Investigation of Nucleation and Growth at a Liquid–Liquid Interface by Solvent Exchange and Synchrotron Small-Angle X-Ray Scattering

Hybrid nanomaterials possess complex architectures that are driven by a self-assembly process between an inorganic element and an organic ligand. The properties of these materials can often be tuned by organic ligand variation, or by swapping the inorganic element. This enables the flexible fabrication of tailored hybrid materials with a rich variety of properties for technological applications. Liquid-liquid interfaces are useful for synthesizing these compounds as precursors can be segregated and allowed to interact only at the interface. Although procedurally straightforward, this is a complex reaction in an environment that is not easy to probe. Here, we explore the interfacial crystallization of mithrene, a supramolecular multi-quantum well. This material sandwiches a well-defined silver-chalcogenide layer between layers of organic ligands. Controlling mithrene crystal size and morphology to be useful for applications requires understanding details of its crystal growth, but the specific mechanism for this reaction remain only lightly investigated. We performed a study of mithrene crystallization at an oil-water interfaces to elucidate how the interfacial free energy affects nucleation and growth. We exchanged the oil solvent on the basis of solvent viscosity and surface tension, modifying the dynamic contact angle and interfacial free energy. We isolated and characterized the reaction byproducts via scanning electron microscopy (SEM). We also developed a high-throughput small angle X-ray scattering (SAXS) technique to measure crystallization at short reaction timescales (minutes). Our results showed that modifying interfacial surface energy affects both the reaction kinetics and product size homogeneity and yield. Our SAXS measurements reveal the onset of crystallinity after only 15 min. These results provide a template for exploring directed synthesis of complex materials via experimental methods.

Comparative Effects of Organic and Conventional Cropping Systems on Trace Elements Contents in Vegetable Brassicaceae: Risk Assessment

Genotypes selected from 3 plant species (Brassica rapa, Eruca vesicaria and Sinapis alba) belonging to the Brassicaceae family were chosen to compare the concentrations of 9 inorganic elements (Cd, Co, Cr, Cu, Fe, Ni, Mn, Pb and Zn) in these varieties, that were grown under both conventional and organic conditions during two agricultural seasons (2018/2019 and 2019/2020) on two different experimental farms (Farm I and Farm II). We found that, together with agriculture practices, the inorganic element concentrations in Brassicas depended on many other factors, including soil characteristics. However, there were no conclusive results indicating a lower heavy metal content or a higher nutritionally beneficial trace elements content in vegetables grown under organic agriculture. Finally, a probabilistic assessment (@Risk) derived from the consumption of 150–200 g of these vegetables showed that organic Brassicas fulfill in comparison with the conventional ones, similar Dietary Reference Intakes (DRI) percentages for Co, Cr, Cu, Fe, Mn and Zn. Regarding heavy metals (Cd, Ni and Pb), we only found slight differences (mainly in the case of Pb) in the Tolerable Intakes (TI) between both cropping systems.

Yellow phosphorous ingestion cause liver dysfunction and internal bleeding: a case study

Objective The purpose of this case report was to create awareness among scientific fraternity and those who are in the regular usage of the yellow phosphorous compound. Yellow phosphorus is an inorganic element that is poisonous to humans (yellowish, waxy, crystal-clear solid with a pungent odor). Case presentation The patient treatment chart was reviewed and the patient’s condition was evaluated daily. Consumption of toxic doses causes shock and cardiovascular failure within 2–3 h of ingestion, and peak levels are reached when distributed to all tissues after absorption. Here, we report a case of self-harm with the ingestion of rat killer paste, and the patient suffered internal bleeding and acute liver failure. Conclusion Rodenticides remain the primary cause of morbidity and mortality, internal bleeding is the major risks of rodenticide poisoning.

Determination of Inorganic Element Concentrations in Nardostachys jatamansi DC

Background:: Nardostachys jatamansi DC. is indigenous to the Himalayan regions of India and Tibetan plateau of China, and widely used as drugs for treating various neurological disorders, insomnia, hysteria and depressive illness. However, beyond the huge efforts to the organic components in N. jatamansi, the elemental contents have not been investigated, which are important for the quality control and biosafety evaluation of N. jatamansi. Objective:: In this study, we quantified the element concentrations in N. jatamansi. Methods:: Twenty-five N. jatamansi samples were collected in Sichuan, Tibet, Qinghai and Gansu provinces. The samples were digested and subjected to inductively coupled plasma optical emission spectrometer (ICP-OES) measurements. Results:: The results indicated that Al, B, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pd, Si, Sr, Ti and Zn were detected in N. jatamansi samples. The chemometrics approaches indicated that N. jatamansi samples from Sichuan and Tibet shared similar elemental patterns. The altitude did not statistically influence the elemental patterns of N. jatamansi samples, while the K, P, Ba and Cd showed meaningful decreases. The high Ba contents in all samples suggested the potential toxicity of heavy metal to patients. Conclusion:: The inorganic element quantification of N. jatamansi is useful in the genuine regional drug identification, quality control and biosafety evaluations.

Portable EDXRF and Principal Component Analysis for inorganic element determination and provenance of eye shadows

Nos dias de hoje, produtos cosméticos desempenham um importante papel na vida de quase todas as pessoas. Homens e mulheres dedicam muito tempo, recursos e esforços para cultivar a higiene pessoal e a melhor aparência possível ao longo de suas vidas. Um dos tipos de cosméticos mais utilizados é a sombra para os olhos. A fluorescência de raios X (XRF) é uma técnica bem estabelecida, conhecida por sua capacidade de identificar e quantificar espécies inorgânicas de maneira simples, rápida e não-destrutiva, no entanto, não é amplamente utilizada em análises de produtos cosméticos. A fim de se mostrar a potencialidade da técnica, fluorescência de raios X por dispersão em energia portátil foi empregada na quantificação de elementos inorgânicos em 40 sombras para os olhos brasileiras. Foi possível identificar e quantificar os elementos Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn e Bi. Utilizando a análise de componentes principais, foi possível distinguir os diferentes fabricantes. A metodologia de fluorescência de raios X associada à análise de componentes principais provou ser uma ferramenta valiosa para a discriminação e caracterização de produtos cosméticos.