Publications by authors named "XK Chen"

High prevalence of long COVID symptoms has emerged as a significant public health concern. This study investigated the associations between three doses of COVID-19 vaccines and the presence of any and ≥3 types of long COVID symptoms among people with a history of SARS-CoV-2 infection in Hong Kong, China. This is a secondary analysis of a cross-sectional online survey among Hong Kong adult residents conducted between June and August 2022.

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The use of synthetic biology to construct engineered strains has provided new perspectives for addressing Pb contamination; however, the large-scale treatment of contaminants is still limited by high operating costs and technological constraints. This study introduces a novel technique for applying engineered yeast in the removal of heavy metals, offering a solution to the cost and process scale challenges associated with utilizing engineered yeast. Hydrogen sulfide-producing engineered yeast strains were constructed based on existing strategies by knocking out the gene encoding the O-acetyl-L-homoserine mercapturic enzyme, which plays a role in sulfate assimilation.

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Background: Currently, optimal treatment strategy for resectable primary small cell carcinoma of the esophagus (PSmCCE) remains controversial. To address this, we conducted a multicenter study to evaluate treatment patterns and long-term survival of PSmCCE patients who underwent radical resection.

Methods: This retrospective multicenter study included resected PSmCCE patients who received radical resection at seven high-volume cancer centers.

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Article Synopsis
  • Canadians are experiencing longer wait times for joint replacements, cancer surgery, and diagnostic imaging in 2023 compared to 2019.
  • While wait times for cataract surgery have returned to pre-pandemic levels, other procedures like radiation therapy and hip fracture repair have seen a decrease in the percentage of patients treated within recommended timeframes.
  • Overall, efforts to improve timely care have not fully addressed the increased wait times for many medical services since the pandemic.
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  • Surface passivation effectively reduces trap-state density and non-radiative recombination in perovskite solar cells, but traditional agents may hinder charge transport due to poor conductivity.
  • The study introduces a novel post-treatment method using a blend of two compounds that enhances film crystallinity, molecular packing, and energy band alignment, improving hole extraction and transfer.
  • This approach led to a record 26.0% power conversion efficiency for perovskite solar cells, which retained 81% of their initial efficiency after 450 hours of operation.
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Boron/nitrogen (B/N)-doped polycyclic aromatic hydrocarbons (PAHs) with the multiple resonance (MR) effect are promising for organic light-emitting diodes (OLEDs) because of their narrowband emission and thermally activated delayed fluorescence (TADF) characteristics. Nevertheless, exploring the variety of such emitters is challenging because of the tricky and limited synthetic protocols. Herein, we designed a novel B/N-doped PAH, L-DABNA-1, whose backbone (L-DABNA) could not be achieved via conventional routes (e.

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The strategy of isomerization is known for its simple yet effective role in optimizing molecular configuration and enhancing the power conversion efficiency (PCE) of organic solar cells (OSCs). However, the impact of isomerization on the design of dimer acceptors has been rarely investigated, and the relationship between the chemical structure and optoelectronic property remains unclear. In this study, we designed and synthesized two dimer acceptor isomers named D-TPh and D-TN, which differ in the positional arrangement of their end capping groups.

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Background: The quick sequential [sepsis-related] organ failure assessment (qSOFA) acts as a prompt to consider possible sepsis. The contributions of individual qSOFA elements to assessment of severity and for prediction of mortality remain unknown.

Methods: A total of 3974 patients with community-acquired pneumonia were recruited to an observational prospective cohort study.

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Efficient, narrowband multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters have recently sparked significant interest in high-resolution organic light-emitting diode (OLED) displays. However, almost all the progress in MR-TADF materials has been accomplished using a six-membered ring as the π-core to date. Herein, we present the first example of a five-membered ring π-core-based MR-TADF emitter named Th-BN developed by introducing thiophene instead of hexagonal benzene as the π-core.

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Article Synopsis
  • Researchers developed a new self-assembled multilayer (SAMUL) for hole-extraction in inverted perovskite solar cells, differing from traditional monolayers and disordered bilayers.
  • The SAMULs enhance PSC performance and stability by improving surface coverage and are optimized through variations in molecular structure and deposition methods like thermal evaporation and spin-coating.
  • The CbzNaphPPA SAMUL demonstrated exceptional crystallinity and hole mobility, achieving a power conversion efficiency of 26.07% and maintaining 94% of its initial efficiency after 1200 hours of continuous operation at high temperatures.
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Organic single crystals possess distinct advantages due to their highly ordered molecular structures, resulting in improved stability, enhanced carrier mobility, and superior optical characteristics. However, their mechanical rigidity and brittleness impede the applications in flexible and wearable optoelectronic devices. Here, photoluminescence (PL) emission from 2,6-diphenylanthracene (DPA) single crystals is studied under tensile strain, which shows PL enhancement by more than two times with a strain of ≈1.

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Objective: This study aims to systematically assess physical exercise-related symptoms of post-acute sequelae of SARS-CoV-2 infection (PASC or long COVID) in coronavirus disease 2019 (COVID-19) survivors.

