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Description
Cyanovirin-N (CVN) is a cyanobacterial lectin with potent anti-HIV activity, mediated by binding to the N-linked oligosaccharide moiety of the envelope protein gp120. CVN offers a scaffold to develop multivalent carbohydrate-binding proteins with tunable specificities and affinities. I present here biophysical calculations completed on a monomeric-stabilized mutant of cyanovirin-N, P51G-m4-CVN, in which domain A binding activity is abolished by four mutations; with comparisons made to CVNmutDB, in which domain B binding activity is abolished. Using Monte Carlo calculations and docking simulations, mutations in CVNmutDB were considered singularly, and the mutations E41A/G and T57A were found to impact the affinity towards dimannose the greatest. 15N-labeled proteins were titrated with Manα(1-2)Manα, while following chemical shift perturbations in NMR spectra. The mutants, E41A/G and T57A, had a larger Kd than P51G-m4-CVN, matching the trends predicted by the calculations. We also observed that the N42A mutation affects the local fold of the binding pocket, thus removing all binding to dimannose. Characterization of the mutant N53S showed similar binding affinity to P51G-m4-CVN. Using biophysical calculations allows us to study future iterations of models to explore affinities and specificities. In order to further elucidate the role of multivalency, I report here a designed covalent dimer of CVN, Nested cyanovirin-N (Nested CVN), which has four binding sites. Nested CVN was found to have comparable binding affinity to gp120 and antiviral activity to wt CVN. These results demonstrate the ability to create a multivalent, covalent dimer that has comparable results to that of wt CVN.
WW domains are small modules consisting of 32-40 amino acids that recognize proline-rich peptides and are found in many signaling pathways. We use WW domain sequences to explore protein folding by simulations using Zipping and Assembly Method. We identified five crucial contacts that enabled us to predict the folding of WW domain sequences based on those contacts. We then designed a folded WW domain peptide from an unfolded WW domain sequence by introducing native contacts at those critical positions.
WW domains are small modules consisting of 32-40 amino acids that recognize proline-rich peptides and are found in many signaling pathways. We use WW domain sequences to explore protein folding by simulations using Zipping and Assembly Method. We identified five crucial contacts that enabled us to predict the folding of WW domain sequences based on those contacts. We then designed a folded WW domain peptide from an unfolded WW domain sequence by introducing native contacts at those critical positions.
ContributorsWoodrum, Brian William (Author) / Ghirlanda, Giovanna (Thesis advisor) / Redding, Kevin (Committee member) / Wang, Xu (Committee member) / Arizona State University (Publisher)
Created2014
Description
Spider dragline silk is an outstanding biopolymer with a strength that exceeds steel by weight and a toughness greater than high-performance fibers like Kevlar. For this reason, structural and dynamic studies on the spider silk are of great importance for developing future biomaterials. The spider dragline silk comprises two silk proteins, Major ampullate Spidroin 1 and 2 (MaSp1 and 2), which are synthesized and stored in the major ampullate (MA) gland of spiders. The initial state of the silk proteins within Black Widow MA glands was probed with solution-state NMR spectroscopy. The conformation dependent chemical shifts information indicates that the silk proteins are unstructured and in random coil conformation. 15N relaxation parameters, T1, T2 and 15N-{1H} steady-state NOE were measured to probe the backbone dynamics for MA silk proteins. These measurements indicate fast sub-nanosecond timescale backbone dynamics for the repetitive core of spider MA proteins indicating that the silk proteins are unfolded, highly flexible random coils in the MA gland. The translational diffusion coefficients of the spider silk proteins within the MA gland were measured using 1H diffusion NMR at 1H sites from different amino acids. A phenomenon was observed where the measured diffusion coefficients decrease with an increase in the diffusion delay used. The mean displacement along the external magnetic field was found to be 0.35 μm and independent of the diffusion delay. The results indicate that the diffusion of silk protein was restricted due to intermolecular cross-linking with only segmental diffusion observable.
