Quantitative UPLC‐MS/MS analysis of chlorogenic acid derivatives in antioxidant fractionates from dandelion (Taraxacum officinale) root

While qualitative studies have identified chlorogenic acids in antioxidant extracts, particularly ethyl acetate‐derived extracts, of Taraxacum officinale, quantitative analysis of these phenolic compounds remains largely unreported for this species. In this study, bioactivity‐guided fractionation of an antioxidant crude ethyl acetate extract (DPPH = 295.481 ± 0.955 mg TE g^?1 extract) from T. officinale root resulted in a number of reverse‐phase fractions that demonstrated high antioxidant activity (DPPH = 1058.733–1312.136 mg TE g^?1 extract), stronger than that of the synthetic antioxidant Trolox^®. UPLC‐MS/MS screening of these fractions for the presence of selected mono‐ and di‐caffeoylquinic acids revealed large quantities of 1,5‐dicaffeoylquinic acid present in several fractions (853.052–907.324 μg mg^?1), respectively. Due to the antioxidant potency and high levels of 1,5‐dicaffeoylquinic acid observed in these fractions, it was concluded that specifically this chlorogenic acid derivative is a major contributor to the antioxidant efficacy of dandelion root.     

Pervasive 2007: It's about the User

Pervasive computing is as much about the user as it is about the technology. So, the Fifth International Conference on Pervasive Computing emphasized desirability rather than just feasibility. Featured themes included user benefits, human-computer interaction, group and social interactions, context awareness, finding and positioning people and objects, and personal privacy.     

Creating a Student Centered Learning Environment at the University of Denver

A team of faculty members at the University of Denver changed the learning environment in key courses in the Department of Engineering from predominately teacher centered to student centered. Through this funded project new grading methods were implemented, classrooms were renovated and wired with studio layouts to facilitate learning, the Engineering Circuits Laboratory was rewired and instrumented for automated data acquisition and reporting, and two new pedagogical approaches were developed. At the onset of the project, six goals were established related to student learning. The introduction of industry standard hardware and software provided students with unprecedented hands‐on experience and project related activities stimulated faculty innovations in other current and future courses. Assessment results indicate that the new grading system improved the clarity of expectations for students before assignments were given resulting in increased reported motivation for learning in many courses. Even though course GPAs did not always reflect higher achievement on graded work, faculty members firmly believe that deeper understanding was achieved because more complex material was assimilated.     

Conditioned facilitation of brain reward function after repeated cocaine administration.

Cocaine lowers brain reward thresholds, reflecting increased brain reward function. The authors investigated whether, similar to acute cocaine administration, cocaine-predictive conditioned stimuli would lower intracranial self-stimulation (ICSS) thresholds. Rats received a saline injection for 5 days, a cocaine injection (10 mg/kg) for 20 consecutive days, then saline for 5 additional days. Thresholds were measured immediately before and 10 min after each injection. The initial 5 saline injections had no effect on thresholds, whereas cocaine significantly lowered thresholds for 20 days. There was no tolerance or sensitization to this effect of cocaine over days. During the last 5 days when cocaine administration was substituted with saline, rats demonstrated a conditioned lowering of thresholds during the 2nd daily ICSS session. These data demonstrate that cocaine-predictive conditioned stimuli induce a conditioned facilitation of brain reward function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molecular dynamics simulations of polyphosphazenes: poly[bis(chloro)phosphazene][NPCl2] n

Suitable parameter sets for the CHARMm force field were derived for the structural units in polychlorophosphazene [P=N, P N, P Cl] using the Dinur Hagler energy second derivative procedure based on quantum mechanical SCI calculations using the 6–31G^* basis set. To validate the reliability of the parameter set, structural results obtained with CHARMm for the adopted model compounds (OP₂NCl₅ and OP₃N₂Cl₅) were compared with those derived fromab initio quantum mechanics using the 6–31G^* basis set. Application of molecular dynamics (MD) simulations in combinatioin with the available X-ray diffraction data provided structural and conformational information on the polymer. The calculation made using the periodic boundary conditions (PBC) agree well with the polychlorophosphazene ordered in a monoclinic unit cell (a=5.98,b=12.99,c=4.92 A; β=111.7). This model was stabilized mainly by the image atoms contribution to the electrostatic energy term and had aquasi-planar conformation of the backbone chain (glide symmetry). The MD calculations also provided evidence that the difference between single and double PN bonds is less marked than that measured experimentally. This result is, however, in agreement with more recent and accurate X-ray studies on poly(methylphosphazene). Validation of the polymer model provided a complete picture, otherwise experimentally inaccessible, of the internal fluctuations of the polymeric chains.     

Warfarin anticoagulation in primary care: a regional survey of present practice and clinicians' views

The demand for anticoagulation services is rising. Warfarin anticoagulation has been shown to reduce the risk of stroke in patients with non-valvular atrial fibrillation by 68%. This raises issues about how services are best organized to initiate and monitor anticoagulation in this potentially large group of patients. We report the results of a regional postal survey undertaken to describe the views of general practitioners and consultants regarding warfarin anticoagulation in light of this potentially high increase in demand.     

Introduction to the special series: HIV infection among drug abusers.

Drug users are particularly at risk for contracting the human immunodeficiency virus and serve as a major mechanism for spreading the virus to other sectors of the population. As a result drug abuse treatment and potential behavioral change strategies are primary public health issues. The purpose of this article is to review the contributions included in this special edition, which represent an effort to describe the most current thinking in the field with a blend of theoretical, review, and empirical articles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)