Publications by authors named "Jian-Feng Li"

249 Publications

Toward a quantitative theoretical method for infrared and Raman spectroscopic studies on single-crystal electrode/liquid interfaces.

Chem Sci 2019 Dec 10;11(5):1425-1430. Epub 2019 Dec 10.

State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS), Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China

electrochemical infrared spectroscopy and Raman spectroscopy are powerful tools for probing potential-dependent adstructures at solid/liquid electrochemical interfaces. However, it is very difficult to quantitatively interpret the observed spectral features including potential-dependent vibrational frequency and spectral intensity, even from model systems such as single-crystal electrode/liquid interfaces. The clear understanding of electrochemical vibrational spectra has remained as a fundamental issue for four decades. Here, we have developed a method to combine computational vibrational spectroscopy tools with interfacial electrochemical models to accurately calculate the infrared and Raman spectra. We found that the solvation model and high precision level in the self-consistent-field convergence are critical elements to realize quantitative spectral predictions. This method's predictive power is verified by analysis of a classic spectroelectrochemical system, saturated CO molecules electro-adsorbed on a Pt(111) electrode. We expect that this method will pave the way to precisely reveal the physicochemical mechanism in some electrochemical processes such as electrocatalytic reactions.
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http://dx.doi.org/10.1039/c9sc05429dDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8148070PMC
December 2019

Raman study of the photoinduced behavior of dye molecules on TiO() single crystal surfaces.

Chem Sci 2020 Apr 17;11(25):6431-6435. Epub 2020 Apr 17.

Department of Physics, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, College of Energy, College of Materials, Xiamen University Xiamen 361005 China

In dye-sensitized solar cells (DSSCs), the TiO/dye interface significantly affects photovoltaic performance. However, the adsorption and photoinduced behavior of dye molecules on the TiO substrate remains unclear. Herein, shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) was used to study the adsorption and photoinduced behavior of dye (N719) molecules on different TiO() surfaces. On TiO(001) and TiO(110) surfaces, the SHINERS and mass spectrometry results indicate S[double bond, length as m-dash]C bond cleavage in the anchoring groups of adsorbed N719, whereas negligible bond cleavage occurs on the TiO(111) surface. Furthermore, DFT calculations show the stability of the S[double bond, length as m-dash]C anchoring group on three TiO() surfaces in the order TiO(001) < TiO(110) < TiO(111), which correlated well with the observed photocatalytic activities. This work reveals the photoactivity of different TiO() surface structures and can help with the rational design of DSSCs. Thus, this strategy can be applied to real-time probing of photoinduced processes on semiconductor single crystal surfaces.
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http://dx.doi.org/10.1039/d0sc00588fDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8159273PMC
April 2020

Fecal Fusobacterium nucleatum harbored virulence gene fadA are associated with ulcerative colitis and clinical outcomes.

Microb Pathog 2021 Aug 20;157:104964. Epub 2021 May 20.

Department of Gastroenterology and Hepatology, The First Medical Center, Chinese People's Liberation Army General Hospital, Beijing, China. Electronic address:

Object: Fusobacterium nucleatum (F.nucleatum), a gram-negative, obligately anaerobe of oral commensal,has been regarded as culprit of periodontal diseases previously and is being unveiled as possible pathogen of gastrointestinal disorders. The key virulence factor of F.nucleatum is FadA adhesin for binding and invading of the host's epithelial cells. Here, we detected fecal F.nucleatum and virulence gene fadA in patients with ulcerative colitis(UC) and evaluated the clinical relevance with UC.

Methods And Subjects: A total of 310 subjects were enrolled including 100 patients with UC, 70 healthy controls (HC), 70 patients with irritable bowel syndrome subtype diarrhea(IBS-D), and 70 colorectal cancer patients(CRC). Stool samples of UC patients compared with healthy controls as well as IBS-D and CRC patients were collected for Polymerase Chain Reaction(PCR) detection of F.nucleatum (based on 16s rRNA) and virulence gene fadA.

Results: The detection rate of 16s rRNA based PCR for F.nucleatum of UC patients(39/100, 39.00%) and CRC(26/70, 37.14%) patients are significantly higher than HC (12/70, 17.14%, P < 0.01) and IBS-D patients (14/70, 20.00%, P < 0.01). Moreover, 19 samples were detected fadA positive from 39 F.nucleatum positive samples of UC patients (19/39, 48.72%), which is significantly higher than HC(2/12, 16.66%, P < 0.05). There were 3 samples detected fadA positive from 14 F.nucleatum positive samples of IBS-D patients(3/14, 21.43%) and 13 out of 26(50.00%) of CRC patients, which were both no significant differences compared with UC patients(21.4% vs 48.72%, P > 0.05; 50.00% vs 48.72%, P > 0.05). For both F.nucleatum and fadA gene positive patients, there were no statistical significances between erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), white blood cells(WBC), and hemoglobin compared with negative patients(defined by either F.nucleatum or fadA negative, or both negative). However, it is worth noting that detection rate of F.nucleatum with virulence gene fadA in patients of severe ulcerative colitis was significantly higher than patients with mild and moderate colitis(28.89% vs 10.91%, P < 0.05). In addition, the fecal F.nucleatum and fadA gene positive patients were more likely to have pancolitis other than left-sided colitis(pancolitis/left-sided colitis: 26.92% vs 10.42%, P < 0.05).

