Analyses of Factors Associated with Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Review.

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is the exacerbation of a range of respiratory symptoms during the stable phase of chronic obstructive pulmonary disease (COPD). AECOPD is thus a dangerous stage and key event in the course of COPD, as its deterioration and frequency seriously affects the quality of life of patients and shortens their survival. Acute exacerbations occur and develop due to many factors such as infection, tobacco smoke inhalation, air pollution, comorbidities, airflow limitation, various biomarkers, history of previous deterioration, natural killer cell abnormalities, immunoglobulin G deficiency, genetics, abnormal muscle and nutritional status, negative psychology, and seasonal temperature changes. There is relatively limited research on the impact of the role of standardized management on the alleviation of AECOPD. However, with the establishment of relevant prevention and management systems and the promotion of artificial intelligence technology and Internet medical approaches, long-term effective and standardized management of COPD patients may help to achieve the quality of life and disease prognosis in COPD patients and reduce the risk of AE.

Using the theory of planned behavior model to predict factors influencing breastfeeding behavior among preterm mothers at week 6 postpartum: the mediating effect of breastfeeding intention.

Background: Exclusive breastfeeding (EBF) in the first 6 weeks postpartum is key to continued breastfeeding. This study aimed to explore the role of EBF-related predictors (particularly breastfeeding intention) in breastfeeding behavior among preterm mothers at week 6 postpartum based on the theory of planned behavior (TPB). Methods: A total of 352 mothers of preterm infants were recruited, 340 of whom participated in this study. Prior to discharge, participants completed the Chinese versions of the modified Breastfeeding Attrition Predictive Tool, the Breastfeeding Knowledge Questionnaire (BKQ), the Infant Feeding Intention, and the Edinburgh Postnatal Depression Scale. Responses to the items of the Breastfeeding Behavioral Questionnaire (BBQ) were also collected by telephone at week 6 postpartum. The final analyses included 321 participants who completed the full two-wave data collection. Results: The fitness indices of the modified TPB model were acceptable. Breastfeeding knowledge and EBF before discharge positively impacted breastfeeding intention, whereas depression had a negative impact. Before discharge, breastfeeding intention fully mediated the impacts of breastfeeding attitude, social and professional support, knowledge, depression, and EBF on breastfeeding behavior and partially mediated the influence of perceived breastfeeding control on breastfeeding behavior. Conclusion: These findings indicate that TPB accurately predicts breastfeeding behavior among preterm mothers at week 6 postpartum, and breastfeeding intention is key to the above-mentioned EBF-related factors and breastfeeding behavior. The findings underline the need for further longitudinal studies and corresponding interventions for preterm mothers with a high risk of EBF attrition.

Predictive factors of exclusive breastfeeding attrition at Week 6 post-partum among mothers of preterm infants based on the theory of planned behaviour.

Breastfeeding plays an important role in the growth and development of preterm infants, and exclusive breastfeeding (EBF) in the first 6 weeks post-partum is the key to continuous breastfeeding. This study was designed to explore the influencing factors that contribute to breastfeeding attrition among mothers of preterm infants at Week 6 post-partum based on the theory of planned behaviour (TPB). We herein adopted a prospective observational study design in which 97 mothers who exclusively breastfed at Week 6 post-partum at a tertiary specialised hospital in Shanghai from June 2021 to February 2022 were taken as the EBF group, and 179 mothers without EBF were assigned to the EBF attrition group. Through an extensive literature review and expert consultation, we determined the possible factors influencing EBF attrition, analysed those factors that showed statistical significance in our univariate analysis by applying binary logistic regression, and constructed a nomogram model for predicting EBF attrition. The results revealed that negative breastfeeding sentiment (odds ratio [OR] = 1.006; 95% confidence interval [CI], 1.000-1.011) generated a greater risk of breastfeeding attrition. However, positive breastfeeding sentiment (OR = 0.991; 95% CI, 0.983-0.999), social and professional support (OR = 0.993; 95% CI, 0.987-0.999), breastfeeding control (OR = 0.945; 95% CI, 0.896-0.996), knowledge (OR = 0.893; 95% CI, 0.799-0.998), and intention to EBF at Week 6 post-partum (OR = 0.522; 95% CI, 0.276-0.988) were the protective factors and facilitated the development of our nomogram model. The Hosmer-Lemeshow goodness-of-fit test generated a χ2 value of 11.344 (p = 0.183) and an area under the curve of 0.822 (95% CI, 0.771-0.873). The C-index was 0.800 in the internal bootstrap validation, indicating that the nomogram model possessed favourable predictive accuracy and discrimination.

Probing the glass transition in reversible cross-linked polymer composites.

Understanding the nature of glass transition is still a great challenge. Glass transition is widely observed in many glassy materials; however, it has never been unambiguously observed in reversible cross-linked polymer, which is an ideal model of the percolation process. Herein, we report the synthesis of a reversible cross-linked polymer incorporated with four-armed Diels-Alder (DA) dynamic covalent bonds, and the robust experimental observation of percolation-induced glass transition in this reversible four-armed cross-linked polymer (DAMF1). Temperature-modulated differential scanning calorimetry (TMDSC) experiment results clearly revealed the presence of a glass transition along with an endothermic or exothermic peak associated with DA/retro-DA (RDA) reaction related to the reconstitution/disassociation of the DAMF1's four-armed cross-linked network. In situ 13C variable-temperature solid-state NMR experiments further confirmed the DA/RDA reaction during glass transition at a molecular level. The above experimental results provide a direct experimental evidence for the recently developed percolation model of glass transition, which provides new insights into the nature of glass transition.

Multiple-responsive shape memory polyacrylonitrile/graphene nanocomposites with rapid self-healing and recycling properties.

It still remains a great challenge to endow polymer materials with multiple superior material properties by precise molecular design. Herein, we report a Diels-Alder (DA) based crosslinked polyacrylonitrile/graphene nanocomposite (PAN-DA/GR), which has multiple-responsive properties of shape memory, self-healing, and reprocessing in addition to enhanced mechanical properties. The graphene sheets, which are well dispersed in the DA-based crosslinked PAN network, can act as intrinsic localized thermal sources by converting the absorbed external IR/microwave energies into heat, to trigger the glass transition for elasticity-based shape memory properties and retro-DA (rDA) reactions for healing. The incorporation of Diels-Alder bonds also gives the material solid state plasticity through topological network rearrangement, thus leading to versatile shape adaptability. Moreover, both regional shape control and targeted self-healing of the nanocomposites can be simply achieved by IR laser irradiation. Besides, the incorporation of a small amount of graphene can significantly improve the mechanical strength with respect to the DA-based crosslinked PAN. Both DSC and in situ variable temperature 13C solid-state NMR experiments were used to monitor the reversible DA reactions.