Publications by authors named "Ziqi Yang"

30 Publications

  • Page 1 of 1

Dimensional Design and Core-Shell Engineering of Nanomaterials for Electromagnetic Wave Absorption.

Adv Mater 2021 Nov 10:e2107538. Epub 2021 Nov 10.

Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Department of Materials Science, Fudan University, Shanghai, 200438, P. R. China.

Electromagnetic (EM) wave absorption materials possess exceptionally high EM energy loss efficiency. With vigorous developments in nanotechnology, such materials have exhibited numerous advanced EM functions, including radiation prevention and antiradar stealth. To achieve improved EM performance and multifunctionality, the elaborate control of microstructures has become an attractive research direction. By designing them as core-shell structures with different dimensions, the combined effects, such as interfacial polarization, conduction networks, magnetic coupling, and magnetic-dielectric synergy, can significantly enhance the EM wave absorption performance. This paper outlines the advances in low-dimensional core-shell EM wave absorption materials and discusses a selection of the most remarkable examples. It comprehensively summarizes the derived key information regarding dimensional design, structural engineering, performance, and structure-function relationship. Moreover, the investigation of cutting-edge mechanisms is given particular attention. Additional applications, such as oxidation resistance and self-cleaning functions, are also introduced. Finally, insight into what may be expected from this rapidly expanding field and future challenges are presented. This article is protected by copyright. All rights reserved.
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http://dx.doi.org/10.1002/adma.202107538DOI Listing
November 2021

Multivariate Polycrystalline Metal-Organic Framework Membranes for CO/CH Separation.

J Am Chem Soc 2021 Oct 5;143(42):17716-17723. Epub 2021 Oct 5.

Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585 Singapore.

Membrane technology is attractive for natural gas separation (removing CO, HO, and hydrocarbons from CH) because of membranes' low energy consumption and small environmental footprint. Compared to polymeric membranes, microporous inorganic membranes such as silicoaluminophosphate-34 (SAPO-34) membrane can retain their separation performance under conditions close to industrial requirements. However, moisture and hydrocarbons in natural gas can be strongly adsorbed in the pores of those membranes, thereby reducing the membrane separation performance. Herein, we report the fabrication of a polycrystalline MIL-160 membrane on an AlO substrate by in situ hydrothermal synthesis. The MIL-160 membrane with a thickness of ca. 3 μm shows a remarkable molecular sieving effect in gas separation. Besides, the pore size and environment of the MIL-160 membrane can be precisely controlled using reticular chemistry by regulating the size and functionality of the ligand. Interestingly, the more polar fluorine-functionalized multivariate MIL-160/CAU-10-F membrane exhibits a 10.7% increase in selectivity for CO/CH separation and a 31.2% increase in CO permeance compared to those of the MIL-160 membrane. In addition, hydrophobic MIL-160 membranes and MIL-160/CAU-10-F membranes are more resistant to water vapor and hydrocarbons than the hydrophilic SAPO-34 membranes.
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http://dx.doi.org/10.1021/jacs.1c08404DOI Listing
October 2021

DHNLDA: A novel deep hierarchical network based method for predicting lncRNA-disease associations.

IEEE/ACM Trans Comput Biol Bioinform 2021 Sep 20;PP. Epub 2021 Sep 20.

Recent studies have found that lncRNA (long non-coding RNA) in ncRNA (non-coding RNA) is not only involved in many biological processes, but also abnormally expressed in many complex diseases. Identification of lncRNA-disease associations accurately is of great significance for understanding the function of lncRNA and disease mechanism. In this paper, a deep learning framework consisting of stacked autoencoder(SAE), multi-scale ResNet and stacked ensemble module, named DHNLDA, was constructed to predict lncRNA-disease associations, which integrates multiple biological data sources and constructing feature matrices. Among them, the biological data including the similarity and the interaction of lncRNAs, diseases and miRNAs are integrated. The feature matrices are obtained by node2vec embedding and feature extraction respectively. Then, the SAE and the multi-scale ResNet are used to learn the complementary information between nodes, and the high-level features of node attributes are obtained. Finally, the fusion of high-level feature is input into the stacked ensemble module to obtain the prediction results of lncRNA-disease associations. The experimental results of five-fold cross-validation show that the AUC of DHNLDA reaches 0.975 better than the existing methods. Case studies of stomach cancer, breast cancer and lung cancer have shown the great ability of DHNLDA to discover the potential lncRNA-disease associations.
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http://dx.doi.org/10.1109/TCBB.2021.3113326DOI Listing
September 2021

Ultrathin Covalent Organic Framework Membranes via a Multi-Interfacial Engineering Strategy for Gas Separation.

Adv Mater 2021 Sep 17:e2104946. Epub 2021 Sep 17.

Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.

Covalent organic frameworks (COFs) are promising membrane materials due to their high porosity, ordered arrangements, and high stability. However, the relatively large pore size and complicated membrane preparation processes of COFs limit their applications in sieving small gas molecules, even at a lab scale. Herein, a multi-interfacial engineering strategy is proposed, that is, direct layer-by-layer interfacial reaction of two COFs (TpPa-SO H and TpTG ) with different pore sizes to form narrowed apertures at the COF-COF interfaces atop a relatively large-pore COF (COF-LZU1) film. At 423 K, one fabricated 155 nm-thick ultrathin COF membrane displays H permeance as high as 2163 gas permeation units (GPU) and a H /CO selectivity of 26, transcending the 2008 Robeson upper bound. This strategy not only provides high-performance membrane candidates for H separation, but also enlightens the interfacial engineering and pore engineering manipulation for other COFs, porous polymers, and their membranes.
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http://dx.doi.org/10.1002/adma.202104946DOI Listing
September 2021

IL-17 signaling induces iNOS+ microglia activation in retinal vascular diseases.

