Publications by authors named "Yunfeng Sun"

18 Publications

  • Page 1 of 1

Development of [email protected] nanoparticles coupled to [email protected] core-shell nanoparticles for the sensitive detection of zearalenone.

Anal Chim Acta 2021 Oct 27;1180:338888. Epub 2021 Jul 27.

Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, 300050, China. Electronic address:

Agricultural products are frequently contaminated by mycotoxins; thus, the accurate detection of mycotoxins is important to food safety. Zearalenone (ZEN), a mycotoxin produced by certain Fusarium and Gibberella species, is a group III carcinogen. We developed a universal surface-enhanced Raman scattering (SERS) aptasensor for the detection of ZEN. The SERS biosensor consists of two functional nanomaterials: sulfhydryl (SH)-ZEN aptamer complementary DNA-modified [email protected] was used as a capture probe and SH-ZEN aptamer-modified [email protected] core-shell nanoparticles served as reporter probes. In the absence of ZEN, the highest Raman signal was obtained owing to the SERS effects of [email protected] and [email protected] core-shell nanoparticles. Conversely, the addition of ZEN triggered the release of [email protected] core-shell nanoparticles from [email protected], leading to a decrease in SERS intensity after magnetic separation. Hybridization of the ZEN aptamer and its complementary strand generated a strong SERS signal from the reporter probe. Moreover, preferential binding of the ZEN aptamer to ZEN was observed. The signal intensity in SERS decreased linearly when the capture probes released the reporter. For ZEN detection, a linear range from 0.005 to 500 ng mL, with an R of 0.9981, was obtained. The detection limit was 0.001 ng mL. The SERS aptasensor showed excellent performance for analytical applications with real-world samples (beer and wine). This study presents a new model for the detection of mycotoxins based on simple changes in aptamers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.aca.2021.338888DOI Listing
October 2021

Platelet 3D Preservation Using a Novel Biomimetic Nanofiber Peptide for Reduced Apoptosis and Easy Storage.

ACS Appl Mater Interfaces 2021 Aug 4;13(32):38040-38049. Epub 2021 Aug 4.

Institute of Health Service and Transfusion Medicine, Academy of Military Medical Sciences, 27(1) Taiping Road, Beijing 100850, China.

Human platelets (PLTs) are vulnerable to unfavorable conditions, and their adequate supply is limited by strict transportation conditions. We report here that PLTs preserved under three-dimensional (3D) conditions using novel biomimetic nanofiber peptides showed reduced apoptosis compared with classical PLTs stored at 22 °C and facilitated the storage and transportation of PLTs. The mechanism of PLT 3D preservation involves the formation of cross-links and a 3D nanofibrous network by a self-assembled peptide scaffold material at physiological conditions after initiation by triggers in plasma. PLTs adhere to the surface of the nanofibrous network to facilitate the 3D distribution of PLTs. The 3D microstructure, rheological properties, and effect on the inflammatory response and hemolysis were evaluated. Compared to traditional PLTs stored at 22 °C, PLTs subjected to 3D preservation showed similar morphology, number, aggregation activity, and reduced apoptosis. The detection of the reactive oxygen species (ROS) levels demonstrated that both reduced intracellular and mitochondrial ROS levels were correlated with reduced apoptosis. This study reveals a new 3D preservation method for PLTs based on the use of novel biomimetic nanofiber peptides that presents an attractive opportunity for various biomedical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.1c08394DOI Listing
August 2021

Surface-enhanced Raman spectroscopy aptasensor for simultaneous determination of ochratoxin A and zearalenone using [email protected] core-shell nanoparticles and gold nanorods.

Mikrochim Acta 2021 07 31;188(8):281. Epub 2021 Jul 31.

Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, 300050, China.

