A note on measuring in P

We revisit the problem of generalising Lutz's resource-bounded measure to small complexity classes, and propose a definition of a random-based on , which we argue as being a good generalisation to of Lutz's . We cannot unconditionally prove the existence of such a measure, but we give sufficient and necessary conditions for its existence. We also revisit μ_τ, an for defined by Strauss [Inform. Comput. 136(1) (1997) 1], and correct an erroneous claim concerning the relations between μ_τ and random sets. A correction to this mistake is then proposed, which is a less powerful but accurate relation between μ_τ and random sets.

In order to obtain these results, we introduce a mathematical structure called a measuring system, which is a general setting that can be used to compare different s on any fixed complexity class through a partial ordering relation.     

Systematic Analysis of Clemastine,a Candidate Apicomplexan Parasite-Selective Tubulin-Targeting Agent

Apicomplexan parasites, such as Toxoplasma gondii, Plasmodium spp., Babesia spp., and Cryptosporidium spp., cause significant morbidity and mortality. Existing treatments are problematic due to toxicity and the emergence of drug-resistant parasites. Because protozoan tubulin can be selectively disrupted by small molecules to inhibit parasite growth, we assembled an in vitro testing cascade to fully delineate effects of candidate tubulin-targeting drugs on Toxoplasma gondii and vertebrate host cells. Using this analysis, we evaluated clemastine, an antihistamine that has been previously shown to inhibit Plasmodium growth by competitively binding to the CCT/TRiC tubulin chaperone as a proof-of-concept. We concurrently analyzed astemizole, a distinct antihistamine that blocks heme detoxification in Plasmodium. Both drugs have EC₅₀ values of ~2 µM and do not demonstrate cytotoxicity or vertebrate microtubule disruption at this concentration. Parasite subpellicular microtubules are shortened by treatment with either clemastine or astemizole but not after treatment with pyrimethamine, indicating that this effect is not a general response to antiparasitic drugs. Immunoblot quantification indicates that the total α-tubulin concentration of 0.02 pg/tachyzoite does not change with clemastine treatment. In conclusion, the testing cascade allows profiling of small-molecule effects on both parasite and vertebrate cell viability and microtubule integrity.     

Effects of Tansy Essential Oil from Tanacetum vulgare on Biology of Oblique-Banded Leafroller, Choristoneura rosaceana

The formulations TSW (tansy essential oil, surfactant, distilled water) and TSWD (tansy essential oil, surfactant, distilled water, dillapiol) increased the feeding rate of oblique-banded leafroller (OBLR) larvae with increasing concentrations of tansy essential oil. When tansy essential oil was continuously present at 0.1% and 1% in the diet, all OBLR larvae from susceptible and resistant populations died. The presence of 0.01% tansy essential oil in the diet affected female pupal weight, but not larval weight gain, larval developmental time and male pupal weight. Our results suggest that the concentration of tansy essential oil that significantly affects the developmental variables should be between 0.01% and 0.1% of tansy essential oil. Residues of the formulation TE (tansy essential oil, ethanol 95%) deterred oviposition of OBLR female.     

Predetermined Helical Chirality in Octahedral Complexes with a Novel Pentadentate C2‐Symmetrical Chiral Bis(oxazoline) Ligand

The first example of the pentadentate bis(oxazolines) has been synthesized using a modular approach that readily provides access to this ligand class. This ligand allows the controlled transfer of carbon‐centered to octahedral, metal‐centered chirality, as demonstrated both in the solid state as well as in solution. The characteristic CD band has been identified for dicationic, octahedral transition metal complexes with the Δ₂‐configuration.     

Fast atom bombardment and tandem mass spectrometry of phosphatidylserine and phosphatidylcholine

Fast atom bombardment (FAB) desorption of phosphatidylserine and various phosphatidylcholines produces a limited number of very informative negative ions. Especially significant is the formation of (M-H)⁻ ions for phosphatidylserine, a compound which does not yield informative high mass ions by other ionization methods. Phosphatidylcholines of not yield (M-H)⁻ ions but instead produce three characteristic high mass ions, (M-CH ₃ ⁺ _⁻, [M-HN(CH₃) ₃ ⁺ ]⁻ and [M-HN(CH_{3 3} ⁺ -C₂H₂]⁻. Both classes of lipids also yield anions attributed to the carboxylate components of these complex lipids. FAB desorption in combination with collisional activation allows for characterization of fragmentation and determination of structural features. Collisional activation of the carboxylate anion fragments from the complex lipids is especially informative. Structural characterization of the fatty acid chain can be achieved as the released saturated carboxylate anions undergo a highly specific 1,4-elimination of H₂, which results in the losses of the elements of CH₄, C₂H₆, C₃H₈...in a fashion entirely consistent with the chemistry of carboxylate anions desorbed from free fatty acids. These C_nH_2n+2 losses begin at the alkyl terminus and progress along the entire alkyl chain. Modified fatty acids undergo a similar fragmentation; however, the modification affects the series of C_nH_2n+2 losses in a manner which permits determining the type of modification and its location on the fatty acid chain.     

Modeling of Thermal Spalling During Electrical Discharge Machining of Titanium Diboride

Erosion in electrical discharge machining has been described as occurring by melting and flushing the liquid formed. Recently, however, thermal spalling was reported as the mechanism for machining refractory materials with low thermal conductivity and high thermal expansion. The process is described, here, by a model based on a ceramic surface exposed to a constant circular heating source which supplies a constant flux over the pulse duration. The calculations were based on TiB₂ mechanical properties along a and c directions. Theoretical predictions were verified by machining hexagonal TiB₂. Large flakes of TiB₂ with sizes close to grain size and maximum thickness close to the predicted values were collected, together with spherical particles of Cu and Zn eroded from cutting wire. The cutting surfaces consist of cleavage planes sometimes contaminated with Cu, Zn, and impurities from the dielectric fluid.