Glia 2021 Nov 21;69(11):2644-2657. Epub 2021 Jul 21.

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, P. R. China.

Activation of microglia and inflammation-mediated vascular damages are suggested to play a decisive role in the pathogenesis of various retinopathies. The inducible nitric oxide synthase (iNOS) was required for activated microglia-mediated injuries. However, the induction mechanism of microglia activation during retinal vascular diseases is still elusive. Here we showed that IL-17 induced microglia activation with high expression of iNOS and promoted the development of retinal vascular diseases. IL-17-dependent activation of the STAT3-iNOS pathway was essentially required for microglia activation, which promoted endothelial cell growth and accelerated vascular leakage and leukostasis via IL-6 in vitro and in vivo. Taken together, our data provide novel mechanistic insights on microglia activation-mediated retinopathy, unveil the specific role of IL-17 on microglia, and define novel therapeutic targets for treating retinal vascular diseases.
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http://dx.doi.org/10.1002/glia.24063DOI Listing
November 2021

Depth-dependent influence of biochar application on the abundance and community structure of diazotrophic under sugarcane growth.

PLoS One 2021 19;16(7):e0253970. Epub 2021 Jul 19.

Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.

Despite progress in understanding diazotrophic distribution in surface soils, few studies have investigated the distribution of diazotrophic bacteria in deeper soil layers. Here, we leveraged high-throughput sequencing (HTS) of nifH genes obtained to assess the influence of biochar amended soil (BC) and control (CK), and soil depths (0-20, 20-40 and 40-60 cm) on diazotrophic abundance and community structures, soil enzyme activities and physio-chemical properties. Multivariate ANOVA analysis revealed that soil depth had profound impact on majority of the soil parameters measured than fertilization. Although soil physio-chemical properties, enzymes activities, diazotrophic genera and enriched operational taxonomic units (OTUs) were significantly influenced across the entire soil profiles, we also observed that BC amended soil significantly increased cane stalk height and weight, nitrate (NO3-), ammonium (NH4+), organic matter (OM), total carbon (TC) and available potassium (AK), and enhanced diazotrophic genera in soil depth 0-20 cm compared to CK treatment. Soil TC, total nitrogen (TN), OM and NH4+ were the major impact factors shifting diazotrophic community structures in soil depth 0-20 cm. Overall, these results were more pronounced in 0-20 cm soil depth in BC than CK treatment.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0253970PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8289083PMC
November 2021

Hierarchical Magnetic Network Constructed by CoFe Nanoparticles Suspended Within "Tubes on Rods" Matrix Toward Enhanced Microwave Absorption.

Nanomicro Lett 2021 Jan 4;13(1):47. Epub 2021 Jan 4.

Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials (iChem), Fudan University, Shanghai, 200438, People's Republic of China.

Hierarchical magnetic-dielectric composites are promising functional materials with prospective applications in microwave absorption (MA) field. Herein, a three-dimension hierarchical "nanotubes on microrods," core-shell magnetic metal-carbon composite is rationally constructed for the first time via a fast metal-organic frameworks-based ligand exchange strategy followed by a carbonization treatment with melamine. Abundant magnetic CoFe nanoparticles are embedded within one-dimensional graphitized carbon/carbon nanotubes supported on micro-scale MoN rod ([email protected]@C/CNT), constructing a special multi-dimension hierarchical MA material. Ligand exchange reaction is found to determine the formation of hierarchical magnetic-dielectric composite, which is assembled by dielectric MoN as core and spatially dispersed CoFe nanoparticles within C/CNTs as shell. [email protected]@C/CNT composites exhibit superior MA performance with maximum reflection loss of - 53.5 dB at 2 mm thickness and show a broad effective absorption bandwidth of 5.0 GHz. The [email protected]@C/CNT composites hold the following advantages: (1) hierarchical core-shell structure offers plentiful of heterojunction interfaces and triggers interfacial polarization, (2) unique electronic migration/hop paths in the graphitized C/CNTs and MoN rod facilitate conductive loss, (3) highly dispersed magnetic CoFe nanoparticles within "tubes on rods" matrix build multi-scale magnetic coupling network and reinforce magnetic response capability, confirmed by the off-axis electron holography.
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http://dx.doi.org/10.1007/s40820-020-00572-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8187526PMC
January 2021

Heterogeneous postassembly modification of zirconium metal-organic cages in supramolecular frameworks.

Chem Commun (Camb) 2021 Jun;57(51):6276-6279

Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.

We report a heterogeneous postassembly modification (PAM) to synthesize a zirconium metal-organic cage decorated with acrylate functional groups, ZrT-1-AA, which cannot be synthesized by direct coordination-driven self-assembly owing to the reactivity and instability of the ligand. The PAM process is carried out in a single-crystal-to-single-crystal transformation under mild reaction conditions with high efficiency, which is confirmed by ESI-TOF-MS and 1H NMR. In addition, ZrT-1-AA is crosslinked into shaped materials to demonstrate its potential applications. The proposed PAM strategy sheds light on the development of Zr-MOCs decorated with reactive functional groups, whose introduction is challenging or impossible via direct self-assembly.
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http://dx.doi.org/10.1039/d1cc01606gDOI Listing
June 2021

Predicting RBP Binding Sites of RNA with High-order Encoding Features and CNN-BLSTM Hybrid Model.

IEEE/ACM Trans Comput Biol Bioinform 2021 May 26;PP. Epub 2021 May 26.

