Displaying publications 1 - 20 of 31 in total

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  1. Clinical judgement perplexed by initially undisclosed use of herbal medicine and unexpected cross-reactivity of immunoassay
    Liu KT, Lee CW
    Malays J Pathol, 2017 Aug;39(2):189-192.
    PMID: 28866703
    We report a case of symptomatic bradycardia caused by consumption of a Chinese herbal medicine which was initially undisclosed to the attending emergency physician. The scientific name of the herb is Panax japonicus. Electrocardiogram revealed sinus bradycardia. Laboratory tests were normal except for the detection of a high serum digoxin level. Further interrogation of the patient eventually disclosed ingestion of the herb which, however, did not contain any digoxin. Other active ingredients in the herb include various types of ginsenoside. These are digoxin-like substances that had caused the observed false-positive detection of digoxin by fluorescence polarization immunoassay due to cross-reactivity. Our case-report provides an important insight about a blind-spot in the field of laboratory medicine (clinical pathology), namely, the false positive detection of digoxin due to crossreactivity in the immunoassay when we come across digoxin-like substances in clinical scenarios, which has barely received attention in the medical literature. It also conveys a clear educational message that with full understanding of the laboratory methodology and its mechanistic rationale there are actually some tricks-of-the-trade that allow us to optimize the specificity of the biochemical tests and the treatment of digoxin-like substances overdose.
  2. Fulltext Analysis of human standing balance by largest lyapunov exponent
    Liu K, Wang H, Xiao J, Taha Z
    Comput Intell Neurosci, 2015;2015:158478.
    PMID: 25866500 DOI: 10.1155/2015/158478
    The purpose of this research is to analyse the relationship between nonlinear dynamic character and individuals' standing balance by the largest Lyapunov exponent, which is regarded as a metric for assessing standing balance. According to previous study, the largest Lyapunov exponent from centre of pressure time series could not well quantify the human balance ability. In this research, two improvements were made. Firstly, an external stimulus was applied to feet in the form of continuous horizontal sinusoidal motion by a moving platform. Secondly, a multiaccelerometer subsystem was adopted. Twenty healthy volunteers participated in this experiment. A new metric, coordinated largest Lyapunov exponent was proposed, which reflected the relationship of body segments by integrating multidimensional largest Lyapunov exponent values. By using this metric in actual standing performance under sinusoidal stimulus, an obvious relationship between the new metric and the actual balance ability was found in the majority of the subjects. These results show that the sinusoidal stimulus can make human balance characteristics more obvious, which is beneficial to assess balance, and balance is determined by the ability of coordinating all body segments.
  3. Fulltext Rattan spines as deterrence? A spinescence study on different species of rattans
    Liu K, Mansor A, Ruppert N, Fadzly N
    Plant Signal Behav, 2020 10 02;15(10):1795393.
    PMID: 32693670 DOI: 10.1080/15592324.2020.1795393
    Rattan spines are most often regarded as an identification trait and perhaps as a physical protection structure. In this study, we study the spinescence traits from five different species rattan: Daemonorops lewisiana, Daemonorops geniculata, Calamus castaneus, Plectomia griffithii, and Korthalsia scortechinii. We tested length, width, angle, strength, spine density, cross-section surface, spine color, and leaf trichomes (only for D. lewisiana, C. castaneus and D. geniculata). We also tested whether the spines were capable of deterring small climbing mammals (for Plectomia griffithii and Calamus castaneus) by using a choice selection experiment. Due to a variety of spine traits, we could not categorize whether any species is more or less spinescent than the others. We suggest that spines have a much more significant role than merely as a physical defense and work together with other rattan characteristics. This is also evidenced by our choice selection experiment, in which the spines on a single stem donot deter small climbing mammals. However, this is a work in progress, and we have outlined several alternative methods to be used in future work.
  4. The first record of the thomisid genus Ibana Benjamin, 2014 (Araneae, Thomisidae) from China, with the description of a new species
    Liu K, Li W, Yao Y, Li C, Li S
    Biodivers Data J, 2022;10:e93637.
    PMID: 36761648 DOI: 10.3897/BDJ.10.e93637
    BACKGROUND: The genus Ibana Benjamin, 2014 was established, based on the type species Ibanasenagang Benjamin, 2014 from Borneo, Malaysia. No species of this genus has been recorded from China.