To understand how a spider converts the unfolded protein spinning dope into a highly structured and oriented in the super fiber,the effect of acidification on spider silk assembly was investigated on native spidroins from the major ampullate (MA) gland fluid excised from Latrodectus hesperus (Black Widow) spiders. The in vitro spider silk assembly kinetics were monitored as a function of pH with a 13C solid-state Magic Angle Spinning (MAS) NMR approach. The results confirm the importance of acidic pH in the spider silk self-assembly process with observation of a sigmoidal nucleation-elongation kinetic profile. The rates of nucleation and elongation and the percentage of β-sheet structure in the grown fibers depend on pH.
The secondary structure of the major ampullate silk from Peucetia viridians (Green Lynx) spiders was characterized by X-ray diffraction (XRD) and solid-state NMR spectroscopy. From XRD measurement, β-sheet nano-crystallites were observed that are highly oriented along the fiber axis with an orientational order of 0.980. Compare to the crystalline region, the amorphous region was found to be partially oriented with an orientational order of 0.887. Further, two dimensional 13C-13C through-space and through-bond solid-state NMR experiments provide structural analysis for the repetitive amino acid motifs in the silk proteins. The nano-crystallites are mainly alanine-rich β-sheet structures. The total percentage of crystalline region is determined to be 40.0±1.2 %. 18±1 % of alanine, 60±2 % glycine and 54±2 % serine are determined to be incorporated into helical conformations while 82±1 % of alanine, 40±3 % glycine and 46±2 % serine are in the β-sheet conformation.
To understand how a spider converts the unfolded protein spinning dope into a highly structured and oriented in the super fiber,the effect of acidification on spider silk assembly was investigated on native spidroins from the major ampullate (MA) gland fluid excised from Latrodectus hesperus (Black Widow) spiders. The in vitro spider silk assembly kinetics were monitored as a function of pH with a 13C solid-state Magic Angle Spinning (MAS) NMR approach. The results confirm the importance of acidic pH in the spider silk self-assembly process with observation of a sigmoidal nucleation-elongation kinetic profile. The rates of nucleation and elongation and the percentage of β-sheet structure in the grown fibers depend on pH.
The secondary structure of the major ampullate silk from Peucetia viridians (Green Lynx) spiders was characterized by X-ray diffraction (XRD) and solid-state NMR spectroscopy. From XRD measurement, β-sheet nano-crystallites were observed that are highly oriented along the fiber axis with an orientational order of 0.980. Compare to the crystalline region, the amorphous region was found to be partially oriented with an orientational order of 0.887. Further, two dimensional 13C-13C through-space and through-bond solid-state NMR experiments provide structural analysis for the repetitive amino acid motifs in the silk proteins. The nano-crystallites are mainly alanine-rich β-sheet structures. The total percentage of crystalline region is determined to be 40.0±1.2 %. 18±1 % of alanine, 60±2 % glycine and 54±2 % serine are determined to be incorporated into helical conformations while 82±1 % of alanine, 40±3 % glycine and 46±2 % serine are in the β-sheet conformation.
ContributorsXu, Dian (Author) / Yarger, Jeffery L (Thesis advisor) / Holland, Gregory P (Thesis advisor) / Wang, Xu (Committee member) / Liu, Yan (Committee member) / Arizona State University (Publisher)
Created2015
Description
An animal's ability to produce protein-based silk materials has evolved independently in many different arthropod lineages, satisfying various ecological necessities. However, regardless of their wide range of uses and their potential industrial and biomedical applications, advanced knowledge on the molecular structure of silk biopolymers is largely limited to those produced by spiders (order Araneae) and silkworms (order Lepidoptera). This thesis provides an in-depth molecular-level characterization of silk fibers produced by two vastly different insects: the caddisfly larvae (order Trichoptera) and the webspinner (order Embioptera).
