Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

Family Structure and the Nature of Couple Relationships: Relationship Distress, Separation, Divorce, and Repartnering

The goal of this chapter is to review the current state of theoretical and empirical knowledge on the quality of the couple relationship and the family structure as determinants of parenting behavior. Ample evidence has accumulated over the past few decades that the functioning of the interparental relationship is pivotal for positive and supportive parenting. Supporting the spillover theory, relationship distress among parenting couples may increase child maladjustment, both directly and indirectly, by disrupted child-rearing and less optimal coparenting. In separated or divorced families, coparenting is a key concept to explain why some couples succeed in compartmentalizing their parenting from their spousal role. As such, cooperative coparenting has been firmly established as a central protective factor buffering the impact of parental separation on children. Based on the reviewed data among stepfamilies, it can be tentatively concluded that a cohabiting stepparent may become a significant new caregiver for the child, but only on condition of good stepparent–child relationship quality, which has emerged as crucially important for children’s adjustment in the new family environment. This chapter posits that the interparental relationship can be regarded as the key relation which is responsible for family functioning across different family types (nuclear, divorced, and stepfamilies). As a practical implication, it might, therefore, be wise to strengthen this core relationship as a potential leverage point to positively affect parents’ individual parenting and their joint coparental alliance

Mass appeal:metabolite identification in mass spectrometry-focused untargeted metabolomics

Metabolomics has advanced significantly in the past 10 years with important developments related to hardware, software and methodologies and an increasing complexity of applications. In discovery-based investigations, applying untargeted analytical methods, thousands of metabolites can be detected with no or limited prior knowledge of the metabolite composition of samples. In these cases, metabolite identification is required following data acquisition and processing. Currently, the process of metabolite identification in untargeted metabolomic studies is a significant bottleneck in deriving biological knowledge from metabolomic studies. In this review we highlight the different traditional and emerging tools and strategies applied to identify subsets of metabolites detected in untargeted metabolomic studies applying various mass spectrometry platforms. We indicate the workflows which are routinely applied and highlight the current limitations which need to be overcome to provide efficient, accurate and robust identification of metabolites in untargeted metabolomic studies. These workflows apply to the identification of metabolites, for which the structure can be assigned based on entries in databases, and for those which are not yet stored in databases and which require a de novo structure elucidation.