indeed, several non-open burning alternatives are available that would bring in multiple benefits to air quality, climate, health, and economy. For example, the production of rice straw fuel pellets for cooking in clean gasifier cookstoves is one promising option. For the successful elimination of RSOB in SEA, technology development along with formulation and implementation of appropriate policies should be in place to mobilise active participation from all stakeholders.

Study on α-glucosidase inhibitory activity of 40 kinds of vegetables, tubers, and fruits in An Giang

A study on the α-glucosidase inhibitory activity of 40 kinds of vegetables, tubers, and fruits found in the An Giang province was conducted. The results indicated that all 40 extracted samples displayed α-glucosidase inhibitory activity at a concentration of 250 μg ml-1, 36 extracted samples showed an inhibition rate greater than 50% at 250 μg ml-1, 25 extracted samples had over 50% at 100 μg ml-1, 17 extracted samples possessed more than 50% at 50 μg ml-1, 7 extracted samples sampled showed over 50% at 25 μg ml-1, 5 extracted samples were greater than 50% at 10 μg ml-1, and 1 extracted sample was greater than 50% at 1 μg ml-1. Among the 40 samples, those taken from the seeds of Areca catechu, the fruits of Cassia grandis, the fruits of Syzygium cumini, the seeds of Glycine max,andthe stems of Enydra fluctuansexhibited the strongest α-glucosidase inhibitory activity in methanol, with IC50 values of 0.15, 2.54, 4.05, 5.17 and 8.68 μg ml-1, respectively, which were stronger than the positive control acarbose with an IC50 value of 214.5 μg ml-1

Effects of different shrimp extracts on Vibrio parahaemolyticus growth and virulence

Vibrio parahaemolyticus is the main causative agent of acute hepatopancreatic necrosis disease (AHPND) in shrimp. This study aimed to investigate how shrimp extracts affect the growth and virulence of an AHPND-causative strain known as V. parahaemolyticus XN9. To this end, the bacteria was cultured in media containing 3% extract of each of five shrimp types and their growth kinetics were compared against that from bacteria grown in brain-heart infusion (BHI) media. Eight-hour growth curves were constructed using the plate-counting method. The activity of five extracellular enzymes that contribute to bacterial virulence was examined using the agar-based method. The results showed that V. parahaemolyticus XN9’s growth was strongly enhanced in all five shrimp extract media with the highest increase (25% greater than the BHI medium) found in the giant tiger prawn extract. Additionally, all the shrimp extracts boosted the extracellular enzymatic activity of V. parahaemolyticus XN9, although to different extents. In summary, the shrimp extracts, particularly that from the prawns, not only promoted the viability and growth of V. parahaemolyticus XN9 but also its extracellular enzymatic activities.

Establishing 3D hydrogeological solid model and database for sustainable groundwater management in the Vietnam Mekong delta

The Vietnam Mekong delta (VMD) is a tide-dominated delta formed by the Mekong river system. The sediments are dominantly fine grained and were deposited in the receiving basin with slight inclination of pre-existing deposits in the East sea and gulf of Thailand. The VMD is homeland to about 18 million people that exploit about 4-6 million m3/day of groundwater mainly for domestic use. In recent years, significant groundwater depletion has been occurring in many parts of the VMD due to excessive pumping. Consequently, the VMD has become increasingly faced with serious land subsidence, salt groundwater intrusion, and contamination. Establishing a 3D hydrogeological solid model and database are sorely needed to achieve sustainable groundwater management, and to serve as a basis for further in-depth analyses to quantify contributions from the above-mentioned hazards to current hydrogeological conditions. Therefore, a 3D hydrogeological solid model and database were built based on more than 1000 well logs available from the VMD. An areal distribution of the Holocene, Pleistocene, Pliocene, and Late Miocene subsurfaces from this 3D hydrogeological solid model and database showed zones of tectonic depression and uplift from Early Miocene - Quaternary. Also, the resulting areal distribution aquitards and aquifers thicknesses gave hints of ground saltwater intrusion and contamination.

