Mendelian randomization analyses in cardiometabolic disease:the challenge of rigorous interpretations of causality

Mendelian randomization (MR) is a burgeoning field that involves the use of genetic variants to assess causal relationships between exposures and outcomes. MR studies can be straightforward; for example, genetic variants within or near the encoding locus that is associated with protein concentrations can help to assess their causal role in disease. However, a more complex relationship between the genetic variants and an exposure can make findings from MR more difficult to interpret. In this Review, we describe some of these challenges in interpreting MR analyses, including those from studies using genetic variants to assess causality of multiple traits (such as branched-chain amino acids and risk of diabetes mellitus); studies describing pleiotropic variants (for example, C-reactive protein and its contribution to coronary heart disease); and those investigating variants that disrupt normal function of an exposure (for example, HDL cholesterol or IL-6 and coronary heart disease). Furthermore, MR studies on variants that encode enzymes responsible for the metabolism of an exposure (such as alcohol) are discussed, in addition to those assessing the effects of variants on time-dependent exposures (extracellular superoxide dismutase), cumulative exposures (LDL cholesterol), and overlapping exposures (triglycerides and non-HDL cholesterol). We elaborate on the molecular features of each relationship, and provide explanations for the likely causal associations. In doing so, we hope to contribute towards more reliable evaluations of MR findings

4,9-Dihydro-4,4,9,9-tetrahexyl‑<i>s</i>‑indaceno[1,2‑<i>b</i>:5,6‑<i>b</i>′]dithiophene as a π‑Spacer of Donor−π–Acceptor Dye and Its Photovoltaic Performance with Liquid and Solid-State Dye-Sensitized Solar Cells

A new D−π-A organic dye, LC-5, containing 4,9-dihydro-4,4,9,9-tetrahexyl-<i>s</i>-indaceno­[1,2-<i>b</i>:5,6-<i>b</i>′]-dithiophene as a novel π-conjugated spacer has been synthesized and tested as a sensitizer in dye-sensitized solar cells (DSC). Volatile and ionic liquid electrolytes have been used in conjunction with the synthesized dye, and the electrolyte influence on the photovoltaic performance of DSCs was investigated. A detailed investigation, including transient photocurrent/photovoltage decay measurements and electrochemical impedance spectroscopy data, provide important conclusions about the influence of electrolytes on the photovoltaic parameters