Conclusions: The presence of F.nucleatum and fadA gene increased in UC patients, especially in patients with severe colitis and pancolitis. Strains of F.nucleatum harbored virulence gene fadA are suggested to play a role in the pathogenesis of UC.
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http://dx.doi.org/10.1016/j.micpath.2021.104964DOI Listing
August 2021

[email protected] Core-Shell Nanoparticles as a SERS Substrate for Volatile Organic Compound Gas Detection.

Anal Chem 2021 May 4;93(19):7188-7195. Epub 2021 May 4.

MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, College of Energy, College of Materials, Xiamen University, Xiamen 361005, China.

Surface-enhanced Raman spectroscopy (SERS) is a promising ultrasensitive analysis technology due to outstanding molecular fingerprint identification. However, the measured molecules generally need to be adsorbed on a SERS substrate, which makes it difficult to detect weakly adsorbed molecules, for example, the volatile organic compound (VOC) molecules. Herein, we developed a kind of a SERS detection method for weak adsorption molecules with [email protected] core-shell nanoparticles (NPs). The well-uniformed single- and multicore-shell NPs can be synthesized controllably, and the shell thickness of the ZIF-8 was able to be precisely controlled (from 3 to 50 nm) to adjust the distance and electromagnetic fields between metal nanoparticles. After analyzing the chemical and physical characterization, [email protected] core-shell NPs were employed to detect VOC gas by SERS. In contrast with multicore or thicker-shell nanoparticles, [email protected] with a shell thickness of 3 nm could efficiently probe various VOC gas molecules, such as toluene, ethylbenzene, and chlorobenzene. Besides, we were capable of observing the process of toluene gas adsorption and desorption using real-time SERS technology. As observed from the experimental results, this core-shell nanostructure has a promising prospect in diverse gas detection and is expected to be applied to the specific identification of intermediates in catalytic reactions.
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http://dx.doi.org/10.1021/acs.analchem.0c05432DOI Listing
May 2021

Plasmonic Core-Shell Nanoparticle Enhanced Spectroscopies for Surface Analysis.

Anal Chem 2021 05 22;93(17):6573-6582. Epub 2021 Apr 22.

State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen 361005, China.

Probing the properties and components of reactive surfaces is crucial for illustrating reaction mechanisms. However, common surface analysis techniques are restricted to in situ acquisition of surface information at the molecular scale in the human environment and industrial catalysis processes. Plasmonic spectroscopies are promising tools to solve this problem. This Feature is intended to introduce the plasmonic core-shell nanoparticle enhanced spectroscopies for qualitatively and quantitatively analyzing surface trace species. Four different working modalities are designed for meeting varied needs, involving in situ surface species detection, catalytic process monitoring, labeled sensing, and dual mode analysis. These newly developed plasmonic spectroscopies show great potential not only in fundamental research but also in practical applications.
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http://dx.doi.org/10.1021/acs.analchem.1c00233DOI Listing
May 2021

Probing Interfacial Electronic Effects on Single-Molecule Adsorption Geometry and Electron Transport at Atomically Flat Surfaces.

Angew Chem Int Ed Engl 2021 Apr 21. Epub 2021 Apr 21.

State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.

Clarifying interfacial electronic effects on molecular adsorption is significant in many chemical and biochemical processes. Here, we used STM breaking junction and shell-isolated nanoparticle-enhanced Raman spectroscopy to probe electron transport and adsorption geometries of 4,4'-bipyridine (4,4'-BPY) at Au(111). Modifying the surface with 1-butyl-3-methylimidazolium cation-containing ionic liquids (ILs) decreases surface electron density and stabilizes a vertical orientation of pyridine through nitrogen atom σ-bond interactions, resulting in uniform adsorption configurations for forming molecular junctions. Modulation from vertical, tilted, to flat, is achieved on adding water to ILs, leading to a new peak ascribed to CC stretching of adsorbed pyridyl ring and 316 % modulation of single-molecule conductance. The dihedral angle between adsorbed pyridyl ring and surface decreases with increasing surface electronic density, enhancing electron donation from surface to pyridyl ring.
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http://dx.doi.org/10.1002/anie.202102587DOI Listing
April 2021

Nonlinear valley phonon scattering under the strong coupling regime.

Nat Mater 2021 Apr 12. Epub 2021 Apr 12.

NSF Nanoscale Science and Engineering Center, University of California, Berkeley, CA, USA.

