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The food quality of edible oils is dependent on basic chemical and structural changes that can occur by oxidation during preparation and storage. A rapid and efficient analytical method of the different steps of oil oxidation is described using a time-domain nuclear magnetic resonance (TD-NMR) sensor for measuring signals related to the chemical and physical properties of the oil. The degree of thermal oxidation of edible oils at 80 °C was measured by the conventional methodologies of peroxide and aldehyde analysis. Intact non-modified samples of the same oils were more rapidly analyzed for oxidation using a TD-NMR sensor for 2D T1-T2 and self-diffusion (D) measurements. A good linear correlation between the D values and the conventional chemical analysis was achieved, with the highest correlation of R2 = 0.8536 for the D vs. the aldehyde concentrations during the thermal oxidation of poly-unsaturated linseed oils, the oil most susceptible to oxidation. A good correlation between the D and aldehyde levels was also achieved for all the other oils. The possibility to simplify and minimize the time of oxidative analysis using the TD NMR sensors D values is discussed as an indicator of the oil's oxidation quality, as a rapid and accurate methodology for the oil industry. [ABSTRACT FROM AUTHOR]

Blood pressure measurements in the calves of young children vary greatly. This has special significance for the diagnosis of coarctation of the aorta, a congenital anomaly causing abnormal blood flow through the femoral artery of the leg. Researchers measured and compared blood pressure measurements in the calf and arm of 148 healthy children aged 2 weeks through 35 months. Measured at the calf, systolic pressures, the upper of the two blood pressure numbers, showed the greatest correlation with age. However, systolic, diastolic, and mean blood pressure followed the same pattern. In general, calf blood pressures increased from birth to six months, plateaued at six months, and slowly increased over the next two years, but wide individual variations were found at the same age. Systolic calf pressures tended to be less than arm pressures up to six to nine months and to exceed them thereafter. Again, the relationship varied widely within individuals., Objective. Indirect measurement of lower extremity blood pressure is often used in the clinical setting, although normative data after the newborn period are not readily available. Methods. Indirect blood pressure (BP) measurement was obtained in the right arms and right calves of 148 healthy infants and young children 2 weeks to 3 years of age. All measurements were made using an oscillometric device. The infants and children were quiet or asleep and in the supine position. A BP cuff of proper size was chosen. Three measurements were made in both extremities; the average of the second and third measurements was used for all analyses. Results. Age correlated better with calf systolic blood pressure (SBPc) than with arm SBP (SBPa) (r = .52 vs.17). Calf diastolic blood pressure (DBPc) and calf mean blood pressure (MBPc) correlated moderately poorly with age (r = .37 and .39, respectively). There was no order effect. SBPC correlated best with height (r = .53), then age (r = .52), and, finally, weight (r = .51). The correlation between BPc and BPa was moderately low. The correlation of SBPC with SBPA was r = .46; that of DBPc with DBPa was r = .37; and that of MBPc with MBPa was r = .41. From rth to 6 months, SBPc was slightly lower than SBPa (1 to 3 mm Hg). SBPc increased linearly relative to SBPa and began to exceed SBPa at 6 months of age. The pattern of DBP and MBP was similar. Wide variability of blood pressure parameters was noted between the infants and children at all ages. Conclusions. Reference data are presented for BPc and the difference between BPc and BPa in healthy infants and children from 2 weeks to 3 years of age. BPc is not equivalent to BPa and should not be arbitrarily substituted. Because of the wide variability among healthy infants and children, SBPc measurements should be interpreted with caution when evaluating for coarctation of the aorta., Pediatrics 1996;97:220-224; calf blood pressure, indirect blood pressure, oscillometric blood pressure, coarctation of aorta. ABBREVIATIONS. BP, blood pressure; BPc, calf blood pressure; BPa, arm blood pressure; SBP, systolic blood pressure; [...]

Objectives. The purpose of this study was to examine social and psychological factors associated with the use and nonuse of violence among Black adolescents living in a community with a high level of violent crime. Methods. Adolescents (n = 225, 44% male) 11 to 19 years of age living in or around nine housing projects in an urban area were administered an anonymous questionnaire. Results. Self-reported use of violence was associated with exposure to violence and personal victimization, hopelessness, depression, family conflict, previous corporal punishment, purpose in life, self-assessment of the probability of being alive at age 25, and age and was higher among males. Conclusions. These data support the hypothesis that exposure to violence is associated with adolescents' self-reported use of violence. However, adolescents with a higher sense of purpose in life and less depression were better able to withstand the influence of exposure to violence in the home and in the community., Urban black adolescents appear to be more violent if they have been exposed to violence at home or have been victims of violent behavior themselves. Of 225 African-American teenagers living in housing projects in Augusta, GA, 84% indicated they had committed at least one act of violence. Males reported a higher average number of violent acts than did females. They also were more likely to be involved in more serious incidences of violence. For example, 41.4% of the males had carried a hidden weapon, while only 24.6% of the females had. Just over 19% of the males answering the survey had attacked someone with a weapon with intent to do serious or deadly injury. Only 13.5% of the girls had committed such an attack. Previous exposure to violence, being victims of violence, high levels of hopelessness, depression, conflict at home and extensive use of corporal punishment were strongly related to the adolescents' acting violently themselves. Socioeconomic variables had little relationship to self-reported violence.

Two-dimensional low-field hydrogen nuclear magnetic resonance (2D 1H LF-NMR) analysis of chemical compounds measures T1 and T2 relaxation times observed as exponential decay curves. Once relaxation curves are measured and stored in the format of discrete digital signals, they must be transformed, mathematically, into spectra that can be read and interpreted. We used primal-dual interior method for convex objectives (PDCO) that provided more accurate reconstructions than the standard algorithms. It is the objective of this paper to estimate the most suitable PDCO parameterization that provide accurate and robust reconstructions of relaxation curves into 2D spectra for LF-NMR under different signal-to-noise ratios. Finding optimal regularization parameters is an active field of mathematical research. PDCO, however, by making use of two regularization parameters instead of a single one, presents a much harder task, where the consolidated search criteria of a single parameter cannot be extended to two parameters. We featured a method based on numerical experiments and simulations that identified optimal and unique model coefficients that maximize PDCO reconstruction accuracy under different signal-to-noise conditions. The coefficients, as determined for artificial signals, increase the confidence of accurate reconstruction for 2D LF-NMR analysis on real lab samples. [ABSTRACT FROM AUTHOR]