The design and fabrication of a surface-enhanced Raman scattering (SERS) aptasensor for simultaneous detection of zearalenone (ZEN) and ochratoxin A (OTA) in wheat and corn samples is described. The capture and reporter probes were SH-cDNA-modified gold nanorods and SH-Apt-modified [email protected] core-shell nanoparticles, respectively. After recognizing OTA and ZEN aptamers and complementary strands (SH-cDNA), the reporter probe generated a strong SERS signal. The preferred binding of OTA and ZEN aptamers to OTA and ZEN, respectively, caused reporter probes to release the capture probes, resulting in a linear decrease in SERS intensity. The detection of OTA showed good linearity with an R value of 0.986, which could be maintained across a wide concentration range (0.01 to 100 ng/mL), with the limit of detection of 0.018 ng/mL. For detection of ZEN, good linearity with an R value of 0.987 could be maintained across a wide concentration range (0.05 to 500 ng/mL), with 0.054 ng/mL as the limit of detection. Good accuracy (relative standard deviation < 4.2%) during mycotoxin determination as well as excellent quantitative recoveries (96.0-110.7%) during the analysis of spiked real samples was achieved. The proposed SERS aptasensor exhibited excellent performance in the detection of OTA and ZEN in real food samples. Hence, by simply changing the aptamer, this new model can be applied to the detection of multiple mycotoxins in the food industry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00604-021-04919-6DOI Listing
July 2021

Computer-Aided Diagnosis Evaluation of the Correlation Between Magnetic Resonance Imaging With Molecular Subtypes in Breast Cancer.

Front Oncol 2021 23;11:693339. Epub 2021 Jun 23.

Department of Radiology, Third Affiliated Hospital of Harbin Medical University, Harbin, China.

Background: There is a demand for additional alternative methods that can allow the differentiation of the breast tumor into molecular subtypes precisely and conveniently.

Purpose: The present study aimed to determine suitable optimal classifiers and investigate the general applicability of computer-aided diagnosis (CAD) to associate between the breast cancer molecular subtype and the extracted MR imaging features.

Methods: We analyzed a total of 264 patients (mean age: 47.9 ± 9.7 years; range: 19-81 years) with 264 masses (mean size: 28.6 ± 15.86 mm; range: 5-91 mm) using a Unet model and Gradient Tree Boosting for segmentation and classification.

Results: The tumors were segmented clearly by the Unet model automatically. All the extracted features which including the shape features,the texture features of the tumors and the clinical features were input into the classifiers for classification, and the results showed that the GTB classifier is superior to other classifiers, which achieved F1-Score 0.72, AUC 0.81 and score 0.71. Analyzed the different features combinations, we founded that the texture features associated with the clinical features are the optimal features to different the breast cancer subtypes.

Conclusion: CAD is feasible to differentiate the breast cancer subtypes, automatical segmentation were feasible by Unet model and the extracted texture features from breast MR imaging with the clinical features can be used to help differentiating the molecular subtype. Moreover, in the clinical features, BPE and age characteristics have the best potential for subtype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2021.693339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260834PMC
June 2021

A copper monosulfide-nanoparticle-based fluorescent probe for the sensitive and specific detection of ochratoxin A.

Talanta 2021 Jan 22;222:121678. Epub 2020 Sep 22.

Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Tianjin Institute of Environmental and Operational Medicine, Tianjin, 300050, China. Electronic address:

The mycotoxin ochratoxin A (OTA) is a secondary metabolite derived from multiple Aspergillus and Penicillium strains. The development of a rapid, sensitive, and simple method for OTA detection is important to ensure food biosafety and safeguard public health. In this study, we designed a highly specific and sensitive assay for the detection of OTA using copper monosulfide (CuS) nanoparticles conjugated to an anti-OTA antibody (CuS-Ab NPs) and a fluorescent probe for Cu. When OTA is present in the solution, the OTA antigen, bound to the microplate, is competed off by the soluble OTA for binding to CuS-Ab NPs. After washing, the CuS-Ab NPs and bound OTA are removed. Subsequently, HCl is added to dissolve the CuS-Ab NPs bound to the OTA antigen, releasing Cu and activating the Cu fluorescent probe. Thus, the resultant fluorescence emission is inversely proportional to the OTA content in the solution. Under optimal conditions, this method detected 0.1-100 ng mL OTA with a limit of detection of 0.01 ng mL. The assay was tested using corn, soybean, and coffee samples, with recoveries ranging from 94% to 110%. This strategy provides a new approach for the detection of mycotoxins and other small-molecule analytes with broad application potential in food safety and quality control.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2020.121678DOI Listing
January 2021

