Publications by authors named "Xinfeng Gao"

39 Publications

Biomimetic porous scaffolds containing decellularized small intestinal submucosa and Sr/Feco-doped hydroxyapatite accelerate angiogenesis/osteogenesis for bone regeneration.

Biomed Mater 2022 Jan 13. Epub 2022 Jan 13.

Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, Hubei, 430000, CHINA.

The design of bone scaffolds is predominately aimed to well reproduce the natural bony environment by imitating the architecture/composition of host bone. Such biomimetic biomaterials are gaining increasing attention and acknowledged quite promising for bone tissue engineering. Herein, novel biomimetic bone scaffolds containing decellularized small intestinal submucosa matrix (SIS-ECM) and Sr/Feco-doped hydroxyapatite (SrFeHA) are fabricated for the first time by the sophisticated self-assembled mineralization procedure, followed by cross-linking and lyophilization post-treatments. The results indicate the constructed SIS/SrFeHA scaffolds are characterized by highly porous structures, rough microsurface and improved mechanical strength, as well as efficient releasing of bioactive Sr/Feand ECM components. These favorable physico-chemical properties endow SIS/SrFeHA scaffolds with an architectural/componential biomimetic bony environment which appears to be highly beneficial for inducing angiogenesis/osteogenesis both in vitro and in vivo. In particular, the cellular functionality and bioactivity of endotheliocytes/osteoblasts are significantly enhanced by SIS/SrFeHA scaffolds, and the cranial defects model further verifies the potent ability of SIS/SrFeHA to accelerate in vivo vascularization and bone regeneration following implantation. In this view these results highlight the considerable angiogenesis/osteogenesis potential of biomimetic porous SIS/SrFeHA scaffolds for inducing bone regeneration and thus may afford a new promising alternative for bone tissue engineering.
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http://dx.doi.org/10.1088/1748-605X/ac4b45DOI Listing
January 2022

Nickel-mediated N-N bond formation and NO liberation nitrogen oxyanion reduction.

Chem Sci 2021 Aug 13;12(31):10664-10672. Epub 2021 Jul 13.

Indiana University, Department of Chemistry 800 E. Kirkwood Ave. Bloomington IN 47401 USA

The syntheses of (DIM)Ni(NO) and (DIM)Ni(NO), where DIM is a 1,4-diazadiene bidentate donor, are reported to enable testing of bis boryl reduced N-heterocycles for their ability to carry out stepwise deoxygenation of coordinated nitrate and nitrite, forming O(Bpin). Single deoxygenation of (DIM)Ni(NO) yields the tetrahedral complex (DIM)Ni(NO)(ONO), with a linear nitrosyl and κ-ONO. Further deoxygenation of (DIM)Ni(NO)(ONO) results in the formation of dimeric [(DIM)Ni(NO)], where the dimer is linked through a Ni-Ni bond. The lost reduced nitrogen byproduct is shown to be NO, indicating N-N bond formation in the course of the reaction. Isotopic labelling studies establish that the N-N bond of NO is formed in a bimetallic Ni intermediate and that the two nitrogen atoms of (DIM)Ni(NO)(ONO) become symmetry equivalent prior to N-N bond formation. The [(DIM)Ni(NO)] dimer is susceptible to oxidation by AgX (X = NO , NO , and OTf) as well as nitric oxide, the latter of which undergoes nitric oxide disproportionation to yield NO and (DIM)Ni(NO)(ONO). We show that the first step in the deoxygenation of (DIM)Ni(NO)(ONO) to liberate NO is outer sphere electron transfer, providing insight into the organic reductants employed for deoxygenation. Lastly, we show that at elevated temperatures, deoxygenation is accompanied by loss of DIM to form either pyrazine or bipyridine bridged polymers, with retention of a BpinO bridging ligand.
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http://dx.doi.org/10.1039/d1sc02846dDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8356809PMC
August 2021

Bcl-xL mutant promotes cartilage differentiation of BMSCs by upregulating TGF-β/BMP expression levels.

Exp Ther Med 2021 Jul 9;22(1):736. Epub 2021 May 9.

Foot and Ankle Surgery, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430033, P.R. China.

Bcl-xL is a transmembrane molecule in the mitochondria, with apoptosis-related and pro-metabolic functions, that also plays a role in chondrogenesis and differentiation. A Bcl-xL mutant, in which the GRI sequence is replaced by ELN, has no anti-apoptotic effect, while other biological functions of this mutant remain unchanged. The present study investigated the impact of this Bcl-xL mutant on cartilage differentiation and the expression levels of TGF-β and bone morphogenetic protein (BMP). Human bone marrow mesenchymal stem cells (BMSCs) were transfected with Bcl-xL and Bcl-xL mutant (∆Bcl-xL) overexpression vectors. The cells were divided into four groups: Control (not subjected to any transfection), EV (empty pcDNA3.1-Bcl-xL vector), OV (Bcl-xL overexpression) and ∆OV (∆Bcl-xL overexpression). Saffron and toluidine blue staining was performed to observe cartilage tissue formation. Flow cytometry was conducted to measure BMSC apoptosis. The expression levels of TGF-β and BMP were evaluated using reverse transcription-quantitative PCR (RT-qPCR) and western blotting. Compared with that in the control group, the expression levels of Bcl-xL in the OV group increased significantly (P<0.05). Western blotting and RT-qPCR results revealed that OV and ∆OV treatment increased the expression levels of TGF-β and BMP in transfected cells, compared to their expression in the control and EV groups (P<0.05). Saffron and toluidine blue staining results showed that cartilage formation was increased in the ∆OV and ∆OV + Bax-/Bak-groups to similar degrees. Cell apoptosis in the ∆OV group did not change compared with that in the control group. The Bcl-xL mutant promoted cartilage differentiation of BMSCs and upregulated TGF-β/BMP expression. This enhancement of chondrogenic differentiation was not related to the expression of Bax and Bak. Taken together, these findings provided for improved application of bone tissue engineering technology in the treatment of articular cartilage defects.
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http://dx.doi.org/10.3892/etm.2021.10168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8138271PMC
July 2021

4-Hexylresorcinol inhibits osteoclastogenesis by suppressing the NF-κB signaling pathway and reverses bone loss in ovariectomized mice.

