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:

Recently introduced foods as new allergenic sources: sensitisation to Goji berries (Lycium barbarum). Goji berries (GB) have been introduced in Western diet. Preliminary reports have demonstrated its allergenic capacity. The objectives of the study were to investigate the frequency of sensitisation and the allergens involved. 566 individuals, with respiratory or cutaneous symptoms were skin-prick tested with GB extract. Thirty three were positive (5.8%). 94% were sensitised to other allergens. Specific IgE to GB, peach, tomato and nut-mix was measured. Thirteen individuals from 24 available sera (54.2%) had positive specific IgE. 92.3% of GB positive patients were positive to peach. Seven individuals recognised 8 bands and six recognised a 7kDa band. This band was identified as a LTP by MS/MS. Cross-reactivity was demonstrated with tomato, tobacco, nutmix, Artemisia pollen and purified Lyc e 3 and Pru p 3. GB are a new allergenic source with high prevalence of sensitisation. LTP seems to be the major allergen involved in sensitisation and cross-reactivity.
{"Chemical": []}