Mycotoxin contamination in rice can create a health risk for the consumers. In this study, the measurement of 23 mycotoxins in rice samples (n = 180) was performed using a validated LC–MS/MS method. A food frequency questionnaire was used to get rice consumption data for the assessment of mycotoxin dietary exposure, before calculating the health risk in adults and children of north and south regions of the Pakistani Punjab province. The prevalence of aflatoxin B₁ (56%), aflatoxin B₂ (48%), nivalenol (28%), diacetoxyscirpenol (23%), fumonisin B₁ (42%), zearalenone (15%), HT-2 toxin (10%), deoxynivalenol (8%), and ochratoxin A (6%) was estimated in samples with a mean concentration range between 0.61 and 22.98 µg/kg. Aflatoxin degradation by traditional Pakistani cooking recipes was evaluated and observed to be 41–63%. The dietary exposure to aflatoxins exceeded the tolerable daily intake at all levels, and ochratoxin A and zearalenone posed health risk at high contamination and high consumption levels. The margin of aflatoxin B₁ exposure ranged between 10 and 69 in adults and 10 and 62 in children. The mean cancer risk by aflatoxin B₁ exposure was 0.070 (adults) and 0.071 (children) cases/year/100,000 people in South Punjab population, and 0.122 (adults) and 0.127 (children) cases/year/100,000 people in North Punjab population. This study will provide new insights for the planning and management of mycotoxins in Pakistan.

Analysis of regiocontrol in Pd-catalysed C–H activation leads to observations of aryltrimethylsilyl activation and to superior results with urea-based substrates.

Several closely related palladium-catalysed reactions involve the addition of Pd–C across an alkene, and subsequent β-elimination of Pd–H to give a more substituted alkene. The Pd–C precursor, normally possessing an sp² carbon bound to palladium, can be formed in several different ways, leading to sub-classes of reaction based on a common principle and convergent outcomes. The reaction pathway can vary from simple to highly subtle depending on the nature of the reactants and the ligation of the catalyst. Mechanistic analysis provides results that elucidate the pathway and link the different reaction types. The identification of reactive intermediates by NMR, ES-MS and other spectroscopic techniques, or by less direct methods, is an integral part of the process. This Feature Article covers ligand-free palladium catalysis, including the contributions of the authors, and separates catalysis where ligands are involved into cationic and neutral pathways.

The Pd(II)-catalysed oxidative counterpart of the Heck reaction, originally described by Fujiwara and Moritani, has been studied in detail by a combination of NMR, single-crystal X-ray diffraction and substrate variation. The process involves a palladacycle that is a true intermediate in catalysis. Pd(OAc)₂ is first converted into a more electrophilic palladium species for effective catalysis, defining the main role of added acid. In the course of these studies, three palladacyclic intermediates have been characterised by X-ray diffraction, firstly the directly produced acetate complex 1, the camphorsulfonate complex 2, and additionally tosylate 3, isolated from a reacting system, demonstrating the accessibility of a cationic or comparably electrophilic palladium entity under turnover conditions. The isolated palladacycle 3 is also an effective catalyst. The reaction rate shows a first-order dependency on [anilide] and [Pd], but not on benzoquinone, alkene or p-TsOH. Acid, in the form of p-TsOH, is an essential component, whereas acetate is dispensable. A crossover experiment involving distinct substitution in reactant and palladacycle demonstrates that the palladacycle is directly involved in the catalysis.