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Substances of unknown or variable composition, complex reaction products, or biological materials (UVCBs) are over 70 000 “complex” chemical mixtures produced and used at significant levels worldwide. Due to their unknown or variable composition, applying chemical assessments originally developed for individual compounds to UVCBs is challenging, which impedes sound management of these substances. Across the analytical sciences, toxicology, cheminformatics, and regulatory practice, new approaches addressing specific aspects of UVCB assessment are being developed, albeit in a fragmented manner. This review attempts to convey the “big picture” of the state of the art in dealing with UVCBs by holistically examining UVCB characterization and chemical identity representation, as well as hazard, exposure, and risk assessment. Overall, information gaps on chemical identities underpin the fundamental challenges concerning UVCBs, and better reporting and substance characterization efforts are needed to support subsequent chemical assessments. To this end, an information level scheme for improved UVCB data collection and management within databases is proposed. The development of UVCB testing shows early progress, in line with three main methods: whole substance, known constituents, and fraction profiling. For toxicity assessment, one option is a whole-mixture testing approach. If the identities of (many) constituents are known, grouping, read across, and mixture toxicity modeling represent complementary approaches to overcome data gaps in toxicity assessment. This review highlights continued needs for concerted efforts from all stakeholders to ensure proper assessment and sound management of UVCBs.

The article describes the preparation of a magnet-assembled alignment device for the amperometric detection of carbohydrates in combination with capillary electrophoresis (CE). It consists of a self-positioning copper disc detection electrode plate, an NdFeB magnet, a painted iron screw nut as well as a cap bearing a grounding electrode, an auxiliary electrode and a reference electrode. Coaxially aligned copper wire and stainless steel tube were enclosed between two poly(methyl methacrylate) plates by far infrared-assisted encapsulation to fabricate the self-positioning electrode plate. The performance and advantages of the alignment device were demonstrated by the separation and detection of standard mixtures of mannitol, sucrose, glucose and fructose by CE. The four carbohydrates were well separated within 13 min in a 40-cm long capillary at a separation voltage of 9 kV using a 75 mM NaOH aqueous solution. Good linearity was observed between the peak current and concentration of carbohydrates over three orders of magnitude with detection limits (S/N = 3) ranging from 0.7 to 0.9 µM. The present system exhibited long-term stability and reproducibility with relative standard deviations of less than 5% for peak currents (n = 15). The advantages of the magnet-assembled alignment device include its simple design and construction, high alignment reproducibility, ease of operation, high degree of integration, portability and low cost. The method has been successfully applied in the determination of carbohydrates in Zingiber officinale Roscoe. Coaxially aligned copper wire and stainless steel guiding tube were enclosed between two PMMA plates by far infrared-assisted encapsulation to prepare self-positioning copper disc detection plate that was sandwiched between a magnet and a painted iron screw nut to form magnet-assembled alignment device for the amperometric detection of capillary electrophoresis.

A product family optimum design method based on a Novel Immune Clonal Algorithm (NICA-II) is proposes in this paper to realize product family flexible design. Firstly, the product family dynamic uncertain requirements analysis and forecasting techniques are researched in this paper, aims to improve the dynamic response ability of the product family, the concept of flexible product platform is introduced and the product family flexible design model is proposed. Secondly, process model of flexible product family design based on multi-objective optimization has been established. The flexible product family design method is carried out in two stages. In the first stage, each product is optimized independently via NICA-II and the product platform constant parameter and its value is obtained according to the change ratio of design variables; In the second stage, the scaling variables of each product are solved via NICA-II based on the optimization objectives improving the performance in constraint of restrictions. Finally, the design of a family of general motor is used as an example to benchmark the efficiency and superiority of the proposed method.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants of environmental concern. Bioremediation, relying on stimulation of natural microbial degradation processes, is a well-established technology to clean up PAH-contaminated soils. However, bioremediation does not necessarily lead to a reduction in soil toxicity. PAH-contaminated sites are affected by extremely complex mixtures, like coal tar or creosote, and biotransformation products or co-occurring compounds can also contribute to the overall toxicological effects of contaminated soil before and after bioremediation. Therefore, the objective of this dissertation was to use non-target analysis workflows to identify the genotoxic transformation products, important co-occurring pollutants, and the unrecognized biotransformation pathways that could contribute to explain the toxicological effects observed beyond parent PAHs. To identify the source(s) of increased genotoxicity in bioremediated soil, we pursued a non-target analytical approach combining effect-directed analysis (EDA) and metabolite profiling to compare extracts of PAH-contaminated soil before and after bioremediation. A compound with the composition C15H8O2 and four methylated homologues were shown to accumulate as a result of bioreactor treatment, and the C15H8O2 compound was determined to be genotoxic. Its structure was established as a heretofore unidentified α,β-unsaturated lactone, 2H-naphtho[2,1,8-def ]chromen-2-one (NCO), which was confirmed by synthesis. It also accumulated in aerobically incubated soil from two additional PAH-contaminated sites and was formed from pyrene by two pyrene-degrading bacterial cultures known to be geographically widespread, underscoring its potential environmental significance. Azaarenes are nitrogen heterocyclic polyaromatic compounds that co-occur with PAHs but have been poorly studied in environmental systems. High resolution mass spectrometry (HRMS) and mass-defect filtering were applied to four PAH-contaminated samples to analyze the their diversity, abundance, and biodegradation behavior. The diversity, relatively high concentrations, and persistence of high-molecular-weight azaarenes were highlighted, and isomer-selective biodegradation was observed. To help elucidate PAH biodegradation pathways and endpoints in contaminated soil, HRMS and stable isotope-assisted metabolomics (SIAM) workflows were tested and applied to a PAH-contaminated soil. Uniformly 13C-labeled fluoranthene, pyrene, or benzo[a]anthracene were spiked into the soil and incubated in microcosms. With SIAM, known and unknown metabolites such as ring-cleavage products and conjugates were detected, and the transformation pathways leading to their formation proposed.