RNA binding protein (RBP) is extensively involved in various cellular regulatory processes through the interaction with RNAs. Capturing the RBP binding preferences is fundamental for revealing the pathogenesis of complex diseases. Many experimental detection techniques are still time-consuming and labor-intensive, therefore, it is indispensable to develop a computational method with convincing accuracy. In this study, we proposed a CNN-BLSTM hybrid deep learning framework, named DeepDW, for predicting the RBP binding sites on RNAs with high-order encoding features of RNA sequence and secondary structure. The high-order encoding strategy was used to characterize the dependencies among adjacency nucleotides. For CNN-BLSTM hybrid model, DeepDW firstly employed two 1-D convolutional neural networks (CNNs) for learning the local features from high-order encoded matrices of RNA sequence and structure separately, and then applied two bidirectional long short-term memory networks (BLSTMs) to capture the global information in a higher level. Moreover, a series of experiments were carried out on 31 public datasets to evaluate our proposed framework, and DeepDW achieved superior performance than the state-of-the-art methods. The results indicated that the combination of high-order encoding method and CNN-BLSTM hybrid model had advantages in identifying RBP-RNA binding sites.
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http://dx.doi.org/10.1109/TCBB.2021.3083930DOI Listing
May 2021

Tetrazole-Functionalized Zirconium Metal-Organic Cages for Efficient C H /C H and C H /CO Separations.

Angew Chem Int Ed Engl 2021 Aug 14;60(32):17338-17343. Epub 2021 Jun 14.

Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.

Isoreticular functionalization is a well-elucidated strategy for pore environment tuning and the basis of gas separation performance in extended frameworks. The extension of this approach to discrete porous molecules such as metal-organic cages (MOCs) is conceptually straightforward but hindered by synthetic complications, especially stability concerns. We report the successful isoreticular functionalization of a zirconium MOC with tetrazole moiety by bottom-up synthesis. The title compound (ZrT-1-tetrazol) shows promising C H /CO and C H /C H separation performance, as demonstrated by adsorption isotherms, breakthrough experiments, and density functional theory calculations. The design analogy between MOFs and highly stable MOCs may guide the synthesis of novel porous materials for challenging separation applications.
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http://dx.doi.org/10.1002/anie.202102585DOI Listing
August 2021

Sugarcane monoculture drives microbial community composition, activity and abundance of agricultural-related microorganisms.

Environ Sci Pollut Res Int 2021 Sep 26;28(35):48080-48096. Epub 2021 Apr 26.

Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.

Sugarcane monoculture (SM) often leads to soil problems, like soil acidification, degradation, and soil-borne diseases, which ultimately pose a negative impact on agricultural productivity and sustainability. Understanding the change in microbial communities' composition, activities, and functional microbial taxa associated with the plant and soil under SM is unclear. Using multidisciplinary approaches such as Illumina sequencing, measurements of soil properties, and enzyme activities, we analyzed soil samples from three sugarcane fields with different monoculture histories (1-, 2-, and 4-year cultivation times, respectively). We observed that SM induced soil acidity and had adverse effects on soil fertility, i.e., soil organic matter (OM), total nitrogen (TN), total carbon (TC), and available potassium (AK), as well as enzyme activities indicative for carbon, phosphorus, and nitrogen cycles. Non-metric multidimensional scaling (NMDS) analysis showed that SM time greatly affected soil attribute patterns. We observed strong correlation among soil enzymes activities and soil physiochemical properties (soil pH, OM, and TC). Alpha diversity analysis showed a varying response of the microbes to SM time. Bacterial diversity increased with increasing oligotrophs (e.g., Acidobacteria and Chloroflexi), while fungal diversity decreased with reducing copiotrophs (e.g., Ascomycota). β-Diversity analysis showed that SM time had a great influence on soil microbial structure and soil properties, which led to the changes in major components of microbial structure (soil pH, OM, TC, bacteria and soil pH; TC, fungi). Additionally, SM time significantly stimulated (four bacterial and ten fungal) and depleted (12 bacterial and three fungal) agriculturally and ecologically important microbial genera that were strongly and considerably correlated with soil characteristics (soil pH, OM, TC, and AK). In conclusion, SM induces soil acidity, reduces soil fertility, shifts microbial structure, and reduces its activity. Furthermore, most beneficial bacterial genera decreased significantly due to SM, while beneficial fungal genera showed a reverse trend. Therefore, mitigating soil acidity, improving soil fertility, and soil enzymatic activities, including improved microbial structure with beneficial service to plants and soil, can be an effective measure to develop a sustainable sugarcane cropping system.
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http://dx.doi.org/10.1007/s11356-021-14033-yDOI Listing
September 2021

A specific RIP3 subpopulation of microglia promotes retinopathy through a hypoxia-triggered necroptotic mechanism.

Proc Natl Acad Sci U S A 2021 03;118(11)

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, China;

Retinal neovascularization is a leading cause of severe visual loss in humans, and molecular mechanisms of microglial activation-driven angiogenesis remain unknown. Using single-cell RNA sequencing, we identified a subpopulation of microglia named sMG2, which highly expressed necroptosis-related genes Rip3 and Mlkl. Genetic and pharmacological loss of function demonstrated that hypoxia-induced microglial activation committed to necroptosis through the RIP1/RIP3-mediated pathway. Specific deletion of Rip3 gene in microglia markedly decreased retinal neovascularization. Furthermore, hypoxia induced explosive release of abundant FGF2 in microglia through RIP3-mediated necroptosis. Importantly, blocking signaling components of the microglia necropotosis-FGF2 axis largely ablated retinal angiogenesis and combination therapy with simultaneously blocking VEGF produced synergistic antiangiogenic effects. Together, our data demonstrate that targeting the microglia necroptosis axis is an antiangiogenesis therapy for retinal neovascular diseases.
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http://dx.doi.org/10.1073/pnas.2023290118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7980367PMC
March 2021

Extensive Sub-RPE Complement Deposition in a Nonhuman Primate Model of Early-Stage Diabetic Retinopathy.

