Depression and anxiety symptom network structure among patients with coronary heart disease and association with quality of life: protocol for a multicentre cross-sectional and prospective longitudinal study.

BACKGROUND: Anxiety and depression are critical mental health problems among persons with coronary heart disease (CHD). The range of symptoms is an important stressor for adverse cardiovascular events, and these symptoms can be involved in various ways during the course of CHD. However, the characteristics and mechanisms of comorbidity between the two mental states from the viewpoint of symptom interactions in patients with CHD remain unclear. Therefore, we aim to apply a symptom-oriented approach to identify core and bridge symptoms between anxiety and depression in a population with CHD and to identify differences in network structure over time and symptomatic link profiles. METHODS AND ANALYSIS: We designed a multicentre, cross-sectional, longitudinal study of anxiety and depression symptoms among patients with CHD. We will evaluate degrees of symptoms using the Generalized Anxiety Disorder Scale, the Patient Health Questionnaire and the WHO Quality of Life-Brief version. Patients will be followed up for 1, 3 and 6 months after baseline measurements. We will analyse and interpret network structures using R software and its packages. The primary outcomes of interest will include centrality, bridge connections, estimates, differences in network structures and profiles of changes over time. The secondary outcome measures will be the stability and accuracy of the network. By combining cross-sectional and longitudinal analyses, this study should elucidate the central and potential causative pathways among anxiety and depression symptom networks as well as their temporal stability in patients with CHD. ETHICS AND DISSEMINATION: The project conforms to the ethical principles enshrined in the Declaration of Helsinki (2013 amendment) and all local ethical guidelines. The ethics committee at the University of South China approved the study (Approval ID: 2023-USC-HL-414). The findings will be published and presented at conferences for widespread dissemination. TRIAL REGISTRATION NUMBER: ChiCTR2300075813.

Viologen-Based Photochromic Coordination Polymers for Inkless and Erasable Prints.

Four coordination polymers, namely, [Zn(HL1)(L2)0.5]·H2O (1), [Cd(HL1)(L2)0.5]·H2O (2), [Zn(L1)(L3)0.5]·H2O (3), and [Cd(L1)(L3)0.5] (4) (H3L1 = (3,5-dicarboxyl-phenyl)-(4-(2'-carboxyl-phenyl)-benzyl)ether, H2L2Cl2 = 1,1'-bis(4-carboxy-benzyl)-4,4'-bipyridinium dichloride, and L3Cl2 = 1,1'-dimethyl-4,4'-bipyridylium dichloride), have been synthesized hydrothermally. The structures of compounds 1-4 have been determined by single-crystal X-ray diffraction analyses, and further characterized by elemental analyses, infrared (IR) spectra, powder X-ray diffraction (PXRD) analyses, and thermogravimetric analyses. Compounds 1 and 2 display three-dimensional 2-fold interpenetrating frameworks, whereas compounds 3 and 4 exhibit two-dimensional layer structures. These compounds display photochromic behaviors from pale yellow to green under UV light, visible light, or sunlight. The photochromic mechanisms of these compounds have been studied by IR spectra, PXRD analyses, UV-vis absorption spectra, electron paramagnetic resonance spectra, density functional theory calculations, and X-ray photoelectron spectroscopy. The capabilities of compounds 1 and 2 as inkless and erasable printing media have also been tested. Moreover, the photomodulated fluorescence of these compounds has also been investigated.