Non-invasive Pregnancy Diagnosis from Urine by the Cuboni Reaction and the Barium Chloride Test in Donkeys (Equus asinus) and Alpacas (Vicugna pacos)

The aim of the research was to evaluate two chemical tests for non-invasive pregnancy diagnosis from urine, the Cuboni reaction and the barium chloride test, in donkeys (Equus asinus) and alpacas (Vicugna pacos). The research was carried out from April 2013 to September 2014. Urine samples were collected on five private Czech farms from 18 jennies and 12 alpaca females. Urine was collected non-invasively into plastic cups fastened on a telescopic rod, at 6-9 week intervals. In total, 60 and 54 urine samples from alpacas and jennies, respectively, were collected. The Cuboni reaction was performed by the State Veterinary Institute Prague. The barium chloride test was done with 5 ml of urine mixed together with 5 ml of 1% barium chloride solution. Results of the Cuboni reaction were strongly influenced by the reproductive status of jennies; the test was 100% successful throughout the second half of pregnancy. However, no relationship was found between the real reproductive status of alpaca females and results of the Cuboni reaction. It was concluded that the barium chloride test is not suitable for pregnancy diagnosis either in donkeys, due to significant influence of season on the results, or in alpacas, because no relationship between results of the test and the reproductive status of alpaca females was found. In conclusion, the Cuboni reaction has potential to become a standard pregnancy diagnostic method in donkeys.

Reactive Precipitation in Microchannels: Impact of Convective Mixing on Particle Formation

Reactive precipitation in micro- and minichannels currently draws attention of both, chemists and engineers in the field of micro process engineering. Due to intensified mixing and improved heat and mass transfer, fast chemical and thermodynamical processes involved in precipitation can be controlled readily in micro or mini structures. Particularly microchannels are a promising technology for particulate processes allowing continuous operation along with little or no backmixing. However, the sensitivity of microscale channels to blocking and fouling requires careful design and appropriate peripheral equipment. This study presents experimental results of barium sulfate precipitation from barium chloride solution and sulfuric acid in both, T-shaped and injection micromixers. The measured particle size distributions (PSD) are characterized by their first and second moment, reflecting the correlation between fluidic mixing and precipitation: faster mixing results in smaller mean particle sizes (1st moment of the PSD). The homogeneity of the mixing process on the other hand should have impact onto the width of the distribution (2nd moment of the PSD) due to superposition of locally formed particles to the global size distribution. The experimental particle size distributions are compared with simulations based on reduced-order modeling of the diffusive mixing process, coupled with the population balance for particle nucleation and growth. While the simulated size distributions have mean diameters between 40 nm and 68 nm, experimental data are between 90 nm and 130 nm.

Cation exchange capacity of an oxisol amended with an effluent from domestic sewage treatment

The addition of Na-rich anthropogenic residues to tropical soils has stimulated the scientific community to study the role of sodium in both the soil solution and the exchange complex. In this study, several different methods were used to calculate the concentration of exchangeable and soluble cations and this data was then used to establish correlations between the level of these cations and both the accumulation of various elements and the dry weight of maize grown in a greenhouse under different conditions. In the closed environments of the pots, the most suitable method for calculating the effective cation exchange capacity (ECEC) was the cation exchange capacity calculated by cations removed with barium chloride solution (CEC S). Then again, the actual cation exchange capacity (CEC A) should be measured by using Mg adsorption to prevent ionic force from influencing electric charges. A strong positive correlation was obtained between the concentrations of Na in the 1:2 soil:water extracts and the accumulation of Na in the maize plants, indicating saline or double acid extractors are not needed when monitoring the Na concentration only.

A proposed method for the measurement of exchange properties of highly weathered soils

The 'compulsive exchange' method of Bascomb has been modified to allow the determination of cation exchange capacity and anion exchange capacity of soils containing significant quantities of constant potential surfaces. The soil is equilibrated with unbuffered barium chloride solution at an ionic strength approximating that of the soil solution, so that the conditions under which determinations are made are similar to those found in the field. Barium on the exchange complex is then replaced by magnesium when the latter is added as magnesium sulfate, and this is accomplished without altering the solution ionic strength. If desired, exchangeable basic cations can be determined as an additional step in the procedure. Results obtained by the proposed method are compared with other commonly used procedures for determining cation exchange capacity and exchangeable basic cations.

Rudjer Bošković Institute Radiocarbon Measurements V

The following list contains dates of samples measured since our previous list (R, 1977, v 19, p 465-475). As before, age calculations are based on the Libby half-life, 5570 ± 30 years, and reported in years before 1950. The modern standard is 0.95 of the activity of NBS oxalic acid. Solid sample pretreatment, combustion and counting technique are essentially the same as described in R, 1971, v 13, p 135-140. Groundwater samples were prepared following the procedure adopted by the IAEA (IAEA, 1977). Carbonates and hydrocarbonates from water samples were precipitated by adding saturated barium chloride solution while the alkalinity was adjusted to pH = 8 by adding carbonate-free saturated solution of sodium hydroxide. The precipitation was enhanced by adding iron salts and Praestol as coagulating medium. Carbon dioxide was evolved by acidification of the precipitate and converted to methane. Statistical processing of data has been computerized (Obelić and Planinić, 1975). Sample descriptions were prepared with collectors and submitters. The errors quoted correspond to 1σ variation of sample net counting rate and do not include the uncertainty in 14C half-life.

Collaborative Study of Microchemical Sulfur Determination, Using Oxygen Flask Combustion: THQ Indicator

A collaborative study was conducted on microchemical sulfur determination by oxygen flask combustion. Seven collaborators performed duplicate determinations on 5 samples: sulf anilamide, benzylisothiourea hydrochloride, cystine, potassium sulfate, and a mixture of potassium sulfate and phosphate. Following oxygen flask combustion, the resultant gases were absorbed in a solution containing 0.1/V NaOH and 30% H2O2. The acidified sample was shaken 30 min and evaporated to dryness on the steam bath; the sulfate was titrated with standard barium chloride solution. The indicator used in this study was tetrahydroxyquinone. Its reliability has been previously proved and adopted by AOAC for use with the Carius-type combustion. Evaluation of the statistical data and overall consideration indicate satisfactory results for all types of compounds studied, with the exception of phosphorus-contaminated samples. Both systematic and random errors for the pure compounds were low. The method has been adopted as official first action.