16 results on '"Zhenjie Lu"'
Search Results
2. The Effect of Organizational Trust on Turnover Intention of Rural Kindergarten Teachers: The Mediating Role of Teaching Efficacy and Job Satisfaction
- Author
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Yan Zhao, Zhenjie Lu, Xiulan Cheng, and Jiaqi Li
- Subjects
Health, Toxicology and Mutagenesis ,Public Health, Environmental and Occupational Health ,mental health ,rural kindergarten teachers ,organizational trust ,teaching efficacy ,job satisfaction ,turnover intention ,COVID-19 ,Humans ,Intention ,Trust ,Pandemics ,Job Satisfaction - Abstract
Recent studies have focused on turnover among rural kindergarten teachers. However, none of these studies have shown a clear connection between turnover intention and organizational trust, although there are studies in other areas showing that organizational trust can affect turnover intention. Drawing on a sample of 330 kindergarten teachers in rural areas, this study explores the mechanism of influence between organizational trust and turnover intention with teaching efficacy and job satisfaction as mediators. We found that organizational trust negatively impacted teachers’ turnover intention, and this relationship was mediated by a significant chain mediating effect of teaching efficacy and job satisfaction. The findings enrich knowledge about turnover among rural kindergarten teachers and inspire us to create a more supportive organizational environment against the backdrop of the COVID-19 pandemic to improve job satisfaction and alleviate turnover among rural kindergarten teachers.
- Published
- 2022
- Full Text
- View/download PDF
3. Probing Catalyst Function – Electronic Modulation of Chiral Polyborate Anionic Catalysts
- Author
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Emily C. Matthews, Wynter E. G. Osminski, Jennifer S. Hirschi, Aliakbar Mohammadlou, Zhenjie Lu, William D. Wulff, Connor J. Allen, Virginia M. Canestraight, Richard J. Staples, Xiaopeng Yin, and Wenjun Zhao
- Subjects
Steric effects ,Anions ,Organic Chemistry ,Imine ,Aziridines ,Enantioselective synthesis ,Protonation ,Stereoisomerism ,Combinatorial chemistry ,Asymmetric induction ,Article ,Catalysis ,chemistry.chemical_compound ,chemistry ,Covalent bond ,Lewis acids and bases ,Electronics - Abstract
Boroxinate complexes of VAPOL and VANOL are a chiral anionic platform that can serve as a versatile staging arena for asymmetric catalysis. The structural underpinning of the platform is a chiral polyborate core that covalently links together alcohols (or phenols) and vaulted biaryl ligands. The polyborate platform is assembled in situ by the substrate of the reaction, and thus a multiplex of chiral catalysts can be rapidly assembled from various alcohols (or phenols) and bis-phenol ligands for screening of catalyst activity. In the present study, variations in the steric and electronic properties of the phenol/alcohol component of the boroxinate catalyst are probed to reveal their effects on the asymmetric induction in the catalytic asymmetric aziridination reaction. A Hammett study is consistent with a mechanism in which the two substrates are hydrogen-bonded to the boroxinate core in the enantiogenic step. The results of the Hammett study are supported by a computational study in which it is found that the H-O distance of the protonated imine hydrogen bonded to the anionic boroxinate core decreases with an increase in the electron releasing ability of the phenol unit incorporated into the boroxinate. The results are not consistent with a mechanism in which the boroxinate catalyst functions as a Lewis acid and activates the imine by a Lewis acid/Lewis base interaction.