The molecular structure of caddisfly larval silk from the species Hesperophylax consimilis was characterized using solid-state nuclear magnetic resonance (ss-NMR) and Wide Angle X-ray Diffraction (WAXD) techniques. This insect, which typically dwells in freshwater riverbeds and streams, uses silk fibers as a strong and sticky nanoadhesive material to construct cocoons and cases out available debris. Conformation-sensitive 13C chemical shifts and 31P chemical shift anisotropy (CSA) information strongly support a unique protein motif in which phosphorylated serine- rich repeats (pSX)4 complex with di- and trivalent cations to form rigid nanocrystalline β-sheets. Additionally, it is illustrated through 31P NMR and WAXD data that these nanocrystalline structures can be reversibly formed, and depend entirely on the presence of the stabilizing cations.
Nanofiber silks produced by webspinners (order Embioptera) were also studied herein. This work addresses discrepancies in the literature regarding fiber diameters and tensile properties, revealing that the nanofibers are about 100 nm in diameter, and are stronger (around 500 MPa mean ultimate stress) than previous works suggested. Fourier-transform Infrared Spectroscopy (FT-IR), NMR and WAXD results find that approximately 70% of the highly repetitive glycine- and serine-rich protein core is composed of β-sheet nanocrystalline structures. In addition, FT-IR and Gas-chromatography mass spectroscopy (GC-MS) data revealed a hydrophobic surface coating rich in long-chain lipids. The effect of this surface coating was studied with contact angle techniques; it is shown that the silk sheets are extremely hydrophobic, yet due to the microstructural and nanostructural details of the silk surface, are surprisingly adhesive to water.
The molecular structure of caddisfly larval silk from the species Hesperophylax consimilis was characterized using solid-state nuclear magnetic resonance (ss-NMR) and Wide Angle X-ray Diffraction (WAXD) techniques. This insect, which typically dwells in freshwater riverbeds and streams, uses silk fibers as a strong and sticky nanoadhesive material to construct cocoons and cases out available debris. Conformation-sensitive 13C chemical shifts and 31P chemical shift anisotropy (CSA) information strongly support a unique protein motif in which phosphorylated serine- rich repeats (pSX)4 complex with di- and trivalent cations to form rigid nanocrystalline β-sheets. Additionally, it is illustrated through 31P NMR and WAXD data that these nanocrystalline structures can be reversibly formed, and depend entirely on the presence of the stabilizing cations.
Nanofiber silks produced by webspinners (order Embioptera) were also studied herein. This work addresses discrepancies in the literature regarding fiber diameters and tensile properties, revealing that the nanofibers are about 100 nm in diameter, and are stronger (around 500 MPa mean ultimate stress) than previous works suggested. Fourier-transform Infrared Spectroscopy (FT-IR), NMR and WAXD results find that approximately 70% of the highly repetitive glycine- and serine-rich protein core is composed of β-sheet nanocrystalline structures. In addition, FT-IR and Gas-chromatography mass spectroscopy (GC-MS) data revealed a hydrophobic surface coating rich in long-chain lipids. The effect of this surface coating was studied with contact angle techniques; it is shown that the silk sheets are extremely hydrophobic, yet due to the microstructural and nanostructural details of the silk surface, are surprisingly adhesive to water.
