Surfactant-Assisted Sono-breakage of Wastewater Particles for Improved UV Disinfection

Ultraviolet (UV) disinfection of wastewater is adversely affected by the presence of particle-associated bacteria. Earlier studies have shown that disrupting these particles by ultrasonic cavitation can enhance the UV disinfection of wastewater. However, the use of ultrasound as a pretreatment technology for UV disinfection is hindered by its high energy demand. In this work, the addition of several organic solutes, including 1-propanol, 1-hexanol, and pentyl acetate, to promote the cavitation process and to improve the breakage of wastewater particles was examined. It was found that the enhancement in the cavitation and the breakage efficiency of particles was positively related to the hydrophobicity of surfactant. In addition, particle breakage was a function of the concentration of surfactant as well as the delivered ultrasound energy density. Sonication of wastewater samples containing small amounts of 1-hexanol (16 mM) or pentyl acetate (12 mM) increased the UV disinfection efficiency and decreased the required UV dose to achieve the disinfection target by a factor of more than 2.5.     

Evaluation of intra-ring wood density profiles using NIRS: comparison with the X-ray method

Key message

Pith-to-bark wood density profiling is interesting in forestry science. By comparing it with the X-ray method, this study proved that a fiber optic NIR spectrometer with a high-precision displacement system could accurately measure intra-ring wood density with a spatial resolution of 0.5 mm.

Context

Most near-infrared spectroscopy (NIRS) studies for wood density determination use samples that have been pulverized beforehand. Attenuation of ionizing radiation is still the standard method to determine wood density with high spatial resolution. However, there is evidence that NIRS could be an accurate and affordable method for determining intra-ring density in solid wood strips.

Aims

In this study, we research whether the results published for intra-ring density predictions in wood can be improved when calibrated with X-ray microdensitometry.

Methods

The measurements were made using a fiber optic probe with a separation between measurement points of 0.508 mm in a range between 1200 and 2200 nm. A total of 4520 density points were used to create partial least squares regression (PLSR). X-ray densitometry data were used as reference values. Twenty PLSR calibrations were randomly executed on 31 samples collected from 28 Pinus radiata D. Don trees.

Results

Upon selecting 20 latent variables, the R ² value was 0.873 for the training group and 0.895 for the validation group, while RMSEP values are 43.1 × 10^?3 and 47.1 × 10^?3 g cm^?3 for the training and validation groups, respectively. The range error ratio (RER) was 13.7.

Conclusion

The RER was high and almost in the range suggested for quantification purposes. Results are superior to wood density studies in the literature which do not employ spatial resolution and to those found in studies using hyperspectral imaging.

     

Proper supply of S increases GSH synthesis in the establishment and reduces tiller mortality during the regrowth of Tanzania guinea grass used for Cd phytoextraction

Purpose

Cadmium has caused serious environmental problems due to its phytotoxicity, requiring solutions to reduce its concentration in the environment. Because S can alleviate the phytotoxicity caused by heavy metals, the evaluation of the effects of S supply is a promising approach to address this problem. The aim of this study was to determine the influence of S in reducing the phytotoxicity caused by Cd to Panicum maximum Jacq. cv. Tanzania (guinea grass) and to evaluate the potential of this grass for Cd phytoextraction.

Materials and methods

Tanzania guinea grass was cultivated in a nutrient solution to evaluate the combinations of five rates of S (0.1, 1.0, 1.9, 2.8, and 3.7 mmol L^?1) and five rates of Cd (0.0, 0.5, 1.0, 1.5, and 2.0 mmol L^?1), in a 5² fractional factorial design with six replications. Six plants were grown per pot in two growth periods to evaluate the effect of Cd on the establishment (51 days of age) and on the regrowth (18 days of growth) of the plants. During regrowth, Cd was not supplied in the nutrient solution. At the end of each growth period, growth parameters, concentrations of S and Cd, Cd transport factor, and concentrations of hydrogen peroxide (H₂O₂), malondialdehyde, reduced glutathione, and oxidized glutathione were evaluated.

Results and discussion

On the establishment of Tanzania guinea grass, application of Cd reduced mass production by 39 % due to the increases in the concentration of Cd (30 times compared with the treatment without Cd) and in lipid peroxidation (124 %). During regrowth, the residual effect of Cd resulted in a lower number of tillers (62 %) and leaves (89 %) caused by the increase in concentrations of Cd, H₂O₂ (49 %), and lipid peroxidation, which resulted in a 65 % lower dry mass production. The proper supply of S reduced concentration of Cd and tiller mortality rate due to the residual effect of Cd on the regrowth of the grass. Mass production by the roots was 43 % lower because of Cd, but the transport of Cd from roots to shoots increased. The increase in the concentration of glutathione (GSH) associated with a possible higher activity of antioxidant enzymes alleviated the phytotoxic effects of Cd on the guinea grass.