Research efforts of cavity quantum electrodynamics have focused on the manipulation of matter hybridized with photons under the strong coupling regime. This has led to striking discoveries including polariton condensation and single-photon nonlinearity, where the phonon scattering plays a critical role. However, resolving the phonon scattering remains challenging for its non-radiative complexity. Here we demonstrate nonlinear phonon scattering in monolayer MoS that is strongly coupled to a plasmonic cavity mode. By hybridizing excitons and cavity photons, the phonon scattering is equipped with valley degree of freedom and boosted with superlinear enhancement to a stimulated regime, as revealed by Raman spectroscopy and our theoretical model. The valley polarization is drastically enhanced and sustained throughout the stimulated regime, suggesting a coherent scattering process enabled by the strong coupling. Our findings clarify the feasibility of valley-cavity-based systems for lighting, imaging, optical information processing and manipulating quantum correlations in cavity quantum electrodynamics.
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http://dx.doi.org/10.1038/s41563-021-00972-xDOI Listing
April 2021

Plasmonic Core-Shell Nanomaterials and their Applications in Spectroscopies.

Adv Mater 2021 Apr 2:e2005900. Epub 2021 Apr 2.

College of Energy, State Key Laboratory for Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Materials, Xiamen University, Xiamen, 361005, China.

Plasmonic core-shell nanostructures have attracted considerable attention in the scientific community recently due to their highly tunable optical properties. Plasmon-enhanced spectroscopies are one of the main applications of plasmonic nanomaterials. When excited by an incident laser of suitable wavelength, strong and highly localized electromagnetic (EM) fields are generated around plasmonic nanomaterials, which can significantly boost excitation and/or radiation processes that amplify Raman, fluorescence, or nonlinear signals and improve spectroscopic sensitivity. Herein, recent developments in plasmon-enhanced spectroscopies utilizing core-shell nanostructures are reviewed, including shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), plasmon-enhanced fluorescence spectroscopy, and plasmon-enhanced nonlinear spectroscopy.
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http://dx.doi.org/10.1002/adma.202005900DOI Listing
April 2021

Corrigendum: Prevalence and Socio-Demographic Correlates of Poor Mental Health Among Older Adults in Agricultural Areas of China.

Front Psychiatry 2021 10;12:664145. Epub 2021 Mar 10.

Unit of Psychiatry, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macao, China.

[This corrects the article DOI: 10.3389/fpsyt.2020.549148.].
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http://dx.doi.org/10.3389/fpsyt.2021.664145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992037PMC
March 2021

Introduction to advances in plasmonics and its applications.

Nanoscale 2021 Mar 18;13(12):5935-5936. Epub 2021 Mar 18.

Department of Physical Chemistry, Universitat Rovira i Virgili, Carrer de Marcellí Domingo s/n, 43007 Tarragona, Spain.

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http://dx.doi.org/10.1039/d1nr90053fDOI Listing
March 2021

The receptor-like cytoplasmic kinase CDG1 negatively regulates Arabidopsis pattern-triggered immunity and is involved in AvrRpm1-induced RIN4 phosphorylation.

Plant Cell 2021 May;33(4):1341-1360

Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.

Arabidopsis CDG1 negatively regulates flg22- and chitin-triggered immunity by promoting FLS2 and CERK1 degradation and is partially required for bacterial effector AvrRpm1-induced RIN4 phosphorylation. Negative regulators play indispensable roles in pattern-triggered immunity in plants by preventing sustained immunity impeding growth. Here, we report Arabidopsis thaliana CONSTITUTIVE DIFFERENTIAL GROWTH1 (CDG1), a receptor-like cytoplasmic kinase VII member, as a negative regulator of bacterial flagellin/flg22- and fungal chitin-triggered immunity. CDG1 can interact with the flg22 receptor FLAGELLIN SENSITIVE2 (FLS2) and chitin co-receptor CHITIN ELICITOR RECEPTOR KINASE1 (CERK1). CDG1 overexpression impairs flg22 and chitin responses by promoting the degradation of FLS2 and CERK1. This process requires the kinase activity of MEK KINASE1 (MEKK1), but not the Plant U-Box (PUB) ubiquitin E3 ligases PUB12 and PUB13. Interestingly, the Pseudomonas syringae effector AvrRpm1 can induce CDG1 to interact with its host target RPM1-INTERACTING PROTEIN4 (RIN4), which depends on the ADP-ribosyl transferase activity of AvrRpm1. CDG1 is capable of phosphorylating RIN4 in vitro at multiple sites including Thr166 and the AvrRpm1-induced Thr166 phosphorylation of RIN4 is diminished in cdg1 null plants. Accordingly, CDG1 knockout attenuates AvrRpm1-induced hypersensitive response and increases the growth of AvrRpm1-secreting bacteria in plants. Unexpectedly, AvrRpm1 can also induce FLS2 depletion, which is fully dependent on RIN4 and partially dependent on CDG1, but does not require the kinase activity of MEKK1. Collectively, this study reveals previously unknown functions of CDG1 in both pattern-triggered immunity and effector-triggered susceptibility in plants.
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http://dx.doi.org/10.1093/plcell/koab033DOI Listing
May 2021

z-Piezo Pulse-Modulated STM Break Junction: Toward Single-Molecule Rectifiers with Dissimilar Metal Electrodes.