Induction and evaluation of secondary metabolite and antioxidant activity in adventitious root of Codonopsis javanica

In this study, the effects of auxin (IBA, NAA), explants, and culture conditions (light/dark) on adventitious root induction of Codonopsis javanica were investigated. The results showed that dark conditions were more suitable for adventitious root induction than light conditions. All three types of explants (internodes, leaves, and nodes) induced adventitious roots, and the appropriate concentration of auxin was 0.5 mg/l IBA. After 4 weeks of incubation under dark conditions, the rooting percentage and number of roots/explant of internode, leaf, and node segments on media supplemented with 0.5 mg/l IBA were 100% and 33.87 roots, 97.78% and 23.48 roots, 100% and 25.20 roots, respectively. These adventitious roots were analysed for the presence of alkaloids, carbohydrates, saponin, fixed oils and fats, phenol, flavonoids, gum, and mucilage. The total polysaccharide content, total phenolic content, and the antioxidant activity (IC50) of C. javanica adventitious root biomass were 16.98%, 1.876 (mg GAE/g DW), and 2.44 (mg/ml), respectively. These results indicate that the adventitious roots of C. javanica contain bioactive compounds, which can be used as a material source for multiplication in large-scale systems.

Physicochemical parameters and mineral components in Vietnam honey as a promising tool for classifying biological origin of honeys

Honey is known as a natural sweetener agent with high nutritional value and health benefits, especially premium honey because of its desirable flavour and medicinal properties. Because of this, honey has been a target of adulteration through the mixing of low-quality honey and mislabelling of the honey’s origin. The aim of this research considers the potential of using mineral and physicochemical data to authenticate the origin of honey. To this end, 40 samples of 8 botanica collected from 18 different regions of Vietnam were analysed for its metal contents (Na, K, Mg, Ca, Al, Cu, Fe, Mn, Zn, Pb, Cd, Ni, Cr, Co, As, Hg) and physicochemical parameters (pH and electrical conductivity). The data were processed by multivariate analysis, which allowed the classification of honey according to its botanical origin.

An empirical relationship between PM2.5 and aerosol optical depth from MODIS satellite images for spatial simulation over Ho Chi Minh city

Air quality in megacities has been a pressing concern of environmental managers and scientists for decades. Indeed, particulate matter (PM), especially PM2.5, is considered a dangerousparticle that is harmful to human health. The current sparse monitoring network in Ho Chi Minh city (HCMC) does not accurately reflect the spatial distribution of fine particles in ambient air. Therefore, this research examines the relationship between ground-based station data and aerosol optical depth (AOD) imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra/Aqua satellite to establish a PM2.5 distribution map of HCMC. PM2.5 concentration values monitored from two ground stations were collocated by time and space with Terra/MODIS AOD data from the period of 2016-2020. Pairs of values were checked for correlation and then fit to several regression functions. The most suitable function was chosen to simulate the quantified PM2.5distributions in the study area. A high correlation between PM2.5 concentrations and AOD at the wavelength of green light (R2=0.810) was found with a linear regression model. The results showed that the highest concentration of PM2.5 was in February, and the mean value was higher than QCVN 05:2013 (32.5 μg/m3compared with 25 μg/m3, annual mean). These results support the need for essential air quality monitoring in HCMC.

Clinical and subclinical characteristics of brain-dead donors for liver transplantation in Viet Duc University Hospital

Since 2010, 49 cases of liver transplants from brain-dead donors were performed at Viet Duc University Hospital. This study is a descriptive cross-section cohort study with a combined analysis of retrospective and prospective occurrences of a series of cases of liver procurement from brain-dead donors in Viet Duc University Hospital from March 2010 to March 2020. The results of this study showed several features: the average age of the brain-dead donors was 29.8±10.9 (18-69), donors were mostly male (7.17/1, 87.8%), and the main cause of brain death was head trauma. Clinically, 40.8 and 63.3% of the subjects were hypothermic and diagnosed with diabetes insipidus, however, the subjects were all well resuscitated before procurement. Therefore, haemodynamic indices and temperatures were maintained at stable levels and there was no statistically significant difference. In subclinical aspects, haemoglobin and platelet levels decreased significantly but remained within the target criteria during resuscitation while blood sodium levels increased significantly during resuscitation when compared with levels at the time of admission (p<0.001) thus corresponding to diabetes insipidus. In general, 44.90% of donors were within the ideal standard, and in the extended standard group, the highest rate was electrolyte disorders (32.65%). In conclusion, there are many variations in clinical and paraclinical body signs as well as homeostasis in the brain-dead donors. Of these signs, the most prominent were changes in haemodynamics, temperature, urine output, complete blood count, blood clotting, and blood sodium levels. These are all factors that are included in the criteria to consider the selection of a liver donor.