- Published
- 2021
4. Blockchain-based engine data trustworthy swarm learning management method
- Author
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Zhenjie Luo and Hui Zhang
- Subjects
Engine ,Data integrity ,Data management ,Blockchain ,Swarm learning ,Information technology ,T58.5-58.64 - Abstract
Engine data management is of great significance for ensuring data security and sharing, as well as facilitating multi-party collaborative learning. Traditional data management approaches often involve decentralized data storage that is vulnerable to tampering, making it challenging to conduct multi-party collaborative learning under privacy protection conditions and fully leverage the value of data. Moreover, data with compromised integrity can lead to incorrect results if used for model training. Therefore, this paper aims to break down data sharing barriers and fully utilize decentralized data for multi-party collaborative learning under privacy protection conditions. We propose a trustworthy engine data management method based on blockchain technology to ensure data immutability and non-repudiation. To address the issue of limited data samples for some users resulting in poor model performance, we introduce swarm learning techniques based on centralized machine learning and design a trustworthy data management method for swarm learning, achieving trustworthy regulation of the entire process. We conduct research on engine models under swarm learning based on the NASA open dataset, effectively organizing decentralized data samples for collaborative training while ensuring data privacy and fully leveraging the value of data.
- Published
- 2024
- Full Text
- View/download PDF
5. Trace metals dramatically boost oxygen electrocatalysis of N-doped coal-derived carbon for zinc–air batteries
- Author
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Zhenjie Lu, Xinning Huang, Alex W. Robertson, Huimin Liu, Tao Wang, Junxia Cheng, Zhenyu Sun, Xingxing Chen, Yue Wang, Yaming Zhu, and Dongling Wu
- Subjects
Materials science ,business.industry ,Heteroatom ,Oxygen evolution ,Oxide ,Carbon nanotube ,Electrocatalyst ,law.invention ,Catalysis ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,law ,General Materials Science ,Coal ,Bifunctional ,business - Abstract
The commercialization of metal-air batteries requires efficient, low-cost, and stable bifunctional electrocatalysts for reversible electrocatalysis of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The modification of natural coal by heteroatoms such as N and S, or metal oxide species, has been demonstrated to form very promising electrocatalysts for the ORR and OER. However, it remains elusive and underexplored as to how the impurity elements in coal may impact the electrocatalytic properties of coal-derived catalysts. Herein, we explore the influence of the presence of various trace metals that are notable impurities in coal, including Al, Si, Ca, K, Fe, Mg, Co, Mn, Ni, and Cu, on the electrochemical performance of the prepared catalysts. The constructed Zn-air batteries are further shown to be able to power green LED lights for more than 80 h. The charge-discharge polarization curves exhibited excellent and durable rechargeability over 500 (ca. 84 h) continuous cycles. The promotional effect of the trace elements is believed to accrue from a combination of electronic structure modification of the active sites, enhancement of the active site density, and formation of a conductive 3-dimensional hierarchical network of carbon nanotubes.
- Published
- 2020
6. β-Amino Esters from the Reductive Ring Opening of Aziridine-2-carboxylates
- Author
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Zhenjie Lu, William D. Wulff, and Wenjun Zhao
- Subjects
Trimethylsilyl Compounds ,Amino esters ,Stereochemistry ,Aryl ,Organic Chemistry ,Aziridines ,Benzenesulfonates ,Substituent ,Esters ,Stereoisomerism ,Aziridine ,Cleavage (embryo) ,Article ,3. Good health ,chemistry.chemical_compound ,Sulfonate ,chemistry ,Carboxylate ,Bond cleavage ,Palladium - Abstract
A general study is undertaken to examine the scope of the reductive ring opening of aziridine-2-carboxylates with samarium diiodide. The competition between C-C and C-N bond cleavage is examined as a function of the nature of the N-substituent of the aziridine, the nature of the substituent in the 3-position of the aziridine, and whether the substituent in the 3-position is in a cis or trans relationship with the carboxylate in the 2-position. The desired C-N bond cleavage leads to β-amino esters that are the predominant products for most aziridines with an N-activating group. However, C-C cleavage products are observed with an aryl group in the 3-position; this can be particularly pronounced with cis-aziridines where a nearly equal mixture of the two is observed. Exclusive formation of the C-N cleavage product is observed for all aziridines with the strongly N-activating p-toluene sulfonate group. Similarly high selectivity is observed for the 2-trimethylsilylethyl sulfonate group (SES), which is easier to remove. The utility of these methods is illustrated in the synthesis of protected forms of (R)-β(3)-DOPA and L-DOPA from the same aziridine, the former by SmI2-mediated reductive opening at C-2 and the latter by palladium-mediated reductive opening at C-3.