Alisma Shugan Decoction (ASD) Ameliorates Hepatotoxicity and Associated Liver Dysfunction by Inhibiting Oxidative Stress and p65/Nrf2/JunD Signaling Dysregulation In Vivo.

Med Sci Monit 2020 Jul 16;26:e921738. Epub 2020 Jul 16.

Department of Pharmacy, Tongde Hospital Zhejiang Province, Hangzhou, Zhejiang, China (mainland).

BACKGROUND Liver fibrosis, defined as the aberrant accumulation of extracellular matrix (ECM) proteins such as collagen in the liver, is a common feature of chronic liver disease, and often culminates in portal hypertension, liver cirrhosis, and hepatic failure. Though therapeutically manageable, fibrosis is not always successfully treated by conventional antifibrotic agents. While the traditional Chinese medicine (TCM) Alisma Shugan Decoction (ASD) has several health benefits, including anti-inflammation, anti-oxidation, and limitation of cardiovascular and respiratory disorders, it remains unclear if it has any hepato-protective potential. MATERIAL AND METHODS The present study examined the therapeutic effect of ASD in thioacetamide (TAA)-induced liver injury and fibrosis rat models. RESULTS We demonstrated that 50 mg/kg ASD significantly reversed TAA-induced elevation of alanine or aspartate transaminase levels, elicited no dyscrasia, and conferred a 40% (p<0.01) or 20% (p<0.05) survival advantage, compared to rats treated with TAA or TAA+ASD, respectively. Treatment with ASD reversed TAA-induced liver injury and fibrogenesis via repression of alpha-SMA protein and reduction of the collagen area and fibrosis score. Concurrently, ASD markedly suppressed the mRNA expression of fibrogenic procollagen, ICAM-1, MMP2, MMP9, and MMP13, and production of TIMP-1, ICAM-1, CXCL7, or CD62L cytokine in rat liver injury models. Interestingly, ASD-elicited reduction of liver injury and fibrogenesis was mediated by dysregulated p65/NrF-2/JunD signaling, with a resultant 3.18-fold (p<0.05) increase in GSH/GSSH ratio, and a 3.61-fold (p<0.01) or 1.51-fold (p<0.01) reduction in the 4-hydroxynonenal and malondialdehyde (MDA) levels, respectively, indicating reduced oxidative stress in the ASD-treated rats, and suggesting an hepato-protective role for ASD. CONCLUSIONS In conclusion, the present study provides supplementary evidence of the therapeutic benefit of ASD as an efficient treatment option in cases of liver injury and fibrosis. Further large-cohort validation of these findings is warranted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12659/MSM.921738DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7384331PMC
July 2020

Sestrin proteins in cardiovascular disease.

Clin Chim Acta 2020 Sep 11;508:43-46. Epub 2020 May 11.