Conclusions

The supply of S reduces the phytotoxicity caused by Cd to guinea grass, especially during the regrowth of the plant, when the concentration of Cd is higher because of the transport from roots to shoots. Tanzania guinea grass showed to be very promising for phytoextraction of Cd due to its high mass production, even when Cd was largely available in the nutrient solution.

     

Plant characteristics mediated by growing conditions can impact parasitoid’s ability to attack host aphids in winter canola

Winter canola (Brassica napus) is an important crop in various parts of the world. It is planted in fall, vernalized during winter and offers higher yields than spring canola. One of the key aphid pests of this crop is Myzus persicae Sulzer (Homoptera: Aphididae). Recent surveys in Europe showed that M. persicae in winter canola is parasitized by Aphidius matricariae and Diaeretiella rapae, but not by other aphidiine parasitoid species known to attack M. persicae in other crops. During vernalization, winter canola plants acclimatize to survive specific climatic conditions of winter, e.g. through the formation of epicuticular waxes on leaves. These waxes could affect efficiency on natural enemies. In this study, we characterized (1) the ability of aphidiine parasitoids to locate and attack M. persicae on winter canola, and (2) how plant vernalization influences parasitoid ability to attack suitable hosts. In the laboratory, the ability of A. ervi, A. matricariae and D. rapae to orient toward odors of the M. persicae-winter canola complex was studied in an olfactometer, as well as their ability to attack M. persicae on winter canola. In addition, the impact of plant species and plant vernalization on the ability of A. colemani to attack and locate M. persicae was evaluated. The results show that A. matricariae and D. rapae readily locate and attack M. persicae on winter canola as does A. ervi, albeit to lesser extent. Aphidius colemani shows low ability to parasitize M. persicae on this plant species. Vernalization of canola is an important factor mediating the ability of A. colemani to attack M. persicae and it likely results from the presence of Brassica’s waxes that reduce parasitoid mobility and impact foraging behavior. These results show that aphid parasitoids differ in their ability to locate and attack M. persicae on winter canola, the latter being a function of parasitoids’ capacity to cope with plant characteristics that are mediated by growing conditions.     

Effect of three bacterial isolates from a commercial hatchery on early red abalone (Haliotis rufescens) postlarvae

Three bacterial strains, GHrC11, GHrC13 and GHrC15, were isolated from an abalone postlarval culture system in a commercial farm at Baja California, México. The strains were phenotypically characterized and sequenced (16S rDNA). Strain GHrC11 was a Gram-positive coccobacillum, while strains GHrC13 and GHrC15 were Gram-negative bacilli. Strain GHrC11 was identified as Exiguobacterium sp. The strains GHrC13 and GHrC15 were identified as Vibrio splendidus. The effects of these strains for the development of early abalone postlarvae (2 days old) were evaluated following a completely randomized design with three replicates using 5-mL-volume Petri dishes as experimental units. The experiment considered two different bacterial concentrations of each strain (10³ and 10⁵?cells?ml^?1) and two controls (with and without the benthic diatom Navicula incerta). After 10?days of experimentation, the highest mortality (90?±?5.8?%) and the lowest growth rate (4.1?±?0.1?μm?day^?1) were recorded for the strain GHrC11. In contrast, the lower mortality (16.7?±?3.3?%) and the highest growth rate (11.2?±?0.9?μm?day^?1) corresponded to the control fed N. incerta. Our results suggest that pathogenic effects of these bacterial strains were stronger than any potential benefits derived from the ingestion of bacteria by early abalone postlarvae. In conclusion, the most pathogenic strain was GHrC11, and the intensity of pathogenicity could be ordered as Exiguobacterium sp.?>?V. splendidus (C13)?>?V. splendidus (C15).     

