Computational Fluid Dynamics Studies of a Flow Reactor: Free Energies of Clusters of Sulfuric Acid with NH3 or Dimethyl Amine.

Computational fluid dynamics simulations of a flow reactor provided 3D spatial distributions of its temperature and flow profiles and abundances of sulfuric acid, nitrogeneous base, and the acid-base clusters formed from them. Clusters were simulated via their kinetic formation and decomposition involving sulfuric acid and base molecules. Temperature and flow profiles and the base and sulfuric acid distributions are characterized and the latter is compared to mass spectrometer measurements. Concentrations of simulated clusters of sulfuric acid with either NH3 or dimethylamine were compared to experimentally measured particle concentrations. Cluster thermodynamics were adjusted to better the agreement between simulated and experimental results. Free energies of acid-base clusters derived here are also compared to recent quantum chemistry calculations. Sensitivities to the thermodynamics were explored with a 2D laminar flow simulation and the abundance of large clusters was most sensitive to the thermodynamics of the smallest cluster, consisting of 1 base and 1 acid. Comparisons of this model to the computational fluid dynamics models provide verification of the implemented cluster chemistry. A box model was used to calculate nucleation rates for the conditions of other experimental work, and to provide predictions of nucleation for typical atmospheric conditions.

Peripheral intravenous nutrition therapy: outpatient, office-based administration.

BACKGROUND: The use of peripheral intravenous nutrition (PIN) has been growing in recent years due to the increase in awareness of the pathophysiological mechanisms of peripheral vein thrombophlebitis, as well as the availability of techniques to prevent or retard its onset. With the increase in public and medical practitioner awareness of the importance of nutritional interventions in health and disease, more outpatient-based PIN therapy is being performed. Outpatient, office-based PIN has unique features including high osmolality, high infusion rates, and short infusion duration. METHODS: Previous intravenous nutrition studies were used to estimate safety parameters for outpatient, office-based PIN. CONCLUSIONS: Osmolalities of the infusion can approach 1000 mOsm/L if the duration of the infusion is only several hours. The infusion should be diluted to reduce the osmolality, even if an increase in infusion rate is necessary. Duration of infusion should be less than three hours to reduce the time the irritating mixture contacts the vein wall. This requires high (150 - 330 mL/hour) infusion rates. The largest vein, and smallest and shortest catheter possible to achieve the infusion rate desired should be used, with in-line filtration of at least 0.45mm. The cannula should be removed at the first sign of pain or redness. Standard procedures to reduce infection risks should be followed.

The effect of vitamin-mineral supplementation on juvenile delinquency among American schoolchildren: a randomized, double-blind placebo-controlled trial.

CONTEXT: Numerous studies conducted in juvenile correctional institutions have reported that violence and serious antisocial behavior have been cut almost in half after implementing nutrient-dense diets that are consistent with the World Health Organization's guidelines for fats, sugar, starches, and protein ratios. Two controlled trials tested whether the cause of the behavioral improvements was psychological or biological in nature by comparing the behavior of offenders who either received placebos or vitamin-mineral supplements designed to provide the micronutrient equivalent of a well-balanced diet. These randomized trials reported that institutionalized offenders, aged 13 to 17 years or 18 to 26 years, when given active tablets produced about 40% less violent and other antisocial behavior than the placebo controls. However, generalization could not be made to typical schoolchildren without a controlled trial examining violence and antisocial behavior in public schools. OBJECTIVES: To determine if schoolchildren, aged 6 to 12 years, who are given low dose vitamin-mineral tablets will produce significantly less violence and antisocial behavior in school than classmates who are given placebos. DESIGN: A stratified randomized, double-blind, placebo-controlled trial with pretest and post-test measures of antisocial behavior on school property. SETTINGS AND SUBJECTS: Two "working class," primarily Hispanic elementary schools in Phoenix, Arizona. Approximately half of the potential schoolchildren participated, i.e., 468 students aged 6 to 12 years. INTERVENTION: Daily vitamin-mineral supplementation at 50% of the U.S. recommended daily allowance (RDA) for 4 months versus placebo. The supplement was designed to raise vitamin-mineral intake up to the levels currently recommended by the National Academy of Sciences for children aged 6 to 11 years. OUTCOME MEASURE: Violent and nonviolent delinquency as measured by official school disciplinary records. RESULTS: Of the 468 students randomly assigned to active or placebo tablets, the 80 who were disciplined at least once between September 1st and May 1st served as the research sample. During intervention, the 40 children who received active tablets were disciplined, on average, 1 time each, a 47% lower mean rate of antisocial behavior than the 1.875 times each for the 40 children who received placebos (95% confidence interval, 29% to 65%, < 5 .020). The children who took active tablets produced lower rates of antisocial behavior in 8 types of recorded infractions: threats/fighting, vandalism, being disrespectful, disorderly conduct, defiance, obscenities, refusal to work or serve, endangering others, and nonspecified offenses. CONCLUSION: Poor nutritional habits in children that lead to low concentrations of water-soluble vitamins in blood, impair brain function and subsequently cause violence and other serious antisocial behavior. Correction of nutrient intake, either through a well-balanced diet or low-dose vitamin-mineral supplementation, corrects the low concentrations of vitamins in blood, improves brain function and subsequently lowers institutional violence and antisocial behavior by almost half. This paper adds to the literature by enabling previous research to be generalized from older incarcerated subjects with a history of antisocial behavior to a normal population of younger children in an educational setting.