Guangdong Second Provincial General Hospital. Add: Xingangzhong Road, Guangzhou City, Guangdong Province, China. Electronic address:

Cardiovascular diseases are the main cause of mortality and morbidity worldwide. Cardiovascular diseases such as AMI, AS, cardiac hypertrophy and cardiac fibrosis can be alleviated by controlling the inflammatory response, cellular proliferation, production of ROS and secretion of cytokines. Sestrins are considered to be protective proteins which can prevent age-related diseases. A potential mechanism is an inhibitory effect on mTORC, which depends on the sestrin-AMPK-mTORC pathway. Sestrins regulate the M1/M2 macrophage balance, level of ROS and certain cytokines during stress and cardiovascular diseases through the above pathway. Sestrins exert different functions in diverse organs and tissue. According to existing studies, the main functions of sestrins are strongly associated with the pathological features of cardiovascular disease and exert protective roles in cardiovascular disease. Based on the current evidence, we present a mini-review on the physiological functions and mechanism of sestrins in cardiology. The purpose of this review is to summarize the functions and mechanism of sestrins in common cardiovascular diseases, to raise awareness in clinicians that sestrins may be an important potential target for controlling progression of disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cca.2020.05.013DOI Listing
September 2020

Sestrin1 inhibits oxidized low-density lipoprotein-induced activation of NLRP3 inflammasome in macrophages in a murine atherosclerosis model.

Eur J Immunol 2020 08 19;50(8):1154-1166. Epub 2020 May 19.

Department of Cardiology, Jingzhou Central Hospital of Yangtze University, Jingzhou, China.

Macrophages play a crucial role in the progression of atherosclerotic lesions. In the current study, we analyzed the expression and function of sestrin1 (SESN1) in the aorta macrophages in a murine atherosclerosis model. We identified high SESN1 expression in the aorta macrophages in atherosclerotic mice. Using lentivirus-mediated SESN1 overexpression in macrophages, we found that SESN1 inhibited oxidized low-density lipoprotein-induced NLRP3 inflammasome activation in lipopolysaccharide (LPS)-primed macrophages, as evidenced by less ASC-NLRP3 complex formation, lower caspase-1 activation, and lower generation of mature IL-1β. Besides, SESN1 impeded oxidized low-density lipoprotein-induced activation of NK-κB signaling in macrophages. Furthermore, SESN1 suppressed cholesterol crystal-induced NLRP3 inflammasome activation and foam cell formation. Adoptive transfer of SESN1 overexpressing macrophages reduced the expression of pro-inflammatory cytokines in infiltrating macrophages and the whole aorta tissue. Adoptive transfer of SESN1 knockdown macrophages enhanced the expression of pro-inflammatory cytokines in infiltrating macrophages and the whole aorta tissue. Overall, our study sheds light on the significance of SESN1 for macrophage-mediated aorta inflammation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/eji.201948427DOI Listing
August 2020

PD-1/PD-L1 in cardiovascular disease.

Clin Chim Acta 2020 Jun 19;505:26-30. Epub 2020 Feb 19.

Yangtze University Health Science Center, 434020 Jingzhou City, Hubei Province, China; Department of Cardiology, Jingzhou Central Hospital, 434020 Jingzhou City, Hubei Province, China. Electronic address:

The PD-1/PD-L1 coinhibitory pathway has critical roles in the immune response and autoimmunity via the regulation of T cell activity. Excessive activity and high expression of this pathway suppresses the function of T cells and immunity. Recent research has indicated that tumour cells express high levels of PD-L1, which has an immunosuppressive effect and can result in treatment failure. Anti-PD-L1 or anti-PD-1 agents have well-established beneficial effects on mortality and quality of life in cancer patients. Based on the regulatory effects and therapeutic value of the PD-1/PD-L1 pathway in malignant disorders, we propose that it also regulates cell immunity and in CHD and atherosclerosis. Low expression level of PD-1/ PD-L1 or anti-PD-1/PD-L1 therapy accelerates the immune processes in CHD and aggravates disease according to numerous studies. A few studies have provided strong evidence that changes in the expression levels of PD-1 or PD-L1 can alter the degree of inflammation and the state of coronary plaques in atherosclerosis. In this review, we summarise the alterations of the PD-1/PD-L1 pathway and discuss its role in CHD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cca.2020.02.019DOI Listing
June 2020

Highly sensitive detection of ochratoxin A based on bio-barcode immunoassay and catalytic hairpin assembly signal amplification.

