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1.
Toxicol Rep ; 10: 76-86, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36590868

RESUMEN

Child lead poisoning damages central nervous system, immune, and renal function, and is the longest-standing public health epidemic in U.S. history. While primary prevention is the ultimate goal, secondary intervention is critical for curbing effects among children already exposed. Despite the lowering of child blood lead level (BLL) reference value in 2012 and again in 2021, few changes to secondary intervention approaches have been discussed. This study tested a novel interdisciplinary approach integrating ongoing child BLL-monitoring with education and home mitigation for families living in neighborhoods at high-risk of child lead exposure. In children ages 6 months to 16 years, most of whom had lowest range exposures, we predicted significantly reduced BLLs following intervention. Methods: Twenty-one families with 49 children, were offered enrollment when at least 1 child in the family was found to have a BLL > 2.5 µg/dL. Child BLLs, determined by ICPMS, were monitored at 4- to 6-month intervals. Education was tailored to family needs, reinforced through repeated parent engagement, and was followed by home testing reports with detailed case-specific information and recommendations for no-cost/low-cost mitigation. Results: Ninety percent of enrolled families complied with the mitigation program. In most cases, isolated, simple-to-mitigate lead hazard sources were found. Most prevalent were consumer products, found in 69% (11/16) of homes. Lead paint was identified in 56% (9/16) of homes. Generalized linear regression with Test Wave as a random effect showed that children's BLLs decreased significantly following the intervention despite fluctuations. Conclusion: Lower-level lead poisoning can be reduced through an interdisciplinary approach that combines ongoing child BLL monitoring; repeated, one-on-one parent prevention education; and identification and no-cost/low-cost mitigation of home lead hazards. Biannual child BLL monitoring is essential for detecting and responding to changes in child BLLs, particularly in neighborhoods deemed high-risk for child lead poisoning.

2.
J Org Chem ; 81(17): 7419-7431, 2016 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-27400400

RESUMEN

Thioureas are an important scaffold in organocatalysis because of their ability to form hydrogen bonds that activate substrates and fix them in a defined position, which allows a given reaction to occur. Structures that enhance the acidity of the thiourea are usually used to increase the hydrogen-bonding properties, such as 3,5-bis(trifluoromethyl)phenyl and boronate ureas. Herein, we report the synthesis of bifunctional thioureas with a chiral moiety that include either a trifluoromethyl or methyl group. Their catalytic performance in representative Michael addition reactions was used in an effort to compare the electronic effects of the fluorination at the methyl group. The observed differences concerning yields and ee values cannot be attributed solely to the different steric environments; theoretical results indicate distinct interactions within the corresponding transition states. The calculated transition states show that the fluorinated catalysts have stronger N-H···O and C-H···F hydrogen bonds, while the nonfluorinated systems have C-H···π contacts. These results have shown that a variety of hydrogen-bonding interactions are important in determining the yield and selectivity of thiourea organocatalysis. These details can be further exploited in catalyst design.

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