ACS Appl Mater Interfaces 2021 Feb 15;13(7):8656-8663. Epub 2021 Feb 15.

State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

Fabricating single-molecule junctions with asymmetric metal electrodes is significant for realizing single-molecule diodes, but it remains a big challenge. Herein, we develop a z-piezo pulse-modulated scanning tunneling microscopy break junction (STM-BJ) technique to construct a robust asymmetric junction with different metal electrodes. The asymmetric Ag/BPY-EE/Au single-molecule junctions exhibit a middle conductance value in between those of the two individual symmetric metal electrode junctions, which is consistent with the order of calculated energy-dependent transmission coefficient () of the asymmetric junctions at . Furthermore, the single-molecule conductance of Ag/BPY-EE/Au decreases by about 70% when reversing the bias voltage from 100 to -100 mV, and a clear asymmetric - feature at the single-molecule level is observed for these junctions. This rectifying behavior could be ascribed to a different interfacial coupling of molecules at the two end electrodes, which is confirmed by the different displacement of () at the two bias voltages. Other asymmetric junctions exhibit similar rectifying behavior. The current work provides a feasible way to fabricate hybrid junctions based on asymmetric metal electrodes and investigate their electron transport toward the design of molecular rectifiers.
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http://dx.doi.org/10.1021/acsami.0c21435DOI Listing
February 2021

Probing Single-Atom Catalysts and Catalytic Reaction Processes by Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy.

Angew Chem Int Ed Engl 2021 Apr 17;60(17):9306-9310. Epub 2021 Mar 17.

College of Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces,iChEM, College of Chemistry and Chemical Engineering, Fujian Key Laboratory of Advanced Materials, College of Energy, Xiamen University, Xiamen, 361005, China.

Developing advanced characterization techniques for single-atom catalysts (SACs) is of great significance to identify their structural and catalytic properties. Raman spectroscopy can provide molecular structure information, and thus, the technique is a promising tool for catalysis. However, its application in SACs remains a great challenge because of its low sensitivity. We develop a highly sensitive strategy that achieves the characterization of the structure of SACs and in situ monitoring of the catalytic reaction processes on them by shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) for the first time. Using the strategy, Pd SACs on different supports were identified by Raman spectroscopy and the nucleation process of Pd species from single atoms to nanoparticles was revealed. Moreover, the catalytic reaction processes of the hydrogenation of nitro compounds on Pd SACs were monitored in situ, and molecular insights were obtained to uncover the unique catalytic properties of SACs. This work provides a new spectroscopic tool for the in situ study of SACs, especially at solid-liquid interfaces.
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http://dx.doi.org/10.1002/anie.202100198DOI Listing
April 2021

Arabidopsis lysin motif/F-box-containing protein InLYP1 fine-tunes glycine metabolism by degrading glycine decarboxylase GLDP2.

Plant J 2021 Apr 11;106(2):394-408. Epub 2021 Mar 11.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.

Lysin motif (LysM) is a carbohydrate-binding module often found in secreted or transmembrane proteins in living organisms from prokaryotes to eukaryotes. Thus far, all characterized LysM-containing proteins in plants are plasma membrane-resident receptors or co-receptors playing roles in plant-microbe interactions. Here, we interrogate the Arabidopsis LysM/F-box-containing protein InLYP1 and reveal its function in glycine metabolism. InLYP1 was mainly expressed by vigorously growing tissues, encoding a nuclear-cytoplasmic protein. We validated InLYP1 as part of the SKP1-CULLIN1-F-box E3 complex for mediating protein degradation. The glycine decarboxylase P-protein 1 (GLDP1) was identified as an InLYP1-interacting protein by both immunoprecipitation/mass spectrometry and yeast two-hybrid library screening. InLYP1 could also interact with GLDP2, a paralog of GLDP1 with weaker catalytic activity, and could mediate the degradation of GLDP2 but not GLDP1. Interestingly, both GLDPs could be O-glycosylated and form homodimers or heterodimers. Overexpression of InLYP1 encoding a dominant-negative variant could cause seedling germination retardation on the medium containing glycine. Collectively, these results shed light on the function of plant intracellular LysM-containing proteins, and suggest that InLYP1 may deplete GLDP2 to facilitate glycine decarboxylation in Arabidopsis.
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http://dx.doi.org/10.1111/tpj.15171DOI Listing
April 2021

In Situ Surface-Enhanced Raman Spectroscopy Characterization of Electrocatalysis with Different Nanostructures.

Annu Rev Phys Chem 2021 Apr 20;72:331-351. Epub 2021 Jan 20.