Exp Ther Med 2021 Apr 11;21(4):354. Epub 2021 Feb 11.

Department of Spine Surgery, Pu Ai Hospital of Wuhan City, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430000, P.R. China.

4-Hexylresorcinol (4HR) is a small organic compound that is widely used as an antiseptic and antioxidant. In the present study, its role in osteoclastogenesis was investigated. Bone marrow-derived macrophages from mice were used to examine the role of 4HR in osteogenesis. An ovariectomy (OVX) mouse model was constructed to examine the effect of 4HR , followed by hematoxylin and eosin and tartrate resistant acid phosphatase staining. In the present study, 4HR effectively suppressed receptor activator of NF-κB ligand-induced osteoclastogenesis in a dose-dependent manner. 4HR was also found to significantly suppress the expression of osteoclast (OC)-specific markers, including tartrate-resistant acid phosphatase, cathepsin K, nuclear factor of activated T-cell cytoplasmic 1 and c-Fos in the presence of RANKL in BMMs. Furthermore, 4HR inhibited osteoclastogenesis by inhibiting the activation of the NF-κB signaling pathway in BMMs. Consistent with the results, 4HR effectively ameliorated OVX-induced bone loss and markedly reduced OC number in the proximal tibia . In conclusion, the present results suggested that 4HR inhibited osteoclastogenesis and rescued bone loss , suggesting that 4HR may serve as a novel therapeutic agent for osteoporosis treatment.
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http://dx.doi.org/10.3892/etm.2021.9785DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7903454PMC
April 2021

Chain Entropy Beats Hydrogen Bonds to Unfold and Thread Dialcohol Phosphates inside Cyanostar Macrocycles To Form [3]Pseudorotaxanes.

J Org Chem 2021 03 26;86(6):4532-4546. Epub 2021 Feb 26.

Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.

The recognition of substituted phosphates underpins many processes including DNA binding, enantioselective catalysis, and recently template-directed rotaxane synthesis. Beyond ATP and a few commercial substrates, however, little is known about how substituents effect organophosphate recognition. Here, we examined alcohol substituents and their impact on recognition by cyanostar macrocycles. The organophosphates were disubstituted by alcohols of various chain lengths, dipropanol, dihexanol, and didecanol phosphate, each accessed using modular solid-phases syntheses. Based on the known size-selective binding of phosphates by π-stacked dimers of cyanostars, threaded [3]pseudorotaxanes were anticipated. While seen with butyl substituents, pseudorotaxane formation was disrupted by competitive OH···O hydrogen bonding between both terminal hydroxyls and the anionic phosphate unit. Crystallography also showed formation of a backfolded propanol conformation resulting in an 8-membered ring and a perched cyanostar assembly. Motivated by established entropic penalties accompanying ring formation, we reinstated [3]pseudorotaxanes by extending the size of the substituent to hexanol and decanol. Chain entropy overcomes the enthalpically favored OH···O contacts to favor random-coil conformations required for seamless, high-fidelity threading of dihexanol and didecanol phosphates inside cyanostars. These studies highlight how chain length and functional groups on phosphate's substituents can be powerful design tools to regulate binding and control assembly formation during phosphate recognition.
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http://dx.doi.org/10.1021/acs.joc.0c02887DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8063573PMC
March 2021

Identification of -benzothiazolyl-2-benzenesulfonamides as novel ABCA1 expression upregulators.

RSC Med Chem 2020 Mar 11;11(3):411-418. Epub 2020 Mar 11.

Hebei Key Laboratory of Organic Functional Molecules , College of Chemistry and Materials Science , Hebei Normal University , Shijiazhuang , 050024 , China . Email:

ATP binding cassette transporter A1 (ABCA1) is a critical transporter that mediates cellular cholesterol efflux from macrophages to apolipoprotein A-I (ApoA-I). Therefore, increasing the expression level of ABCA1 is anti-atherogenic and ABCA1 expression upregulators have become novel choices for atherosclerosis treatment. In this study, a series of -benzothiazolyl-2-benzenesulfonamides, based on the structure of WY06 discovered in our laboratory, were designed and synthesized as novel ABCA1 expression upregulators. Based on an ABCA1 upregulatory cell model, ABCA1 upregulation of target compounds was evaluated. Compounds , , and have good upregulated ABCA1 expression activities, with EC values of 0.97, 0.37, and 0.41 μM, respectively. A preliminary structure-activity relationship is summarized. Replacing the methoxy group on the benzothiazole moiety of WY06 with a fluorine or chlorine atom and exchanging the ester group with a cyano group resulted in more potent ABCA1 upregulating activity. Moreover, compound increased ABCA1 mRNA and protein expression and significantly promoted cholesterol efflux in RAW264.7 cells. In conclusion, -benzothiazolyl-2-benzenesulfonamides were identified as novel ABCA1 expression upregulators.
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http://dx.doi.org/10.1039/c9md00556kDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7593777PMC
March 2020

Stabilization of the Dinitrogen Analogue, Phosphorus Nitride.

