Buffer Chain Model for Understanding Crystallization Competition in Conjugated Polymers.

It remains challenging to comprehensively understand the packing models of conjugated polymers, in which side chains play extremely critical roles. The side chains are typically flexible and non-conductive and are widely used to improve the polymer solubility in organic solutions. Herein, a buffer chain model is proposed to describe link between conjugated backbone and side chains for understanding the relationship of crystallization competition of conductive conjugated backbones and non-conductive side chains. A longer buffer chain is beneficial for alleviating such crystallization competition and further promoting the spontaneous packing of conjugated backbones, resulting in enhanced charge transport properties. Our results provide a novel concept for designing conjugated polymers towards ordered organization and enhanced electronic properties and highlight the importance of balancing the competitive interactions between different parts of conjugated polymers.

Association of fat distribution differences in infertile women with assisted reproductive outcomes: A prospective cohort study.

OBJECTIVE: To investigate the impacts of fat distribution on assisted reproductive outcomes in infertile women. METHODS: The study randomly recruited 576 infertile women who underwent assisted reproductive technology treatment at the Reproductive Medicine Center of the First Affiliated Hospital of Anhui Medical University between July and October 2022. Questionnaires and body composition measurements were administered to assess baseline information and fat distribution. The numbers of oocytes, zygotes presenting with two pronuclei (2PN), and available embryos were tracked at the end of the cycle. Multifactorial logistic regression models and restricted cubic spline (RCS) curve models were used to explore the relationships between fat distribution and reproductive outcomes while controlling for confounding factors. RESULTS: The study found that the participants had a mean age of 30.82 years. The analysis showed that there was a significant difference between the amount of leg body fat mass (LBFM) and the distribution of reproductive outcomes. However, there was no significant correlation between the level of visceral fat and reproductive outcomes. After taking confounding factors into account, the multifactorial regression analysis showed that the total body fat mass and the number of oocytes (odds ratio (OR) 0.92, 95% confidence interval (CI) 0.84-0.99), 2PN (OR 0.92, 95% CI 0.84-0.99), and embryos available for transfer (OR 0.90, 95% CI 0.82-0.99) were negatively correlated. RCS modeling revealed a linear dose-response relationship between LBFM and assisted reproductive outcomes. CONCLUSION: Fat distribution varies among infertile women, and higher amounts of fat are associated with poorer assisted reproductive outcomes.

Assessing the Role of BN-Embedding Position in B2N2-Perylenes.

Incorporating heteroatoms can effectively modulate the molecular optoelectronic properties. However, the fundamental understanding of BN doping effects in BN-embedded polycyclic aromatic hydrocarbons (PAHs) is underexplored, lacking rational guidelines to modulate the electronic structures through BN units for advanced materials. Herein, a concise synthesis of novel B2N2-perylenes with BN doped at the bay area is achieved to systematically explore the doping effect of BN position on the photophysical properties of PAHs. The shift of BN position in B2N2-perylenes alters the π electron conjugation, aromaticity and molecular rigidness significantly, achieving substantially higher electron transition abilities than those with BN doped in the nodal plane. It is further clarified that BN position dominates the photophysical properties over BN orientation. The revealed guideline here may apply generally to novel BN-PAHs, and aid the advancement of BN-PAHs with highly-emissive performance.

Achieving Ideal and Environmentally Stable n-Type Charge Transport in Polymer Field-Effect Transistors.

Realizing ideal charge transport in field-effect transistors (FETs) of conjugated polymers is crucial for evaluating device performance, such as carrier mobility and practical applications of conjugated polymers. However, the current FETs using conjugated polymers as the active layers generally show certain non-ideal transport characteristics and poor stability. Here, ideal charge transport of n-type polymer FETs is achieved on flexible polyimide substrates by using an organic-inorganic hybrid double-layer dielectric. Deposited conjugated polymer films show highly ordered structures and low disorder, which are supported by grazing-incidence wide-angle X-ray scattering, near-edge X-ray absorption fine structure, and molecular dynamics simulations. Furthermore, the organic-inorganic hybrid double-layer dielectric provides low interfacial defects, leading to excellent charge transport in FETs with high electron mobility (1.49 ± 0.46 cm2 V-1 s-1) and ideal reliability factors (102 ± 7%). Fabricated polymer FETs show a self-encapsulation effect, resulting in high stability of the FET charge transport. The polymer FETs still work with high mobility above 1 cm2 V-1 s-1 after storage in air for more than 300 days. Compared with state-of-the-art conjugated polymer FETs, this work simultaneously achieves ideal charge transport and environmental stability in n-type polymer FETs, facilitating rapid device optimization of high-performance polymer electronics.