State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, iChEM, College of Energy, Xiamen University, Xiamen 361005, China; email:

As energy demands increase, electrocatalysis serves as a vital tool in energy conversion. Elucidating electrocatalytic mechanisms using in situ spectroscopic characterization techniques can provide experimental guidance for preparing high-efficiency electrocatalysts. Surface-enhanced Raman spectroscopy (SERS) can provide rich spectral information for ultratrace surface species and is extremely well suited to studying their activity. To improve the material and morphological universalities, researchers have employed different kinds of nanostructures that have played important roles in the development of SERS technologies. Different strategies, such as so-called borrowing enhancement from shell-isolated modes and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS)-satellite structures, have been proposed to obtain highly effective Raman enhancement, and these methods make it possible to apply SERS to various electrocatalytic systems. Here, we discuss the development of SERS technology, focusing on its applications in different electrocatalytic reactions (such as oxygen reduction reactions) and at different nanostructure surfaces, and give a brief outlook on its development.
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http://dx.doi.org/10.1146/annurev-physchem-090519-034645DOI Listing
April 2021

Molecular Insight of the Critical Role of Ni in Pt-Based Nanocatalysts for Improving the Oxygen Reduction Reaction Probed Using an SERS Borrowing Strategy.

J Am Chem Soc 2021 Jan 15;143(3):1318-1322. Epub 2021 Jan 15.

College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Materials, iChEM, Xiamen University, Xiamen 361005, China.

PtNi alloy catalysts have excellent catalytic activity and are considered some of the most promising electrocatalysts capable of replacing pure Pt for the oxygen reduction reaction (ORR). For PtNi alloys, Ni-doping can improve performance by changing the electronic and structural properties of the catalyst surface and its interaction with reaction intermediates. However, to date there is no direct spectral evidence detecting or identifying the effect of Ni on the ORR in PtNi alloy catalysts. Herein, we introduce a surface-enhanced Raman spectroscopic (SERS) "borrowing" strategy for investigating ORR processes catalyzed by [email protected] nanoparticles (NPs). The bond vibration of adsorbed peroxide intermediate species (*OOH) was obtained, and the effect of Ni on the interaction between surface Pt and *OOH was studied by varying the Ni content in the alloy. The frequency of the *OOH spectral band has an obvious red-shift with increasing Ni content. Combined with density functional theory (DFT) calculations, we show that Ni-doping can optimize *OOH surface binding on the Pt surface, achieving more efficient electron transfer, thus improving the ORR rate. Notably, these results evidence the SERS borrowing strategy as an effective technique for observations of catalytic processes.
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http://dx.doi.org/10.1021/jacs.0c12755DOI Listing
January 2021

The Efficacy of Fecal Microbiota Transplantation for Children With Tourette Syndrome: A Preliminary Study.

Front Psychiatry 2020 23;11:554441. Epub 2020 Dec 23.

Department of Gastroenterology and Hepatology, The First Medical Center, Chinese People's Liberation Army General Hospital, Beijing, China.

Therapies for Tourette syndrome (TS) are insufficient, and novel therapies are needed. Fecal microbiota transplantation (FMT) has been a potential therapy for several neurological diseases. Here, we report a preliminary study to investigate the effects of FMT on patients with TS. Five patients with TS received a single administration of FMT via endoscopy. Tic symptoms were assessed by Yale Global Tic Severity Scale-Total Tic Score (YGTSS-TTS) and adverse effects were recorded at week 8 following FMT. Lipopolysaccharide (LPS) levels and 14 cytokines levels were measured. The microbiota profile in feces were analyzed by shotgun metagenomics. Four patients (4/5) responded positively to FMT (YGTSS-TTS reduction rate >25%) at week 8 with high safety. The levels of LPS and cytokines varied after FMT. FMT shifted the composition of the gut microbiota in patients close to that of the donor and continuously changed the abundance of and . The restoration of was correlated with the improvement in tic symptoms (Spearman = -0.900, = 0.037). In conclusion, FMT was indicated a potential effective and safe alternative for patients with TS. However, larger clinical trials are needed to confirm the influence of microbiota in TS. chictr.org.cn Identifier: ChiCTR-IIR-17011871, URL: http://www.chictr.org.cn/showproj.aspx?proj=19941.
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http://dx.doi.org/10.3389/fpsyt.2020.554441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7793740PMC
December 2020

Ligand-Free Fabrication of Ag Nanoassemblies for Highly Sensitive and Reproducible Surface-Enhanced Raman Scattering Sensing of Antibiotics.

ACS Appl Mater Interfaces 2021 Jan 29;13(1):1766-1772. Epub 2020 Dec 29.

MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

The assemblies of plasmonic nanoparticles (NPs) are the universal methods for enhancing their surface-enhanced Raman scattering (SERS) activities. However, the present methods suffer from the problems of poor reproducibility, complicated fabrication, or the adsorption of ligands on the surface, which limit their practical applications. In this work, by using a facile freeze-thaw method, we are able to fabricate the assemblies of Ag NPs with highly reproducible SERS activity without the use of ligands. Moreover, the Ag NPs can be well kept in a frozen state for a long time with few influences on the reproducibility (relative standard deviation, RSD ca. 7%), while those kept in colloid (4 °C) suffer from gradual surface oxidation and aggregation. Such a simple freeze-thaw method does not require the introduction of any ligands (or linkers) with long-term stability and reproducibility, implying its wide applications in practical SERS sensing.
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http://dx.doi.org/10.1021/acsami.0c16529DOI Listing
January 2021

Spectroscopic Verification of Adsorbed Hydroxy Intermediates in the Bifunctional Mechanism of the Hydrogen Oxidation Reaction.