ACS Cent Sci 2020 Sep 1;6(9):1572-1577. Epub 2020 Sep 1.

Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States.

The N analogue phosphorus nitride (PN) was the first phosphorus-containing compound to be detected in the interstellar medium; however, this thermodynamically unstable compound has a fleeting existence on Earth. Here, we show that reductive coupling of iron(IV) nitride and molybdenum(VI) phosphide complexes assembles PN as a bridging ligand in a structurally characterized bimetallic complex. Reaction with C≡N Bu releases the mononuclear complex [(NN)Mo-PN], NN = [(MeSiNCHCH)N]), which undergoes light-induced linkage isomerization to provide [(NN)Mo-NP], as revealed by photocrystallography. While structural and spectroscopic characterization, supported by electronic structure calculations, reveals the PN multiple bond character, coordination to molybdenum induces a nucleophilic character at the terminal atom of the PN/NP ligands. Indeed, the linkage isomers can be trapped in solution by reaction with a Rh(I) electrophile.
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http://dx.doi.org/10.1021/acscentsci.0c00944DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7517109PMC
September 2020

HuR Affects Proliferation and Apoptosis of Chronic Lymphocytic Leukemia Cells via NF-B Pathway.

Biomed Res Int 2020 27;2020:1481572. Epub 2020 Aug 27.

Department of Orthopedic, Wuhan Fourth Hospital, Puai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

Objective: To investigate the effects of HuR protein on the treatment of chronic lymphocytic leukemia (CLL).

Methods: LCL lymphoblast cells and B lymphocytes were subjected to HuR overexpression (OV) or interference (IV). Western blot was used to observe the protein expression of human tumor necrosis factor-associated factor 1 (TRAF1), human inhibitor of nuclear factor kappa-B kinase (IKK-), NF-B-inducing kinase (NIK), and p52. Flow cytometry was performed to evaluate apoptosis, and the mRNA expression of TRAF1 was examined by quantitative reverse transcription polymerase chain reaction. Immunofluorescence was carried out to visualize the expression of HuR, and the relationship between HuR and TRAF1 was observed by pull-down test. Cell sensitivity to chlorambucil (CLB) and fludarabine (Flu) was assessed by Cell Counting Kit-8.

Results: The expression of HuR and TRAF1 in LCLs was significantly increased compared to that in B lymphocytes. Compared with the control, HuR OV significantly increased the expression of TRAF1 ( < 0.05), whereas it was significantly decreased in the IV group ( < 0.05). HuR can bind to TRAF1 directly, and the binding rate is positively correlated with HuR expression. After inhibiting HuR, the expression of TRAF1, IKK-, NIK, p52, pro-Caspase 3, and PARP was significantly upregulated in LCLs and B lymphocytes ( < 0.05), while Caspase 3 was downregulated ( < 0.05). Compared with the control, the proliferation of LCLs and B lymphocytes treated by CLB and Flu decreased significantly after HuR blockade ( < 0.05).

Conclusion: HuR may be a key protein regulating CLL resistance. After inhibiting HuR, inflammatory response and apoptosis were significantly increased, and the cell sensitivity to CLB and Flu increased, suggesting that inhibiting HuR activity may be a potential strategy to solve the problem of drug resistance in CLL cells.
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http://dx.doi.org/10.1155/2020/1481572DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7474742PMC
April 2021

Electrosynthesis of a Biaurone by Controlled Dimerization of Flavone: Mechanistic Insight and Large-Scale Application.

J Org Chem 2020 08 2;85(16):10658-10669. Epub 2020 Aug 2.

Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.

The electrochemistry of flavone () has been carefully investigated at glassy carbon cathodes in dimethylformamide containing 0.10 M tetra--butylammonium tetrafluoroborate as supporting electrolyte. In this medium, a cyclic voltammogram for a reduction of exhibits a reversible cathodic process ( = -1.58 V and = -1.47 V vs SHE) that is followed by an irreversible cathodic peak ( = -2.17 V vs SHE). When water (5.0 M) is introduced into the medium, the first peak for becomes irreversible ( = -1.56 V vs SHE), and the second (irreversible) peak shifts to -2.07 V vs SHE. Bulk electrolyses of at -1.60 V vs SHE afford flavanone, 2'-hydroxychalcone, 2'-hydroxy-3-phenylpropionate, and two new compounds, namely ()-1,6-bis(2-hydroxyphenyl)-3,4-diphenylhex-3-ene-1,6-dione () and ()-2,2'-(1,2-diphenylethene-1,2-bis(benzofuran-3(2))-one) (), obtained in significant amounts, that were characterized by means of H and C NMR spectrometry as well as single-crystal X-ray diffraction. Along with the above findings, we have proposed a mechanism for the electroreduction of , which has been further corroborated by our quantum mechanical study.
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http://dx.doi.org/10.1021/acs.joc.0c01220DOI Listing
August 2020

Broadband Tunable Mid-infrared Plasmon Resonances in Cadmium Oxide Nanocrystals Induced by Size-Dependent Nonstoichiometry.

Nano Lett 2020 Apr 10;20(4):2821-2828. Epub 2020 Mar 10.

Department of Chemistry, Indiana University Bloomington, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States.

