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  1. Book ; Thesis: Comprehensive mechanism research of different periods of adipogenic and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs)

    Liu, Yu

    2022  

    Author's details vorgelegt von Yu Liu
    Language English
    Size vi, 100 Seiten, Illustrationen, Diagramme
    Publishing place Aachen
    Publishing country Germany
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2022
    Note Englische und deutsche Zusammenfassung
    HBZ-ID HT021569916
    Database Catalogue ZB MED Medicine, Health

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    In stock of ZB MED Cologne/Königswinter

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  2. Article ; Online: eClock

    Yu Liu

    PLoS ONE, Vol 17, Iss 5, p e

    An ensemble-based method to accurately predict ages with a biased distribution from DNA methylation data.

    2022  Volume 0267349

    Abstract: DNA methylation is closely related to senescence, so it has been used to develop statistical models, called clock models, to predict chronological ages accurately. However, because the training data always have a biased age distribution, the model ... ...

    Abstract DNA methylation is closely related to senescence, so it has been used to develop statistical models, called clock models, to predict chronological ages accurately. However, because the training data always have a biased age distribution, the model performance becomes weak for the samples with a small age distribution density. To solve this problem, we developed the R package eClock, which uses a bagging-SMOTE method to adjust the biased distribution and predict age with an ensemble model. Moreover, it also provides a bootstrapped model based on bagging only and a traditional clock model. The performance on three datasets showed that the bagging-SMOTE model significantly improved rare sample age prediction. In addition to model construction, the package also provides other functions such as data visualization and methylation feature conversion to facilitate the research in relevant areas.
    Keywords Medicine ; R ; Science ; Q
    Subject code 310
    Language English
    Publishing date 2022-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: On the definition of a self-sustaining chemical reaction system and its role in heredity

    Yu Liu

    Biology Direct, Vol 15, Iss 1, Pp 1-

    2020  Volume 16

    Abstract: Abstract Background The ability to self-sustain is one of the essential properties of life. However, a consistent and satisfying definition of self-sustainability is still missing. Currently, self-sustainability refers to either “no-intervention by a ... ...

    Abstract Abstract Background The ability to self-sustain is one of the essential properties of life. However, a consistent and satisfying definition of self-sustainability is still missing. Currently, self-sustainability refers to either “no-intervention by a higher entity” or “regeneration of all the system’s components”. How to connect self-sustainability with heredity, another essential of life, is another problem, as they are often considered to be independent of each other. Last but not least, current definitions of self-sustainability failed to provide a practical method to empirically discern whether a chemical system is self-sustaining or not. Results Here I propose a definition of self-sustainability. It takes into account the chemical reaction network itself and the external environment which is simplified as a continuous-flow stirred tank reactor. One distinct property of self-sustaining systems is that the system can only proceed if molecular triggers (or called, seeds) are present initially. The molecular triggers are able to establish the whole system, indicating that they carry the preliminary heredity of the system. Consequently, life and a large group of fires (and other dissipative systems) can be distinguished. Besides, the general properties and various real-life examples of self-sustaining systems discussed here together indicate that self-sustaining systems are not uncommon. Conclusions The definition I proposed here naturally connects self-sustainability with heredity. As this definition involves the continuous-flow stirred tank reactor, it gives a simple way to empirically test whether a system is self-sustaining or not. Moreover, the general properties and various real-life examples of self-sustaining systems discussed here provide practical guidance on how to construct and detect such systems in real biology and chemistry. Reviewers This article was reviewed by Wentao Ma and David Baum.
    Keywords Definition of life ; Origin of life ; Autocatalysis ; Self-replication ; Non-equilibrium ; CSTR ; Biology (General) ; QH301-705.5
    Subject code 120
    Language English
    Publishing date 2020-10-01T00:00:00Z
    Publisher BMC
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Construction of macromolecular structure in KunNing coal and analysis of Macro-Micro oxidation characteristics

    Dongjie Hu / Zongxiang Li / Yu Liu / Lin Li

    Arabian Journal of Chemistry, Vol 17, Iss 1, Pp 105499- (2024)

    1481  

    Abstract: To explore the macro–micro coal oxidation characteristics for the purpose of preventing coal spontaneous combustion and achieving efficient coal conversion and utilization, the enclosed coal oxidation characteristics of KunNing coal sample (KN) under 25– ... ...