    NEW INFORMATION: A new species of Ibana is described and illustrated, representing the first record of the genus for China. Ibanagan sp. n. differs from its congener by the yellowishbrown longitudinal band on the abdomen and the round, contiguous spermathecae. The distribution of the new species in Jiangxi Province is mapped.

  5. The possible hormetic effects of fluorene-9-bisphenol on regulating hypothalamic-pituitary-thyroid axis in zebrafish
    Jin M, Dang J, Paudel YN, Wang X, Wang B, Wang L, et al.
    Sci Total Environ, 2021 Jul 01;776:145963.
    PMID: 33639463 DOI: 10.1016/j.scitotenv.2021.145963
    Fluorene-9-bisphenol (BHPF) is a bisphenol A substitute, which has been introduced for the production of so-called 'bisphenol A (BPA)-free' plastics. However, it has been reported that BHPF can enter living organisms through using commercial plastic bottles and cause adverse effects. To date, the majority of the toxicologic study of BHPF focused on investigating its doses above the toxicological threshold. Here, we studied the effects of BHPF on development, locomotion, neuron differentiation of the central nervous system (CNS), and the expression of genes in the hypothalamic-pituitary-thyroid (HPT) axis in zebrafish exposed to different doses of BHPF ranging from 1/5 of LD1 to LD50 (300, 500, 750, 1500, 3000, and 4500 nM). As a result, the possible hormetic effects of BHPF on regulating the HPT axis were revealed, in which low-dose BHPF positively affected the HPT axis while this regulation was inhibited as the dose increased. Underlying mechanism investigation suggested that BHPF disrupted myelination through affecting HPT axis including related genes expression and TH levels, thus causing neurotoxic characteristics. Collectively, this study provides the full understanding of the environmental impact of BHPF and its toxicity on living organisms, highlighting a substantial and generalized ongoing dose-response relationship with great implications for the usage and risk assessment of BHPF.
  6. Fulltext Rattan litter-collecting structures attract nest-building and defending ants
    Liu K, Mansor A, Ruppert N, Lee CY, Azman NM, Fadzly N
    Plant Signal Behav, 2019;14(8):1621245.
    PMID: 31132922 DOI: 10.1080/15592324.2019.1621245
    Rattan is an important climbing palm taxon in Malaysian tropical rain forests. Many rattan species have unique structures directly associated with certain ant species. In this study, four rattan species (Daemonorops lewisiana, Calamus castaneus, Daemonorops geniculata and Korthalsia scortechinii) were inspected and documented in a field survey concerning their relationships with several ant species. We noticed that two rattan species (D. lewisiana and C. castaneus) were more likely to be associated with ants compared to their neighbouring rattan (Plectomia griffithii). However, D. lewisiana and C. castaneus did not directly provide shelters for ant colonies, but possessed unique structures: upward-pointing spines and funnel-shaped leaves, which are equipped to collect more litter than P. griffithii. To test our litter collecting hypothesis, we measured the inclination of spines from the stem. Our results showed the presence of ant colonies in the litter-collecting rattans (D. lewisiana and C. castaneus), which was significantly higher compared to a non-litter-collecting rattan (P. griffithii). We propose a complex and novel type of adaptation (litter-collection and provision of nesting materials) for rattans, which promotes interactions between the rattan and ants through the arrangements of leaves, leaflets, and spines. In return, the rattan may benefit from ants' services, such as protection, nutrient enhancement, and pollination.
  7. Efficient transport of atmospheric microplastics onto the continent via the East Asian summer monsoon
    Wang X, Liu K, Zhu L, Li C, Song Z, Li D
    J Hazard Mater, 2021 07 15;414:125477.