Angew Chem Int Ed Engl 2021 Mar 29;60(11):5708-5711. Epub 2021 Jan 29.

State Key Laboratory of Physical Chemistry of Solid Surfaces,iChEM, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen, 361005, China.

Elucidating hydrogen oxidation reaction (HOR) mechanisms in alkaline conditions is vital for understanding and improving the efficiency of anion-exchange-membrane fuel cells. However, uncertainty remains around the alkaline HOR mechanism owing to a lack of direct in situ evidence of intermediates. In this study, in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and DFT were used to study HOR processes on PtNi alloy and Pt surfaces, respectively. Spectroscopic evidence indicates that adsorbed hydroxy species (OH ) were directly involved in HOR processes in alkaline conditions on the PtNi alloy surface. However, OH species were not observed on the Pt surface during the HOR. We show that Ni doping promoted hydroxy adsorption on the platinum-alloy catalytic surface, improving the HOR activity. DFT calculations also suggest that the free energy was decreased by hydroxy adsorption. Consequently, tuning OH adsorption by designing bifunctional catalysts is an efficient method for promoting HOR activity.
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http://dx.doi.org/10.1002/anie.202015571DOI Listing
March 2021

Spectroscopic Verification of Adsorbed Hydroxy Intermediates in the Bifunctional Mechanism of the Hydrogen Oxidation Reaction.

Angew Chem Int Ed Engl 2021 Mar 29;60(11):5708-5711. Epub 2021 Jan 29.

State Key Laboratory of Physical Chemistry of Solid Surfaces,iChEM, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen, 361005, China.

Elucidating hydrogen oxidation reaction (HOR) mechanisms in alkaline conditions is vital for understanding and improving the efficiency of anion-exchange-membrane fuel cells. However, uncertainty remains around the alkaline HOR mechanism owing to a lack of direct in situ evidence of intermediates. In this study, in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and DFT were used to study HOR processes on PtNi alloy and Pt surfaces, respectively. Spectroscopic evidence indicates that adsorbed hydroxy species (OH ) were directly involved in HOR processes in alkaline conditions on the PtNi alloy surface. However, OH species were not observed on the Pt surface during the HOR. We show that Ni doping promoted hydroxy adsorption on the platinum-alloy catalytic surface, improving the HOR activity. DFT calculations also suggest that the free energy was decreased by hydroxy adsorption. Consequently, tuning OH adsorption by designing bifunctional catalysts is an efficient method for promoting HOR activity.
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http://dx.doi.org/10.1002/anie.202015571DOI Listing
March 2021

Multiplex and optimization of dCas9-TV-mediated gene activation in plants.

J Integr Plant Biol 2021 Apr 11;63(4):634-645. Epub 2021 Feb 11.

Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.

Synthetic gene activators consisting of nuclease-dead Cas9 (dCas9) for single-guide RNA (sgRNA)-directed promoter binding and a transcriptional activation domain (TAD) represent new tools for gene activation from endogenous genomic locus in basic and applied plant research. However, multiplex gene coactivation by dCas9-TADs has not been demonstrated in whole plants. There is also room to optimize the performance of these tools. Here, we report that our previously developed gene activator, dCas9-TV, could simultaneously upregulate OsGW7 and OsER1 in rice by up to 3,738 fold, with one sgRNA targeting to each promoter. The gene coactivation could persist to at least the fourth generation. Astonishingly, the polycistronic tRNA-sgRNA expression under the maize ubiquitin promoter, a Pol II promoter, could cause enormous activation of these genes by up to >40,000-fold in rice. Moreover, the yeast GCN4 coiled coil-mediated dCas9-TV dimerization appeared to be promising for enhancing gene activation. Finally, we successfully introduced a self-amplification loop for dCas9-TV expression in Arabidopsis to promote the transcriptional upregulation of AtFLS2, a previously characterized dCas9-TV-refractory gene with considerable basal expression. Collectively, this work illustrates the robustness of dCas9-TV in multigene coactivation and provides broadly useful strategies for boosting transcriptional activation efficacy of dCas9-TADs in plants.
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http://dx.doi.org/10.1111/jipb.13023DOI Listing
April 2021

In Situ Raman Study of CO Electrooxidation on Pt(hkl) Single-Crystal Surfaces in Acidic Solution.

Angew Chem Int Ed Engl 2020 Dec 25;59(52):23554-23558. Epub 2020 Oct 25.

College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Environment and Ecology, State key Laboratory of Marine Environmental Science, iChEM, Xiamen University, Xiamen, 361005, China.

