Magnesium-modified biochars for nitrate adsorption and removal in continuous flow system

Excess utilization of chemical fertilizers in agriculture has caused nitrate pollution to groundwater and watershed, which has raised urgent need for effectively removing nitrate from water. Biochar has been suggested as one of the most promising adsorbent materials to remove nitrate from aqueous solution. However, adsorption capacity of pristine biochar is limited; therefore, several modification methods have been proposed to improve the adsorption capacity of biochar for nitrate. Therefore, the objectives of this study were to evaluate effects of magnesium (Mg)-modified biochars on the adsorption capacity for nitrate and removal efficiency as the sole filter media in a continuous flow system (biofilter). Pristine biochars were pyrolyzed at 550°C from oak sawdust (OS) and water hyacinth (WH), and Mg-modified biochars were produced by soaking feedstock in MgCl2 solution followed by pyrolysis at the same temperature as the pristinebiochars (OS/Mg and WH/Mg, respectively). Mg-modified biochars showed 84%–89% greater adsorption capacity for nitrate than pristine biochars. The highest adsorption capacity for nitrate was 19.1 mg g–1 obtained from WH/Mg biochar. Flow direction in the biofilter did not affect nitrate removal efficiency of biochar, but slower flow speed was more efficient because nitrate had more retention time to find adsorption sites on biochar surface. When used in a continuous flowsystem, the total amount of nitrate removed by WH/Mg biochar in the biofilter represented 27%–30% of the maximum adsorption capacity of the biochar depending on flow direction and speed. Optimization of biofilter structure (size and packing layer) and flow mechanics (flow direction and speed) for the maximum nitrate removal by biochar needs to be considered when used in the continuous flow system

Hydrothermal carbonization of compressed water hyacinth: Effects of operation parameters on energy conversion and characterization of products

A massive infestation of a free-floating aquatic invasive plant, water hyacinth (Eichhornia crassipes) has been causing numerous problems in Ethiopia. Water hyacinth (WH) is mainly composed of lignin, crystalline cellulose, and hemicellulose polymer, thus its solid part can be used as a potential alternative energy source through thermochemical treatment. Hydrothermal carbonization (HTC) is a conversion of biomass into solid components of char (biochar) and carbon-rich liquid products (biooil and aqueous phase) by heating biomass in the presence of water in a closed and autogenous environment. The objective of this study was to evaluate the effects of various operating conditions on energy conversion efficiency and characteristics of the final products using water hyacinth through hydrothermal carbonization. Hydrothermal treatment was carried out at three different operating temperatures (210ºC, 240ºC, and 270ºC) for three different retention times (1, 2, and 4 hr) to obtain biochar, biooil, and aqueous phases. The study shows the possibility to convert WH biomass to biochar and biooil through HTC, where the best performance in energy conversion from both products was 64.5% at operating temperature of 240ºC and retention time of 4 hr. Operation temperature and retention time significantly affected yield and higher heating value of biochar and biooil. Biochar yield decreased and biooil yield increased with increasing operating temperature and retention time. However, there are still low yield of biooil which potentially contains high gross energy. Therefore, it is necessary to evaluate other variables such as type of feedstock, amount and type of liquid mixed with feedstock, and operating environment to improve energy conversion efficiency through hydrothermal carbonization

Regional flood dynamics in a bifurcating mega delta simulated in a global river model

In this paper we show the importance of bifurcation channels for flow in river mega deltas through the use of a new computational scheme implemented in the CaMa-Flood global hydrodynamic model. First, we developed a new river network map based on SRTM3 and HydroSHEDS which includes bifurcation channels. Next we implemented a new bifurcation scheme in CaMa-Flood capable of routing flow along this network and used the model to simulate the Mekong River. We show that in the Mekong delta such channels route about 50% of total flow, and that their representation is essential for realistic hydrodynamic simulations. A simulation without bifurcation channels was obviously unrealistic because no flow occurred between the mainstem and adjacent channels even when their water level difference was >6 m. The bifurcation channels are extracted from globally-available datasets, thus it is straightforward to expand the proposed scheme to global-scale studies