Azonia-Naphthalene: A Cationic Hydrophilic Building Block for Stable N-Type Organic Mixed Ionic-Electronic Conductors.

Conjugated polymers that can efficiently transport both ionic and electronic charges have broad applications in next-generation optoelectronic, bioelectronic, and energy storage devices. To date, almost all the conjugated polymers have hydrophobic backbones, which impedes efficient ion diffusion/transport in aqueous media. Here, we design and synthesize a novel hydrophilic polymer building block, 4a-azonia-naphthalene (AN), drawing inspiration from biological systems. Because of the strong electron-withdrawing ability of AN, the AN-based polymers show typical n-type charge transport behaviors. We find that cationic aromatics exhibit strong cation-π interactions, leading to smaller π-π stacking distance, interesting ion diffusion behavior, and good morphology stability. Additionally, AN enhances the hydrophilicity and ionic-electronic coupling of the polymer, which can help to improve ion diffusion/injection speed, and operational stability of organic electrochemical transistors (OECTs). The integration of cationic building blocks will undoubtedly enrich the material library for high-performance n-type conjugated polymers.

Research Progress on Neurodevelopmental Toxicity in Offspring after Indirect Exposure to PFASs in Early Life.

Per- and polyfluoroalkyl substances (PFASs) are widespread environmental pollutants. There is increasing evidence that PFASs have various adverse health effects, including renal toxicity, metabolic dysfunction, endocrine disruption, and developmental toxicity. PFASs have been found to accumulate in the placenta, and some PFASs can cross the placental barrier and subsequently accumulate in the fetus via the maternal-fetal circulation. An increasing number of studies have shown that early life exposure to PFASs can affect fetal neurodevelopment. This paper reviews the characteristics of indirect exposure to PFASs in early life, the effects on neurodevelopment in offspring, and the possible mechanisms of toxic effects.

Visualizing the multi-level assembly structures of conjugated molecular systems with chain-length dependent behavior.

It remains challenging to understand the structural evolution of conjugated polymers from single chains to solvated aggregates and film microstructures, although it underpins the performance of optoelectrical devices fabricated via the mainstream solution processing method. With several ensemble visual measurements, here we unravel the morphological evolution process of a model system of isoindigo-based conjugated molecules, including the hidden molecular assembly pathways, the mesoscale network formation, and their unorthodox chain dependence. Short chains show rigid chain conformations forming discrete aggregates in solution, which further grow to form a highly ordered film that exhibits poor electrical performance. In contrast, long chains exhibit flexible chain conformations, creating interlinked aggregates networks in solution, which are directly imprinted into films, forming interconnective solid-state microstructure with excellent electrical performance. Visualizing multi-level assembly structures of conjugated molecules provides a deep understanding of the inheritance of assemblies from solution to solid-state, accelerating the optimization of device fabrication.

Polymer Semiconductors: Synthesis, Processing, and Applications.

Polymer semiconductors composed of a carbon-based π conjugated backbone have been studied for several decades as active layers of multifarious organic electronic devices. They combine the advantages of the electrical conductivity of metals and semiconductors and the mechanical behavior of plastics, which are going to become one of the futures of modulable electronic materials. The performance of conjugated materials depends both on their chemical structures and the multilevel microstructures in solid states. Despite the great efforts that have been made, they are still far from producing a clear picture among intrinsic molecular structures, microstructures, and device performances. This review summarizes the development of polymer semiconductors in recent decades from the aspects of material design and the related synthetic strategies, multilevel microstructures, processing technologies, and functional applications. The multilevel microstructures of polymer semiconductors are especially emphasized, which plays a decisive role in determining the device performance. The discussion shows the panorama of polymer semiconductors research and sets up a bridge across chemical structures, microstructures, and finally devices performances. Finally, this review discusses the grand challenges and future opportunities for the research and development of polymer semiconductors.

Origin and diversification of a Himalayan orchid genus Pleione.