    PMID: 33647626 DOI: 10.1016/j.jhazmat.2021.125477
    The presence of microplastics (MPs) in the atmosphere is a global concern because of its environmental and health impacts; however, the monsoonal transport of atmospheric MPs has not yet been investigated. To fully understand the effect of the monsoon on atmospheric MP transport, we conducted a study along the southeast coast of China during the East Asian summer monsoon (EASM). We found that the EASM transports atmospheric MPs back onto the continent at a flux of up to 212.977-213.433 kg/EASM/year. The backward trajectory and wind field results indicate that the EASM provides an effective MP transport pathway from Vietnam, the Philippines, and Malaysia to southeastern China. This suggests that only some of the airborne MPs over the ocean enter the marine ecosystem. The average abundance of atmospheric MPs over the sampling area was 0.39 items/100 m3 (0.39 ± 0.43 items/100 m3) during the EASM season, with high variability among the sampling sites. This study improves our understanding of the impact of the EASM on atmospheric MP transport, which can help quantify the contributions of atmospheric MPs to marine or terrestrial ecosystems.
  8. Schaftoside Suppresses Pentylenetetrazol-Induced Seizures in Zebrafish via Suppressing Apoptosis, Modulating Inflammation, and Oxidative Stress
    Dang J, Paudel YN, Yang X, Ren Q, Zhang S, Ji X, et al.
    ACS Chem Neurosci, 2021 07 07;12(13):2542-2552.
    PMID: 34128378 DOI: 10.1021/acschemneuro.1c00314
    The lack of disease-modifying therapeutic strategies against epileptic seizures has caused a surge in preclinical research focused on exploring and developing novel therapeutic candidates for epilepsy. Compounds from traditional Chinese medicines (TCMs) have gained much attention for a plethora of neurological diseases, including epilepsy. Herein, for the first time, we evaluated the anticonvulsive effects of schaftoside (SS), a TCM, on pentylenetetrazol (PTZ)-induced epileptic seizures in zebrafish and examined the underlying mechanisms. We observed that SS pretreatments significantly suppressed seizure-like behavior and prolonged the onset of seizures. Zebrafish larvae pretreated with SS demonstrated downregulation of c-fos expression during seizures. PTZ-induced upregulation of apoptotic cells was decreased upon pretreatment with SS. Inflammatory phenomena during seizure progression including the upregulation of interleukin 6 (IL-6), interleukin 1 beta (IL-1β), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were downregulated upon pretreatment with SS. The PTZ-induced recruitment of immunocytes was in turn reduced upon SS pretreatment. Moreover, SS pretreatment modulated oxidative stress, as demonstrated by decreased levels of catalase (CAT) and increased levels of glutathione peroxidase-1a (GPx1a) and manganese superoxide dismutase (Mn-SOD). However, pretreatment with SS modulated the PTZ-induced downregulation of the relative enzyme activity of CAT, GPx, and SOD. Hence, our findings suggest that SS pretreatment ameliorates PTZ-induced seizures, suppresses apoptosis, and downregulates the inflammatory response and oxidative stress, which potentially protect against further seizures in zebrafish.
  9. Fulltext Protective Effect of Chlorogenic Acid and Its Analogues on Lead-Induced Developmental Neurotoxicity Through Modulating Oxidative Stress and Autophagy
    Ji X, Wang B, Paudel YN, Li Z, Zhang S, Mou L, et al.
    Front Mol Biosci, 2021;8:655549.
    PMID: 34179077 DOI: 10.3389/fmolb.2021.655549
    Lead (Pb) is among the deleterious heavy metal and has caused global health concerns due to its tendency to cause a detrimental effect on the development of the central nervous system (CNS). Despite being a serious health concern, treatment of Pb poisoning is not yet available, reflecting the pressing need for compounds that can relieve Pb-induced toxicity, especially neurotoxicity. In the quest of exploring protective strategies against Pb-induced developmental neurotoxicity, compounds from natural resources have gained increased attention. Chlorogenic acid (CGA) and its analogues neochlorogenic acid (NCGA) and cryptochlorogenic acid (CCGA) are the important phenolic compounds widely distributed in plants. Herein, utilizing zebrafish as a model organism, we modeled Pb-induced developmental neurotoxicity and investigated the protective effect of CGA, NCGA, and CCGA co-treatment. In zebrafish, Pb exposure (1,000 μg/L) for 5 days causes developmental malformation, loss of dopaminergic (DA) neurons, and brain vasculature, as well as disrupted neuron differentiation in the CNS. Additionally, Pb-treated zebrafish exhibited abnormal locomotion. Notably, co-treatment with CGA (100 µM), NCGA (100 µM), and CCGA (50 µM) alleviated these developmental malformation and neurotoxicity induced by Pb. Further underlying mechanism investigation revealed that these dietary phenolic acid compounds may ameliorate Pb-induced oxidative stress and autophagy in zebrafish, therefore protecting against Pb-induced developmental neurotoxicity. In general, our study indicates that CGA, NCGA, and CCGA could be promising agents for treating neurotoxicity induced by Pb, and CCGA shows the strongest detoxifying activity.