Invest Ophthalmol Vis Sci 2021 03;62(3):30

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

Purpose: This study aims to reveal retinal abnormities in a spontaneous diabetic nonhuman primate model and explore the mechanism of featured injuries.

Methods: Twenty-eight cynomolgus monkeys were identified to suffer from spontaneous type 2 diabetes from a colony of more than eight-hundred aged monkeys, and twenty-six age-matched ones were chosen as controls. Their blood biochemistry profiles were determined and retinal changes were examined by multimodal imaging, hematoxylin and eosin staining, and immunofluorescence. Retinal pigment epithelium (RPE) cells were further investigated by RNA sequencing and computational analyses.

Results: These diabetic monkeys were characterized by early retinal vascular and neural damage and dyslipidemia. The typical acellular capillaries and pericyte ghost were found in the diabetic retina, which also exhibited reduced retinal nerve fiber layer thickness compared to controls (all P < 0.05). Of note, distinct sub-RPE drusenoid lesions were extensively observed in these diabetic monkeys (46.43% vs. 7.69%), and complements including C3 and C5b-9 were deposited in these lesions. RNA-seq analysis revealed complement activation, AGE/RAGE activation and inflammatory response in diabetic RPE cells. Consistently, the plasma C3 and C4 were particularly increased in the diabetic monkeys with drusenoid lesions (P = 0.028 and 0.029).

Conclusions: The spontaneous type 2 diabetic monkeys featured with early-stage retinopathy including not only typical vascular and neural damage but also a distinct sub-RPE deposition. The complement activation of RPE cells in response to hyperglycemia might contribute to the deposition, revealing an unrecognized role of RPE cells in the early-stage pathological process of diabetic retinopathy.
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http://dx.doi.org/10.1167/iovs.62.3.30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7991921PMC
March 2021

Compressible and flexible [email protected]/C microwave absorption foam with strong dielectric polarization from 2D semiconductor intermediate sandwich structure.

Nanoscale 2021 Mar;13(9):5115-5124

Laboratory of Advanced Materials, Department of Materials Science and Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, P. R. China.

Structural engineering represents a major trend in the field of two-dimensional (2D) materials regarding microscopic interfacial electric/dielectric properties and macroscopic device strategies. 2D molybdenum disulfide (MoS2) with semiconductive features and lamellar architecture has been widely applied in the microwave absorption (MA) field. However, due to its limitations of weak dielectric loss capacity and poor intrinsic mechanical property, MoS2-based MA devices are a considerable design challenge for practical applications with the peculiarities of light weight, high absorption performance, flexibility, and compressibility. Herein, 2D MoS2 was riveted on carbonized melamine foam (CMF) templated from a commercial foam skeleton, which was cladded with the conductive polymer polypyrrole (PPy). The as-prepared [email protected]/CMF was integrated to simultaneously achieve an excellent MA performance including a maximum reflection loss (RL) value of -45.40 dB and a wide absorption bandwidth of 3.8 GHz, together with mechanical practicability including a high compression ratio of over 45.6% in volume and a bending angle of over 43.2°. This excellent MA performance is attributed to the synergetic effect from its sandwiched multi-layered skeleton, consisting of a conductive/semiconductive/conductive ternary conductive network, and multiple polarizations from the 2D MoS2 interlayer. Our strategy sheds novel insight into the construction of advanced carbon-supported composites and 2D materials for use in devices, which can be further extended to energy storage and conversion applications.
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http://dx.doi.org/10.1039/d0nr08794gDOI Listing
March 2021

Accurately Engineering 2/2D/0D Heterojunction In Hierarchical TiCT MXene Nanoarchitectures for Electromagnetic Wave Absorption and Shielding.

ACS Appl Mater Interfaces 2021 Feb 24;13(4):5866-5876. Epub 2021 Jan 24.

Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials (iChem), Fudan University, Shanghai 200438, P. R. China.

The accurate heterojunction engineering in MXene-based composites unprecedentedly boosts their electromagnetic (EM) wave absorption and shielding performance. However, the flocculation of MXene caused by abundant termination groups severely restricts the regulation of heterojunction, which hankers for a revolutionary compositing strategy against unmanageable self-aggregation. Herein, electrically neutral coordination compound with large molecular volume is decorated on TiCT lamellas to protect them from self-precipitation. A rapid polymerization reaction then controllably assembles them into a hierarchical microsphere composed of superlattice-like 2/2D polymer/MXene building blocks. In the carbonized TiCT/C/MoO microspheres, 2/2D/0D heterojunctions can be precisely tuned to regulate electric/dielectric properties. These heterojunctions simultaneously trigger the intensive interfacial polarization and out-plane electron flowing to exhaust the EM energy as much as possible, confirmed by electron holography. Therefore, our products achieve the first-rate EM wave absorption with an ultrabroad absorption bandwidth of 7.7 GHz at the thickness of 2.5 mm. By altering the heterojunction, the composite acquires excellent EM interference shielding performance with an average shielding effectiveness of 35.9 dB. These accomplishments light a new way to microstructure construction and heterojunction design of MXene-based composites and lay out a profound insight into their EM wave absorption mechanism.
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http://dx.doi.org/10.1021/acsami.0c21833DOI Listing
February 2021

Enantioselective Addition-Alkylation of α,β-Unsaturated Carbonyls via Bisguanidinium Silicate Ion Pair Catalysis.