Pleione is an orchid endemically distributed in high mountain areas across the Hengduan Mountains (HDM), Himalayas, Southeast Asia and South of China. The unique flower shapes, rich colors and immense medicinal importance of Pleione are valuable ornamental and economic resources. However, the phylogenetic relationships and evolutionary history of the genus have not yet been comprehensively resolved. Here, the evolutionary history of Pleione was investigated using single-copy gene single nucleotide polymorphisms and chloroplast genome datasets. The data revealed that Pleione could be divided into five clades. Discordance in topology between the two phylogenetic trees and network and D-statistic analyses indicated the occurrence of reticulate evolution in the genus. The evolution could be attributed to introgression and incomplete lineage sorting. Ancestral area reconstruction suggested that Pleione was originated from the HDM. Uplifting of the HDM drove rapid diversification by creating conditions favoring rapid speciation. This coincided with two periods of consolidation of the Asian monsoon climate, which caused the first rapid diversification of Pleione from 8.87 to 7.83 Mya, and a second rapid diversification started at around 4.05 Mya to Pleistocene. The interaction between Pleione and climate changes, especially the monsoons, led to the current distribution pattern and shaped the dormancy characteristic of the different clades. In addition to revealing the evolutionary relationship of Pleione with orogeny and climate changes, the findings of this study provide insights into the speciation and diversification mechanisms of plants in the East Asian flora.

Disorder-tuned conductivity in amorphous monolayer carbon.

Correlating atomic configurations-specifically, degree of disorder (DOD)-of an amorphous solid with properties is a long-standing riddle in materials science and condensed matter physics, owing to difficulties in determining precise atomic positions in 3D structures1-5. To this end, 2D systems provide insight to the puzzle by allowing straightforward imaging of all atoms6,7. Direct imaging of amorphous monolayer carbon (AMC) grown by laser-assisted depositions has resolved atomic configurations, supporting the modern crystallite view of vitreous solids over random network theory8. Nevertheless, a causal link between atomic-scale structures and macroscopic properties remains elusive. Here we report facile tuning of DOD and electrical conductivity in AMC films by varying growth temperatures. Specifically, the pyrolysis threshold temperature is the key to growing variable-range-hopping conductive AMC with medium-range order (MRO), whereas increasing the temperature by 25 °C results in AMC losing MRO and becoming electrically insulating, with an increase in sheet resistance of 109 times. Beyond visualizing highly distorted nanocrystallites embedded in a continuous random network, atomic-resolution electron microscopy shows the absence/presence of MRO and temperature-dependent densities of nanocrystallites, two order parameters proposed to fully describe DOD. Numerical calculations establish the conductivity diagram as a function of these two parameters, directly linking microstructures to electrical properties. Our work represents an important step towards understanding the structure-property relationship of amorphous materials at the fundamental level and paves the way to electronic devices using 2D amorphous materials.

Density of States Engineering of n-Doped Conjugated Polymers for High Charge Transport Performances.

Charge transport of conjugated polymers in functional devices closely relates to their density of states (DOS) distributions. However, systemic DOS engineering for conjugated polymers is challenging due to the lack of modulated methods and the unclear relationship between DOS and electrical properties. Here, the DOS distribution of conjugated polymers is engineered to enhance their electrical performances. The DOS distributions of polymer films are tailored using three processing solvents with different Hansen solubility parameters. The highest n-type electrical conductivity (39 ± 3 S cm-1 ), the highest power factor (63 ± 11 µW m-1 K-2 ), and the highest Hall mobility (0.14 ± 0.02 cm2 V-1 s-1 ) of the polymer (FBDPPV-OEG) are obtained in three films with three various DOS distributions, respectively. Through theoretical and experimental exploration, it is revealed that the carrier concentration and transport property of conjugated polymers can be efficiently controlled by DOS engineering, paving the way for rationally fabricating organic semiconductors.

Posttraumatic stress disorder symptoms among Chinese college students following the COVID-19 outbreak.

Objective: This study examined the prevalence of posttraumatic stress disorder (PTSD) symptoms in college students 1 month after the lockdown of Wuhan to identify possible risk factors for PTSD symptoms in a cross-sectional study. Methods: Out of 10,502 who responded, 9,274 students impacted by the COVID-19 pandemic were included in our study. PTSD symptoms was evaluated by the Impact of Event Scale-revised (IES-R). Anxiety/depression symptoms were evaluated by the Kessler Psychological Distress Scale (K10). Personality traits, coping style, and social support were assessed by the Eysenck Personality Questionnaire-Revised Short Scale for Chinese (EPQ-RSC), the Simplified Coping Style Questionnaire (SCSQ), and the Social Support Rating Scale (SSRS). Logistic regression analysis was utilized to further explore risk factors for PTSD symptoms. Results: More than 1 month after the COVID-19 outbreak, 13.1% of college students developed PTSD symptoms, indicating that COVID-19 associated stressful experiences were connected with PTSD symptoms. After the COVID-19 outbreak, subjects with symptomatologic PTSD symptoms were more likely to experience strained relationships with their family, to have close contact with COVID-19 patients and to drop out of college. The logistic regression model demonstrated the association factors of PTSD symptoms. Neuroticism, psychoticism and an avoidant coping style were associated with increased risk for PTSD symptoms, while an active coping style was protective against PTSD symptoms during this pandemic. Conclusion: The results showed that PTSD symptoms was prevalent in Chinese college students 1 month after the COVID-19 outbreak. Effective psychological support work should be carried out accordingly.