  10. Fulltext Neuroprotective effect of YIAEDAER peptide against Parkinson's disease like pathology in zebrafish
    Ren Q, Jiang X, Zhang S, Gao X, Paudel YN, Zhang P, et al.
    Biomed Pharmacother, 2022 Mar;147:112629.
    PMID: 35030435 DOI: 10.1016/j.biopha.2022.112629
    Parkinson's disease (PD) is characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN) and aggregation of α-synuclein (α-syn). Current PD therapies merely provide symptomatic relief, lacking the disease-modifying therapeutic strategies against that could reverse the ongoing neurodegeneration. In the quest of exploring novel disease modifying therapeutic strategies, compounds from natural sources have gained much attention in recent days. YIAEDAER (Tyr-Ile-Ala-Glu-Asp-Ala-Glu-Arg) peptide is a multi-functional peptide isolated and purified from the visceral mass extract of Neptunea arthritica cumingii (NAC) with plethora of pharmacological activities, however its neuroprotective effect against MPTP induced PD model is not yet reported. We found YIAEDAER peptide co-treatment could suppressed the MPTP-induced locomotor impairment in zebrafish, ameliorates the MPTP induced degeneration of DA neurons, inhibited the loss of vasculature and loss of cerebral vessels, suppressed α-syn levels. Moreover, YIAEDAER peptide modulates several genes related to autophagy (α-syn, pink1, parkin, atg5, atg7, beclin1, ulk1b, ulk2, and ambra1a), and oxidative stress (sod1, sod2, gss, gpx4a, gsto2, and cat). Hence, our finding suggests that YIAEDAER peptide might be a potential therapeutic candidate against MPTP-induced PD like condition.
  11. Evaluation of vegetable sauerkraut quality during storage based on convolution neural network
    Du J, Zhang M, Teng X, Wang Y, Lim Law C, Fang D, et al.
    Food Res Int, 2023 Feb;164:112420.
    PMID: 36738024 DOI: 10.1016/j.foodres.2022.112420
    Vegetable sauerkraut is a traditional fermented food. Due to oxidation reactions that occur during storage, the quality and flavor in different periods will change. In this study, the quality evaluation and flavor characteristics of 13 groups of vegetable sauerkraut samples with different storage time were analyzed by using physical and chemical parameters combined with electronic nose. Photographs of samples of various periods were collected, and a convolutional neural network (CNN) framework was established. The relationship between total phenol oxidative decomposition and flavor compounds was linearly negatively correlated. The vegetable sauerkraut during storage can be divided into three categories (full acceptance period, acceptance period and unacceptance period) by principal component analysis and Fisher discriminant analysis. The CNN parameters were fine-tuned based on the classification results, and its output results can reflect the quality changes and flavor characteristics of the samples, and have better fitting, prediction capabilities. After 50 epochs of the model, the accuracy of three sets of data namely training set, validation set and test set recorded 94%, 85% and 93%, respectively. In addition, the accuracy of CNN in identifying different quality sauerkraut was 95.30%. It is proved that the convolutional neural network has excellent performance in predicting the quality of Szechuan Sauerkraut with high reliability.
  12. Fulltext A serial mediation model of negative life events on school adjustment of left-behind adolescents in rural china: the central role of hope and gratitude
    Zhang L, Roslan S, Zaremohzzabieh Z, Liu K, Tang X, Jiang Y, et al.
    BMC Psychiatry, 2023 Aug 14;23(1):588.