J Am Chem Soc 2020 11 29;142(45):19065-19070. Epub 2020 Oct 29.

Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore.

Silicon hydrides, alkynylsilanes, and alkoxylsilanes were activated by fluoride in the presence of bisguanidinium catalyst to form hypervalent silicate ion pairs. These activated silicates undergo 1,4-additions with chromones, coumarins, and α-cyanocinnamic esters generating enolsilicate intermediates, for a consequent stereoselective alkylation reaction. The reduction-alkylation reaction proceeded under mild conditions using polymethylhydrosiloxane, a cheap and environmentally friendly hydride source. The addition-alkylation reactions with alkynylsilanes and alkoxylsilanes resulted in the construction of two vicinal chiral carbon centers with excellent enantioselectivities and diastereoselectivities (up to 99% ee, >99:1 dr). Density functional theory calculations and experimental NMR studies revealed that penta-coordinated silicates are crucial intermediates.
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http://dx.doi.org/10.1021/jacs.0c00183DOI Listing
November 2020

Dandelion-like carbon nanotube assembly embedded with closely separated Co nanoparticles for high-performance microwave absorption materials.

Nanoscale 2020 May;12(18):10149-10157

Laboratory of Advanced Materials, Department of Materials Science and Collaborative Innovation Center of Chemistry for Energy Materials (iChem), Fudan University, Shanghai 200438, P. R. China.

Enhancing the magnetic loss capacity by microstructure design remains a considerable challenge in the microwave absorption field. Herein, a high-performance microwave absorbent is developed by dispersing a considerable amount of magnetic nanoparticles within the dandelion-like carbon nanotube assembly. A controllable fabrication method is further exploited to adjust the distribution feature of these embedded nanomagnets. In such a hierarchical composite, parts of the interaction network among the coupled closely spaced nanomagnets can be frequently broken and rebuilt to intensively dissipate the microwave energy, which is confirmed by electron holography and micromagnetic simulation for the first time. By virtue of this dynamic magnetic coupling network mechanism, the hierarchical C/Co composite acquires the first-rate microwave absorption performance. The maximum reflection loss value reaches as much as -52.9 dB (absorbance >0.99999) and the effective absorption bandwidth (absorbance >0.9) occupies the entire X band. It is believed that the above insightful mechanism provides a new opportunity to lower the density of the magnet-based microwave absorbent as much as possible. Besides, the unique method for dispersing magnetic nanoparticles also broadens the pathway to assemble the hierarchical architecture.
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http://dx.doi.org/10.1039/d0nr01447hDOI Listing
May 2020

Bcl-6-directed follicular helper T cells promote vascular inflammatory injury in diabetic retinopathy.

Theranostics 2020 4;10(9):4250-4264. Epub 2020 Mar 4.

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou 510060, P. R. China.

Diabetic retinopathy (DR) is a vision-threatening complication of diabetes mellitus characterized by chronic retinal microvascular inflammation. The involvement of CD4+ T cells in retinal vascular inflammation has been considered, but the specific subset and mechanism of T cell-mediated response during the process remains unclear. Here, we aim to investigate the potential role of follicular helper T (Tfh) cells, a newly identified subset of CD4+ T cells in retinal vascular inflammation in DR. : Patients with DR were enrolled and the PD-1CXCR5CD4 Tfh cells were detected in the peripheral blood by flow cytometry. The streptozotocin (STZ)-induced DR model and oxygen-induced retinopathy (OIR) model were established, and 79-6, an inhibitor of Bcl-6, was injected intraperitoneally to suppress Tfh cells. The Tfh cells-related genes were investigated in the spleen, lymph nodes, and retina of mice by flow cytometry, immunofluorescence, and qPCR. : The Tfh cells expanded in the circulation of patients with DR and also increased in circulation, lymph nodes and retinal tissues from the STZ-induced DR mice and OIR mice. Notably, inhibition of Bcl-6, a critical transcription factor for Tfh cells development, prevented upregulation of Tfh cells and its typical IL-21 cytokine, and ameliorated vascular leakage in DR mice or retinal angiogenesis in OIR mice, indicating that Bcl-6-directed Tfh cells could promote vascular inflammation and angiogenesis. : Our results suggested that excessive Bcl-6-directed Tfh cells represent an unrecognized feature of DR and be responsible for the retinal vascular inflammation and angiogenesis, providing opportunities for new therapeutic approaches to DR.
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http://dx.doi.org/10.7150/thno.43731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086358PMC
May 2021

A coumarin-fused 'off-on' fluorescent probe for highly selective detection of hydrazine.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Apr 16;230:118075. Epub 2020 Jan 16.

College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China; Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding 071002, China; Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Hebei University, Baoding 071002, China. Electronic address:

Hydrazine is a kind of widely used industrial raw material and a toxic biochemical reagent. Due to its toxic to organisms, hydrazine has been classified to be a hazardous environmental pollutant. It is urgent to develop fluorescent probe tools for selective sensitivity detection of hydrazine in the environment and the body. We developed here a new coumarin-based fluorescent probe for hydrazine detection. The probe can selectively detect hydrazine over other environmental and endogenous interfering analytes with a large off-on fluorescence response. The detection limit is 8.55 ppb, which is well below the allowed threshold limit value. The sensing mechanism is hydrazine-induced pyrazole ring formation, which is confirmed by HRMS and DFT calculation methods. Additionally, the probe could also be applied for hydrazine imaging in living HeLa cells.
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http://dx.doi.org/10.1016/j.saa.2020.118075DOI Listing
April 2020

Three-Dimensional-Structured Boron- and Nitrogen-Doped Graphene Hydrogel Enabling High-Sensitivity NO Detection at Room Temperature.

