Macroinvertebrate Community and Chemistry of the Most Atmospherically Acidified Streams in the Czech Republic

We performed a comparative study of strongly acidified mountain streams covering 10 sites in the Czech Republic in the season 1999/2000. The aim of the study was to determine how acidification influenced macroinvertebrate community structure within a relatively narrow pH range. We focused on strongly acidified, non-humic running waters with low ionic content (pH < 4.6, total organic carbon < 10 mg l^?1, specific conductivity < 100 μS cm^?1) and minimum human influence in the catchment. The actual pH values ranged from 3.98 to 4.65, and concentrations of reactive aluminium ranged from 0.2 to 2.0 mg l^?1. Characteristic macroinvertebrates were the stoneflies Leuctra nigra, Nemurella pictetii, and Protonemura spp.; the chironomids Corynoneura spp.; and the caddisfly Plectrocnemia conspersa – the former two stoneflies formed together 46% of total organisms. The sites were divided into three groups with use of divisive classification. Individual groups reflected similarity in water chemistry, catchment characteristics, and geographical proximity. The largest biotic difference detected by PCA was in the abundance of stoneflies, mainly Diura bicaudata and Leuctra major. The strongest correlation with this gradient was shown by pH (and associated heavy metals), followed by the distance from source. The results show that even in such narrow pH range, the number of taxa is determined by the low pH value and related high concentrations of aluminium and heavy metals.     

HPLC analysis of rosmarinic acid in feed enriched with aerial parts of Prunella vulgaris and its metabolites in pig plasma using dual-channel coulometric detection

This paper describes a sensitive isocratic HPLC/ECD method developed for the determination of rosmarinic acid (RA) in plant material, animal feed, and pig plasma. The plasma sample preparation only includes protein precipitation and adjustment of the pH. The applicability of the method was tested on plasma samples of pigs that were exposed to a 91-day oral intake of RA via feed enriched by aerial parts of Prunella vulgaris. The plasma was directly analyzed using the method described as well as after enzymatic hydrolysis. When no hydrolysis step was included, RA and caffeic acid (CA) were quantified in the plasma. In hydrolyzed plasma samples, several other metabolites were determined, including dihydrocaffeic, ferulic, and dihydroferulic acid. The dual-channel coulometric detection employed, as an alternative to mass spectrometry, offers good selectivity and sensitivity owing to the electrochemical properties of the phenolic constituents.     

Parasitic infection of Cobitis elongatoides Băcescu & Mayer, 1969 by zoonotic metacercariae Clinostomum complanatum (Rudolphi, 1814)

An infection of zoonotic Clinostomum complanatum metacercariae with potential human transmission was recorded close to fish farms in the Tisa River Basin of Slovakia and Ukraine. The prevalence varied from 19.4% to 81.3%, and the intensity of infection varied from 7 to 41. The results of a generalized linear model predicted a positive trend for the Cobitis elongatoides host and a standard length and intensity of infection, with females having a higher number of parasites. However, no significant impact was found of the intensity of infection on Clark's condition of the host. The metacercariae were primarily located in the anterior part of the host's body. Our study also showed significant evidence that water velocity affects the number of C. complanatum metacercariae, regardless of the host's (Cobitis) microhabitat.     

Effect of medetomidine-butorphanol and dexmedetomidine-butorphanol combinations on intraocular pressure in healthy dogs

ObjectiveTo assess the effects of intravenous (IV) medetomidine-butorphanol and IV dexmedetomidine-butorphanol on intraocular pressure (IOP).Study designProspective, randomized, blinded clinical study.AnimalsForty healthy dogs. Mean ± SD body mass 37.6 ± 6.6 kg and age 1.9 ± 1.3 years.MethodsDogs were allocated randomly to receive an IV combination of dexmedetomidine, 0.3 mg m^?2, combined with butorphanol, 6 mg m^?2, (group DEX) or medetomidine 0.3 mg m^?2, combined with butorphanol 6 mg m^?2, (group MED). IOP and pulse (PR) and respiratory (f_R) rates were measured prior to (baseline) and at 10 (T10), 20 (T20), 30 (T30) and 40 (T40) minutes after drug administration. Oxygen saturation of hemoglobin (SpO₂) was monitored following sedation. Data were analyzed by anova followed by Dunnett's tests for multiple comparisons. Changes were considered significant when p < 0.05.ResultsFollowing drug administration, PR and f_R were decreased significantly at all time points but did not differ significantly between groups. Baseline IOP in mmHg was 14 ± 2 for DEX and 13 ± 2 for MED. With both treatments, at T10, IOP increased significantly (p < 0.001), reaching 20 ± 3 and 17 ± 2 for DEX and MED respectively. This value for DEX was significantly higher than for MED. There were no significant differences in IOP values between groups at any other time points. At T30 and T40, IOP in both groups was below baseline (DEX, 12 ± 2 and 11 ± 2: MED 12 ± 2 and 11 ± 2) and this was statistically significant, for DEX.Conclusions and clinical relevanceAt the documented doses, both sedative combinations induced a transient increase and subsequent decrease of IOP relative to baseline, which must be taken into consideration when planning sedation of animals in which marked changes in IOP would be undesirable.     