    PMID: 37580685 DOI: 10.1186/s12888-023-05102-2
    Adjustment difficulties of school students are common and their school adjustment has gained wide concern in recent years. Negative life events (NLEs) hope, and gratitude have been associated with school adjustment. However, the potential effect of NLEs on hope and gratitude and whether hope and gratitude mediate the association between NLEs and school adjustment among high students have not been studied. Thus, this study aims to investigate the association between NLEs, hope and gratitude, and school adjustment in high school students in China. Additionally, the study aims to examine the mediating role of hope and gratitude in the association between NLEs and school adjustment. A total of 700 junior high school students in Guangxi Province (336 boys, 364 girls, M age = 15 years) completed the questionnaire. The results indicated significant mediating effects of hope and gratitude in the sequential positive association between NLEs and school adjustment. Furthermore, this study unraveled the complexity of the link between NLEs and school adjustment with the combination of hope and gratitude. The findings emphasized the importance of fostering hope and gratitude in left-behind adolescents to combat the negative consequences of NLEs. The study is also one of the first to investigate a serial mediation model to determine which NLEs influence Chinese left-behind adolescents' school adjustment.
  13. Shift in algal blooms from micro- to macroalgae around China with increasing eutrophication and climate change
    Feng Y, Xiong Y, Hall-Spencer JM, Liu K, Beardall J, Gao K, et al.
    Glob Chang Biol, 2024 Jan;30(1):e17018.
    PMID: 37937464 DOI: 10.1111/gcb.17018
    Blooms of microalgal red tides and macroalgae (e.g., green and golden tides caused by Ulva and Sargassum) have caused widespread problems around China in recent years, but there is uncertainty around what triggers these blooms and how they interact. Here, we use 30 years of monitoring data to help answer these questions, focusing on the four main species of microalgae Prorocentrum donghaiense, Karenia mikimotoi, Noctiluca scintillans, and Skeletonema costatum) associated with red tides in the region. The frequency of red tides increased from 1991 to 2003 and then decreased until 2020, with S. costatum red tides exhibiting the highest rate of decrease. Green tides started to occur around China in 1999 and the frequency of green tides has since been on the increase. Golden tides were first reported to occur around China in 2012. The frequency of macroalgal blooms has a negative linear relationship with the frequency and coverage of red tides around China, and a positive correlation with total nitrogen and phosphorus loads as well as with atmospheric CO2 and sea surface temperature (SST). Increased outbreaks of macroalgal blooms are very likely due to worsening levels of eutrophication, combined with rising CO2 and SST, which contribute to the reduced frequency of red tides. The increasing grazing rate of microzooplankton also results in the decline in areas affected by red tides. This study shows a clear shift of algal blooms from microalgae to macroalgae around China over the past 30 years driven by the combination of eutrophication, climate change, and grazing stress, indicating a fundamental change in coastal systems in the region.
  14. Fulltext The effects of musical feedback training on metacognition and self-directed learning
    Li W, Manoharan P, Cui X, Liu F, Liu K, Dai L
    Front Hum Neurosci, 2023;17:1304929.
    PMID: 38173798 DOI: 10.3389/fnhum.2023.1304929
    INTRODUCTION: Metacognition and self-directed learning are key components in educational research, recognized for their potential to enhance learning efficiency and problem-solving skills. This study explores the effects of musical feedback training on these competencies.

    METHODS: The study involved 84 preservice teachers aged 18 to 21. Participants were randomly assigned to either an experimental group, which received musical feedback training, or a control group.

    RESULTS: The findings indicate that musical feedback training effectively improved metacognitive abilities. However, its impact on the readiness for self-directed learning was inconclusive. A notable difference in metacognition and self-directed learning readiness was observed between the experimental and control groups during the session, indicating a significant interaction effect. Furthermore, a positive correlation was identified between metacognition and self-directed learning.

    DISCUSSION: These results contribute to educational discourse by providing empirical evidence on the utility of musical feedback training in fostering metacognition. They also highlight the importance of consistent and long-term engagement in self-directed learning practices. The significance of these findings advocates for incorporating music feedback training into music education curricula to enhance metacognition and improve overall learning efficiency.

  15. Fulltext The dual defensive strategy of Amorphophallus throughout its ontogeny
    Liu K, Fadzly N, Mansor A, Zakaria R, Ruppert N, Lee CY
    Plant Signal Behav, 2017 Oct 03;12(10):e1371890.