ACS Sens 2019 07 11;4(7):1889-1898. Epub 2019 Jul 11.

School of Chemistry , Beihang University , 100191 Beijing , China.

Heteroatom-doping has been proved as an effective method to modulate the electronic, physical, and chemical properties of graphene (Gr). Developing a new strategy of heteroatom-doping for high-performance gas sensing is a pivotal issue. Here, we demonstrate novel Gr-based gas sensors through three-dimensional (3D)-structured B-/N-doping nanomaterials for high-performance NO sensing. The 3D porous B- and N-doped reduced graphene oxide hydrogels (RGOH) are synthesized via one-step hydrothermal self-assembly and employed as transducing materials to fabricate room-temperature high-performance chemiresistors. The systematic characterizations of the as-synthesized B- and N-RGOH clearly show the uniform doping of the B and N heteroatoms and the formation of B and N components with C/O. In comparison with the pristine RGOH counterpart, the 3D B- and N-RGOH sensors exhibit 38.9 and 18.0 times enhanced responses toward 800 ppb NO, respectively, suggesting the remarkable doping effect of the heteroatoms in improving the sensitivity. Significantly, B- and N-RGOH display the exceptionally low limit of detection of 9 and 14 ppb NO, respectively, which are much lower than the threshold limit recommended by the U.S. Environmental Protection Agency. In addition, the developed NO sensors show good linearity, reversibility, fast recovery, and impressive selectivity. This work opens up a new avenue to fabricate room-temperature and high-performance NO sensors by incorporating B and N heteroatoms into 3D RGOH via a convenient hydrothermal self-assembly approach.
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http://dx.doi.org/10.1021/acssensors.9b00769DOI Listing
July 2019

Spatial distribution characteristics of tumor marker CA724 reference values in China.

Cancer Med 2019 08 14;8(9):4465-4474. Epub 2019 Jun 14.

Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong Unversity Health Science Center, Xi'an, Shaanxi, China.

Objects: This study aims to explore the Cancer antigen 724 (CA724) reference values spatial distribution characteristics in healthy Chinese adults. The study can provide regional reference for medical diagnosis.

Study Design: The relationship between CA724 and 25 geographical environmental factors was analyzed firstly. Artificial neural network simulation training was used to construct the prediction model. The national forecast distribution map of the CA724 reference values was obtained by the geostatistical mapping method. Analyzing and exploring the influence mechanism of geographical environment factors on CA724 reference values.

Methods: Collecting 34470 cases from more than 106 cities healthy adults CA724 reference values via several paper databases in 10 recent years. Correlation analysis, RBF artificial neural networks and trend surface analysis were applied to explore if there was any tendency of spatial variation. The Kriging interpolation of geostatistical analysis was developed to reveal the spatial distribution characteristics of the CA724 reference values.

Results: The distribution of CA724 reference values of Chinese healthy adults shows a downward trend from south to north. CA724 reference values have negative correlations with latitude, annual sunshine duration and topsoil cation exchange capacity in clay. CA724 have positive correlations with annual mean air temperature, annual mean relative humidity, and annual precipitation amount. High temperature and high humidity environment will reduce gastrointestinal function and breeze various mold bacteria. Lack of sunshine can easily lead to vitamin C deficiency in the body. These will increase the incidence of gastrointestinal diseases and gastric cancer, then increase the CA724 value.

Conclusion: CA724 reference values show spatial autocorrelation and regional variation. There are some geographical environment factors effected Chinese healthy adults CA724 reference values. Geographic factors such as sunshine, temperature, and humidity have effects on CA724 reference values can provide new ideas and directions of prevention and clinical diagnosis in the future.
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http://dx.doi.org/10.1002/cam4.2176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6675733PMC
August 2019

Red Room-Temperature Phosphorescence of [email protected] Composites Triggered by Heteroatoms in Zeolite Frameworks.

ACS Cent Sci 2019 Feb 22;5(2):349-356. Epub 2019 Jan 22.

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China.

Carbon dots (CDs) with red-emitting room-temperature phosphorescence (RTP) are rarely reported because of the increasing nonradiative decay of the excited states and the decreasing energy gap between the excited states and ground states. Herein, we demonstrate a facile strategy for modulating the RTP properties of CDs in terms of donor-acceptor energy transfer (EnT) in the CDs-in-zeolite system. Upon tuning of the heteroatoms (Zn, Mn) doped in the aluminophosphate zeolite frameworks, [email protected] composites with green and red phosphorescence have been prepared via in situ hydrothermal synthesis. In such composites, the zeolite matrix provides an efficient confinement role in stabilizing the triplet states of CDs. Significantly, the Mn-doped zeolite could act as an energy acceptor allowing EnT from excitons of CDs to the dopant in the host matrix, generating the intriguing red RTP behavior. This work provides an effective strategy for developing CD-based composite materials with special RTP emissions as well as new fields for applications.
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http://dx.doi.org/10.1021/acscentsci.8b00844DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396386PMC
February 2019

Formation and origin of multicenter photoluminescence in zeolite-based carbogenic nanodots.

Nanoscale 2018 Jun 30;10(22):10650-10656. Epub 2018 May 30.

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China.