The adsorption and electrooxidation of CO molecules at well-defined Pt(hkl) single-crystal electrode surfaces is a key step towards addressing catalyst poisoning mechanisms in fuel cells. Herein, we employed in situ electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) coupled with theoretical calculation to investigate CO electrooxidation on Pt(hkl) surfaces in acidic solution. We obtained the Raman signal of top- and bridge-site adsorbed CO* molecules on Pt(111) and Pt(100). In contrast, on Pt(110) surfaces only top-site adsorbed CO* was detected during the entire electrooxidation process. Direct spectroscopic evidence for OH* and COOH* species forming on Pt(100) and Pt(111) surfaces was afforded and confirmed subsequently via isotope substitution experiments and DFT calculations. In summary, the formation and adsorption of OH* and COOH* species plays a vital role in expediting the electrooxidation process, which relates with the pre-oxidation peak of CO electrooxidation. This work deepens knowledge of the CO electrooxidation process and provides new perspectives for the design of anti-poisoning and highly effective catalysts.
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http://dx.doi.org/10.1002/anie.202010431DOI Listing
December 2020

Polarization- and Wavelength-Dependent Shell-Isolated-Nanoparticle-Enhanced Sum-Frequency Generation with High Sensitivity.

Phys Rev Lett 2020 Jul;125(4):047401

State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen 361005, China.

Sum-frequency generation (SFG) spectroscopy is a highly versatile tool for surface analysis. Improving the SFG intensity per molecule is important for observing low concentrations of surface species and intermediates in dynamic systems. Herein, Shell-Isolated-Nanoparticle-Enhanced SFG (SHINE-SFG) was used to probe a model substrate. The model substrate, p-mercaptobenzonitrile adsorbed on a Au film with SHINs deposited on top, provided an enhancement factor of up to 10^{5}. Through wavelength- and polarization-dependent SHINE-SFG spectroscopy, the majority of the signal enhancement was found to come from both plasmon enhanced emission and chemical enhancement mechanisms. A new enhancement regime, i.e., the nonlinear coupling of SHINE-SFG with difference frequency generation, was also identified. This novel mechanism provides insight into the enhancement of nonlinear coherent spectroscopies and a possible strategy for the rational design of enhancing substrates utilizing coupling processes.
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http://dx.doi.org/10.1103/PhysRevLett.125.047401DOI Listing
July 2020

The bacterial quorum sensing signal DSF hijacks sterol biosynthesis to suppress plant innate immunity.

Life Sci Alliance 2020 10 11;3(10). Epub 2020 Aug 11.

School of Biological Sciences, Nanyang Technological University, Singapore, Singapore

Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (-11-methyl-dodecenoic acid) produced by pv. can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in , mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of , with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.
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http://dx.doi.org/10.26508/lsa.202000720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7425213PMC
October 2020

Observation of inhomogeneous plasmonic field distribution in a nanocavity.

Nat Nanotechnol 2020 11 10;15(11):922-926. Epub 2020 Aug 10.

College of Energy, State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, College of Energy, College of Materials, Xiamen University, Xiamen, China.

The progress of plasmon-based technologies relies on an understanding of the properties of the enhanced electromagnetic fields generated by the coupling nanostrucutres. Plasmon-enhanced applications include advanced spectroscopies, optomechanics, optomagnetics and biosensing. However, precise determination of plasmon field intensity distribution within a nanogap remains challenging. Here, we demonstrate a molecular ruler made from a set of viologen-based, self-assembly monolayers with which we precisely measures field distribution within a plasmon nanocavity with ~2-Å spatial resolution. We observed an unusually large plasmon field intensity inhomogeneity that we attribute to the formation of a plasmonic comb in the nanocavity. As a consequence, we posit that the generally adopted continuous media approximation for molecular monolayers should be used carefully.
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http://dx.doi.org/10.1038/s41565-020-0753-yDOI Listing
November 2020

Antimicrobial activity and mechanism of peptide CM4 against Pseudomonas aeruginosa.

Food Funct 2020 Aug;11(8):7245-7254

Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang Province 311121, China.

Antibacterial peptide CM4 (ABP-CM4) is a small cationic peptide with broad-spectrum activities against bacteria, fungi and tumor cells and may possibly be used as an antimicrobial agent. In this study, a C-terminal amidated antibacterial peptide ABP-CM4 (ABP-CM4N) with the strongest antibacterial activity was obtained through screening the antibacterial activities of ABP-CM4 with different modifications. The minimal inhibitory concentration of ABP-CM4N was 8 μM against P. aeruginosa (ATCC 27853) which was lower than that of ABP-CM4 (16 μM). The strengthened antimicrobial activity of ABP-CM4N may be associated with the increased membrane binding capacity, being two times that of ABP-CM4 (p < 0.001). The antibacterial mechanism of ABP-CM4N to Pseudomonas aeruginosa was examined by means of cell membrane integrity analysiss, the intracellular ultrastructure change observation and E. coli genomic DNA binding assay. It was found that ABP-CM4N had the same antimicrobial mechanism as ABP-CM4, and the aim of the antimicrobial mechanism was mainly to destroy the cell membrane which caused nucleic acid or protein leakage, and secondly to interact with E. coli genomic DNA after penetrating the cell membrane. Furthermore, in vitro ABP-CM4N showed a better bacteriostatic activity in meats, with the treated samples showing two to three times less positive colonies than ABP-CM4.
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http://dx.doi.org/10.1039/d0fo01031fDOI Listing
August 2020

SINAT E3 Ubiquitin Ligases Mediate FREE1 and VPS23A Degradation to Modulate Abscisic Acid Signaling.