Prevalence and risk factors of post-traumatic stress disorder symptoms among Chinese health care workers following the COVID-19 pandemic.

In December 2019, coronavirus disease 2019 (COVID-19) appeared in Wuhan (Hubei, China) and subsequently swept the globe. In addition to the risk of infection, there is a strong possibility that post-traumatic stress disorder (PTSD) may be a secondary effect of the pandemic. Health care workers (HCWs) participating in the pandemic are highly exposed to and may bear the brunt out of stressful or traumatic events. In this cross-sectional study, we assessed the morbidity and risk factors of PTSD symptoms among Chinese HCWs. A total of 457 HCWs were recruited from March 15, 2020, to Mach 22, 2020, including HCWs in Wuhan and Hubei Province (excluding Wuhan), the areas first and most seriously impacted by COVID-19. The morbidity of PTSD symptoms was assessed by the Event Scale-Revised (IES-R). The risk factors for PTSD symptoms were explored by means of logistic regression analysis. Over 40% of the respondents experienced PTSD symptoms more than one month after the COVID-19 outbreak, and this proportion increased to 57.7% in Wuhan HCWs, especially females and HCWs on the frontline. Thus, rapid mental health assessment and effective psychological interventions need to be developed for frontline HCWs to prevent long-term PTSD-related disabilities. Moreover, Negative coping style and neuroticism personality may be regarded as high risk factors for PTSD symptoms. Improving individual coping strategies to enhance resilience should be the focus of further preventive intervention strategies.

High n-type and p-type conductivities and power factors achieved in a single conjugated polymer.

The charge transport properties of conjugated polymers are commonly limited by the energetic disorder. Recently, several amorphous conjugated polymers with planar backbone conformations and low energetic disorder have been investigated for applications in field-effect transistors and thermoelectrics. However, there is a lack of strategy to finely tune the interchain π-π contacts of these polymers that severely restricts the energetic disorder of interchain charge transport. Here, we demonstrate that it is feasible to achieve excellent conductivity and thermoelectric performance in polymers based on thiophene-fused benzodifurandione oligo(p-phenylenevinylene) through reducing the crystallization rate of side chains and, in this way, carefully controlling the degree of interchain π-π contacts. N-type (p-type) conductivities of more than 100 S cm-1 (400 S cm-1) and power factors of more than 200 µW m-1 K-2 (100 µW m-1 K-2) were achieved within a single polymer doped by different dopants. It further demonstrated the state-of-the-art power output of the first flexible single-polymer thermoelectric generator.

Resilience of infertile families undergoing in vitro fertilization: An application of the double ABC-X model.

BACKGROUND: Family resilience plays a crucial role in protecting the mental health and family stability of infertile patients. However, information associated with infertile families resilience is scarce. The double ABC-X model provides a roadmap for this, helps organize knowledge, and lays the foundation for knowledge development. AIMS: To describe the current situation of family resilience of infertile women, and to test the predictive theoretical model of family resilience based on infertility stigma, individual resilience, coping style, and posttraumatic growth. DESIGN: A cross-sectional study. METHODS: A convenience sample of 372 infertile women undergoing in vitro fertilization were recruited between April and August 2020. The Chinese-Family Resilience Assessment Scale, Infertility Stigma Scale, Simplified Coping Style Questionnaire, Chinese version of Connor-Davidson Resilience Scale, and Chinese version of Post Traumatic Growth Inventory were used to measure family resilience, infertility stigma, individual resilience, coping style, and posttraumatic growth. Structural equation models were used to analyze the relationship among these variables. RESULTS: The results showed that family resilience was related to infertility stigma, positive coping, and individual resilience. Moreover, the path analysis indicated that positive coping and individual resilience mediated the effects of infertility stigma on family resilience. CONCLUSIONS: A high level of stigma among infertile women should be identified. Interventions for targeting positive coping and individual resilience might ultimately increase their family resilience.

The Saururus chinensis genome provides insights into the evolution of pollination strategies and herbaceousness in magnoliids.