A central theme of nanocrystal (NC) research involves synthesis of dimension-controlled NCs and studyof size-dependent scaling laws governing their optical, electrical, magnetic, and thermodynamic properties. Here, we describe the synthesis of monodisperse CdO NCs that exhibit high quality-factor (up to 5.5) mid-infrared (MIR) localized surface plasmon resonances (LSPR) and elucidate the inverse scaling relationship between carrier concentration and NC size. The LSPR wavelength is readily tunable between 2.4 and ∼6.0 μm by controlling the size of CdO NCs. Structural and spectroscopic characterization provide strong evidence that free electrons primarily originate from self-doping due to NC surface-induced nonstoichiometry. The ability to probe and to control NC stoichiometry and intrinsic defects will pave the way toward predictive synthesis of doped NCs with desirable LSPR characteristics.
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http://dx.doi.org/10.1021/acs.nanolett.0c00542DOI Listing
April 2020

Hydrosilylation of an Iron(IV) Nitride Complex.

Inorg Chem 2020 Jan 26;59(1):579-583. Epub 2019 Dec 26.

Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States.

The nitride ligand in iron(IV) complex PhB(MesIm)Fe≡N reacts with excess HSiPh to afford PhB(MesIm)Fe(μ-H)(SiHPh) as the major product, which has been structurally and spectroscopically characterized. Bulkier silane HSiPh provides iron(II) amido complex PhB(MesIm)FeN(H)(SiHPh) as the initial product of the reaction, with excess HSiPh affording diamagnetic PhB(MesIm)Fe(μ-H)(SiPh) as the major product. Unobserved iron(II) hydride PhB(MesIm)Fe-H is implicated as an intermediate in this reaction, as suggested by the results of the reaction between iron(II) amido PhB(MesIm)FeN(H)Bu and HSiPh, which provides PhB(MesIm)Fe(H)(μ-H)(Si(NHBu)Ph) as the sole product.
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http://dx.doi.org/10.1021/acs.inorgchem.9b02831DOI Listing
January 2020

Multi-state amine sensing by electron transfers in a BODIPY probe.

Org Biomol Chem 2020 01;18(3):431-440

Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN 47405, USA.

Amines are ubiquitous in the chemical industry and are present in a wide range of biological processes, motivating the development of amine-sensitive sensors. There are many turn-on amine sensors, however there are no examples of turn-on sensors that utilize the amine's ability to react by single electron transfer (SET). We investigated a new turn-on amine probe with a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) fluorophore. BODIPY fluorescence is first preprogrammed into an off state by internal photoinduced electron transfer (PET) to an electron-deficient quinolinium ring, resulting in fluorescence quenching. At low concentrations of aliphatic amine (0 to 10 mM), this PET pathway is shut down by external SET from the amine to the photoexcited charge-transfer state of the probe and the fluorescence is turned on. At high concentrations of amine (50 mM to 1 M), we observed collisional quenching of the BODIPY fluorescence. The probe is selective for aliphatic amines over aromatic amines, and aliphatic thiols or alcohols. The three molecular processes modulate the BODIPY fluorescence in a multi-mechanistic way with two of them producing a direct response to amine concentrations. The totality of the three molecular processes produced the first example of a multi-state and dose-responsive amine sensor.
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http://dx.doi.org/10.1039/c9ob02466bDOI Listing
January 2020

Tuning infrared plasmon resonances in doped metal-oxide nanocrystals through cation-exchange reactions.

Nat Commun 2019 03 27;10(1):1394. Epub 2019 Mar 27.

Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA.

Metal-oxide nanocrystals doped with aliovalent atoms can exhibit tunable infrared localized surface plasmon resonances (LSPRs). Yet, the range of dopant types and concentrations remains limited for many metal-oxide hosts, largely because of the difficulty in establishing reaction kinetics that favors dopant incorporation by using the co-thermolysis method. Here we develop cation-exchange reactions to introduce p-type dopants (Cu, Ag, etc.) into n-type metal-oxide nanocrystals, producing programmable LSPR redshifts due to dopant compensation. We further demonstrate that enhanced n-type doping can be realized via sequential cation-exchange reactions mediated by the Cu ions. Cation-exchange transformations add a new dimension to the design of plasmonic nanocrystals, allowing preformed nanocrystals to be used as templates to create compositionally diverse nanocrystals with well-defined LSPR characteristics. The ability to tailor the doping profile postsynthetically opens the door to a multitude of opportunities to deepen our understanding of the relationship between local structure and LSPR properties.
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http://dx.doi.org/10.1038/s41467-019-09165-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6437201PMC
March 2019

Correction to: Total disc replacement versus fusion for lumbar degenerative disc disease: a systematic review of overlapping meta-analyses.

Eur Spine J 2018 Oct;27(10):2663

Department of Orthopaedics, Wuhan Pu'Ai Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 473 Hanzheng Street, Wuhan, 430033, China.

The authors declare that when writing their article [1] they referenced two previously published papers [2, 3]. Several sentences on pages 807, 808, and 813 were similar to sentences from these two previously published articles.
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http://dx.doi.org/10.1007/s00586-018-5735-5DOI Listing
October 2018

Lone-Pair-Induced Topicity Observed in Macrobicyclic Tetra-thia Lactams and Cryptands: Synthesis, Spectral Identification, and Computational Assessment.

J Org Chem 2018 09 1;83(17):10025-10036. Epub 2018 Aug 1.

Department of Chemistry , Texas A&M University , College Station , Texas 77842 , United States.

The synthesis of a rigid macrobicyclic N,S lactam L1 and a topologically favored in/in N,S cryptand L2 are reported with X-ray structure analysis, dynamic correlation NMR spectroscopy, and computational analysis. Lactam L1 exhibits two distinct rotameric conformations (plus their enantiomeric counterparts) at 25 °C, as confirmed via NMR spectroscopy and computational analysis. Coalescence of the resonances of L1 was observed at 115 °C, allowing for complete nuclei to frequency correlation. Combining computational investigations with experimental data, topological equilibria and relative energies/strain relating to the perturbation of the pore were determined. Due to the increased conformational strain of the NS template, the nitrogen lone pairs in L2 elicit a unique transannular interaction, resulting in a thermodynamically favored in/in nephroidal racemate. The combination of preferred topology, steric relief, and electronic localization of L2 induces a chiral environment imparted through the amine with a computed inversion barrier of 10.3 kcal mol.
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http://dx.doi.org/10.1021/acs.joc.8b01382DOI Listing
September 2018

A flexible, redox-active macrocycle enables the electrocatalytic reduction of nitrate to ammonia by a cobalt complex.

