The feedstock anatomical properties determine biochar adsorption capacities: A study using woody bamboos (Bambuseae) and methylene blue as a model molecule.

Feedstock characteristics impact biochar physicochemical properties, and reproducible biochar properties are essential for any potential application. However, in most articles, feedstock aspects (i.e., taxonomic name of the species, part of the plant, and phenological phase) are scarcely reported. This research aimed at studying the effect of species and phenological stage of the feedstock on the properties of the derived biochars and, thus, adsorption capacities in water treatment. In this study, we analysed the anatomical characteristics of three different woody bamboo species [Guadua chacoensis (GC), Phyllostachys aurea (PA), and Bambusa tuldoides (BT)] in culms harvested at two different phenological phases (young and mature), and statistically correlated them with the characteristics of the six derived biochars, including their adsorption performance in aqueous media. Sclerenchyma fibres and parenchyma cells diameter and cell-wall width significantly differed among species. Additionally, sclerenchyma fibres and parenchyma cell-wall width as well as sclerenchyma fibre cell diameters are dependent on the phenological phase of the culms. Consequently, differences in biochar characteristics (i.e., yield and average pore diameter) were also observed, leading to differential methylene blue (MB) adsorption capacities between individuals at different phenological phases. MB adsorption capacities were higher for biochar produced from young culms compared to those obtained from matures ones (i.e., GC: 628.66 vs. 507.79; BT: 537.45 vs. 477.53; PA: 477.52 vs. 462.82 mg/g), which had smaller cell wall widths leading to a lower percentage of biochar yield. The feedstock anatomical properties determined biochar characteristics which modulated adsorption capacities.

Prevalence of infection with hantavirus in rodent populations of central Argentina.

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3% for a total sample of 291 A. azarae and 13.5% for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today.

Prevalence of infection with hantavirus in rodent populations of central Argentina

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3 percent for a total sample of 291 A. azarae and 13.5 percent for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today