Carbogenic nanodots (CNDs) are inspiring intensive research efforts owing to their excellent optical properties; however, their chemical structures and photoluminescent origins are still under study. Herein, CNDs with interesting multicenter photoluminescence (PL) have been successfully prepared by pyrolysis of organo-templated zeolites. The simultaneously observed excitation-dependent blue and excitation-independent green PL emissions as well as an uncommon ultraviolet-excited cyan emission are quite different from those of the known multicenter emissive CNDs. To get a thorough understanding of the formation of these CNDs and their PL origins, structural characterizations coupled with femtosecond transient absorption and fluorescence lifetime spectra analyses have been employed to study such PL behavior. The results show that the as-prepared CNDs consist of three main batches with different polarities, and they are composed of a combination of six small fluorophores with diverse ratios. The multicenter PL is obtained due to competition between the conjugated domain fluorophores and the surface-occupied functional group fluorophores. This study provides a comprehensive insight into the origin of multicenter photoluminescence in zeolite-based CNDs.
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http://dx.doi.org/10.1039/c8nr02043dDOI Listing
June 2018

Contractile heterogeneity in ventricular myocardium.

J Cell Physiol 2018 08 12;233(8):6273-6279. Epub 2018 Mar 12.

Department of Cardiology, Zhongnan Hospital of Wuhan University, Wuhan, China.

The transmural heterogeneity of the contractility in ventricular muscle has not been well-studied. Here, we investigated the calcium transient and sarcomere contraction/relaxation in the endocardial (Endo) and epicardial (Epi) myocytes. Endo and Epi myocytes were isolated from C57/BL6 mice by Langendorff perfusion. Ca transient and sarcomere contraction/relaxation were recorded simultaneously at different stimulation frequencies using a dual excitation fluorescence photomultiplier system. We found that the Endo myocytes have higher baseline diastolic calcium, significantly larger calcium transient and stronger sarcomere shortening than Epi myocytes. However, both the rising and decline phases for calcium transient and sarcomere shortening were slower in Endo than in Epi myocytes. When simulation frequency was increased from 1 to 3 Hz, a greater percent increase in the diastole calcium level, Ca transient and sarcomere shortening amplitude has been observed in the Endo myocytes. Accordingly, the frequency-dependent acceleration in the decay rate of calcium transient and sarcomere relaxation was more profound in the Endo than in Epi myocytes. Western blot analysis showed that CaMKII activity was significantly higher in Epi than in Endo myocardium before stimulation. However, this transmural heterogeneity was reversed by rapid pacing. CaMKII inhibition by KN93 diminished the frequency-dependent alterations of Ca transient and sarcomere contraction. Our results suggest that the contractility of ventricular myocytes is heterogeneous. The Endo-myocardium is the major force generating layer in the heart, both at slow and fast heart rate, and the transmural heterogeneity of CaMKII activation plays an important role in the frequency-dependent alterations.
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http://dx.doi.org/10.1002/jcp.26512DOI Listing
August 2018

Michael-Michael Addition Reactions Promoted by Secondary Amine-Thiourea: Stereocontrolled Construction of Barbiturate-Fused Tetrahydropyrano Scaffolds and Pyranocoumarins.

J Org Chem 2017 12 27;82(24):13594-13601. Epub 2017 Nov 27.

School of Chemical Engineering and Technology, Tianjin University , Tianjin 300072, PR China.

Bifunctional secondary amine-thiourea organocatalysts were successfully applied in the stereocontrolled synthesis of barbiturate-fused tetrahydropyrano scaffolds. Compared with typically used tertiary amine-thiourea organocatalysts, the developed catalysts exhibited excellent catalytic performance in the domino Michael-Michael reaction between N, N'-dimethylbarbituric acid and Morita-Baylis-Hillman acetates of nitroalkenes to yield pharmaceutically important heterocycles in good yields with excellent enantioselectivities. Moreover, this catalytic protocol can also be applied to synthesize biologically active pyranocoumarin compounds.
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http://dx.doi.org/10.1021/acs.joc.7b01902DOI Listing
December 2017

Base-Promoted Intermolecular Cyclization of Substituted 3-Aryl(Heteroaryl)-3-chloroacrylaldehydes and Tetrahydroisoquinolines: An Approach to Access Pyrrolo[2,1-a]isoquinolines.

J Org Chem 2016 12 10;81(23):11950-11955. Epub 2016 Nov 10.

Department of Organic Chemistry, College of Chemistry, Jilin University , Changchun 130012, P. R. China.

We have developed a new base-promoted intermolecular cascade cyclization reaction of substituted 3-aryl(heteroaryl)-3-chloroacrylaldehydes and tetrahydroisoquinolines in one pot. The reaction provides a facile and practical synthesis of pyrrolo[2,1-a]isoquinolines. A number of pyrrolo[2,1-a]isoquinolines were synthesized in moderate to high yields (up to 97%).
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http://dx.doi.org/10.1021/acs.joc.6b01781DOI Listing
December 2016

Hydroxytyrosol mildly improve cognitive function independent of APP processing in APP/PS1 mice.

Mol Nutr Food Res 2016 11 25;60(11):2331-2342. Epub 2016 Jul 25.

Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China.

Scope: Olive products, the hallmark of Mediterranean diet, are associated with reduced risk of mild cognitive impairment and Alzheimer's disease (AD). We and other groups have shown that hydroxytyrosol (HT), a bioactive compound of olive products, ameliorates oxidative stress, mitochondrial dysfunction, and neural toxicity. However, whether HT in Mediterranean diet acts as a functional ingredient in delaying AD pathogenesis remains unclear.