Chem Sci 2018 Jun 15;9(22):4950-4958. Epub 2018 May 15.

Department of Chemistry , Indiana University , 800 E. Kirkwood Ave. , Bloomington , Indiana 47401 , USA . Email:

The cobalt macrocycle complex [Co(DIM)Br] (DIM = 2,3-dimethyl-1,4,8,11-tetraazacyclotetradeca-1,3-diene) is an electrocatalyst for the selective reduction of nitrate to ammonia in aqueous solution. The catalyst operates over a wide pH range and with very high faradaic efficiency, albeit with large overpotential. Experimental investigations, supported by electronic structure calculations, reveal that catalysis commences when nitrate binds to the two-electron reduced species Co(DIM), where cobalt and the macrocycle are each reduced by a single electron. Several mechanisms for the initial reduction of nitrate to nitrite were explored computationally and found to be feasible at room temperature. The reduced DIM ligand plays an important role in these mechanisms by directly transferring a single electron to the bound nitrate substrate, activating it for further reactions. These studies further reveal that the DIM macrocycle is critical to nitrate reduction, specifically its combination of redox non-innocence, hydrogen-bonding functionality and flexibility in coordination mode.
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http://dx.doi.org/10.1039/c8sc00721gDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5994878PMC
June 2018

Reductive defluorination of graphite monofluoride by weak, non-nucleophilic reductants reveals low-lying electron-accepting sites.

Phys Chem Chem Phys 2018 May;20(21):14287-14290

Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.

Graphite monofluoride (GF) can undergo reductive defluorination in the presence of weak, non-nucleophilic reductants. This leads to a new approach to GF-polyaniline composites as cathode materials for significantly improving the discharge capacity of primary lithium batteries. We postulate that the reduction is mediated by residual π-bonds in GF.
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http://dx.doi.org/10.1039/c8cp00384jDOI Listing
May 2018

Mapping of Id locus for dermal shank melanin in a Chinese indigenous chicken breed.

J Genet 2017 Dec;96(6):977-983

College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong, People's Republic of China.

The dermal shank pigmentation, one of the defining traits of chicken breeds, is caused by an abnormal deposition of melanin in the dermis of the shank. The abnormal deposition is controlled by the sex-linked inhibitor of dermal melanin (Id). In this study, we aim to locate the gene responsible for the dermal shank pigmentation in chickens by an association analysis and a differential expression analysis. Based on our results, 72 single-nucleotide polymorphisms (SNPs) located in Z chromosome (chrZ): 71-73 Mb (galGal3) were selected to further explore their relationships with the dermal shank pigmentation in pure lines of 96 Gushi hens and 96 Gushi hens with a yellow shank skin colour. The results of the association analysis showed that the SNPs located in chrZ: 72.58-72.99 Mb (galGal3) (chrZ: 79.02-79.44 Mb (galGal4)) are significantly associated with the dermal shank pigmentation. Based on the results of our previous studies and the present association analysis, the zinc-finger protein 608 (ZNF608), GRAM domain containing 3 (GRAMD3), aldehyde dehydrogenase 7 family member A1 (ALDH7A1), fem-1 homologue C (FEM1C), beta-1,4-galactosyltransferase 1 (B4GALT1) and versican (VCAN) genes were selected for the differential expression analysis. The gene expression profiles showed that the expression of GRAMD3 gene in the dermis tissues of the shank was significantly (P = 0.010738 < 0.05) higher in 350-day-old Gushi chickens characterized by the dermal shank pigmentation than in one-day-old Gushi chickens. The dermal shank pigmentation was not present in the one-day-old Gushi chickens. Additionally, the results of the association analysis and the expression analysis showed that GRAMD3 could be the most likely candidate gene for the Id locus. However, we did not detect a mutation, i.e. significantly associated with this trait within GRAMD3. Therefore, we concluded that the variations located in the flanking region of GRAMD3 led to the abnormal expression of GRAMD3, which requires further study.
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http://dx.doi.org/10.1007/s12041-017-0862-zDOI Listing
December 2017

Associations of and polymorphisms with laying traits in Muscovy duck.

PeerJ 2017 23;5:e4083. Epub 2017 Nov 23.

National-Local Joint Engineering Research Center for Livestock Breeding, College of Animal Science, South China Agricultural University, Guangzhou, Guangdong, China.

Insulin-like growth factor 2 (IGF2) and dopamine receptor 2 (DRD2) play important roles in ovarian follicular development. In this study, we analyzed tissue-specific expression of the Muscovy duck and genes and cloned those genes transcripts. Polymorphisms in these genes were tightly linked with egg production traits and both genes were highly expressed in the ovary. Moreover, we identified five single nucleotide polymorphisms (SNPs) for and 28 for Mutations A-1864G and C-1704G of were positively correlated with increased egg laying at 59 weeks (E59W) ( < 0.05). The C+7T and C+364G mutations of were highly and significantly associated with first-egg age (FEA) and egg numbers at 300 days (E300D) ( < 0.01). Moreover, C+3301G and C+3545G of were highly significantly associated with FEA, E59W and E300D ( < 0.01). Other mutations were positively associated with FEA or E300D or E59W ( < 0.05). These data suggest specific roles for and polymorphisms in egg production in Muscovy ducks.
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http://dx.doi.org/10.7717/peerj.4083DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5702507PMC
November 2017

Cyanide Ligand Assembly by Carbon Atom Transfer to an Iron Nitride.