ContributorsAddison, John Bennett (Author) / Yarger, Jeffery L (Thesis advisor) / Holland, Gregory P (Thesis advisor) / Wang, Xu (Committee member) / Ros, Robert (Committee member) / Arizona State University (Publisher)
Created2014
Description
Glycosaminoglycans (GAGs) are a class of complex biomolecules comprised of linear, sulfated polysaccharides whose presence on cell surfaces and in the extracellular matrix involve them in many physiological phenomena as well as in interactions with pathogenic microbes. Decorin binding protein A (DBPA), a Borrelia surface lipoprotein involved in the infectivity of Lyme disease, is responsible for binding GAGs found on decorin, a small proteoglycan present in the extracellular matrix. Different DBPA strains have notable sequence heterogeneity that results in varying levels of GAG-binding affinity. In this dissertation, the structures and GAG-binding mechanisms for three strains of DBPA (B31 and N40 DBPAs from B. burgdorferi and PBr DBPA from B. garinii) are studied to determine why each strain has a different affinity for GAGs. These three strains have similar topologies consisting of five α-helices held together by a hydrophobic core as well as two long flexible segments: a linker between helices one and two and a C-terminal tail. This structural arrangement facilitates the formation of a basic pocket below the flexible linker which is the primary GAG-binding epitope. However, this GAG-binding site can be occluded by the flexible linker, which makes the linker a negative regulator of GAG-binding. ITC and NMR titrations provide KD values that show PBr DBPA binds GAGs with higher affinity than B31 and N40 DBPAs, while N40 binds with the lowest affinity of the three. Work in this thesis demonstrates that much of the discrepancies seen in GAG affinities of the three DBPAs can be explained by the amino acid composition and conformation of the linker. Mutagenesis studies show that B31 DBPA overcomes the pocket obstruction with the BXBB motif in its linker while PBr DBPA has a retracted linker that exposes the basic pocket as well as a secondary GAG-binding site. N40 DBPA, however, does not have any evolutionary modifications to its structure to enhance GAG binding which explains its lower affinity for GAGs. GMSA and ELISA assays, along with NMR PRE experiments, confirm that structural changes in the linker do affect GAG-binding and, as a result, the linker is responsible for regulating GAG affinity.
ContributorsMorgan, Ashli M (Author) / Wang, Xu (Thesis advisor) / Allen, James (Committee member) / Yarger, Jeffery (Committee member) / Arizona State University (Publisher)
Created2015
Description
This dissertation will investigate two of the most promising high-capacity anode
materials for lithium-based batteries: silicon (Si) and metal lithium (Li). It will focus on
studying the mechanical behaviors of the two materials during charge and discharge and
understanding how these mechanical behaviors may affect their electrochemical
performance.
In the first part, amorphous Si anode will be studied. Despite many existing studies
on silicon (Si) anodes for lithium ion batteries (LIBs), many essential questions still exist
on compound formation, composition, and properties. Here it is shown that some
previously accepted findings do not truthfully reflect the actual lithiation mechanisms in
realistic battery configurations. Furthermore the correlation between structure and
mechanical properties in these materials has not been properly established. Here, a rigorous
and thorough study is performed to comprehensively understand the electrochemical
reaction mechanisms of amorphous-Si (a-Si) in a realistic LIB configuration. In-depth
microstructural characterization was performed and correlations were established between
Li-Si composition, volumetric expansion, and modulus/hardness. It is found that the
lithiation process of a-Si in a real battery setup is a single-phase reaction rather than the
accepted two-phase reaction obtained from in-situ TEM experiments. The findings in this
dissertation establish a reference to quantitatively explain many key metrics for lithiated a
Si as anodes in real LIBs, and can be used to rationally design a-Si based high-performance
LIBs guided by high-fidelity modeling and simulations.
In the second part, Li metal anode will be investigated. Problems related to dendrite
growth on lithium metal anodes such as capacity loss and short circuit present major
barriers to the next-generation high-energy-density batteries. The development of
successful mitigation strategies is impeded by the incomplete understanding of the Li
dendrite growth mechanisms. Here the enabling role of plating residual stress in dendrite
initiation through novel experiments of Li electrodeposition on soft substrates is confirmed,
and the observations is explained with a stress-driven dendrite growth model. Dendrite
growth is mitigated on such soft substrates through surface-wrinkling-induced stress
relaxation in deposited Li film. It is demonstrated that this new dendrite mitigation
mechanism can be utilized synergistically with other existing approaches in the form of
three-dimensional (3D) soft scaffolds for Li plating, which achieves superior coulombic
efficiency over conventional hard copper current collectors under large current density.
materials for lithium-based batteries: silicon (Si) and metal lithium (Li). It will focus on
studying the mechanical behaviors of the two materials during charge and discharge and
understanding how these mechanical behaviors may affect their electrochemical
performance.
