Patients presenting with hair loss should be screened by medical history, dietary history and physical exam for risk factors for nutrient deficiency. If warranted, laboratory studies may be performed. In patients with no risk factors, further laboratory evaluation searching for nutritional deficiencies is not warranted. For patients with nutritional deficiencies, it is clear that those deficiencies should be corrected. Further research is required to determine whether any benefit exists for nutrient supplementation in the absence of documented deficiency. At this time, patients must be informed that such research is lacking and that in fact some supplements carry the risk of worsening hair loss or the risk of toxicity.
Dicarboxylic acid esters possessing the consistency of conventional hydrocarbon oils have been utilized as biolubricants and additives. In general, dicarboxylic acid ester biolubricants are obtained by catalytic transesterification between fatty acids, methyl esters, or triglycerides as precursors. Here, we develop a new strategy to produce dicarboxylic acid esters through the chemical recycling of thermosetting polymer waste. Thermosets with tunable mechanical properties derived from epoxy oligomer and dicarboxyl acid can be decomposed in a zinc acetylacetonate/2-ethyl-hexanol solution at relatively mild temperatures (<170 °C) and ordinary pressure. The epoxy dissolution rate can be enhanced by increasing the temperature and catalyst loading. The depolymerized epoxy oligomer of dicarboxylic acid ester was obtained as a biolubricant. In addition, the catalyst can be facilely reclaimed and reused. This work presents a new approach in engineering polymer waste to generate eco-friendly high-value oil, such as biolubricant, which is beneficial to reduce environmental pollution and alleviate petrochemical source consumption.
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