J Am Chem Soc 2017 10 26;139(40):14037-14040. Epub 2017 Sep 26.

Department of Chemistry, Indiana University , 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States.

The new iron(IV) nitride complex PhB(PrIm)Fe≡N reacts with 2 equiv of bis(diisopropylamino)cyclopropenylidene (BAC) to provide PhB(PrIm)Fe(CN)(N)(BAC). This unusual example of a four-electron reaction involves carbon atom transfer from BAC to create a cyanide ligand along with the alkyne PrN-C≡C-NPr. The iron complex is in equilibrium with an N-free species. Further reaction with CO leads to formation of a CO analogue, which can be independently prepared using NaCN as the cyanide source, while reaction with B(CF) provides the cyanoborane derivative.
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http://dx.doi.org/10.1021/jacs.7b08704DOI Listing
October 2017

Membrane complement regulatory protein reduces the damage of transplanting autologous bone marrow mesenchymal stem cells by suppressing the activation of complement.

Injury 2017 Oct 5;48(10):2089-2094. Epub 2017 Aug 5.

Wuhan Puai Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology, China.

There are few studies on the interaction of transplanting autologous bone marrow mesenchymal stem cells (BMSCs) and complement. In order to further explore the effect of complement on BMSCs, BMSCs were obtained from bone marrow of 20 cases clinical patients, and then experimented in vitro. The cytotoxicity of complement on the mesenchymal stem cells in autologous human serum (AHS) was measured by Europium cytotoxicity assay. The complement membrane attack complex (MAC) deposited on the membrane surface was detected by flow cytometry. Finally, the cytotoxicity on BMSCs was measured after mCRPs overexpression or knockdown. We found that more than 90% of cells derived from bone marrow were identified to be mesenchymal stem cells through detection of cell membrane surface markers by flow cytometry. BMSCs harvested from the 20 patients all had cytotoxicity after incubated with AHS, and the cytotoxicity was significant higher than that incubated with complement inactivated autologous human serum (iAHS). Complement attack complex (MAC) could be detected on the BMSCs incubated with AHS, which implied the complement activation. We also found that mCRPs CD55 and CD59 overexpressions can resist the cytotoxicity induced by complement activation, while mCRPs CD55 and CD59 knockdown can enhance the cytotoxicity. Thus, the results indicated that mCRPs could effectively protect BMSCs from attacking by complement by suppressing the activation of complement.
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http://dx.doi.org/10.1016/j.injury.2017.08.008DOI Listing
October 2017

Molecular characterization, expression profile of the FSHRgene and its association with egg production traits in muscovy duck.

J Genet 2017 Jun;96(2):341-351

National-Local Joint Engineering Research Center for Livestock Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, Guangdong, People's Republic of China.

Follicle-stimulating hormone (FSH) and its receptor play a key role in the follicular development and regulation of steroidogenesis in the ovary and spermatogenesis in the testis. The purpose of this study was to characterize themuscovy duck FSHR gene, identify SNPs and their association with egg production traits in muscovy ducks. Here, we cloned the complementary DNA (cDNA) sequence of FSHR, and examined the expression patterns of FSHR gene in adult female muscovy duck tissues. The cloned cDNA of the muscovy duck FSHR gene shared high similarity to those of pekin duck (Anas platyrhynchos) (95.7%) and chicken (93.2%). Three different muscovy duck FSHR transcripts were identified. Quantitative real-time PCR (RT-qPCR) results showed that the FSHR gene was expressed in all the 14 tested tissues, and the highest expression level was seen in the ovary. A total of 16 SNPs were identified, among which, four SNPs were located in the coding region of FSHR. The SNP C320T is significantly associated with egg production at 59 weeks of age (P < 0.05), whereas the SNP A227G is significantly associated with age at first egg stage (P < 0.05). These results suggest that the two SNPs (A227G and C320T) of FSHR gene are associated with egg production traits and could be potential markers that can be used for marker-assisted selection programmes to increase egg production in muscovy duck.
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http://dx.doi.org/10.1007/s12041-017-0783-xDOI Listing
June 2017

Total disc replacement versus fusion for lumbar degenerative disc disease: a systematic review of overlapping meta-analyses.

Eur Spine J 2017 03 23;26(3):806-815. Epub 2016 Jul 23.

Department of Orthopaedics, Wuhan Pu'Ai Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 473 Hanzheng Street, Wuhan, 430033, China.

Purpose: Although many meta-analyses have been performed to compare total disc replacement (TDR) and fusion for treating lumbar degenerative disc disease (LDDD), their findings are inconsistent. This study aimed to conduct a systematic review of overlapping meta-analyses comparing TDR with fusion for treating LDDD, to assist decision makers in selection among conflicting meta-analyses, and to provide treatment recommendations based on the best available evidence.

Methods: This study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Multiple databases were comprehensively searched for meta-analyses comparing TDR with fusion for treating LDDD. Meta-analyses only comprising randomised controlled trials (RCTs) were included. Two authors independently assessed meta-analysis quality and extracted data. The Jadad decision algorithm was used to ascertain which meta-analyses represented the best evidence.