In the first part, amorphous Si anode will be studied. Despite many existing studies
on silicon (Si) anodes for lithium ion batteries (LIBs), many essential questions still exist
on compound formation, composition, and properties. Here it is shown that some
previously accepted findings do not truthfully reflect the actual lithiation mechanisms in
realistic battery configurations. Furthermore the correlation between structure and
mechanical properties in these materials has not been properly established. Here, a rigorous
and thorough study is performed to comprehensively understand the electrochemical
reaction mechanisms of amorphous-Si (a-Si) in a realistic LIB configuration. In-depth
microstructural characterization was performed and correlations were established between
Li-Si composition, volumetric expansion, and modulus/hardness. It is found that the
lithiation process of a-Si in a real battery setup is a single-phase reaction rather than the
accepted two-phase reaction obtained from in-situ TEM experiments. The findings in this
dissertation establish a reference to quantitatively explain many key metrics for lithiated a
Si as anodes in real LIBs, and can be used to rationally design a-Si based high-performance
LIBs guided by high-fidelity modeling and simulations.
In the second part, Li metal anode will be investigated. Problems related to dendrite
growth on lithium metal anodes such as capacity loss and short circuit present major
barriers to the next-generation high-energy-density batteries. The development of
successful mitigation strategies is impeded by the incomplete understanding of the Li
dendrite growth mechanisms. Here the enabling role of plating residual stress in dendrite
initiation through novel experiments of Li electrodeposition on soft substrates is confirmed,
and the observations is explained with a stress-driven dendrite growth model. Dendrite
growth is mitigated on such soft substrates through surface-wrinkling-induced stress
relaxation in deposited Li film. It is demonstrated that this new dendrite mitigation
mechanism can be utilized synergistically with other existing approaches in the form of
three-dimensional (3D) soft scaffolds for Li plating, which achieves superior coulombic
efficiency over conventional hard copper current collectors under large current density.
ContributorsWang, Xu (Author) / Jiang, Hanqing (Thesis advisor) / Yu, Hongbin (Thesis advisor) / Chan, Candace (Committee member) / Wang, Liping (Committee member) / Qiong, Nian (Committee member) / Arizona State University (Publisher)
Created2018
Description
This study investigates the relation between credit supply competition among banks and their clients’ conditional accounting conservatism (i.e., asymmetric timely loss recognition). The Interstate Banking and Branching Efficiency Act (IBBEA) of 1994 permits banks and bank holding companies to expand their business across state lines, introducing a positive shock to credit supply competition in the banking industry. The increase in credit supply competition weakens banks’ bargaining power in the negotiation process, which in turn may weaken their ability to demand conservative financial reporting from borrowers. Consistent with this prediction, results show that firms report less conservatively after the IBBEA is passed in their headquartered states. The effect of the IBBEA on conditional conservatism is particularly stronger for firms in states with a greater increase in competition among banks, firms whose operations are more concentrated in their headquarter states, firms with greater financial constraints, and firms subject to less external monitoring. Robustness tests confirm that the observed decline in conditional conservatism is causally related to the passage of IBBEA. Overall, this study highlights the impact of credit supply competition on financial reporting practices.
ContributorsHuang, Wei (Author) / Li, Yinghua (Thesis advisor) / Huang, Xiaochuan (Committee member) / Kaplan, Steve (Committee member) / Arizona State University (Publisher)
Created2018
Description
The physiological phenomenon of sensing temperature is detected by transient
receptor (TRP) ion channels, which are pore forming proteins that reside in the
membrane bilayer. The cold and hot sensing TRP channels named TRPV1 and TRPM8
respectively, can be modulated by diverse stimuli and are finely tuned by proteins and
lipids. PIRT (phosphoinositide interacting regulator of TRP channels) is a small
membrane protein that modifies TRPV1 responses to heat and TRPM8 responses to cold.