Plant Cell 2020 10 4;32(10):3290-3310. Epub 2020 Aug 4.

State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, People's Republic of China

In plants, the ubiquitin-proteasome system, endosomal sorting, and autophagy are essential for protein degradation; however, their interplay remains poorly understood. Here, we show that four Arabidopsis () E3 ubiquitin ligases, SEVEN IN ABSENTIA OF 1 (SINAT1), SINAT2, SINAT3, and SINAT4, regulate the stabilities of FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING1 (FREE1) and VACUOLAR PROTEIN SORTING23A (VPS23A), key components of the endosomal sorting complex required for transport-I, to modulate abscisic acid (ABA) signaling. GFP-SINAT1, GFP-SINAT2, and GFP-SINAT4 primarily localized to the endosomal and autophagic vesicles. SINATs controlled FREE1 and VPS23A ubiquitination and proteasomal degradation. SINAT overexpressors showed increased ABA sensitivity, ABA-responsive gene expression, and PYRABACTIN RESISTANCE1-LIKE4 protein levels. Furthermore, the SINAT-FREE1/VPS23A proteins were codegraded by the vacuolar pathway. In particular, during recovery post-ABA exposure, SINATs formed homo- and hetero-oligomers in vivo, which were disrupted by the autophagy machinery. Taken together, our findings reveal a novel mechanism by which the proteasomal and vacuolar turnover systems regulate ABA signaling in plants.
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http://dx.doi.org/10.1105/tpc.20.00267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7534459PMC
October 2020

Rapid and Quantitative Detection of Aflatoxin B in Grain by Portable Raman Spectrometer.

Appl Spectrosc 2020 Nov 27;74(11):1365-1373. Epub 2020 Aug 27.

State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, 12466Xiamen University, Xiamen, China.

Many foodstuffs are extremely susceptible to contamination with aflatoxins, in which aflatoxin B is highly toxic and carcinogenic. Therefore, it is crucial to develop a rapid and effective analytical method for detecting and monitoring aflatoxin B in food. Herein, a surface-enhanced Raman spectroscopic (SERS) method combined with QuEChERS (quick, easy, cheap-effective, rugged, safe) sample pretreatment technique was used to detect aflatoxin B. Sample preparation was optimized into a one-step extraction method using an Au nanoparticle-based solution (Au sol) as the SERS detection substrate. An affordable portable Raman spectrometer was then used for rapid, label-free, quantitative detection of aflatoxin B levels in foodstuffs. This method showed a good linear log relationship between the Raman signal intensity of aflatoxin B in the 1-1000 µg L concentration range with a limit of detection of 0.85 µg kg and a correlation coefficient of 0.9836. Rapid aflatoxin B detection times of ∼10 min for wheat, corn, and protein feed powder samples were also achieved. This method has high sensitivity, strong specificity, excellent stability, is simple to use, economical, and is suitable for on-site detection, with good prospects for practical application in the field of food safety.
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http://dx.doi.org/10.1177/0003702820951891DOI Listing
November 2020

Prevalence and socio-demographic correlates of poor sleep quality among older adults in Hebei province, China.

Sci Rep 2020 07 23;10(1):12266. Epub 2020 Jul 23.

Unit of Psychiatry, Centre for Precision Medicine Research and Training, Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, 3/F, Building E12, Avenida da Universidade, Taipa, Macau SAR, China.

Poor sleep quality is associated with negative health outcomes and high treatment burden. This study investigated the prevalence of poor sleep quality and its socio-demographic correlates among older adults in Hebei province, which is a predominantly agricultural region of China. A large-scale cross-sectional epidemiological survey was conducted from April to August 2016. The study used a multistage, stratified, cluster random sampling method. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI). A total of 3,911 participants were included. The prevalence of poor sleep quality (defined as PSQI > 7) was 21.0% (95% CI 19.7-22.2%), with 22.3% (95% CI 20.9-23.8%) in rural areas and 15.9% (95% CI 13.4-18.4%) in urban areas. Multivariable logistic regression analyses found that female gender (P < 0.001, OR 2.4, 95% CI 2.00-2.82), rural areas (P = 0.002, OR 1.5, 95% CI 1.14-1.86), presence of major medical conditions (P < 0.001, OR 2.4, 95% CI 2.02-2.96) and family history of psychiatric disorders (P < 0.001, OR 2.7, 95% CI 1.60-4.39) were independently associated with higher risk of poor sleep quality. Poor sleep quality was common among older adults in Hebei province of China. Regular assessment of sleep quality and accessible sleep treatments for older population should be provided in agricultural areas of China.
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http://dx.doi.org/10.1038/s41598-020-68997-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7378171PMC
July 2020