Evaluating the potential of aquaculture in the Hoa Binh reservoir with carrying capacity and water quality indices

Not only does the Hoa Binh reservoir play essential roles in water storage for electricity generation and flood regulation, but also it has great potential to aid aquaculture production. Presently, aquaculture production sits at around 9,200 tons/year; however, a recent MARD circular (#16 in 2015) estimated that maximum production would approach 10,000 tons/year in the productive photic zone. This paper supports increased capacity towards a sustainable commodity production model by optimizing production levels and farming practices. To reach this goal, it is necessary to determine water quality parameters using the Relative Water Quality Index (ReWQI) and carrying capacity (CC) analysis. Data was obtained from 30 sites at upstream, midstream, and downstream sections of the reservoir during the 2019 dry and wet seasons. The results from the ReWQI reflected good water quality potential (rated between 92-100) for aquaculture. The total nitrogen (TN) and total phosphorus (TP) levels of 10,794.9 kg/day and 1,965.4 kg/day, respectively, indicate high biological productivity resulting in strong fish growth potential. CC analysis and overall water quality reflect the potential for sustainable and increased productivity to 22,730.4 tons/year, which is an increase in production of over 13,200 tons/year compared to the current period. To reach a higher yield of 40 kg/year/m3 within each cage (5,040 kg/cage/year), the corresponding increase in number needs to be 4,510 cages based on a common cage size of 126 m3 (6x6x3.5 m). In order to reach these future production goals, this work concludes that the local government should begin spatial planning decisions based on appropriate cage allocation and distribution with respect for regular monitoring of water quality and nutrient load capacity of the environment to reach sustainable aquaculture development.

The antidepressant-like effects of an n-butanol fraction of Ocimum sanctum Linn. extract in unpredictable chronic mild stress-induced depression in mice

We previously reported that Ocimum sanctum Linn. (OS) ethanolic extract and its n-butanol fraction (OS-B) could improve depression-like behaviour in olfactory bulbectomized mice. The present study aims to clarify the antidepressant-like effects of OS-B and the possible mechanism of its action using mice subjected to unpredictable chronic mild stress (UCMS). UCMS mice were administered daily with OS-B (50 mg/kg, 100 mg/kg, p.o.) or imipramine (IMP, 8 mg/kg, i.p.), a reference drug. The UCMS-induced anhedonia in mice was analysed by the sucrose preference test, while behavioural despair was assessed using the tail suspension test (TST) and forced swimming test (FST). Locomotor activities and grooming behaviour of mice were elucidated using the open-field test (OFT). The UCMS procedure for 5 weeks induced anhedonia, and this symptom was significantly ameliorated by the administration of OS-B (100 mg/kg) as well as IMP during the UCMS period. Moreover, the OS-B and IMP treatment attenuated the UCMS-induced enhancement of behavioural despair in the TST and FST. In OFT, mice subjected to UCMS showed a decrease in grooming behaviour, and the effect of UCMS was reversed by OS-B and IMP administrations. No significant difference in locomotor activities between each animal group was observed. The amelioration effects of OS-B and IMP on UCMS-induced behavioural despair in the TST were abolished by administrating of ρ-chlorophenylalanine (PCPA, 80 mg/kg, i.p), a tryptophan hydroxylase inhibitor, and α-methyl-ρ-tyrosine (AMPT, 100 mg/kg), a tyrosine hydroxylase inhibitor. The present results suggest that OS-B attenuates UCMS-induced depression-like symptoms via monoaminergic systems including in the noradrenergic, dopaminergic, and serotonergic system