    Abstract To explore the macro–micro coal oxidation characteristics for the purpose of preventing coal spontaneous combustion and achieving efficient coal conversion and utilization, the enclosed coal oxidation characteristics of KunNing coal sample (KN) under 25–70 °C were investigated. KN coal molecular models were constructed based on analysis and testing results of X-ray Photoelectron Spectroscopy (XPS), Carbon-13 Nuclear Magnetic Resonance Spectroscopy (13C NMR), Fourier Transform Infrared Spectroscopy (FTIR) and other techniques. The pyrolysis processes of coal-oxygen reaction systems with different oxygen contents were simulated using ReaxFF force field. The results show that the oxygen consumption rate, CO release rate, CO2 release rate and oxidation heat release intensity of coal increase exponentially with rising temperature. The ratio of aromatic bridge carbon to peripheral carbon in KN coal molecular structure is 0.08, and the molecular formula is C149H76O15N2S2. In the later stage of the experimental and molecular dynamics simulation processes, the CO content decreased while the growth rate of CO2 increased. Different indicator gases exhibit varied responses to oxygen content. The C-atom labeling and traceback results for the four indicator gas molecules demonstrate that CO2 mainly comes from aldehyde, hydroxyl, carboxyl and methoxy groups in coal molecules, CO is primarily generated from esters, phenols, carbonyls, C2H2 is predominantly derived from ring-opening and cracking of cycloalkanes, and the source of C2H4 is related to cycloalkanes and alcohols.
    Keywords Enclosed coal oxidation test ; Oxidation heat release intensity ; Reaction kinetics ; Indicator gas molecule traceback ; Active groups ; Chemistry ; QD1-999
    Subject code 660
    Language English
    Publishing date 2024-01-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: A review of the powderpost beetle genera Xylothrips Lesne, 1901 and Calophagus Lesne, 1902 (Coleoptera

    Lan-Yu Liu

    European Journal of Taxonomy, Vol 746, Iss

    Bostrichidae: Bostrichinae: Xyloperthini)

    2021  Volume 1

    Abstract: This paper reviews the genera Xylothrips Lesne, 1901 and Calophagus Lesne, 1902, and their species, and proposes that Calophagus should be reinstated as a full genus from a subgenus of Xylothrips (contra Borowski & Węgrzynowicz 2019). The genera and ... ...

    Abstract This paper reviews the genera Xylothrips Lesne, 1901 and Calophagus Lesne, 1902, and their species, and proposes that Calophagus should be reinstated as a full genus from a subgenus of Xylothrips (contra Borowski & Węgrzynowicz 2019). The genera and their included species are diagnosed and redescribed, and a summary of information on the distribution and biology of all species is provided. The importance of characters of the antennal club and pronotum in separating the two genera is stressed. A key to the two genera and the two species of Xylothrips is provided.
    Keywords review ; Xylothrips ; Calophagus ; reinstatement ; Zoology ; QL1-991 ; Botany ; QK1-989
    Language English
    Publishing date 2021-04-01T00:00:00Z
    Publisher Consortium of European Natural History Museums
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: The Politics of Unionisation in Hong Kong

    Hong Yu Liu

    Global Labour Journal, Vol 12, Iss

    An Interview with Dr Bill Taylor

    2021  Volume 3

    Abstract: Unions in Hong Kong played an important role in the historical develoopment of civil society and labour rights long before the handover of Hong Kong to the Chinese sovereignty in 1997. But what are the possible impacts of the new union movement in Hong ... ...

    Abstract Unions in Hong Kong played an important role in the historical develoopment of civil society and labour rights long before the handover of Hong Kong to the Chinese sovereignty in 1997. But what are the possible impacts of the new union movement in Hong Kong today? KEYWORDS: labour activism; unionism; Hong Kong studies; social movement; industrial relations
    Keywords Social Sciences ; H
    Language English
    Publishing date 2021-09-01T00:00:00Z
    Publisher McMaster University Library Press
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Multilevel determinants of COVID-19 vaccination hesitancy in the United States

    Ying Wang / Yu Liu

    Preventive Medicine Reports, Vol 25, Iss , Pp 101673- (2022)

    A rapid systematic review

    2022  

    Abstract: Vaccine hesitancy is a challenge for the success and optimal implementation of COVID-19 immunization programs in the US. The objective of this study was to summarize multilevel determinants of COVID-19 vaccination intention in the US to inform future ... ...

    Abstract Vaccine hesitancy is a challenge for the success and optimal implementation of COVID-19 immunization programs in the US. The objective of this study was to summarize multilevel determinants of COVID-19 vaccination intention in the US to inform future intervention opportunities. To this end, we conducted a rapid systematic review by searching published articles via PubMed published by October 5, 2021, following the PRISMA guidelines. One hundred and six articles were included. According to nationally representative studies, the overall COVID-19 acceptance rate ranges from 53.6% to 84.4%. Individual (demographics, health history, behaviors and health beliefs), interpersonal (having a close friend/family member impacted by COVID-19), healthcare and societal level factors (healthcare provider recommendations, source/credential of COVID-19 related information, and COVID-19 related conspiracy theories) all contributed to COVID-19 vaccine hesitancy in the US. This study demonstrates that the acceptance to COVID-19 vaccines is influenced by various factors, particularly the role of healthcare providers in enhancing public intent to vaccination. Potential interventions to mitigate people’s concerns over the vaccines and address vaccine-related conspiracy/misinformation from social media are also critical to encourage vaccine uptake in the US.
    Keywords COVID-19 ; Vaccine acceptance ; Vaccine hesitancy ; Multilevel determinants ; Implementation ; United States ; Medicine ; R
    Language English
    Publishing date 2022-02-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Understanding the Association between PrEP Stigma and PrEP Cascade Moderated by the Intensity of HIV Testing

    Chen Zhang / Yu Liu

    Tropical Medicine and Infectious Disease, Vol 7, Iss 74, p

    2022  Volume 74

    Abstract: 1) Background: In the U.S., men who have sex with men (MSM) account for the majority of new HIV infections. On the other hand, pre-exposure prophylaxis (PrEP) is an effective strategy to curb HIV transmission, but it is widely underutilized. It is ... ...