    PMID: 28841358 DOI: 10.1080/15592324.2017.1371890
    Amorphophallus bufo is a rarely studied plant in Malaysian tropical rainforests. We measured the spectral reflectance of different developmental stages of A. bufo (seedlings, juveniles and adults), background soil/ debris and leaves from other neighboring plant species. Results show that the leaves of A. bufo seedling have a similar reflectance curve as the background soil and debris. Adults and juveniles of A. bufo are similar to other neighboring plants' leaf colors. We hypothesize that the cryptic coloration of A. bufo seedlings plays an important role in camouflage and that the numerous black spots on the surface of the petioles and rachises, may serve as a defensive mimicry against herbivores.
  16. Extensive intragenomic variations of the 18S rDNA V4 region in the toxigenic diatom species Pseudo-nitzschia multistriata revealed through high-throughput sequencing
    Wang H, Liu K, He Z, Chen Y, Hu Z, Chen W, et al.
    Mar Pollut Bull, 2024 Apr;201:116198.
    PMID: 38428045 DOI: 10.1016/j.marpolbul.2024.116198
    Metabarcoding analysis is an effective technique for monitoring the domoic acid-producing Pseudo-nitzschia species in marine environments, uncovering high-levels of molecular diversity. However, such efforts may result in the overinterpretation of Pseudo-nitzschia species diversity, as molecular diversity not only encompasses interspecies and intraspecies diversities but also exhibits extensive intragenomic variations (IGVs). In this study, we analyzed the V4 region of the 18S rDNA of 30 strains of Pseudo-nitzschia multistriata collected from the coasts of China. The results showed that each P. multistriata strain harbored about a hundred of unique 18S rDNA V4 sequence varieties, of which each represented by a unique amplicon sequence variant (ASV). This study demonstrated the extensive degree of IGVs in P. multistriata strains, suggesting that IGVs may also present in other Pseudo-nitzschia species and other phytoplankton species. Understanding the scope and levels of IGVs is crucial for accurately interpreting the results of metabarcoding analysis.
  17. Fulltext Genetic Identification of Edible Bird's Nest in Thailand Based on ARMS-PCR
    Lv D, Fan Y, Zhong W, Lonan P, Liu K, Wu M, et al.
    Front Genet, 2021;12:632232.
    PMID: 33763113 DOI: 10.3389/fgene.2021.632232
    Edible bird's nest (EBN) is a popular delicacy in the Asian Pacific region originating from Indonesia, Malaysia, Thailand and Vietnam, which consist of various potential medicine value in Traditional Chinese Medicine (TCM). Thailand is one of the main exporters of EBN. However, the genetic information of EBN, a key part of molecular biology, has yet to be reported in Thailand. It is necessary to explore the genetic information of EBN in Thailand based on a quick and simple method to help protect the rights and interests of consumers. This research aimed to systematically evaluate different methods of extracting EBN DNA to improve the efficiency of the analysis of cytochrome b (Cytb) and NADH dehydrogenase subunit 2 (ND2) gene sequences, the establishment of phylogenetic trees, and the genetic information of EBN in Thailand. Additionally, we aimed to develop a quick and simple method for identifying EBN from different species based on the genetic information and amplification-refractory mutation system PCR (ARMS-PCR). By comparing the four methods [cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), kit and guanidinium isothiocyanate methods] for EBN extraction, we found that the guanidinium isothiocyanate method was the optimal extraction method. Phylogenetic trees generated on the basis of Cytb and ND2 gene analyses showed that 26 samples of house EBN and 4 samples of cave EBN came from Aerodramus fuciphagus and Aerodramus maximus, respectively. In addition, to distinguish different samples from different species of Apodiformes, we designed 4 polymerase chain reaction (PCR) amplification primers based on the ND2 gene sequences of A. fuciphagus and A. maximus. The ARMS-PCR results showed band lengths for A. fuciphagus EBN of 533, 402, and 201 bp, while those for A. maximus EBN were 463, 317, and 201 bp. Collectively, the results showed that ARMS-PCR is a fast and simple method for the genetic identification of EBN based on designing specific original identification primers.
  18. H3PO4 activation mediated the iron phase transformation and enhanced the removal of bisphenol A on iron carbide-loaded activated biochar
    Zhao N, Liu K, He C, Zhao D, Zhu L, Zhao C, et al.
    Environ Pollut, 2022 Feb 05;300:118965.
