Response of selected water chemical quality parameters to slight thinning in a mature oak–beech forest ecosystem under sub-humid climate conditions

The objective of this study was to determine the effect of 18% thinning on streamflow nutrient flux from a mature oak–beech forest ecosystem by paired watershed approach. Two experimental watersheds including control (W-I) and treatment (W-IV) watersheds were used in the study. The experimental watersheds were monitored about 6 years from 2006 to 2011 for the calibration period and 4 years from 2012 to 2015 for the treatment period. The forest in the treatment watershed was thinned between October and December in 2011, and the forest in the control watershed was left untreated. Water grab samples were collected from the streams in the watersheds on weekly basis during both the calibration and treatment periods and analyzed for calcium (Ca²⁺), magnesium (Mg²⁺), Kjeldahl nitrogen (KN), sodium (Na⁺), potassium (K⁺), iron (Fe³⁺), aluminum (Al³⁺), ammonium nitrogen (NH₄ ⁺-N), and sulfate (SO₄ ²⁻). The simple linear regression equations were developed between mean monthly nutrient fluxes of two watersheds in the calibration period with significantly high correlation coefficients, and they were used to estimate nutrient fluxes from the treatment watershed during the treatment period as if thinning had not been applied. The changes in the monthly nutrient fluxes were estimated as the differences between measured and values calculated with the linear regression equations. Results showed that removal of 18% standing timber volume did not significantly change nutrient exports except for KN and Na⁺ from the treatment watershed.

     

Imposex in Thais gradata as a Biomarker for TBT Contamination on the Southern Coast of Peninsular Malaysia

Thais gradata samples were collected from six locations along the southern shores of Peninsular Malaysia and analyzed for imposex incidence and organotin (butyltins (BTs), including tributyltin, dibutyltin, and monobutyltin, and phenyltins (PTs), including triphenyltin, diphenyltin, and monophenyltin concentrations), in tissue burden. On average, the BT levels were found to be higher than the levels reported a year before for other biota. In contrast, the PT compounds were found to be lower than in the previous report. The present study also classified the morphological expressions of the imposex scheme for this species into seven stages (stage 0 to stage 6) by observing the development of vas deference sequence (VDS) and penis bulk. This latest imposex scheme clearly indicates the mechanism of VDS growth, the structural changes from penis bulk to a penis with flagellum, and from a normal vaginal opening to a swollen vaginal opening. The degree of imposex was assessed using the vas deference sequence index and the percentage of females possessing the imposex characteristics. It was found that locations possessing high imposex levels also tended to show high BT levels in the snail tissue samples. However, correlation analysis did not show a significant relationship among the two parameters. A better result could be obtained if more samples and sampling locations were added in order to prove the hypothesis. The nonsignificant correlation between the shell height and any of the organotin compounds, along with no significant differences between BT levels in female and lower imposex stage samples, suggests that the BT concentration detected was a recent contamination.     

Effects of composts and vermicomposts obtained from forced aerated and mechanically turned composting method on growth,mineral nutrition and nutrient uptake of wheat

Abstract

This study aimed to assess the efficiencies of composts and vermicomposts obtained from two different composting methods on the growth, mineral nutrition and nutrient uptake of wheat. Composts and vermicomposts were applied to plastic pots under greenhouse condition with the application doses of 0, 5, 10, 20, and 40 t ha^?1. The pot-experiment lasted three months. The results showed that plant dry weight increased with the increase in doses when compared to the control groups where no composts and vermicomposts were applied. However, no differences were found among the doses from 5 to 40 t ha^?1 of composts and vermicomposts. Although application doses did not affect significantly on the most of the plant nutrient concentrations, Fe concentration in plant decreased with the increase in application doses. Additionally, no significant differences among the composts and vermicomposts on plant nutrient concentrations except for Mg were detected. Comparing to the control dose (0 t ha^?1), nutrient uptakes by plant from the soil significantly increased with the increase of application doses, but no significant differences were determined amongst the doses of 5 and 40 t ha^?1, generally. The effect of production methods on the most of investigated parameters including plant dry weight was similar.     

Pharmacokinetics and bioavailability of cefquinome and ceftriaxone in premature calves

The aim of this study was to evaluate the pharmacokinetics and bioavailability of cefquinome (CFQ) and ceftriaxone (CTX) following intravenous (IV) and intramuscular (IM) administrations in premature calves. Using a parallel design, 24 premature calves were randomly divided into the two antibiotic groups. Each of the six animals in the first group received CFQ (2 mg/kg) through IV or IM administration. The second group received CTX (20 mg/kg) via the same administration route. Plasma concentrations of the drugs were analyzed by high‐performance liquid chromatography and noncompartmental methods. Mean pharmacokinetic parameters of CFQ and CTX following IV administration were as follows: elimination half‐life (t_1/2λz) 1.85 and 3.31 hr, area under the plasma concentration–time curve (AUC_0–∞) 15.74 and 174 hr * μg/ml, volume of distribution at steady‐state 0.37 and 0.45 L/kg, and total body clearance 0.13 and 0.12 L hr^?1 kg^?1, respectively. Mean pharmacokinetic parameters of CFQ and CTX after IM injection were as follows: peak concentration 4.56 and 25.04 μg/ml, time to reach peak concentration 1 and 1.5 hr, t_1/2λz 4.74 and 3.62 hr, and AUC_0–∞ 22.75 and 147 hr * μg/ml, respectively. The bioavailability of CFQ and CTX after IM injection was 141% and 79%, respectively. IM administration of CFQ (2 mg/kg) and CTX (20 mg/kg) can be recommended at 12‐hr interval for treating infections caused by susceptible bacteria, with minimum inhibitory concentration values of ≤0.5 and ≤4 μg/ml, respectively, in premature calves. However, further research is indicated to assess the pharmacokinetic parameters following multiple doses of the drug in premature calves.     