Saururus chinensis, an herbaceous magnoliid without perianth, represents a clade of early-diverging angiosperms that have gone through woodiness-herbaceousness transition and pollination obstacles: the characteristic white leaves underneath inflorescence during flowering time are considered a substitute for perianth to attract insect pollinators. Here, using the newly sequenced S. chinensis genome, we revisited the phylogenetic position of magnoliids within mesangiosperms, and recovered a sister relationship for magnoliids and Chloranthales. By considering differentially expressed genes, we identified candidate genes that are involved in the morphogenesis of the white leaves in S. chinensis. Among those genes, we verified - in a transgenic experiment with Arabidopsis - that increasing the expression of the "pseudo-etiolation in light" gene (ScPEL) can inhibit the biosynthesis of chlorophyll. ScPEL is thus likely responsible for the switches between green and white leaves, suggesting that changes in gene expression may underlie the evolution of pollination strategies. Despite being an herbaceous plant, S. chinensis still has vascular cambium and maintains the potential for secondary growth as a woody plant, because the necessary machinery, i.e., the entire gene set involved in lignin biosynthesis, is well preserved. However, similar expression levels of two key genes (CCR and CAD) between the stem and other tissues in the lignin biosynthesis pathway are possibly associated with the herbaceous nature of S. chinensis. In conclusion, the S. chinensis genome provides valuable insights into the adaptive evolution of pollination in Saururaceae and reveals a possible mechanism for the evolution of herbaceousness in magnoliids.

Conjugated Polymers in Solution: A Physical Perspective.

Excellent progress has been made in the optoelectronic properties of conjugated polymers by controlling solution-state aggregation. However, due to the wide variety and complex structures of conjugated polymers, it is still challenging to fully understand the complex aggregation process and microstructures both in solution and in the solid state. This Perspective focuses on the chain conformations and the aggregation of conjugated polymers in solution. We discuss the factors in detail which affect solution-state aggregation and microstructures from the perspective of polymer physics in solutions, including chemical structures and environmental conditions. Based on the understanding of multiple interactions of conjugated polymers in solution, strategies to regulate solid-state microstructures and obtain high-performance polymer-based devices from solution-state aggregation are summarized.

Sexual Function, Self-Esteem, and Quality of Life in Infertile Couples Undergoing in vitro Fertilization: A Dyadic Approach.

Purpose: Infertility has adverse effects on the quality of life (QoL) of infertile couples. Previous studies found important associations between sexual function, self-esteem and QoL, but mainly focused on one individual's approach rather than both partners. This study adopted a dyadic approach to evaluate the relationship between sexual function and QoL in couples with infertility through mediation and improving self-esteem. Patients and Methods: Between October 2020 and January 2021, 428 couples with infertility (n=856) undergoing in-vitro fertilization (IVF) at a tertiary hospital in Hefei, China, were registered for the current descriptive cross-sectional research. The dyads' sociodemographic and clinical features, as well as their sexual function, self-esteem, and QoL were evaluated. The Fertility quality of life scale (FertiQoL), Rosenberg Self-Esteem Scale (RSES), Female Sexual Function Index (FSFI), and International Index of Erectile Function-15 (IIEF-15) were used to evaluate the participants. The Actor-Partner Interdependence Mediation Model (APIMeM) was utilized to examine data from the dyadic relationships. Results: According to the APIMeM analysis, sexual function of individuals with infertility was directly and indirectly connected with their QoL, mediated through their self-esteem. The women's sexual function was found to be positively associated with their partner's QoL, with the women's self-esteem acting as a complete mediator. The men's sexual function was found to be positively associated with partner's QoL, with the men's self-esteem acting as a complete mediator. Conclusion: The findings suggest that boosting participants' self-esteem can help them and their partners have a better QoL. Also, therapies aimed at improving and sustaining self-esteem of couples with infertility could help mitigate the negative influence of low sexual function on their QoL.

Genomes of leafy and leafless Platanthera orchids illuminate the evolution of mycoheterotrophy.

To improve our understanding of the origin and evolution of mycoheterotrophic plants, we here present the chromosome-scale genome assemblies of two sibling orchid species: partially mycoheterotrophic Platanthera zijinensis and holomycoheterotrophic Platanthera guangdongensis. Comparative analysis shows that mycoheterotrophy is associated with increased substitution rates and gene loss, and the deletion of most photoreceptor genes and auxin transporter genes might be linked to the unique phenotypes of fully mycoheterotrophic orchids. Conversely, trehalase genes that catalyse the conversion of trehalose into glucose have expanded in most sequenced orchids, in line with the fact that the germination of orchid non-endosperm seeds needs carbohydrates from fungi during the protocorm stage. We further show that the mature plant of P. guangdongensis, different from photosynthetic orchids, keeps expressing trehalase genes to hijack trehalose from fungi. Therefore, we propose that mycoheterotrophy in mature orchids is a continuation of the protocorm stage by sustaining the expression of trehalase genes. Our results shed light on the molecular mechanism underlying initial, partial and full mycoheterotrophy.