In this dissertation, the first direct measurements between PIRT and TRPM8 are
quantified with nuclear magnetic resonance and microscale thermophoresis. Using
Rosetta computational biology, TRPM8 is modeled with a regulatory, and functionally
essential, lipid named PIP2. Furthermore, a PIRT ligand screen identified several novel
small molecular binders for PIRT as well a protein named calmodulin. The ligand
screening results implicate PIRT in diverse physiological functions. Additionally, sparse
NMR data and state of the art Rosetta protocols were used to experimentally guide PIRT
structure predictions. Finally, the mechanism of thermosensing from the evolutionarily
conserved sensing domain of TRPV1 was investigated using NMR. The body of work
presented herein advances the understanding of thermosensing and TRP channel function
with TRP channel regulatory implications for PIRT.
receptor (TRP) ion channels, which are pore forming proteins that reside in the
membrane bilayer. The cold and hot sensing TRP channels named TRPV1 and TRPM8
respectively, can be modulated by diverse stimuli and are finely tuned by proteins and
lipids. PIRT (phosphoinositide interacting regulator of TRP channels) is a small
membrane protein that modifies TRPV1 responses to heat and TRPM8 responses to cold.
In this dissertation, the first direct measurements between PIRT and TRPM8 are
quantified with nuclear magnetic resonance and microscale thermophoresis. Using
Rosetta computational biology, TRPM8 is modeled with a regulatory, and functionally
essential, lipid named PIP2. Furthermore, a PIRT ligand screen identified several novel
small molecular binders for PIRT as well a protein named calmodulin. The ligand
screening results implicate PIRT in diverse physiological functions. Additionally, sparse
NMR data and state of the art Rosetta protocols were used to experimentally guide PIRT
structure predictions. Finally, the mechanism of thermosensing from the evolutionarily
conserved sensing domain of TRPV1 was investigated using NMR. The body of work
presented herein advances the understanding of thermosensing and TRP channel function
with TRP channel regulatory implications for PIRT.
ContributorsSisco, Nicholas John (Author) / Van Horn, Wade D (Thesis advisor) / Mills, Jeremy H (Committee member) / Wang, Xu (Committee member) / Yarger, Jeff L (Committee member) / Arizona State University (Publisher)
Created2018
Description
Glycosaminoglycans (GAGs) are long chains of negatively charged sulfated polysaccharides. They are often found to be covalently attached to proteins and form proteoglycans in the extracellular matrix (ECM). Many proteins bind GAGs through electrostatic interactions. GAG-binding proteins (GBPs) are involved in diverse physiological activities ranging from bacterial infections to cell-cell/cell-ECM contacts. This thesis is devoted to understanding how interactions between GBPs and their receptors modulate biological phenomena. Bacteria express GBPs on surface that facilitate dissemination and colonization by attaching to host ECM. The first GBP investigated in this thesis is decorin binding protein (DBP) found on the surface of Borrelia burgdorferi, causative pathogens in Lyme disease. DBPs bind GAGs of decorin, a proteoglycan in ECM. Of the two isoforms, DBPB is less studied than DBPA. In current work, structure of DBPB from B. burgdorferi and its GAG interactions were investigated using solution NMR techniques. DBPB adopts a five-helical structure, similar to DBPA. Despite similar GAG affinities, DBPB has its primary GAG-binding site on the lysine-rich C terminus, which is different from DBPA. Besides GAGs, GBPs in ECM also interact with cell surface receptors, such as integrins. Integrins belong to a big family of heterodimeric transmembrane proteins that receive extracellular cues and transmit signals bidirectionally to regulate cell adhesion, migration, growth and survival. The second part of this thesis focuses on αM I-domain of the promiscuous integrin αMβ2 (Mac-1 or CD11b/CD18) and explores the structural mechanism of αM I-domain interactions with pleiotrophin (PTN) and platelet factor 4 (PF4), which are cationic proteins with high GAG affinities. After completing the backbone assignment of αM I-domain, paramagnetic relaxation enhancement (PRE) experiments were performed to show that both PTN and PF4 bind αM I-domain using metal ion dependent adhesion site (MIDAS) in an Mg2+ independent way, which differs from the classical Mg2+ dependent mechanism used by all known integrin ligands thus far. In addition, NMR relaxation dispersion analysis revealed unique inherent conformational dynamics in αM I-domain centered around MIDAS and the crucial C-terminal helix. These dynamic motions are potentially functionally relevant and may explain the ligand promiscuity of the receptor, but requires further studies.