- Published
- 2014
7. Ynamides: a modern functional group for the new millennium
- Author
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DeKorver, Kyle A., Hongyan Li, Lohse, Andrew G., Hayashi, Ryuji, Zhenjie Lu, Yu Zhang, and Hsung, Richard P.
- Subjects
Amides -- Chemical properties ,Ring formation (Chemistry) -- Analysis ,Elimination reactions -- Analysis ,Chemistry - Published
- 2010
8. Microwave-Assisted Synthesis of Co/CoOx Supported on Earth-Abundant Coal-Derived Carbon for Electrocatalysis of Oxygen Evolution.
- Author
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Haoran Pan, Dongling Wu, Xinning Huang, Kunpeng Xie, Bingcai He, Zhenjie Lu, Penggao Liu, Junxia Cheng, Xuefei Zhao, Justus Masa, and Xingxing Chen
- Subjects
ELECTROCATALYSIS ,NITROGEN ,HYDROGEN evolution reactions ,HYDROGEN as fuel ,OXYGEN evolution reactions ,WATER currents ,DENSITY currents ,CARBON - Abstract
The evident demand for hydrogen as the ultimate energy fuel for posterity calls for the development of low-cost, efficient and stable electrocatalysts for water splitting. Herein, we report the synthesis of Co/CoO
x supported on coal-derived N-doped carbon via a simple microwave-assisted method and demonstrate its application as an efficient catalyst for the oxygen evolution reaction (OER). With the optimal amount of cobalt introduced into the N-doped coal-derived, the developed catalyst achieved overpotentials of 0.370 and 0.429 V during water oxidation at current densities of 1 mA cm-2 and 10 mA cm-2 , respectively. There was no noticeable loss in the activity of the catalyst during continuous galvanostatic polarization at a current density of 10 mA cm-2 for a test period of 66 h. The synergistic interaction of the Co/CoOx moieties with the pyridinic and pyrollic nitrogen functional groups in the N-doped carbon, as well with the other heteroatoms species in the pristine coal favored enhancement of the OER electrocatalytic performance. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
9. Co-Mn Hybrid Oxides Supported on N-Doped Graphene as ad Efficient Electrocatalysts for Reversible Oxygen Electrodes.
- Author
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Zhenjie Lu, Xingxing Chen, Penggao Liu, Xinning Huang, Jiong Wei, Zhong Ren, Songdong Yao, Zhigang Fanga, Tao Wanga, and Justus Masas
- Subjects
GRAPHENE ,ELECTROCATALYSTS ,ELECTRODES - Abstract
Despite metal-air batteries possessing very high theoretical energy densities, inefficient reversibility of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) at the oxygen electrode undermines their rechargeability, which has slowed their market entry. Herein, we demonstrate a simple procedure for synthesis of a hybrid of MnO and metallic Co supported on N-doped graphene that exhibits activity and stability as a bifunctional ORR/OER catalyst, with a round trip ORR/OER overvoltage of 0.85 V, which remained constant for at least 70 h when cycling alternately, between oxygen evolution at a current density of 10 mA cm
-2 and oxygen reduction at-1 mA cm-2 . Insights into the key properties of the catalyst that influence its performance are proposed based on structural characterization by TEM, SEM, Raman spectroscopy, XRD and XPS. Besides MnO and metallic Co as the predominant crystalline species in the Co-Mn hybrid oxide, XPS revealed Mn3 O4 and CoO rich surfaces, ascribed to oxidation of MnO and metallic Co due to atmospheric exposure. The synergetic interaction between the Co-Mn hybrid oxides and N-doped graphene, as well as Co-Mn interaction, favor improved ORR, OER and bifunctional ORR/OER performance of the catalyst. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
10. Thrombospondin 1—a key astrocyte-derived neurogenic factor
- Author
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Jonathan Kipnis and Zhenjie Lu