Results: A total of five meta-analyses were included. All these studies only included RCTs were determined as Level-II evidence. The scores of Assessment of Multiple Systematic Reviews (AMSTAR) ranged from 6 to 9 (median 7). A high-quality Cochrane review was chosen according to the Jadad algorithm. This best available evidence found that statistical significances were observed between TDR and fusion for LDDD regarding disability, pain relief, and pain in the short term, but it was not over clinically important differences. The prevent effects on adjacent segment and facet joint degeneration, as the primary goal of adopting TDR stated by the manufacturers, were not appropriately evaluated.

Conclusions: There is discord in results from meta-analyses that assessed TDR and fusion for LDDD. According to this systematic review of overlapping meta-analyses comparing TDR and fusion for LDDD, the current best available evidence suggests that TDR may be an effective technique for the treatment of selected patients with LDDD, and is at least equal to lumbar fusion in the short term. However, considering that disadvantages may appear after years, spine surgeons should be cautions about performing TDR on a large scale.
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http://dx.doi.org/10.1007/s00586-016-4714-yDOI Listing
March 2017

Basal Plane Fluorination of Graphene by XeF2 via a Radical Cation Mechanism.

J Phys Chem Lett 2015 Sep 3;6(18):3645-9. Epub 2015 Sep 3.

Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States.

Graphene fluorination with XeF2 is an attractive method to introduce a nonzero bandgap to graphene under mild conditions for potential electro-optical applications. Herein, we use well-defined graphene nanostructures as a model system to study the reaction mechanism of graphene fluorination by XeF2. Our combined experimental and theoretical studies show that the reaction can proceed through a radical cation mechanism, leading to fluorination and sp(3)-hybridized carbon in the basal plane.
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http://dx.doi.org/10.1021/acs.jpclett.5b01756DOI Listing
September 2015

Addition of Si-H and B-H bonds and redox reactivity involving low-coordinate nitrido-vanadium complexes.

Inorg Chem 2015 Mar 2;54(6):3068-77. Epub 2015 Mar 2.

Department of Chemistry and Molecular Structure Center, Indiana University , Bloomington, Indiana 47405, United States.

In this study we enumerate the reactivity for two molecular vanadium nitrido complexes of [(nacnac)V≡N(X)] formulation [nacnac = (Ar)NC(Me)CHC(Me)(Ar)(-), Ar = 2,6-(CHMe2)2C6H3); X(-) = OAr (1) and N(4-Me-C6H4)2 (Ntolyl2) (2)]. Density functional theory calculations and reactivity studies indicate the nitride motif to have nucleophilic character, but where the nitrogen atom can serve as a conduit for electron transfer, thus allowing the reduction of the vanadium(V) metal ion with concurrent oxidation of the incoming substrate. Silane, H2SiPh2, readily converts the nitride ligand in 1 into a primary silyl-amide functionality with concomitant two-electron reduction at the vanadium center to form the complex [(nacnac)V{N(H)SiHPh2}(OAr)] (3). Likewise, addition of the B-H bond in pinacolborane to the nitride moiety in 2 results in formation of the boryl-amide complex [(nacnac)V{N(H)B(pinacol)}(Ntolyl2)] (4). In addition to spectroscopic data, complexes 3 and 4 were also elucidated structurally by single-crystal X-ray diffraction analysis. One-electron reduction of 1 with 0.5% Na/Hg on a preparative scale allowed for the isolation and structural determination of an asymmetric bimolecular nitride radical anion complex having formula [Na]2[(nacnac)V(N)(OAr)]2 (5), in addition to room-temperature solution X-band electron paramagnetic resonance spectroscopic studies.
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http://dx.doi.org/10.1021/acs.inorgchem.5b00302DOI Listing
March 2015

Dehydrogenation of hydrocarbons with metal-carbon multiple bonds and trapping of a titanium(II) intermediate.

Dalton Trans 2014 Jul 20;43(26):9834-7. Epub 2014 May 20.

Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405, USA.

Reacting (PNP)Ti[double bond, length as m-dash]CH(t)Bu(CH2(t)Bu) with 2,2'-bipyridine (bipy) in cyclohexane or heptane results in dehydrogenation, cleanly producing cyclohexene and 1-heptene, respectively, and a Ti(II) intermediate that is trapped by bipy to produce [(PNP)Ti(III)(CH2(t)Bu)(bipy˙(-))] (1). This titanium(ii) intermediate reduces the bipy ligand upon coordination to form a Ti(III) center, where the unpaired electron is antiferromagnetically coupled to the electron of the reduced [bipy˙(-)] π-radical moiety, giving an overall diamagnetic species. Complex 1 has been characterized by NMR and UV-vis spectroscopies as well as single crystal X-ray diffraction studies.
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http://dx.doi.org/10.1039/c4dt01037jDOI Listing
July 2014

Room temperature dehydrogenation of ethane, propane, linear alkanes C4-C8, and some cyclic alkanes by titanium-carbon multiple bonds.

J Am Chem Soc 2013 Oct 23;135(39):14754-67. Epub 2013 Sep 23.

Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States.