ContributorsFeng, Wei (Biologist) (Author) / Wang, Xu (Thesis advisor) / Yarger, Jeff L (Committee member) / Ghirlanda, Giovanna (Committee member) / Arizona State University (Publisher)
Created2019
Description摘要
在复杂多变的商业环境中，企业传统的人力资源管理已经难以应对日益频发的员工职业倦怠、人际间矛盾冲突、频繁跳槽等局面与问题。企业员工工作的价值与意义早已不再是传统的雇佣模式下，通过出卖劳动力或智力从而获得工资以实现“养家糊口”的目的那么单纯与简单，员工也希望通过辛勤的工作，以获得个体的幸福感、荣誉感与认同感等。对于现代企业的管理者而言，员工追求事业的提升、个人价值的实现，不仅体现在薪酬、福利待遇的提升，更重要的是员工个人的成长以及潜能和竞争力的提升。
随着组织行为学和心理学的不断发展与演变，与员工幸福感相关的研究备受关注。对现代企业而言，管理者借助制度设计对员工幸福积极管理，可以最大限度地发挥员工的积极性、主动性与创造性，实现员工与企业之间的利益相趋同，从而更为高效地实现组织的目标。基于此，本文以民营企业员工工作幸福感作为研究的切入点，借助理论分析、问卷调查和实证分析相结合的研究方法，系统深入地研究我国民营企业员工工作幸福感的构成、可控前因和绩效后果等问题。
本文研究发现：
第一，员工薪酬的提高有助于员工工作幸福感的提升，薪资对基层员工幸福感的影响显著高于其对高层员工幸福感的影响；
第二，完善的晋升机制对于中层员工而言更能提升其幸福感，完善的晋升机制更有利于中层员工；
第三，公平性的提高有助于提高员工工作幸福感，而且这种正效应更多体现在基层员工群体之中；
第四，高层员工更注重自我价值的实现，高层员工的工作挑战性越高，其自我实现需求获得的满足感则约高，但是对于基层员工和中层员工而言，其效果则恰恰相反，基础员工和高层员工更多地将工作挑战性和压力看作是一种负面的因素；
第五，员工幸福感的确会给企业带来正向的绩效。
本文的研究框架和实证结论不仅可以丰富学术界有关员工工作幸福感的研究，而且为企业管理者进行绩效管理以及员工工作质量的提升提供理论和实证借鉴。
在复杂多变的商业环境中，企业传统的人力资源管理已经难以应对日益频发的员工职业倦怠、人际间矛盾冲突、频繁跳槽等局面与问题。企业员工工作的价值与意义早已不再是传统的雇佣模式下，通过出卖劳动力或智力从而获得工资以实现“养家糊口”的目的那么单纯与简单，员工也希望通过辛勤的工作，以获得个体的幸福感、荣誉感与认同感等。对于现代企业的管理者而言，员工追求事业的提升、个人价值的实现，不仅体现在薪酬、福利待遇的提升，更重要的是员工个人的成长以及潜能和竞争力的提升。
随着组织行为学和心理学的不断发展与演变，与员工幸福感相关的研究备受关注。对现代企业而言，管理者借助制度设计对员工幸福积极管理，可以最大限度地发挥员工的积极性、主动性与创造性，实现员工与企业之间的利益相趋同，从而更为高效地实现组织的目标。基于此，本文以民营企业员工工作幸福感作为研究的切入点，借助理论分析、问卷调查和实证分析相结合的研究方法，系统深入地研究我国民营企业员工工作幸福感的构成、可控前因和绩效后果等问题。
本文研究发现：
第一，员工薪酬的提高有助于员工工作幸福感的提升，薪资对基层员工幸福感的影响显著高于其对高层员工幸福感的影响；
第二，完善的晋升机制对于中层员工而言更能提升其幸福感，完善的晋升机制更有利于中层员工；
第三，公平性的提高有助于提高员工工作幸福感，而且这种正效应更多体现在基层员工群体之中；
第四，高层员工更注重自我价值的实现，高层员工的工作挑战性越高，其自我实现需求获得的满足感则约高，但是对于基层员工和中层员工而言，其效果则恰恰相反，基础员工和高层员工更多地将工作挑战性和压力看作是一种负面的因素；
