You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Thirteen week rodent feeding study with grain from molecular stacked trait lepidopteran and coleopteran protected (DP-ØØ4114-3) maize. The results from a subchronic feeding study conducted in Sprague–Dawley rats fed with diets containing grain from 4114 (OECD unique identifier: DP-ØØ4114-3) maize that was untreated (4114) or sprayed in field with glufosinate ammonium (4114GLU) in a design similar to previous studies are reported. The test material, 4114 maize, is a hybrid maize produced by transformation with a DNA construct encoding 4 different transgenic proteins for resistance to lepidopteran pests, coleopteran pests, and tolerance to the herbicidal active ingredient glufosinate ammonium. There were a total of 144 rats divided into 12 groups of 12 rats/sex/group. All experimental diets were formulated by Purina Mills, LLC (St. Louis, MO) in accordance with the standards of Purina Mills Labdiet® Certified Rodent LabDiet® 5002. The incorporation rate of maize grain in all diets was 32% (wt/wt). No biologically significant, treatment related differences in body weight, food consumption, clinical pathology parameters (hematology, blood chemistry, urinalysis, or organ weight) were observed in rats consuming the diets containing 4114 maize grain compared with rats fed conventional maize diets. A number of histologic observations were noted in this study but were background lesions and representative of what would be expected for rats of this age and strain. An independent panel of experts determined certain observations to be spontaneous and not related to the test diet. Accordingly, these results support the conclusion that 4114 maize grain is as safe and nutritious as conventional maize grain.
{"Chemical": ["glufosinate ammonium"]}