Mineral to matrix ratio determines biomaterial and biomechanical properties of rat femur : application of Fourier transform infrared spectroscopy

We studied the changes of biomaterial and biomechanical properties of the rat femur during development. Thirty male Wistar rats were allocated to 6 groups : aged 6 weeks (n=5), 9 weeks (n=5), 12 weeks (n=5), 15 weeks (n=5), 24 weeks (n=5), and 36 weeks (n=5). The mineral to matrix ratio (M/M ratio) of rat femur by Fourier transform infrared spectroscopy was 0.97 0.10 at the age of 6 weeks, and reached the maximum of 1.52 0.17 at the age of 36 weeks. Total bone mineral density (BMD) by peripheral quantitative computed tomography of the femoral shaft aged 6 weeks was 479.1 58.7 mg/cm3, and reached the maximum of 1022.2 42.3 mg/cm3 at the age of 36 weeks. The ultimate load to failure of the femur of the rat aged 6 weeks by the three-point bending test was 29.6 6.1 N. At the age of 36 weeks, the ultimate load to failure of the rat femur increased to the maximum of 283.5 14.7 N. The results showed that the M/M ratio increased with development as total BMD and bone strength increased. The results suggest that the M/M ratio is one of the determinants of the biomaterial and biomechanical properties of bone

Function of KAI2 signaling in plant drought adaptation

Drought causes substantial reductions in crop yields worldwide. Therefore, we set out to identify new chemical and genetic factors that regulate drought resistance in Arabidopsis thaliana. Karrikins (KARs) are a class of butenolide compounds found in smoke that promote seed germination, and have been reported to improve seedling vigor under stressful growth conditions. Here, we discovered that mutations in KARRIKIN INSENSITIVE2 (KAI2), encoding the proposed karrikin receptor, result in hypersensitivity to water deprivation. We performed transcriptomic, physiological and biochemical analyses of kai2 plants to understand the basis for KAI2-regulated drought resistance. We found that kai2 mutants have increased rates of water loss and drought-induced cell membrane damage, enlarged stomatal apertures, and higher cuticular permeability. In addition, kai2 plants have reduced anthocyanin biosynthesis during drought, and are hyposensitive to abscisic acid (ABA) in stomatal closure and cotyledon opening assays. We identified genes that are likely associated with the observed physiological and biochemical changes through a genome-wide transcriptome analysis of kai2 under both well-watered and dehydration conditions. These data provide evidence for crosstalk between ABA- and KAI2-dependent signaling pathways in regulating plant responses to drought. A comparison of the strigolactone receptor mutant d14 (DWARF14) to kai2 indicated that strigolactones also contributes to plant drought adaptation, although not by affecting cuticle development. Our findings suggest that chemical or genetic manipulation of KAI2 and D14 signaling may provide novel ways to improve drought resistance

AsiaPEX:Challenges and Prospects in Asian Precipitation Research

The Asian Precipitation Experiment (AsiaPEX) was initiated in 2019 to understand terrestrial precipitation over diverse hydroclimatological conditions for improved predictions, disaster reduction, and sustainable development across Asia under the framework of the Global Hydroclimatology Panel (GHP)/Global Energy and Water Exchanges (GEWEX). AsiaPEX is the successor to GEWEX Asian Monsoon Experiment (GAME; 1995-2005) and Monsoon Asian Hydro-Atmosphere Scientific Research and Prediction Initiative (MAHASRI; 2006-16). While retaining the key objectives of the aforementioned projects, the scientific targets of AsiaPEX focus on land-atmosphere coupling and improvements to the predictability of the Asian hydroclimatological system. AsiaPEX was designed for both fine-scale hydroclimatological processes occurring at the land surface and the integrated Asian hydroclimatological system characterized by multiscale interactions. We adopt six approaches including observation, process studies, scale interactions, high-resolution hydrological modeling, field campaigns, and climate projection, which bridge gaps in research activities conducted in different regions. Collaboration with mesoscale and global modeling researchers is one of the core methods in AsiaPEX. We review these strategies based on the literature and our initial outcomes. These include the estimation and validation of highresolution satellite precipitation, investigations of extreme rainfall mechanisms, field campaigns over the Maritime Continent and Tibetan Plateau, areas of significant impact on the entire AsiaPEX region, process studies on diurnal- to interdecadal-scale interactions, and evaluation of the predictabilities of climate models for long-term variabilities. We will conduct integrated observational and modeling initiative, the Asian Monsoon Year (AMY)-II around 2025-28, whose strategies are the subregional observation platforms and integrated global analysis.</p