The use of tannic acid to remove adhesiveness from pikeperch, Sander lucioperca, eggs

The studies conducted in 2003–2004 focused on the possibilities of applying a tannic solution to remove adhesiveness from pikeperch eggs. Spawners were caught in Lake P?tnowskie (central Poland) and then transported to the Gos?awice Fish Farm. After initial selection, the fish were weighed, measured and stimulated with human chorionic gonadotropin. Gametes were obtained 5 days after the first injection. The weight and diameter of the eggs, and the commercial fecundity of individual females were determined. The eggs were fertilized with the dry method. After the addition of water, the eggs were mixed for 4 min, and then divided into 20 g portions. After determining the number of eggs in the various portions, the adhesiveness removal procedure was performed. Three concentrations of tannic acid solution (500, 1000, 1500 mg L^?1) and three exposure times (0.5, 2, 5 min) were applied. The eggs were incubated in Weiss jars. The studies indicated that both the solution concentration and the exposure time significantly (P<0.05) impacted pikeperch egg hardening, the degree of adhesive removal and embryo survival. The tannic acid solution concentration of ≤500 mg L^?1 applied for 0.5–2 min was not effective; the eggs clumped and it was impossible to separate them even with intensive mixing. Better results were obtained using higher tannic acid concentrations and/or by lengthening exposure time. The adhesiveness of pikeperch eggs disappeared completely after 5 min exposure to tannic acid solution concentrations of 500–1500 mg L^?1 or after 2 min exposure to solution concentrations of 1000–1500 mg L^?1. In these variants, the embryo survival rate to the eyed‐egg stage was 78.0–84.0% (2003) and 82.3–84.7% (2004). However, high tannic acid concentration had a negative impact on the pikeperch larvae hatching. The greatest decrease in survival rate was observed in groups exposed to a tannic acid solution of 1500 mg L^?1 for 2 and 5 min periods. Thus, the optimum method for removing pikeperch egg adhesiveness was to apply a solution of tannic acid at a concentration of 500 mg L^?1 for 5 min or 1000 mg L^?1 for 2–5 min.     

Evaluation of surface smoothness by laser displacement sensor 1: effect of wood species

The best methods for determining surface roughness in an industrial environment are of the noncontact variety, with reproduction of the profile. The objective of this work was to compare the roughness profile obtained by a contact stylus with a commercial laser displacement sensor (LDS). Measurements were done using 15 wood species with different densities and colors, based on which special triangle profiles were prepared. The accuracy of the laser sensor was examined by statistical analysis of roughness parameters measured from the profiles. Experimental results show that LDS profiles were imitated correctly. However, LDS accuracy depends on the scanned wood properties (density and color), installation position of the sensor, and profile shape. It was found that evaluation of dark and high-density wooden surfaces was imperfect.Part of this work was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000; and at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

Production potential,biodiversity and soil properties of forest reclamations: Opportunities or risk of introduced coniferous tree species under climate change?

European Journal of Forest Research - In the time of ongoing climate change and the increasing area of post-mining landscape, the successful afforestation of reclamation sites by suitable adaptive...     

Changes in selected hydrophobic components during composting of municipal solid wastes

Purpose

One of the most practical ways to utilise municipal solid waste is composting, thereby producing materials that may be productively used to improve soil properties. Wastes, as well as mature composts, contain hydrophobic substances, including fats, which are more resistant to microbiological decomposition than other constituents. The aim of this work was to determine qualitative and quantitative changes of hydrophobic substances, especially fatty acids, during the course of municipal solid waste composting. This provides new information on intensity of hydrophobic versus other substances decomposition undergoing during these processes.

Materials and methods

Raw materials, prepared according to MUT-DANO technology, were composted in a pile, and samples were taken after 1, 14, 28, 42, 56, 90 and 180 days of the composting. Temperature, moisture, total organic carbon, hydrophobic substances carbon (HSC) and fatty acid carbon (FAC) contents were determined in all samples. Hydrophobic substances were extracted with 1:2 (v/v) mixture of ethanol/benzene, while fats were extracted with petroleum ether and determined by GC analysis after transesterification with BF₃ in methanol.

Results and discussion

The HSC decreased from 27.8 to 9.3 g kg^?1 during first 90 days of composting, and thereafter remained constant. Similarly, the highest content of FAC was in raw compost, while the lowest was after 90 days. Octadecenoic acid predominated in the raw compost and decreased from 56 to 23 % FAC after 180 days. During the composting processes, domination of octadecenoic acid was replaced by hexadecanoic and octadecanoic acids, which increased from 18.8 to 36.7 % and 8.3 to 19.4 % FAC, respectively. The share of hexadecanoic, eicosanoic and docosanoic acids increased after the thermophilic phase. The presence of odd-numbered fatty acids (pentadecanoic and heptadecanoic) was noted, which are known to be products of the bacterial transformation-synthesis of lipid substances.

Conclusions

The extent of decomposition of hydrophobic substances, especially fatty acids, is greater than other components in composted municipal solid waste, and intensity of the biotransformation is significantly correlated with composting parameters, mainly temperature and time. During the thermophilic phase of municipal solid waste composting, the decrease in total content of hydrophobic substances is approximately fivefold, while the reduction in fatty acids can be about tenfold. Unsaturated fatty acids are more intensively decomposed during the composting processes, while saturated fatty acids are more resistant. Moreover, transformation of fatty matter may result in the creation of specific isomers with odd numbers of carbon atoms.