Talanta 2020 Feb 28;208:120405. Epub 2019 Sep 28.

Tianjin Key Laboratory of Risk Assessment and Control Technology for Environment and Food Safety, Institute of Environmental and Operational Medicine, Academy of Military Medical Science, Academy of Military Science, Tianjin, 300050, China. Electronic address:

Herein, a highly sensitive ochratoxin A (OTA) detection strategy was developed based on a bio-barcode immunoassay with catalytic hairpin assembly (CHA). Two nanoprobes were designed for the assay: one was a gold nanoparticle (AuNP) harbouring numerous bio-barcode DNA and antibodies, and the other was an antigen-functionalized magnetic nanoparticle (MNP). In the presence of target OTA, the antigens of the MNPs competed with OTA for binding to the antibodies on the AuNPs. After magnetic separation, the unbound AuNPs and target OTA were washed away. Dithiothreitol (DTT) was then added to the MNP-bound AuNPs to elute the bio-barcode DNAs of AuNPs, which triggered the CHA reaction. Under optimal conditions, the proposed method could sensitively detect target OTA ranging from 0.001 to 10000 ng/mL. The limit of detection (LOD, 3 N/S) and limit of quantification (LOQ, 10 N/S) for OTA were 0.54 pg/mL and 1.80 pg/mL, respectively. The bio-barcode immunoassay was used to analyse food samples (corn, wheat, and peanut), and the recovery and relative standard deviations (RSD) ranged from 93.30% to 108.80% and from 3.2% to 6.9%, respectively. The total assay time was 6 h. Therefore, the proposed strategy will provide a new approach for the detection of mycotoxins and other small molecule analytes and can be applied for quality control to ensure food safety.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2019.120405DOI Listing
February 2020

Insights Into the Resistance Mechanisms of Inhibitors to FLT3 F691L Mutation an Integrated Computational Approach.

Front Pharmacol 2019 20;10:1050. Epub 2019 Sep 20.

Department of Pharmacy, Tongde Hospital of Zhejiang Province, Hangzhou, China.

Research has shown that FMS-like tyrosine kinase 3 (FLT3) may be a vital drug target for acute myeloid leukemia (AML). However, even though the clinically relevant F691L gatekeeper mutation conferred resistance to current FLT3 drug quizartinib, PLX3397 remained unaffected. In this study, the protein-ligand interactions between FLT3 kinase domain (wild-type or F691L) and quizartinib or PLX3397 were compared an integrated computational approach. The classical molecular dynamics (MD) simulations in conjunction with dynamic cross-correlation (DCC) analysis, solvent-accessible surface area (SASA), and free energy calculations indicated that the resistant mutation may induce the conformational change of αC-helix and A-loop of the FLT3 protein. The major variations were controlled by the electrostatic interaction and SASA, which were allosterically regulated by residues Glu-661 and Asp-829. When FLT3-F691L was bound to quizartinib, a large conformational change was observed combination of accelerated MD simulations (aMDs), principal component analysis (PCA), and free energy landscape (FEL) calculations. The umbrella sampling (US) simulations were applied to investigate the dissociation processes of the quizartinib or PLX3397 from FLT3-WT and FLT3-F691L. The calculated results suggested that PLX3397 had similar dissociation processes from both FLT3-WT and FLT3-F691L, but quizartinib dissociated more easily from FLT3-F691L than from FLT3-WT. Thus, reduced residence time was responsible for the FLT3-F691L resistance to inhibitors. These findings indicated that both the conformational changes of αC-helix and A-loop and the drug residence time should be considered in the design of drugs so that rational decisions can be made to overcome resistance to FLT3-F691L.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphar.2019.01050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6763581PMC
September 2019

Dynamic Titania Nanotube Surface Achieves UV-Triggered Charge Reversal and Enhances Cell Differentiation.

