Effiiency of the Essential Oil of Porophyllum linaria (Asteraceae) a Mexican Endemic Plant Against Sitophilus zeamais (Coleoptera: Curculionidae).

The insecticidal and repellent effect of essential oil isolated from fresh leaves of Porophyllum linaria on maize weevil was evaluated, as well as the effect on the grain germination after treated. In total, 28 constituents were identified by gas chromatography coupled with mass spectrometry accounting for 99.86% of whole essential oil. The main majority compounds were ß-myrcene (41.94%), D-limonene (20.29%), and estragole (20.03%). Contact toxicity significantly increased with dose and time after treatment. With the 800 ppm (highest concentration), the mortality (%) obtained for the tenth and fifteenth day was 43 and 82%, respectively, whereas with 50 ppm (lowest concentration) 30% mortality was obtained at the end of the experiment (fifteenth day). At 15 d (end of the experiment), the LC50 y LC90 were obtained with values of 329.01 ± 44.35 y 1058.86 ± 117.76 ppm, respectively. For a concentration of 800 ppm, a selection index of zero was obtained, indicating the preference of the pest to the untreated maize (control). The maize grains germination test showed a significant reduction both in the length of hypocotyl and radicle of maize grain. So, in the highest dose, the hypocotyl and radicle length was 1.40 ± 0.34 and 9.14 ± 0.55 cm, respectively, whereas the control group registered 3.28 ± 0.39 and 13.02 ± 0.97 cm, respectively. This finding is promising since as it could result in the identification of botanical substances capable of suppressing maize weevil, Sitophilus zeamais development.

A quality improvement project to reduce overutilization of blood tests in a teaching hospital.

Objective: In hospitals, physicians-in-training are major contributors to the burden of tests ordered, increasing cost and resource utilization. We implemented an intervention to discourage overutilization of the complete blood count (CBC) and the basic metabolic panel (BMP). Methods: An intervention was designed, comprising education on high-value care and burden of over-testing, encouragement of competition, and use of positive reinforcement. The intervention was monitored by a test index determined by dividing the total number of a specific laboratory test ordered for a patient by the total number of hospital days. Results: Following a 6-month intervention, the mean CBC index decreased from 1.56 ± 0.02 to 1.45 ± 0.03 (p < 0.001), and the BMP index, from 1.35 ± 0.02 to 1.14 ± 0.03 (p < 0.001). There was significant interaction between the intervention and the slope of the BMP index trend (p = 0.03), but not the CBC index trend. The intervention had no impact on hospital length of stay and mortality. Conclusion: This quality improvement intervention is an effective approach to reducing overutilization of laboratory tests.

A new specific mechanism for the acid catalysis of the addition step in the Baeyer-Villiger rearrangement.

[structure: see text] A new transition state of the addition step in the Baeyer-Villiger reaction was found. The role of proton acceptor is played by the carbonyl oxygen atom, and the free energy barrier is 12.7 kcal/mol lower than that previously reported. This finding changes the mechanism for the acid catalysis and could be of interest for similar reactions in which it is known that such catalysis occurs, especially in nonpolar solvents.

On the CH...Cu agostic interaction: chiral copper(II) compounds with ephedrine and pseudoephedrine derivatives.

The ephedrine derivative, (H2ceph), yields [Cu(Hceph)2], showing a CH...Cu(II) agostic interaction; while in the analogous compound [Cu(Hcpse)2], with pseudoephedrine (H2cpse), that interaction is absent, despite the fact that these two diasteromers differ only in the orientation of the methyl and phenyl groups: erythro in H2ceph and threo in H2cpse. The X-ray crystal structure of [Cu(Hceph)2], indicates a Cu...HC length of 2.454 A and the theoretical study reveals the formation of a Cu...HC bond since the associated electronic density shows both a bond critical point and a bond ring critical point.

Substituent effects in the migration step of the Baeyer-Villiger rearrangement. A theoretical study.

Quantum mechanical calculations have been performed on the migration step of the Baeyer-Villiger (BV) rearrangements of some acetophenones, p-RC6H4COCH3 (R = CN, Cl, H, CH3, CH3O) with m-chloroperbenzoic acid. The energy barriers, charge distributions, and frontier molecular orbitals determined for the aryl migration step explain the effects of substituents on the reactivity of these ketones. A plot of the log of relative oxidation rates of the ketones versus their corresponding calculated energy barriers of the migration stage showed a downward deviation for the p-OCH3 derivative. This result is consistent with a change in the rate-determining step, from the aryl migration to the carbonyl addition, in the case of p-methoxyacetophenone, according to the suggestion that the rate-determining step of the BV oxidation can change with variations in the substituent group.