第五，员工幸福感的确会给企业带来正向的绩效。
本文的研究框架和实证结论不仅可以丰富学术界有关员工工作幸福感的研究，而且为企业管理者进行绩效管理以及员工工作质量的提升提供理论和实证借鉴。
ContributorsShu, Man (Author) / Shen, Wei (Thesis advisor) / Wu, Fei (Thesis advisor) / Chen, Xin (Committee member) / Arizona State University (Publisher)
Created2019
Description当前，上市公司的盈余管理问题已是我国资本市场中普遍存在的突出问题。一般来说，一些企业为了满足资本市场对于上市、增发等条件的要求,以及为有效推动企业的并购、重组等行为的顺利实现,甚至为了谋求公司管理层的个别利益,往往运用盈余管理等举措实施公司财报及关键指标的粉饰修正，让不知情的股民蒙受一定的损失。普遍分析显示，我国股市中民营企业比其他企业遭遇的问题和压力更多、更大、更突出,因此民营企业从客观上来说拥有更强的盈余管理动机。而从当前我国资本市场的实际情况来看，我国相关专家学者对盈余管理的系统性深入研究，一般都瞄准了上市企业群体或持续亏损企业，对盈余管理的研究不系统、不全面、不深入，这将对我国进一步提升盈余管理监管水平构成一定不利影响。当前，由于我国民企在自身管理及发展动力方面的特殊性,我国民企的管理、盈余管理特点和国外上市公司还存在着很大的不同,进一步深入研究我国民企上市公司自身管理方面的突出特点，以及其对企业盈余管理等方面的深层次影响,有助于监管层对症下药，更有针对性地研究出台全新的监管措施,进一步提升管理水平。这还可以为公司发展的决策层及相关会计信息使用人员提供一定的决策参考, 因此其拥有十分重要的意义。
本文首先认真总结分析了有关上市企业治理结构和盈余管理等方面的历史文献资料，依托当前资本市场上普遍运用的委托代理、内部人控制和契约等理论，系统研究了我国民企上市公司在自身治理结构方面的突出特征以及其对盈余管理方面所构成影响的深层次原理。在此基础上，本文通过2015-2017年我国上市企业数据，基于截面Jones模型对民营企业和非民营企业盈余管理程度进行测算和比较分析，发现民营企业盈余管理程度更高；从四个层面系统研究民企公司自身的治理结构突出特点,设立回归模型论证了民营企业独特的公司治理结构特征对盈余管理程度确实会产生影响；最后,本文进一步利用修正的费尔萨姆一奥尔森估价模型对民营上市公司盈余管理有公司价值的关系进行了验证，发现两者具有显著相关性。
本文首先认真总结分析了有关上市企业治理结构和盈余管理等方面的历史文献资料，依托当前资本市场上普遍运用的委托代理、内部人控制和契约等理论，系统研究了我国民企上市公司在自身治理结构方面的突出特征以及其对盈余管理方面所构成影响的深层次原理。在此基础上，本文通过2015-2017年我国上市企业数据，基于截面Jones模型对民营企业和非民营企业盈余管理程度进行测算和比较分析，发现民营企业盈余管理程度更高；从四个层面系统研究民企公司自身的治理结构突出特点,设立回归模型论证了民营企业独特的公司治理结构特征对盈余管理程度确实会产生影响；最后,本文进一步利用修正的费尔萨姆一奥尔森估价模型对民营上市公司盈余管理有公司价值的关系进行了验证，发现两者具有显著相关性。
ContributorsChen, Hui (Author) / Shen, Wei (Thesis advisor) / Chang, Chun (Thesis advisor) / Huang, Xiaochuan (Committee member) / Arizona State University (Publisher)
Created2019