The effect of vitamin-mineral supplementation on the intelligence of American schoolchildren: a randomized, double-blind placebo-controlled trial.

CONTEXT: Many medical, nutrition, and education professionals have long suspected that poor diet impairs the academic performance of Western schoolchildren; academic performance often improves after improved diet. However, others have suggested that such academic gains may be due to psychologic effects rather than nutrition. To resolve this issue, two independent research teams conducted randomized trials in which children were given placebos or low-dose vitamin-mineral tablets designed to raise nutrient intake to the equivalent of a well-balanced diet. Both teams reported significantly greater gains in nonverbal intelligence among the supplemented groups. The findings were important because of the apparent inadequacy of diet they revealed and the magnitude of the potential for increased intelligence. However, none of the ten subsequent replications, or the two original trials, were without limitations leaving this issue in controversy. OBJECTIVES: To determine if schoolchildren who consume low-dose vitamin-mineral tablets will have a significantly larger increase in nonverbal intelligence than children who consume placebos in a study that overcomes the primary criticisms directed at the previous 12 controlled trials. DESIGN: A double-blind, placebo-controlled trial using stratified randomization within each teacher's class based on preintervention nonverbal intelligence. SETTINGS AND SUBJECTS: Two "working class," primarily Hispanic, elementary schools in Phoenix, Arizona, participated in the study. Slightly more than half the teachers in each school distributed the tablets daily to 245 schoolchildren aged 6 to 12 years. INTERVENTION: Daily vitamin-mineral supplementation at 50% of the U.S. daily recommended allowance (RDA) for 3 months versus placebo. OUTCOME MEASURES: Post-test nonverbal IQ, as measured by the Wechsler Intelligence Scale for Children-Revised (WISC-R), while controlling for pretest nonverbal IQ as a covariate. FOUR MAIN RESULTS: First, a significant difference of 2.5 IQ points (95% CI: 1.85-3.15) was found between 125 children given active tablets and 120 children given placebo tablets (p = 0.038). Second, this finding is consistent with the mean 3.2 IQ point net gain found in the 12 similar but less rigorous studies. Third, a significantly higher proportion of children in the active group gained 15 or more IQ points when compared to the placebo group (p < 0.01). Fourth, although 81 matched pairs produced no difference at all in nonverbal IQ gain, the modest 2.5 IQ point net gain for the entire sample can be explained by the remaining 24 children who took active tablets, and had a 16 point higher net gain in IQ than the remaining 19 placebo controls. CONCLUSIONS: This study confirms that vitamin-mineral supplementation modestly raised the nonverbal intelligence of some groups of Western schoolchildren by 2 to 3 points but not that of most Western schoolchildren, presumably because the majority were already adequately nourished. This study also confirms that vitamin-mineral supplementation markedly raises the non-verbal intelligence of a minority of Western schoolchildren, presumably because they were too poorly nourished before supplementation for optimal brain function. Because nonverbal intelligence is closely associated with academic performance, it follows that schools with children who consume substandard diets should find it difficult to produce academic performance equal to those schools with children who consume diets that come closer to providing the nutrients suggested in the U.S. RDA. The parents of schoolchildren whose academic performance is substandard would be well advised to seek a nutritionally oriented physician for assessment of their children's nutritional status as a possible etiology.