The transient titanium neopentylidyne, [(PNP)Ti≡C(t)Bu] (A; PNP(-)≡N[2-P(i)Pr2-4-methylphenyl]2(-)), dehydrogenates ethane to ethylene at room temperature over 24 h, by sequential 1,2-CH bond addition and β-hydrogen abstraction to afford [(PNP)Ti(η(2)-H2C═CH2)(CH2(t)Bu)] (1). Intermediate A can also dehydrogenate propane to propene, albeit not cleanly, as well as linear and volatile alkanes C4-C6 to form isolable α-olefin complexes of the type, [(PNP)Ti(η(2)-H2C═CHR)(CH2(t)Bu)] (R = CH3 (2), CH2CH3 (3), (n)Pr (4), and (n)Bu (5)). Complexes 1-5 can be independently prepared from [(PNP)Ti═CH(t)Bu(OTf)] and the corresponding alkylating reagents, LiCH2CHR (R = H, CH3(unstable), CH2CH3, (n)Pr, and (n)Bu). Olefin complexes 1 and 3-5 have all been characterized by a diverse array of multinuclear NMR spectroscopic experiments including (1)H-(31)P HOESY, and in the case of the α-olefin adducts 2-5, formation of mixtures of two diastereomers (each with their corresponding pair of enantiomers) has been unequivocally established. The latter has been spectroscopically elucidated by NMR via C-H coupled and decoupled (1)H-(13)C multiplicity edited gHSQC, (1)H-(31)P HMBC, and dqfCOSY experiments. Heavier linear alkanes (C7 and C8) are also dehydrogenated by A to form [(PNP)Ti(η(2)-H2C═CH(n)Pentyl)(CH2(t)Bu)] (6) and [(PNP)Ti(η(2)-H2C═CH(n)Hexyl)(CH2(t)Bu)] (7), respectively, but these species are unstable but can exchange with ethylene (1 atm) to form 1 and the free α-olefin. Complex 1 exchanges with D2C═CD2 with concomitant release of H2C═CH2. In addition, deuterium incorporation is observed in the neopentyl ligand as a result of this process. Cyclohexane and methylcyclohexane can be also dehydrogenated by transient A, and in the case of cyclohexane, ethylene (1 atm) can trap the [(PNP)Ti(CH2(t)Bu)] fragment to form 1. Dehydrogenation of the alkane is not rate-determining since pentane and pentane-d12 can be dehydrogenated to 4 and 4-d12 with comparable rates (KIE = 1.1(0) at ~29 °C). Computational studies have been applied to understand the formation and bonding pattern of the olefin complexes. Steric repulsion was shown to play an important role in determining the relative stability of several olefin adducts and their conformers. The olefin in 1 can be liberated by use of N2O, organic azides (N3R; R = 1-adamantyl or SiMe3), ketones (O═CPh2; 2 equiv) and the diazoalkane, N2CHtolyl2. For complexes 3-7, oxidation with N2O also liberates the α-olefin.
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http://dx.doi.org/10.1021/ja4060178DOI Listing
October 2013

A four-coordinate thionitrosyl complex of vanadium.

Chem Commun (Camb) 2013 Apr;49(27):2768-70

Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, USA.

Addition of elemental sulfur to the vanadium nitride [(nacnac)V≡N(OAr)] forms the first thionitrosyl complex of vanadium, [(nacnac)V(NS)(OAr)]. Single crystal X-Ray diffraction studies and DFT calculations reveal an almost linear thionitrosyl ligand resulting from an extended π-resonance across the VNS moiety.
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http://dx.doi.org/10.1039/c3cc38799bDOI Listing
April 2013

A four coordinate parent imide via a titanium nitridyl.

Chem Commun (Camb) 2012 Feb 5;48(10):1529-31. Epub 2011 Oct 5.

Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana, USA.

Treatment of d(1) [(nacnac)TiCl(Ntol(2))] with NaN(3) results in NaCl formation and N(2) ejection to yield the first four coordinate, parent imide [(nacnac)Ti=NH(Ntol(2))] (nacnac(-)=[ArNC(CH(3))](2)CH, Ar = 2,6-iPr(2)C(6)H(3), tol = 4-CH(3)C(6)H(4)).
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http://dx.doi.org/10.1039/c1cc14574fDOI Listing
February 2012

Hydrophilization of Magnetic Nanoparticles with Modified Alternating Copolymers. Part 1: The Influence of the Grafting.

J Phys Chem C Nanomater Interfaces 2010 Dec;114(50):21900-21907

Indiana University, Department of Chemistry, 800 E. Kirkwood Av., Bloomington, IN 47405, USA.

Iron oxide nanoparticles (NPs) with a diameter 21.6 nm were coated with poly(maleic acid-alt-1-octadecene) (PMAcOD) modified with grafted 5,000 Da poly(ethyelene glycol) (PEG) or short ethylene glycol (EG) tails. The coating procedure utilizes hydrophobic interactions of octadecene and oleic acid tails, while the hydrolysis of maleic anhydride moieties as well as the presence of hydrophilic PEG (EG) tails allows the NP hydrophilicity. The success of the NP coating was found to be independent of the degree of grafting which was varied between 20 and 80% of the -MacOD-units, but depended on the length of the grafted tail. The NP coating and hydrophilization did not occur when the modified copolymer contained 750 Da PEG tails independently of the grafting degree. To explain this phenomenon the micellization of the modified PMAcOD copolymers in water was analyzed by small angle x-ray scattering (SAXS). The PMAcOD molecules with the grafted 750 Da PEG tails form compact non-interacting disk-like micelles, whose stability apparently allows for no interactions with the NP hydrophobic shells. The PMAcOD containing the 5,000 Da PEG and EG tails form much larger aggregates capable of an efficient coating of the NPs. The coated NPs were characterized using transmission electron microscopy, dynamic light scattering, ζ-potential measurements, and thermal gravimetry analysis. The latter method demonstrated that the presence of long PEG tails in modified PMAcOD allows the attachment of fewer macromolecules (by a factor of ~20) compared to the case of non-modified or EG modified PMAcOD, emphasizing the importance of PEG tails in NP hydrophilization. The NPs coated with PMAcOD modified with 60% (towards all -MAcOD- units) of the 5,000 PEG tails bear a significant negative charge and display good stability in buffers. Such NPs can be useful as magnetic cores for virus-like particle formation.
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http://dx.doi.org/10.1021/jp107283wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3017398PMC
December 2010
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