Acyclic Stereocontrol in the Additions of Nucleophilic Alkenes to α-Chiral N-Sulfonyl Imines.

Diastereoselective Lewis acid-mediated additions of nucleophilic alkenes to N-sulfonyl imines are reported. The canonical polar Felkin-Anh model describing additions to carbonyls does not adequately describe analogous additions to N-sulfonyl imines. Herein, we describe the development of conditions to produce both syn and anti products with high diastereoselectivity and good yields. A stereoelectronic model consistent with experimental outcomes is also proposed.

Diastereoselective Base-Catalyzed Formal [4 + 2] Cycloadditions of N-Sulfonyl Imines and Cyclic Anhydrides.

A diastereoselective base-catalyzed Mannich reaction of cyclic, enolizable anhydrides and N-sulfonyl imines for the synthesis of δ-lactams is reported. This anhydride Mannich reaction tolerates imines derived from aryl and enolizable aldehydes. A base-catalyzed product epimerization pathway ensures high anti diastereoselectivity in aryl and achiral enolizable imines.

Targeting quinolone- and aminocoumarin-resistant bacteria with new gyramide analogs that inhibit DNA gyrase.

Bacterial DNA gyrase is an essential type II topoisomerase that enables cells to overcome topological barriers encountered during replication, transcription, recombination, and repair. This enzyme is ubiquitous in bacteria and represents an important clinical target for antibacterial therapy. In this paper we report the characterization of three exciting new gyramide analogs-from a library of 183 derivatives-that are potent inhibitors of DNA gyrase and are active against clinical strains of gram-negative bacteria (Escherichia coli, Shigella flexneri, and Salmonella enterica; 3 of 10 wild-type strains tested) and gram-positive bacteria (Bacillus spp., Enterococcus spp., Staphylococcus spp., and Streptococcus spp.; all 9 of the wild-type strains tested). E. coli strains resistant to the DNA gyrase inhibitors ciprofloxacin and novobiocin display very little cross-resistance to these new gyramides. In vitro studies demonstrate that the new analogs are potent inhibitors of the DNA supercoiling activity of DNA gyrase (IC50s of 47-170 nM) but do not alter the enzyme's ATPase activity. Although mutations that confer bacterial cells resistant to these new gyramides map to the genes encoding the subunits of the DNA gyrase (gyrA and gyrB genes), overexpression of GyrA, GyrB, or GyrA and GyrB together does not suppress the inhibitory effect of the gyramides. These observations support the hypothesis that the gyramides inhibit DNA gyrase using a mechanism that is unique from other known inhibitors.

How active are rural children and adolescents during PE class? An examination of light physical activity.

BACKGROUND: Few studies have examined non-exercise activity thermogenesis (NEAT) or light physical activity among a group of rural youth, particularly during physical education (PE) class. The purpose of this study was to determine whether the percent of PE class time spent in NEAT is related to school level (elementary versus high school) in a group of rural youth. METHODS: Accelerometer data from 357 students (192 elementary, 165 high school) were included in the analysis. Mixed model linear regression was performed to examine the effect of school level on the percent of PE class time spent in NEAT. Covariates included gender, PE teacher, and the duration of the PE class. RESULTS: School level was a significant predictor of the percent of PE class time spent in NEAT. Specifically, elementary school students spent more of their PE class time in NEAT than high school students (p < .001). No other significant predictors were identified. CONCLUSIONS: The results of this study suggest an association between lower levels of light (NEAT) physical activity among high school versus elementary school students during PE class.

Assessing moderate to vigorous physical activity in rural West Virginia elementary school physical education classes.

BACKGROUND: Physical education (PE) provides a natural opportunity for students to be physically active during the school day; however, the amount and intensity of this activity varies. The Centers for Disease Control and Prevention recommends that students engage in MVPA for at least 50% of their PE class period. The purpose of the present study was to quantify the amount of MVPA that occurs during elementary school PE. METHODS: Accelerometer data were collected from 203 students (100 2nd grade; 103 5th grade) in 10 West Virginia elementary schools. At each school, PE teachers identified three 2nd grade classes and three 5th grade classes in which to collect the physical activity data. For each selected class, the teachers identified the first 4 students on their alphabetic roll to wear the accelerometers. PE teachers recorded the date and time of the class and the gender of the students wearing the accelerometers. RESULTS: Using 5-second epochs and Puyau's cut-offs, results indicated that, on average, students engaged in MVPA for 27% of their PE class. No significant differences were observed in MVPA between 2nd and 5th grade students or between males and females. Male and female students spent equal amounts of PE class in MVPA. CONCLUSION: Findings support policy to increase the required minimum amount of MVPA during each PE class.

Exploring the relationship between parental concern and the management of childhood obesity.

Parental concern about child weight has been identified as a factor in parental monitoring and regulation of child diet. However, little is known about factors that influence parental concern or about how concern may influence parent management of child physical activity. The objectives of the current study were to identify the factors associated with parental concern about child weight and determine if parental concern is associated with specific actions to improve diet and increase physical activity. A stratified random sample of 1,500 parents of children in kindergarten, 2nd, 4th, 5th, 7th, and 9th grade were interviewed. Interviews addressed: (a) child and parent physical activity, (b) child and family nutrition, (c) child and parent BMI weight category, (d) interactions with health care providers, (e) parent obesity knowledge, (f) school assessment of BMI, and (g) parent perception of and concern about child weight. Child gender, weight status, and parent perception of child weight were significant predictors of parental concern. Parents were significantly more likely to report concern if their child was female, they believed their child to be overweight/obese, or their child was overweight/obese as indicated by BMI percentile. Concerned parents were significantly more likely to limit child screen time, take steps to improve child diet, and increase child physical activity than were parents who reported no concern. Treatment and prevention efforts should emphasize parental concern and awareness about child weight by providing accurate feedback on child weight status and education regarding the health risks associated with childhood overweight and obesity. Schools can play an important role in this process through the incorporation of BMI screenings.