Practical Science and Environmental Education Workshop in Manaus, Brazil

It is an unequivocal fact that Amazonian tropical forest is the largest remaining primary forest in the world. The ecosystem in the region is e tremely comple with high biodiversity (Peres et al. 2010). Conservation and protection of the dynamic forest and river regions is e tremely important not only for the natural environments, but also for the economy and social dependence of benefits from such abundant natural environments. Important natural parameters that affect status of the natural environments include light (natural sunlight), soil, and water, which abundantly e ist in the Amazon region. Solar energy is the primary energy source for the majority of living organisms in both terrestrial and aquatic ecosystems, and drives the diurnal and seasonal cycles of biogeochemical processes (Monteith & Unsworth 2013). In particular, in situ light data remains one of the most underappreciated data measurements although having a significant impact on the physical, chemical and biological processes in the ecosystem (Johnsen 2012). Soil provides the fundamental basis for all terrestrial living organisms including the Amazonian forests as well as life-sustaining infrastructure for human society. Water is the most essential single entity to constitute all organisms from a single cell to the earth. Understanding of importance and roles of each factor and interaction of such comple dynamics in the natural environments can serve as fundamental platform for natural scientists, particularly for young scientists such as university students. The objective of this workshop was to provide hand- on scientific and environmental education for university students in Manaus, Amazonas, Brazil through practical field measurements using the three most important parameters in the natural ecosystem composed of natural sunlight, soil, and water. The workshop was divided into a series of lectures, in situ field sampling, and data processing, analysis and interpretation with the ultimate goal of empowering the undergraduate students with research-centered environmental education and e perience of developing international collaboration.departmental bulletin pape

Spatial distribution and risk factors of Schistosoma haematobium and hookworm infections among schoolchildren in Kwale, Kenya

Background: Large-scale schistosomiasis control programs are implemented in regions with diverse social and economic environments. A key epidemiological feature of schistosomiasis is its small-scale heterogeneity. Locally profiling disease dynamics including risk factors associated with its transmission is essential for designing appropriate control programs. To determine spatial distribution of schistosomiasis and its drivers, we examined schoolchildren in Kwale, Kenya. Methodology/Principal findings: We conducted a cross-sectional study of 368 schoolchildren from six primary schools. Soil-transmitted helminths and Schistosoma mansoni eggs in stool were evaluated by the Kato-Katz method. We measured the intensity of Schistosoma haematobium infection by urine filtration. The geometrical mean intensity of S. haematobium was 3.1 eggs/10 ml urine (school range, 1.4?9.2). The hookworm geometric mean intensity was 3.2 eggs/g feces (school range, 0?17.4). Heterogeneity in the intensity of S. haematobium and hookworm infections was evident in the study area. To identify factors associated with the intensity of helminth infections, we utilized negative binomial generalized linear mixed models. The intensity of S. haematobium infection was associated with religion and socioeconomic status (SES), while that of hookworm infection was related to SES, sex, distance to river and history of anthelmintic treatment. Conclusions/Significance: Both S. haematobium and hookworm infections showed micro-geographical heterogeneities in this Kwale community. To confirm and explain our observation of high S. haematobium risk among Muslims, further extensive investigations are necessary. The observed small scale clustering of the S. haematobium and hookworm infections might imply less uniform strategies even at finer scale for efficient utilization of limited resources