Investigation of pharmacokinetic interaction between ivermectin and praziquantel after oral administration in healthy dogs

The purpose of this study was to determine the pharmacokinetic interaction between ivermectin (0.4 mg/kg) and praziquantel (10 mg/kg) administered either alone or co‐administered to dogs after oral treatment. Twelve healthy cross‐bred dogs (weighing 18–21 kg, aged 1–3 years) were allocated randomly into two groups of six dogs (four females, two males) each. In first group, the tablet forms of praziquantel and ivermectin were administered using a crossover design with a 15‐day washout period, respectively. Second group received tablet form of ivermectin plus praziquantel. The plasma concentrations of ivermectin and praziquantel were determined by high‐performance liquid chromatography using a fluorescence and ultraviolet detector, respectively. The pharmacokinetic parameters of ivermectin following oral alone‐administration were as follows: elimination half‐life (t_1/2λz) 110 ± 11.06 hr, area under the plasma concentration–time curve (AUC_0–∞) 7,805 ± 1,768 hr^.ng/ml, maximum concentration (C_max) 137 ± 48.09 ng/ml, and time to reach C_max (T_max) 14.0 ± 4.90 hr. The pharmacokinetic parameters of praziquantel following oral alone‐administration were as follows: t_1/2λz 7.39 ± 3.86 hr, AUC_0–∞ 4,301 ± 1,253 hr^.ng/ml, C_max 897 ± 245 ng/ml, and T_max 5.33 ± 0.82 hr. The pharmacokinetics of ivermectin and praziquantel were not changed, except T_max of praziquantel in the combined group. In conclusion, the combined formulation of ivermectin and praziquantel can be preferred in the treatment and prevention of diseases caused by susceptible parasites in dogs because no pharmacokinetic interaction was determined between them.     

Pharmacokinetics of cefquinome after single and repeated subcutaneous administrations in sheep

The purpose of this study was to determine the pharmacokinetics of cefquinome (CFQ) following single and repeated subcutaneous (SC) administrations in sheep. Six clinically healthy, 1.5 ± 0.2 years sheep were used for the study. In pharmacokinetic study, the crossover design in three periods was performed. The withdrawal interval between the study periods was 15 days. In first period, CFQ (Cobactan, 2.5%) was administered by an intravenous (IV) bolus (3 sheep) and SC (3 sheep) injections at 2.5 mg/kg dose. In second period, the treatment administration was repeated via the opposite administration route. In third period, CFQ was administrated subcutaneously to each sheep (n = 6) at a dose of 2.5 mg/kg q. 24 hr for 5 days. Plasma concentrations of CFQ were measured using the HPLC‐UV method. Pharmacokinetic parameters were calculated using non‐compartmental methods. The elimination half‐life and mean residence time of CFQ after the single SC administration were longer than IV administration (p < 0.05). Bioavailability (F%) of CFQ following the single SC administration was 123.51 ± 11.54%. The area under the curve (AUC_0‐∞) and peak concentration following repeated doses (last dose) were higher than those observed after the first dose (p < 0.05). CFQ accumulated after repeated SC doses. CFQ can be given via SC at a dose of 2.5 mg/kg every 24 hr for the treatment of infections caused by susceptible pathogens, which minimum inhibitory concentration is ≤1.0 μg/ml in sheep.     

Determination of milk/plasma ratio and milk and plasma pharmacokinetics of amoxicillin after intramuscular administration in lactating cows

This study was conducted to determine the passage ratio of amoxicillin into milk and its pharmacokinetics in milk and plasma after intramuscular administration. Five healthy dairy cows (Holstein, weighing 450–500 kg, aged 2–4 years) were used in this study. They received single intramuscular amoxicillin at a dose of 14 mg/kg body weight. Blood and milk samples were collected prior to drug administration (0); after 15, 30, 45, 60, and 90 min; and 2, 3, 4, 6, 8, 10, and 12 hr after administration. The plasma and milk concentrations of amoxicillin were determined using high‐performance liquid chromatography with ultraviolet detection. The passage ratio of amoxicillin into milk and plasma was determined using both AUC‐based calculation and milk and plasma concentrations at sampling times; it was calculated 0.46 and 0.52, respectively. The terminal half‐life and mean residence time of amoxicillin were 6.05 and 8.60 hr in plasma and 2.62 and 5.35 hr in milk, respectively. The C_max2 levels of amoxicillin in plasma and milk were measured as 1,096 and 457 ng/ml, respectively. It was observed that amoxicillin exhibited a secondary peak in plasma and milk. This study was the first to report on the passage ratio of amoxicillin into milk in lactating cows.     

Epiphytotics of chickpea Ascochyta blight in Turkey as influenced by climatic factors

Journal of Plant Diseases and Protection - Chickpea Ascochyta blight caused by Didymella rabiei is one of the most important fungal diseases affecting yield and seed quality negatively in Turkey....