    Abstract (1) Background: In the U.S., men who have sex with men (MSM) account for the majority of new HIV infections. On the other hand, pre-exposure prophylaxis (PrEP) is an effective strategy to curb HIV transmission, but it is widely underutilized. It is unknown how stigma affects PrEP care in the context of other HIV prevention strategies. (2) Methods: We included a total of 318 MSM in the current analysis. We employed bivariate and multivariable analyses to assess the association between PrEP stigma and PrEP cascade while controlling for potential confounders on each specific pathway. We further used a series of moderation analyses based upon the intensity of HIV testing within different timeframes to assess the association between PrEP stigma and PrEP cascade. (3) Results: Compared with MSM who used PrEP, those who never used PrEP reported higher internalized and vicarious PrEP stigma. Internalized PrEP stigma has significantly reduced the likelihood of PrEP willingness and PrEP uptake among this group. The trend analysis showed significant trend patterns across different frequencies of HIV testing. (4) Conclusions: A structural-level reform is urgently needed to turn the HIV service encounters into opportunities to facilitate and optimize the PrEP cascade among this group who may benefit from PrEP use.
    Keywords men who have sex with men ; pre-exposure prophylaxis ; PrEP stigma ; United States ; HIV testing ; Medicine ; R
    Subject code 360
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Incorporation of a FRET Pair into a Riboswitch RNA to Measure Mg 2+ Concentration and RNA Conformational Change in Cell

    Yanyan Xue / Yu Liu

    International Journal of Molecular Sciences, Vol 23, Iss 1493, p

    2022  Volume 1493

    Abstract: Riboswitches are natural biosensors that can regulate gene expression by sensing small molecules. Knowledge of the structural dynamics of riboswitches is crucial to elucidate their regulatory mechanism and develop RNA biosensors. In this work, we ... ...

    Abstract Riboswitches are natural biosensors that can regulate gene expression by sensing small molecules. Knowledge of the structural dynamics of riboswitches is crucial to elucidate their regulatory mechanism and develop RNA biosensors. In this work, we incorporated the fluorophore, Cy3, and its quencher, TQ3, into a full-length adenine riboswitch RNA and its isolated aptamer domain to monitor the dynamics of the RNAs in vitro and in cell. The adenine riboswitch was sensitive to Mg 2+ concentrations and could be used as a biosensor to measure cellular Mg 2+ concentrations. Additionally, the TQ3/Cy3-labeled adenine riboswitch yielded a Mg 2+ concentration that was similar to that measured using a commercial assay kit. Furthermore, the fluorescence response to the adenine of the TQ3/Cy3-labeled riboswitch RNA was applied to determine the proportions of multiple RNA conformational changes in cells. The strategy developed in this work can be used to probe the dynamics of other RNAs in cells and may facilitate the developments of RNA biosensors, drugs and engineering.
    Keywords riboswitch ; FRET ; in cell ; structural dynamics ; biosensor ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
    Subject code 333 ; 612
    Language English
    Publishing date 2022-01-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: User Trust Inference in Online Social Networks

    Yu Liu / Bai Wang

    Applied Sciences, Vol 12, Iss 5186, p

    A Message Passing Perspective

    2022  Volume 5186

    Abstract: Online social networks are vital environments for information sharing and user interactivity. To help users of online social services to build, expand, and maintain their friend networks or webs of trust, trust management systems have been deployed and ... ...

    Abstract Online social networks are vital environments for information sharing and user interactivity. To help users of online social services to build, expand, and maintain their friend networks or webs of trust, trust management systems have been deployed and trust inference (or more generally, friend recommendation) techniques have been studied in many online social networks. However, there are some challenging issues obstructing the real-world trust inference tasks. Using only explicit yet sparse trust relationships to predict user trust is inefficient in large online social networks. In the age of privacy-respecting Internet, certain types of user data may be unavailable, and thus existing models for trust inference may be less accurate or even defunct. Although some less interpretable models may achieve better performance in trust prediction, the interpretability of the models may prevent them from being adopted or improved for making relevant informed decisions. To tackle these problems, we propose a probabilistic graphical model for trust inference in online social networks in this paper. The proposed model is built upon the skeleton of explicit trust relationships (the web of trust) and embeds various types of available user data as comprehensively-designed trust-aware features. A message passing algorithm, loop belief propagation, is applied to the model inference, which greatly improves the interpretability of the proposed model. The performance of the proposed model is demonstrated by experiments on a real-world online social network dataset. Experimental results show the proposed model achieves acceptable accuracy with both fully and partially available data. Comparison experiments were conducted, and the results show the proposed model’s promise for trust inference in some circumstances.
    Keywords trust inference ; trust propagation ; online social network ; social network analysis ; probabilistic graphical model ; message passing ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 330
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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