Methods: Eight databases were systematically searched on March 03, 2024. Original studies that compared physical exercise-related parameters measured by exercise testing between COVID-19 survivors who recovered from SARS-CoV-2 infection over 3 months and non-COVID-19 controls were included.

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Dimer acceptors in organic solar cells (OSCs) offer distinct advantages, including a well-defined molecular structure and excellent batch-to-batch reproducibility. Their high glass transition temperature (T) aids in achieving an optimal kinetic morphology, thereby enhancing device stability. Currently, most of dimer acceptor materials are linked with conjugated units in order to obtain high power conversion efficiencies (PCEs).

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Article Synopsis
  • The current research explores the use of 2-chlorothiophene (2Cl-Th) solvent to enhance the coupling between local excitons and charge-transfer excitons, leading to improved exciton dynamics.
  • Experimental findings show that using 2Cl-Th creates stronger intermolecular interactions, which decreases crystallization and traps, resulting in OSC efficiencies of 19.8% for small areas and 17.0% for larger areas, ultimately aiding in the evolution
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TDP-43 proteinopathy, initially disclosed in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), coexists with tauopathy in a variety of neurodegenerative disorders, termed multiple etiology dementias (MEDs), including Alzheimer's Disease (AD). While such co-pathology of TDP-43 is strongly associated with worsened neurodegeneration and steeper cognitive decline, the pathogenic mechanism underlying the exacerbated neuron loss remains elusive. The loss of TDP-43 splicing repression that occurs in presymptomatic ALS-FTD individuals suggests that such early loss could facilitate the pathological conversion of tau to accelerate neuron loss.

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Objective: To investigate the effectiveness of flipped classrooms (FC) based on outcomes-based education (OBE) on clinical ophthalmology clerkships.

Methods: Ninety-nine undergraduates were non-randomly assigned to the FC based on the OBE (FC-OBE) group or traditional lecture (TL) group in the ophthalmology clerkship. Pre- and post-tests were performed to assess student learning outcomes.

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A deselenylative protocol that enables the construction of the C-C and C-N bonds has been disclosed. By using acyl chloride/AgOTf as an efficient acylation reagent, diarylselenides smoothly undergo deselenylative acylation to produce a series of aroyl compounds. In addition, deselenylative nitration can be enabled by a mild nitration reagent consisting of TsCl and AgNO, furnishing a diverse array of nitroaromatic compounds.

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Manipulating dynamic behaviours of charge carriers and excitons in organic light-emitting diodes (OLEDs) is essential to simultaneously achieve high colour purity and superior operational lifetime. In this work, a comprehensive transient electroluminescence investigation reveals that incorporating a thermally activated delayed fluorescence assistant molecule with a deep lowest unoccupied molecular orbital into a bipolar host matrix effectively traps the injected electrons. Meanwhile, the behaviours of hole injection and transport are still dominantly governed by host molecules.

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Although asymmetric molecular design has been widely demonstrated effective for organic photovoltaics (OPVs), the correlation between asymmetric molecular geometry and their optoelectronic properties is still unclear. To access this issue, we have designed and synthesized several symmetric-asymmetric non-fullerene acceptors (NFAs) pairs with identical physical and optoelectronic properties. Interestingly, we found that the asymmetric NFAs universally exhibited increased open-circuit voltage compared to their symmetric counterparts, due to the reduced non-radiative charge recombination.

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Organic photothermal materials have attracted increasing attention because of their structural diversity, flexibility, and compatibility. However, their energy conversion efficiency is limited owing to the narrow absorption spectrum, strong reflection/transmittance, and insufficient nonradiative decay. In this study, two quinoxaline-based D-A-D-A-D-type molecules with ethyl (BQE) or carboxylate (BQC) substituents were synthesized.

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A novel synthetic approach to preparing alkenyl nitriles via the olefination of aldehydes with diazoacetonitrile catalyzed by iron(II) phthalocyanine in the presence of PPh has been developed. A broad variety of aldehydes are efficiently transformed into the corresponding products with the high yields of 75%-97%. And it is also suitable for its gram-scale preparation.

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Organic light-emitting diodes (OLEDs) exploiting simple binary emissive layers (EMLs) blending only emitters and hosts have natural advantages in low-cost commercialization. However, previously reported OLEDs based on binary EMLs hardly simultaneously achieved desired comprehensive performances, e.g.

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Background: To date, few studies have compared effectiveness and survival rates of neoadjuvant chemotherapy combined with immunotherapy (NACI) and conventional neoadjuvant chemoradiotherapy (NCRT) in patients with locally advanced esophageal squamous cell carcinoma (ESCC). The present study was conducted to compare therapeutic response and survival between NACI and NCRT.

Methods: The study cohort comprised patients with locally advanced ESCC treated with either NACI or NCRT followed by surgery between June 2018 and March 2021.

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Background: Evidence suggests that coronavirus disease 2019 (COVID-19) survivors could experience COVID-19 sequelae. Although various risk factors for COVID-19 sequelae have been identified, little is known about whether a sedentary lifestyle is an independent risk factor.

Methods: In this retrospective cohort study, 4850 participants self-reported their COVID-19 sequelae symptoms between June and August 2022.

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