Growth of <Emphasis Type="Italic">Euterpe edulis</Emphasis> Mart. (Arecaceae) under forest and agroforestry in southern Brazil

The palm Euterpe edulis has high ecological and economic importance in Brazil. Currently, this species is being cultivated and managed for spontaneous regeneration in banana plantations. However, there are no data comparing its plantation growth performance to its native forest growth. We evaluated growth and mortality (M) of individuals of E. edulis planted in secondary dense ombrophilous forest and in banana plantations, as well as their relationships with site variables (canopy opening, soil nutrient availability, density of existing E. edulis, and herbivory). Twelve banana plantation sites and 12 sites in secondary dense ombrophilous forests were selected. At each site, 25 young individuals of E. edulis were planted in 2003. Annually until 2008, morphometric, herbivory, and M of the individuals were evaluated. In 2008, canopy and soil variables were measured at each plot. E. edulis growth was five times higher in banana plots compared to forest plots; current annual increment on height reached 38.9 cm in banana plots, compared to 7.3 cm in forest plots. M was relatively low and similar at both sites, presenting an intraspecific density-dependence pattern. Significant correlations were found between morphometric variables, M, and herbivory of E. edulis and canopy and soil variables. Euterpe edulis presented plasticity that allows for its establishment in banana plantations, indicating high potential for management in agroforestry consortia. Such management may be a useful conservation strategy for this and other shade-tolerant species.     

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT ? 64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.     

Ecological analyses of the intestinal helminth communities of the wolf, Canis lupus, in Spain

This work describes the ecological characteristics of the intestinal helminth communities of 50 wolves (Canis lupus L.) from Spain. The species found were classified into three groups according to prevalence, intensity and intestinal distribution. Taenia hydatigena Pallas, 1766 and Uncinaria stenocephala (Railliet, 1884) are the core species of the community. Taenia multiceps (Leske, 1780) is a secondary species. The rest of the species, Alaria alata (Goeze, 1782), Taenia serialis (Gervais, 1847). Taenia pisiformis (Bloch, 1780), Dipylidium caninum (Linnaeus, 1758), Mesocestoides sp. aff. litteratus, Toxocara canis (Werner, 1782), Toxascaris leonina (von Linstow, 1902), Ancylostoma caninum (Ercolani, 1859) and Trichuris vulpis (Froelich, 1789), behave as satellite species. The linear intestinal distribution of all helminth species was analysed. The location of most species can be considered predictable, especially for core and secondary species. The analysis of interspecific relationships between infracommunities shows that negative associations are more numerous than positive associations. The role of A. caninum in the community is compared with that of U. stenocephala.     

Ecological relationships between landscape change and plant guilds in depressional wetlands

Plant guilds used to measure the relationships between wetlandplant community characteristics and landscape change around 31 depressionalwetlands in central Ohio, USA. Characteristics of certain plant guilds withineach wetland site are correlated with changes in: (a) area of urban land cover,forest, grassland, agriculture, and open-water in the local vicinity ofthe wetland; (b) inter-wetland distance; and (c) wetland size (area).Taxa richness is negatively correlated with inter-wetland distance forall plant guilds, except submersed herbaceous plants. Taxa richness of thesubmersed herbaceous plant guild (usually less than 20% of the totalnumber of plant species at a wetland) is positively correlated with the area ofopen-water in the local landscape and with the areaofthe wetland site itself. Significant positive correlationsalso exist between the area of open-water in the vicinity of the wetlandand the proportion of submersed herbaceous plant taxa at the site, the numberofnative submersed herbaceous plant species, the submersed herbaceous plantperennial-to-annual ratio, and the number ofavian-dispersed submersed herbaceous plant species at a site. Theresults suggest that (a) the dominance of submersed herbaceousplantspecies at a site is related to dispersal constraints between wetlands, and (b)the relatively slower physiological response of woody plants to local landscapechange may result in their contribution to greater ecologicalinertia in the plant community as a whole. For these reasons,relationships between the plant community and land cover change may not alwaysbe observed unless analyzed at the level of plant-guild.This revised version was published online in May 2005 with corrections to the Cover Date.     

Neutrophil, glass-adherent, nitroblue tetrazolium assay gives early indication of immunization effectiveness in rainbow trout

Neutrophil activity in rainbow trout (Oncorhynchus mykiss) is increased upon antigenic stimulation with the Yersinia ruckeri O-antigen bacterin. The characteristics of neutrophil attachment to glass and nitroblue tetrazolium (NBT) staining were used to determine the effectiveness of immunization programs with fingerling rainbow trout. Fish immunized by intraperitoneal injection with doses of 100, 10, or 1 μg of the bacterin showed the highest responses in that order in numbers of glass adherent, NBT-positive neutrophils. Studies on the kinetics of the occurrence of numbers of glass-adherent, NBT-positive staining cells from the fish injected with the 10 μg dose showed the numbers of positive cells were largest on Day 2 after injection. The specific immune response was confirmed by demonstrating the presence of plaque-forming cells by the passive hemolytic plaque assay and the rise in humoral antibody titers by passive hemagglutination 12 days after injection. The effects of immunization in trout could be detected earlier by using the neutrophil glass adherence and NBT reduction assays than by using assays based on observations of the specific immune response.