ACS Appl Mater Interfaces 2019 Oct 25;11(40):36939-36948. Epub 2019 Sep 25.

MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027 , China.

Stimuli-responsive biomaterials supply a promising solution to adapt to the complex physiological environment for different biomedical applications. In this study, a dynamic UV-triggered pH-responsive biosurface was constructed on titania nanotubes (TNTs) by loading photoacid generators, diphenyliodonium chloride, into the nanotubes, and grafting 2,3-dimethyl maleic anhydride (DMMA)-modified hyperbranched poly(l-lysine) (HBPLL) onto the surface. The local acidity was dramatically enhanced by UV irradiation for only 30 s, leading to the dissociation of DMMA and thereby the transformation of surface chemistry from negatively charged caboxyl groups to positively charged amino groups. The TNTs-HBPLL-DMMA substrate could better promote proliferation and spreading of rat bone mesenchymal stem cells (rBMSCs) after UV irradiation. The osteogenic differentiation of rBMSCs was enhanced because of the charge reversal in combination with the titania-based substrates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.9b11536DOI Listing
October 2019

The size-controllable preparation of chitosan/silver nanoparticle composite microsphere and its antimicrobial performance.

Carbohydr Polym 2019 Sep 18;220:22-29. Epub 2019 May 18.

State Key Laboratory of Food Nutrition and Safety, Tianjin University of Science & Technology, Tianjin, 300222, China.

The control of chitosan/silver nanoparticle composite microsphere (CAgMs) size is crucial for tuning its function. In the current work, monodisperse organically-modified CAgMs with controllable size were synthesized using a two-step method. The fine-tuning of the microsphere size was confirmed by many reaction parameters while the cross-linking agent was the key research object. Through physical and thermodynamic analysis, we found the cross-linking agent-induced smaller size, higher silver concentration, more heightened glass transition temperature and stronger hydrogen bond network. The as-prepared microspheres exhibited strong bacteriostasis and fresh-keeping function depending on cross-linking agent concentration. The phenomenon is believed to be derived from the difference in microorganism adsorption and killing ability from induced varying specific surface area and encapsulated silver content. Our current work highlights the size-controllable preparation of CAgMs, and based on our findings, small size CAgMs can be a promising candidate in the field of antibacterial and fruit preservation applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.carbpol.2019.05.048DOI Listing
September 2019

A Rapid and Sensitive UPLC-MS/MS Method for Quantification of Bruceantinol in Rat Plasma and Its Application to a Pharmacokinetic Study.

Planta Med 2018 Jan 31;84(2):111-116. Epub 2017 Jul 31.

Key Laboratory of Ministry of Education for TCM Viscera-State Theory and Applications, Liaoning University of Traditional Chinese Medicine, Shenyang, China.

Bruceantinol (BOL), a quassinoid compound isolated from the fruits of , has been reported to have cytotoxic and antibacterial effects. In this study, a rapid, sensitive, and specific ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed for the quantitative determination of BOL in rat plasma. The samples were treated by simple liquid-liquid extraction with ethyl acetate and separated on an UPLC BEH C18 column (2.1 mm × 50 mm) using a 3-min gradient elution scheme, which consists of water (0.1% v/v, formic acid) and methanol (0.1%, v/v, formic acid) to achieve the separation of BOL and sinomenine (IS) with high selectivity. The electrospray ionization source was used in positive ion mode; the multiple reaction monitoring quantified the target fragment ions 629.6 → 569.5 for BOL and 330.5 → 207.3 for IS. This work was evaluated with regards to the specificity, extraction recovery, matrix effect, linearity, accuracy, precision, stability, and dilution integrity. This approach was used to examine the pharmacokinetics of BOL in rats after oral (0.3 mg/kg) and intravenous (0.15 mg/kg) administration. BOL presented fast excretion and very low oral bioavailability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0043-117414DOI Listing
January 2018

A Free-Standing and Self-Healable 2D Supramolecular Material Based on Hydrogen Bonding: A Nanowire Array with Sub-2-nm Resolution.