Vitamin-mineral intake and intelligence: a macrolevel analysis of randomized controlled trials.

CONTEXT: Two independent groups suspected that poor diets in school children might impair intelligence. Because dietary changes produce psychological effects, both groups conducted randomized trials in which children were challenged with placebo or vitamin-mineral tablets. Both reported significantly greater gains in intelligence among the actives. The findings were important because of the apparent inadequacy of diet they revealed, and the magnitude of the potential for increased intelligence. However, 5 of 11 replications were not significant, leaving the issue in doubt. OBJECTIVE: To determine if school children who receive low-dose vitamin-mineral tablets produce significantly higher IQ scores than children who receive placebo. DESIGN: A macrolevel analysis of the 13 known randomized, double-blind trials was undertaken. SETTING AND SUBJECTS: A total of 15 public schools in Arizona, California, Missouri, Oklahoma, Belgium, England, Scotland, and Wales participated, with 1477 school children, aged 6 to 17 years, and 276 young adult males, aged 18 to 25 years, in 2 American correctional facilities. MAIN OUTCOME MEASURES: All studies used 1 of 3 standardized tests of nonverbal intelligence: the Wechsler Intelligence Scale for Children-Revised, the Wechsler Adult Intelligence Scale, or the Calvert Non-verbal test. RESULTS: The activities in each study performed better, on average, than placebo in nonverbal IQ, regardless of formula, location, age, race, gender, or research team composition. The probability of 13 randomly selected experimental groups always performing better than 13 randomly selected independent control groups is one-half to the 13th power (p = 0.000122). The mean difference across all studies is 3.2 IQ points. Furthermore, the standard deviation in the variable "IQ change" was also consistently larger in each active group when compared to its controls. This confirms that a few children in each study, presumably the poorly nourished minority, were producing large differences, rather than a 3.2 point gain in all active children. CONCLUSION: There are important health risks when school children's dietary habits depart substantially from government guidelines; poor dietary habits may lead to impaired intelligence. Low-dose vitamin-mineral supplementation may restore the cognitive abilities of these children by raising low blood nutrient concentrations. However, there is also evidence that supplementation has no measurable effect on the intelligence of well-nourished children with normal blood nutrient concentrations.

Evidence of functional zinc deficiency in Parkinson's disease.

One of the primary areas of investigation in the pathophysiology of Parkinson's disease (PD) is the loss of the dopamine-producing cells in the melanized neurons of the substantia nigra, believed to be caused by oxidative stress resulting from excessive free radical activity. The cuprozinc enzyme, superoxide dismutase (SODCu2Zn2), catalyzes the dismutation of superoxide anions to hydrogen peroxide plus oxygen, and is normally found in high concentrations in the substantia nigra where it protects neurons by scavenging free radicals. Zinc supplementation has been shown to significantly increase SODCu2Zn2 in vitro. A novel oral zinc tally test (ZTT) used in the assessment of zinc status was administered to 100 PD patients and 25 controls. Patients with PD showed a significantly decreased zinc status as compared to controls (p < 0.001). Significance was also established for 3 self-reported health-related variables thought to be related to zinc status: vision problems, olfactory loss, and taste loss (p < 0.05). Relative risks for patients with PD for these variables were 1.51, 1.56, and 1.33, respectively. Zinc status as measured by the ZTT is negatively correlated with PD status. PD status is positively correlated with self-reported vision problems, and olfactory and taste loss. Further study of the role of zinc in the development and treatment of PD is warranted.