- Subjects
Cellular differentiation ,Neurogenesis ,Blotting, Western ,Synaptogenesis ,Fluorescent Antibody Technique ,Biology ,Biochemistry ,Research Communications ,Immunoenzyme Techniques ,Thrombospondin 1 ,Mice ,Genetics ,medicine ,Animals ,RNA, Messenger ,Thrombospondins ,Molecular Biology ,Cells, Cultured ,Cell Proliferation ,Mice, Knockout ,Neurons ,Reverse Transcriptase Polymerase Chain Reaction ,Stem Cells ,Cell Differentiation ,Anatomy ,Flow Cytometry ,Neural stem cell ,Cell biology ,Mice, Inbred C57BL ,medicine.anatomical_structure ,Bromodeoxyuridine ,Astrocytes ,Culture Media, Conditioned ,Stem cell ,Biotechnology ,Astrocyte - Abstract
Thrombospondin 1 (TSP1), an oligomeric matrix protein, is known for its antiangiogenic activity. Recently, TSP1 has been shown to regulate synaptogenesis in the developing brain. In this study, we examine another role of TSP1 in the CNS, namely, in proliferation and differentiation of neural progenitor cells (NPCs). We found that adult mice deficient in TSP1 exhibit reduced proliferation of NPCs in vivo [13,330±826 vs. 4914±455 (mean±se wt vs. TSP1−/−); P
- Published
- 2010
11. β-Amino Esters from the Reductive Ring Opening of Aziridine-2-carboxylates.
- Author
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Wenjun Zhao, Zhenjie Lu, and Wulff, William D.
- Subjects
- *
AMINO acids , *AMINO compounds , *ESTERS , *ALKOXY compounds , *AZIRIDINES - Abstract
A general study is undertaken to examine the scope of the reductive ring opening of aziridine-2-carboxylates with samarium diiodide. The competition between C-C and C-N bond cleavage is examined as a function of the nature of the N-substituent of the aziridine, the nature of the substituent in the 3-position of the aziridine, and whether the substituent in the 3-position is in a cis or trans relationship with the carboxylate in the 2-position. The desired C-N bond cleavage leads to β-amino esters that are the predominant products for most aziridines with an N-activating group. However, C-C cleavage products are observed with an aryl group in the 3-position; this can be particularly pronounced with cis-aziridines where a nearly equal mixture of the two is observed. Exclusive formation of the C-N cleavage product is observed for all aziridines with the strongly N-activating p-toluene sulfonate group. Similarly high selectivity is observed for the 2-trimethylsilylethyl sulfonate group (SES), which is easier to remove. The utility of these methods is illustrated in the synthesis of protected forms of (R)-β³-DOPA and l-DOPA from the same aziridine, the former by SmI2-mediated reductive opening at C-2 and the latter by palladium-mediated reductive opening at C-3. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
12. Allenamides: A Powerful and Versatile Building Block in Organic Synthesis.
- Author
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Ting Lu, Zhenjie Lu, Zhi-Xiong Ma, Yu Zhang, and Richard P. Hsung
- Subjects
- *
CHEMICAL research , *ALLENAMIDES , *CHEMISTRY education , *RING formation (Chemistry) , *CHEMISTS - Abstract
The article provides proper illustrations of the elegant chemistry involving allenamides that elicits a greater amount of interest to create new allenamide chemistry. It conducted a detailed study of cycloaddition using allenamides 491 with a series of heterodienes. It further reflects on various researches conducted by researchers in the field.
- Published
- 2013
- Full Text
- View/download PDF
13. Seeking Passe-Partout in the Catalytic Asymmetric Aziridination of Imines: Evolving Toward Substrate Generality for a Single Chemzyme.
- Author
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Mukherjee, Munmun, Gupta, Anil K., Zhenjie Lu, Yu Zhang, and Wulff, William D.