Small 2017 06 7;13(21). Epub 2017 Apr 7.

School of Materials, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom.

In many 2D materials reported thus far, the forces confining atoms in a 2D plane are often strong interactions, such as covalent bonding. Herein, the first demonstration that hydrogen (H)-bonding can be utilized to assemble polydiacetylene (a conductive polymer) toward a 2D material, which is stable enough to be free-standing, is shown. The 2D material is well characterized by a large number of techniques (mainly different microscopy techniques). The H-bonding allows splitting of the material into ribbons, which can reassemble, similar to a zipper, leading to the first example of a healable 2D material. Moreover, such technology can easily create 2D, organic, conductive nanowire arrays with sub-2-nm resolution. This material may have potential applications in stretchable electronics and nanowire cross-bar arrays.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.201604077DOI Listing
June 2017

Moving away from exhaustion: how core self-evaluations influence academic burnout.

PLoS One 2014 29;9(1):e87152. Epub 2014 Jan 29.

Department of Psychology, Forth Military Medical University, Shaanxi, People's Republic of China.

Background: Academic burnout refers to students who have low interest, lack of motivation, and tiredness in studying. Studies concerning how to prevent academic burnout are rare.

Objective: The present study aimed to investigate the impact of core self-evaluations on the academic burnout of university students, and mainly focused on the confirmation of the mediator role of life satisfaction.

Methods: A total of 470 university students accomplished the core self-evaluation scale, Satisfaction with Life, and academic burnout scale.

Results: Both core self-evaluations and life satisfaction were significantly correlated with academic burnout. Structural equation modeling indicated that life satisfaction partially mediated the relationship between core self-evaluations and academic burnout.

Conclusions: Core self-evaluations significantly influence academic burnout and are partially mediated by life satisfaction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0087152PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3906107PMC
October 2014

Bifactor item response theory model of acute stress response.

PLoS One 2013 7;8(6):e65291. Epub 2013 Jun 7.

Department of Psychology, Fourth Military Medical University, Xi'an City, Shaanxi Province, PR China.

Background: Better understanding of acute stress responses is important for revision of DSM-5. However, the latent structure and relationship between different aspects of acute stress responses haven't been clarified comprehensively. Bifactor item response model may help resolve this problem.

Objective: The purpose of this study is to develop a statistical model of acute stress responses, based on data from earthquake rescuers using Acute Stress Response Scale (ASRS). Through this model, we could better understand acute stress responses comprehensively, and provide preliminary information for computerized adaptive testing of stress responses.

Methods: Acute stress responses of earthquake rescuers were evaluated using ASRS, and state/trait anxiety were assessed using State-trait Anxiety Inventory (STAI). A hierarchical item response model (bifactor model) was used to analyze the data. Additionally, we tested this hierarchical model with model fit comparisons with one-dimensional and five-dimensional models. The correlations among acute stress responses and state/trait anxiety were compared, based on both the five-dimensional and bifactor models.

Results: Model fit comparisons showed bifactor model fit the data best. Item loadings on general and specific factors varied greatly between different aspects of stress responses. Many symptoms (40%) of physiological responses had positive loadings on general factor, and negative loadings on specific factor of physiological responses, while other stress responses had positive loadings on both general and specific factors. After extracting general factor of stress responses using bifactor analysis, significant positive correlations between physiological responses and state/trait anxiety (r = 0.185/0.112, p<0.01) changed into negative ones (r = -0.177/-0.38, p<0.01).

Conclusion: Our results demonstrated bifactor structure of acute stress responses, and positive and negative correlations between physiological responses and stress responses suggested physiological responses could have negative feedback on severity of stress responses. This finding has not been convincingly demonstrated in previous research.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065291PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3676469PMC
January 2014
-->