Comparison of acetate tape impression with squeezing versus skin scraping for the diagnosis of canine demodicosis

This study compared the sensitivity of acetate tape impression and skin squeezing with that of deep skin scraping for the diagnosis of demodicosis in dogs. Demodex canis was detected in 100% of acetate tape impressions obtained after skin squeezing and in 90% of deep skin scrapings. There was a significant difference (P < 0.001) between the techniques in the total number of mites detected. Acetate tape impression with skin squeezing was found to be more sensitive than deep skin scraping and is an alternative diagnostic method for canine demodicosis.     

Topochemical polymerization of C70 controlled by monomer crystal packing

Polymeric forms of C60 are now well known, but numerous attempts to obtain C70 in a polymeric state have yielded only dimers. Polymeric C70 has now been synthesized by treatment of hexagonally packed C70 single crystals under moderate hydrostatic pressure (2 gigapascals) at elevated temperature (300 degrees C), which confirms predictions from our modeling of polymeric structures of C70. Single-crystal x-ray diffraction shows that the molecules are bridged into polymeric zigzag chains that extend along the c axis of the parent structure. Solid-state nuclear magnetic resonance and Raman data provide evidence for covalent chemical bonding between the C70 cages.     

Snake envenomation in cats and its detection by rapid immunoassay

Objective To determine the usefulness of a snake venom detection kit (SVDK) in the management of envenomed cats.
Design A clinical study.  

Animals

Twenty-two cats were investigated.
Procedure Cats injected subcutaneously with approximately 0.25 or 1.0 lethal dose (LD) of tiger snake venom or 1 or 4 LD of brown snake venom were observed for clinical symptoms of envenomation at intervals over the ensuring 24 to 48 hours(h). Blood and urine samples were taken at regular intervals and assayed in a quantitative laboratory assay for snake venoms. Selected samples were assayed in parallel in a rapid, semi-quantitative SVDK.
Results The studies showed that it was important to estimate the elapsed time from envenomation to presentation. If this time was less than 8 h, blood was the most appropriate sample and a negative result should exclude serious envenomation. If the elapsed time exceeded 8 h, it was essential that urine be sampled. Venom levels in urine were high at 8 h and approached the level of test sensitivity over 24 to 48 h; however by this time clinical signs were obvious in endangered cats.  

Conclusions

Careful use of the SVDK is a valuable aid in the management of a potentially envenomed cat.     

Comprehensive study of Pb (II) speciation in soil by X-ray absorption spectroscopy (XANES and EXAFS) and sequential fractionation

Purpose

The study is aimed at the analysis of the spatial–structural organization of Pb(II) in Chernozem soils and the relationship between the metal ion and the soil components using X-ray absorption spectroscopy and chemical extractive fractionation.

Materials and methods

In a model experiment, soil samples were artificially contaminated with elevated rates of Pb(NO₃)₂ and PbO (2000 and 10,000 mg kg^?1). The samples of mineral phases (bentonite, gibbsite, kaolinite, calcite, and hydromuscovite) were saturated with Pb²⁺ ions. The sequential fractionation of Pb in the soil was conducted by the Tessier method. X-ray absorption near-edge fine structure (XANES) spectra at the Pb L_III-edge (13.040 keV) were obtained on a Rigaku R-XAS Looper spectrometer. Extended X-ray absorption fine structure (EXAFS) L_III-edge Pb was measured at the Structural Materials Science beamline of the Kurchatov Center for Synchrotron Radiation.

Results and discussion

The results of successive extraction showed that Pb is associated with strongly bound organic substances, Fe and Mn (hydr)oxides, and carbonates. An increase in the portion of exchangeable fraction is observed under extreme loads. At the addition of Pb in the form of oxide and nitrate to the soil, the fractional compositions were similar, which indicates the good transformation of PbO in Chernozem. The features of XANES spectra indicate different orbital transitions in the electron shells of Pb²⁺ ions for monoxide (PbO) and soluble salt (Pb(NO₃)₂), which affect the ion properties and determine the individual structure of the coordination sphere. The analysis of XANES revealed that sorption of Pb in the soil samples and in the samples of mineral phases does not change its bond valence.

Conclusions

The increased degree of soil contamination with Pb is accompanied by decreasing the stable connection between metal and soil components. Lead ions in bentonite, kaolinite, hydromuscovite, gibbsite, and calcite are incorporated in the positions of the inner-sphere complex replacing some aluminum ions in the octahedral sites. This results in changes the Pb–O distances in Pb-bearing octahedrons. We may suggest that Pb²⁺ is also sorbed by dimer (Pb–Pb) silicate and/or aluminum groups. The structure of adsorbent surface plays the key role in the sorption of Pb²⁺ by mineral phases.