Methods And Results: In the present study, APP/PS1 mice, an animal model of AD, were administrated for 6 months with 5 mg/kg/day of HT, a comparable level of HT in daily Mediterranean diet. HT improved electroencephalography activity and marginally benefited cognitive behavior of transgenic mice. In addition, HT treatment ameliorated mitochondrial dysfunction, reduced mitochondrial carbonyl protein, enhanced superoxide dismutase 2 expression, reversed the phase 2 enzyme system and reduced the levels of brain inflammatory markers, but had no effect on brain β-amyloid (Aβ) accumulation in APP/PS1 mice.

Conclusions: These results suggest that HT may represent as a functional ingredient in Mediterranean diet in ameliorating AD-involved neuronal impairment via modulating mitochondrial oxidative stress, neuronal inflammation, and apoptosis without affecting APP processing.
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http://dx.doi.org/10.1002/mnfr.201600332DOI Listing
November 2016

Hydroxytyrosol improves mitochondrial function and reduces oxidative stress in the brain of db/db mice: role of AMP-activated protein kinase activation.

Br J Nutr 2015 Jun 17;113(11):1667-76. Epub 2015 Apr 17.

Center for Mitochondrial Biology and Medicine, Frontier Institute of Science and Technology, Xi'an Jiaotong University,28 West Xianning Road,Xi'an710049,People's Republic of China.

Hydroxytyrosol (HT) is a major polyphenolic compound found in olive oil with reported anti-cancer and anti-inflammatory activities. However, the neuroprotective effect of HT on type 2 diabetes remains unknown. In the present study, db/db mice and SH-SY-5Y neuroblastoma cells were used to evaluate the neuroprotective effects of HT. After 8 weeks of HT administration at doses of 10 and 50 mg/kg, expression levels of the mitochondrial respiratory chain complexes I/II/IV and the activity of complex I were significantly elevated in the brain of db/db mice. Likewise, targets of the antioxidative transcription factor nuclear factor erythroid 2 related factor 2 including p62 (sequestosome-1), haeme oxygenase 1 (HO-1), and superoxide dismutases 1 and 2 increased, and protein oxidation significantly decreased. HT treatment was also found to activate AMP-activated protein kinase (AMPK), sirtuin 1 and PPARγ coactivator-1α, which constitute an energy-sensing protein network known to regulate mitochondrial function and oxidative stress responses. Meanwhile, neuronal survival indicated by neuron marker expression levels including activity-regulated cytoskeleton-associated protein, N-methyl-d-aspartate receptor and nerve growth factor was significantly improved by HT administration. Additionally, in a high glucose-induced neuronal cell damage model, HT effectively increased mitochondrial complex IV and HO-1 expression through activating AMPK pathway, followed by the prevention of high glucose-induced production of reactive oxygen species and declines of cell viability and VO2 capacity. Our observations suggest that HT improves mitochondrial function and reduces oxidative stress potentially through activation of the AMPK pathway in the brain of db/db mice.
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http://dx.doi.org/10.1017/S0007114515000884DOI Listing
June 2015

Haplotypes and effects on growth traits of bovine Wnt7a gene in Chinese Qinchuan cattle.

Gene 2013 Jul 21;524(2):241-5. Epub 2013 Apr 21.

College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, China.

Wnt7a is a member of the WNT gene family, which encodes secreted signaling proteins and responds to many biological processes. Specifically Wnt7a influences satellite stem cells and regulates the regenerative potential of the muscle. However, similar researches about the bovine Wnt7a gene are lacking. Therefore, in this study, polymorphisms of the bovine Wnt7a gene were detected in 488 individuals from Chinese Qinchuan cattle by DNA pooling, forced PCR-RFLP, and DNA sequencing methods. 3 novel SNPs were identified, two SNPs (g.T4926C and g.A21943G) were in the intron and the last one (g.C63777T) was in the exon. Five haplotypes involved in these three variant sites in the Wnt7a gene were identified and their effects on growth traits were analyzed. The results revealed that haplotype 1 had the highest haplotype frequencies and was highly significantly associated with body height (P<0.01), body weight (P<0.05), chest width (P<0.05) and height at hip cross (P<0.01) respectively.
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http://dx.doi.org/10.1016/j.gene.2013.04.013DOI Listing
July 2013

Separating the effects of internal friction and transition state energy to explain the slow, frustrated folding of spectrin domains.

Proc Natl Acad Sci U S A 2012 Oct 18;109(44):17795-9. Epub 2012 Jun 18.

Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.

The elongated three-helix bundle domains spectrin R16 and R17 fold some two to three orders of magnitude more slowly than their homologue R15. We have shown that this slow folding is due, at least in part, to roughness in the free-energy landscape of R16 and R17. We have proposed that this roughness is due to a frustrated search for the correct docking of partly preformed helices. However, this accounts for only a small part of the slowing of folding and unfolding. Five residues on the A helix of R15, when inserted together into R16 or R17, increase the folding rate constants, reduce landscape roughness, and alter the folding mechanism to one resembling R15. The effect of each of these mutations individually is investigated here. No one mutation causes the behavior seen for the five in combination. However, two mutations, E18F and K25V, significantly increase the folding and unfolding rates of both R16 and R17 but without a concomitant loss in landscape roughness. E18F has the greatest effect on the kinetics, and a Φ-value analysis of the C helix reveals that the folding mechanism is unchanged. For both E18F and K25V the removal of the charge and resultant transition state stabilization is the main origin of the faster folding. Consequently, the major cause of the unusually slow folding of R16 and R17 is the non-native burial of the two charged residues in the transition state. The slowing due to landscape roughness is only about fivefold.
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http://dx.doi.org/10.1073/pnas.1201793109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3497808PMC
October 2012
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