    PMID: 35134429 DOI: 10.1016/j.envpol.2022.118965
    Zero valent iron-loaded biochar (Fe0-BC) has shown promise for the removal of various organic pollutants, but is restricted by reduced specific surface area, low utilization efficiency and limited production of reactive oxygen species (ROS). In this study, iron carbide-loaded activated biochar (Fe3C-AB) with a high surface area was synthesized through the pyrolysis of H3PO4 activated biochar with Fe(NO3)3, tested for removing bisphenol A (BPA) and elucidated the adsorption and degradation mechanisms. As a result, H3PO4 activated biochar was beneficial for the transformation of Fe0 to Fe3C. Fe3C-AB exhibited a significantly higher removal rate and removal capacity for BPA than that of Fe0-BC within a wide pH range of 5.0-11.0, and its performance was maintained even under extremely high salinity and different water sources. Moreover, X-ray photoelectron spectra and density functional theory calculations confirmed that hydrogen bonds were formed between the COOH groups and BPA. 1O2 was the major reactive species, constituting 37.0% of the removal efficiency in the degradation of BPA by Fe3C-AB. Density functional reactivity theory showed that degradation pathway 2 of BPA was preferentially attacked by ROS. Thus, Fe3C-AB with low cost and excellent recycling performance could be an alternative candidate for the efficient removal of contaminants.
  19. Deciphering Adverse Detrapped Hole Transfer in Hot-Electron Photoelectric Conversion at Infrared Wavelengths
    Yu Y, Gao L, Niu X, Liu K, Li R, Yang D, et al.
    Adv Mater, 2023 Mar;35(12):e2210157.
    PMID: 36732915 DOI: 10.1002/adma.202210157
    Hot-carrier devices are promising alternatives for enabling path breaking photoelectric conversion. However, existing hot-carrier devices suffer from low efficiencies, particularly in the infrared region, and ambiguous physical mechanisms. In this work, the competitive interfacial transfer mechanisms of detrapped holes and hot electrons in hot-carrier devices are discovered. Through photocurrent polarity research and optical-pump-THz-probe (OPTP) spectroscopy, it is verified that detrapped hole transfer (DHT) and hot-electron transfer (HET) dominate the low- and high-density excitation responses, respectively. The photocurrent ratio assigned to DHT and HET increases from 6.6% to over 1133.3% as the illumination intensity decreases. DHT induces severe degeneration of the external quantum efficiency (EQE), especially at low illumination intensities. The EQE of a hot-electron device can theoretically increase by over two orders of magnitude at 10 mW cm-2 through DHT elimination. The OPTP results show that competitive transfer arises from the carrier oscillation type and carrier-density-related Coulomb screening. The screening intensity determines the excitation weight and hot-electron cooling scenes and thereby the transfer dynamics.
  20. Photoelectrical Dynamics Uplift in Perovskite Solar Cells by Atoms Thick 2D TiS2 Layer Passivation of TiO2 Nanograss Electron Transport Layer
    Alias N, Ali Umar A, Malek NAA, Liu K, Li X, Abdullah NA, et al.
    ACS Appl Mater Interfaces, 2021 Jan 20;13(2):3051-3061.
    PMID: 33410652 DOI: 10.1021/acsami.0c20137
    A deficiency in the photoelectrical dynamics at the interface due to the surface traps of the TiO2 electron transport layer (ETL) has been the critical factor for the inferiority of the power conversion efficiency (PCE) in the perovskite solar cells. Despite its excellent energy level alignment with most perovskite materials, its large density of surface defect as a result of sub lattice vacancies has been the critical hurdle for an efficient photovoltaic process in the device. Here, we report that atoms thick 2D TiS2 layer grown on the surface of a (001) faceted and single-crystalline TiO2 nanograss (NG) ETL have effectively passivated the defects, boosting the charge extractability, carrier mobility, external quantum efficiency, and the device stability. These properties allow the perovskite solar cells (PSCs) to produce a PCE as high as 18.73% with short-circuit current density (Jsc), open-circuit voltage (Voc), and fill-factor (FF) values as high as 22.04 mA/cm2, 1.13 V, and 0.752, respectively, a 3.3% improvement from the pristine TiO2-NG-based PSCs. The present approach should find an extensive application for controlling the photoelectrical dynamic deficiency in perovskite solar cells.
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