- Published
- 2010
- Full Text
- View/download PDF
14. Thrombospondin 1--a key astrocyte-derived neurogenic factor.
- Author
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Zhenjie Lu and Kipnis, Jonathan
- Subjects
- *
THROMBOSPONDINS , *ASTROCYTES , *DEVELOPMENTAL neurobiology , *EXTRACELLULAR matrix proteins , *OLIGOMERS - Abstract
Thrombospondin 1 (TSP1), an oligomeric matrix protein, is known for its antiangiogenic activity. Recently, TSP1 has been shown to regulate synaptogenesis in the developing brain. In this study, we examine another role of TSP1 in the CNS, namely, in proliferation and differentiation of neural progenitor cells (NPCs). We found that adult mice deficient in TSP1 exhibit reduced proliferation of NPCs in vivo [13,330±826 vs. 4914±455 (mean±SE wt vs. TSP1-/-); P<0.001, Student's t test] and impaired neuronal differentiation (1382±83 vs. 879±79; P<0.001). In vitro, NPC obtained from adult TSP1-/- mice display decreased proliferation in BrdU assay (48±8 vs. 24±3.5%; P<0.01) and decreased neuronal fate commitment (8±0.85 vs. 4.6±0.5%; P<0.05) in contrast to wild-type NPCs. Both proliferation and neuronal differentiation deficits are remediable in vitro by exogenous TSP1. Notably, conditioned medium from TSP1-/- astrocytes, unlike that from control astrocytes, fails to promote neurogenesis in wild-type NPCs, suggesting that TSP1 is one of the key molecules responsible for astrocyte-induced neurogenesis. Our data demonstrate that TSP1 is a critical participant in maintenance of the adult NPC pool and in neuronal differentiation. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
15. Mapping the Active Site in a Chemzyme: Diversity in the N-Substituent in the Catalytic Asymmetric Aziridination of Imines.
- Author
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Yu Zhang, Zhenjie Lu, Aman Desai, and William D. Wulff
- Subjects
- *
BINDING sites , *IMINES , *CATALYSTS , *LIGANDS (Biochemistry) , *ENANTIOSELECTIVE catalysis , *ALDEHYDES - Abstract
The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)3is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
16. Direct Access to N-H-Aziridines from Asymmetric Catalytic Aziridination with Borate Catalysts Derived from Vaulted Binaphthol and Vaulted Biphenanthrol Ligands.
- Author
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Zhenjie Lu, Yu Zhang, and Wulff, William D.
- Subjects
- *
CATALYSTS , *BORATES , *IMINES , *ORGANONITROGEN compounds , *ASYMMETRIC synthesis - Abstract
The asymmetric catalytic aziridination reaction (AZ reaction) of N-dianisylmethylimines (N-DAM-imines) with ethyl diazoacetate is developed with chiral catalysts prepared from triphenylborate and both the vaulted binaphthol (VANOL) and vaulted biphenanthrol (VAPOL) ligands. Catalysts derived from both ligands were equally effective in terms of asymmetric induction, but the VANOL catalyst was slightly faster. Up to 400 turnovers could be achieved with the VANOL catalyst while still maintaining ≥90% ee in the aziridine product. The ligand could be recovered in 95% yield with no loss in optical purity. Excellent asymmetric inductions were observed with arylimines, and although slightly lower inductions were observed for alkyl-substituted imines, the optical purity of the aziridines from all of the imine substrates could be enhanced to ≥99% ee with a single crystallization. Methods were developed for deprotection of the N-DAM-aziridines under acidic conditions without causing an acid-promoted opening of the ring. Excellent yields of the N-H-aziridines could be obtained with both alkyl- and aryl-substituted aziridines. Finally, activation of the N-H-aziridines was achieved with Boc, tosyl, and Fmoc groups. The activated aziridines can be converted to β³-amino esters, and unexpectedly, the N-Boc-protected aziridine-2-carboxylate 16b with a phenyl substituent in the 3-position cis to the ester group was found to undergo ring expansion to a mixture of cis- and trans-oxazolidinones. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
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