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Description
The Multiple Antibiotic Resistance Regulator Family (MarR) are transcriptional regulators, many of which forms a dimer. Transcriptional regulation provides bacteria a stabilized responding system to ensure the bacteria is able to efficiently adapt to different environmental conditions. The main function of the MarR family is to create multiple antibiotic resistance from a mutated protein; this process occurs when the MarR regulates an operon. We hypothesized that different transcriptional regulator genes have interactions with each other. It is known that Salmonella pagC transcription is activated by three regulators, i.e., SlyA, MprA, and PhoP. Bacterial Adenylate Cyclase-based Two-Hybrid (BACTH) system was used to research the protein-protein interactions in SlyA, MprA, and PhoP as heterodimers and homodimers in vivo. Two fragments, T25 and T18, that lack endogenous adenylate cyclase activity, were used for construction of chimeric proteins and reconstruction of adenylate cyclase activity was tested. The significant adenylate cyclase activities has proved that SlyA is able to form homodimers. However, weak adenylate cyclase activities in this study has proved that MprA and PhoP are not likely to form homodimers, and no protein-protein interactions were detected in between SlyA, MprA and PhoP, which no heterodimers have formed in between three transcriptional regulators.
ContributorsTao, Zenan (Author) / Shi, Yixin (Thesis advisor) / Wang, Xuan (Committee member) / Bean, Heather (Committee member) / Arizona State University (Publisher)
Created2018
Description
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is the 10th leading cause of death, worldwide. The prevalence of drug-resistant clinical isolates and the paucity of newly-approved antituberculosis drugs impedes the successful eradication of Mtb. Bacteria commonly use two-component systems (TCS) to sense their environment and genetically modulate adaptive responses. The prrAB TCS is essential in Mtb, thus representing an auspicious drug target; however, the inability to generate an Mtb ΔprrAB mutant complicates investigating how this TCS contributes to pathogenesis. Mycobacterium smegmatis, a commonly used M. tuberculosis genetic surrogate was used here. This work shows that prrAB is not essential in M. smegmatis. During ammonium stress, the ΔprrAB mutant excessively accumulates triacylglycerol lipids, a phenotype associated with M. tuberculosis dormancy and chronic infection. Additionally, triacylglycerol biosynthetic genes were induced in the ΔprrAB mutant relative to the wild-type and complementation strains during ammonium stress. Next, RNA-seq was used to define the M. smegmatis PrrAB regulon. PrrAB regulates genes participating in respiration, metabolism, redox balance, and oxidative phosphorylation. The M. smegmatis ΔprrAB mutant is compromised for growth under hypoxia, is hypersensitive to cyanide, and fails to induce high-affinity respiratory genes during hypoxia. Furthermore, PrrAB positively regulates the hypoxia-responsive dosR TCS response regulator, potentially explaining the hypoxia-mediated growth defects in the ΔprrAB mutant. Despite inducing genes encoding the F1F0 ATP synthase, the ΔprrAB mutant accumulates significantly less ATP during aerobic, exponential growth compared to the wild-type and complementation strains. Finally, the M. smegmatis ΔprrAB mutant exhibited growth impairment in media containing gluconeogenic carbon sources. M. tuberculosis mutants unable to utilize these substrates fail to establish chronic infection, suggesting that PrrAB may regulate Mtb central carbon metabolism in response to chronic infection. In conclusion, 1) prrAB is not universally essential in mycobacteria; 2) M. smegmatis PrrAB regulates genetic responsiveness to nutrient and oxygen stress; and 3) PrrAB may provide feed-forward control of the DosRS TCS and dormancy phenotypes. The data generated in these studies provide insight into the mycobacterial PrrAB TCS transcriptional regulon, PrrAB essentiality in Mtb, and how PrrAB may mediate stresses encountered by Mtb during the transition to chronic infection.
ContributorsMaarsingh, Jason (Author) / Haydel, Shelley E (Thesis advisor) / Roland, Kenneth (Committee member) / Sandrin, Todd (Committee member) / Bean, Heather (Committee member) / Arizona State University (Publisher)
Created2019
Description
One out of ten women has a difficult time getting or staying pregnant in the United States. Recent studies have identified aging as one of the key factors attributed to a decline in female reproductive health. Existing fertility diagnostic methods do not allow for the non-invasive monitoring of hormone levels across time. In recent years, olfactory sensing has emerged as a promising diagnostic tool for its potential for real-time, non-invasive monitoring. This technology has been proven promising in the areas of oncology, diabetes, and neurological disorders. Little work, however, has addressed the use of olfactory sensing with respect to female fertility. In this work, we perform a study on ten healthy female subjects to determine the volatile signature in biological samples across 28 days, correlating to fertility hormones. Volatile organic compounds (VOCs) present in the air above the biological sample, or headspace, were collected by solid phase microextraction (SPME), using a 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) coated fiber. Samples were analyzed, using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS). A regression model was used to identify key analytes, corresponding to the fertility hormones estrogen and progesterone. Results indicate shifts in volatile signatures in biological samples across the 28 days, relevant to hormonal changes. Further work includes evaluating metabolic changes in volatile hormone expression as an early indicator of declining fertility, so women may one day be able to monitor their reproductive health in real-time as they age.
ContributorsOng, Stephanie (Author) / Smith, Barbara (Thesis advisor) / Bean, Heather (Committee member) / Plaisier, Christopher (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
Description中国律师制度自“文化大革命”结束后恢复至今，已有近四十年。中国律师行业伴随着中国改革开放的进程，得到了飞速的发展，当然，同时也面临着诸多的问题。重要的问题之一便是，中国律师事务所采用“加盟制合伙人”模式和采用“权益制合伙人”模式之争。本文试图从回顾企业边界的三大理论出发，提出“加盟制合伙人”模式和 “权益制合伙人”模式与合伙人律师的业务专业化程度、业务复杂化程度以及大客户和律师事务所规模关系的四个假设，通过实证分析的方式，试图以企业边界三大理论解释前述四个假设中的关系，并以此期望对律师行业的发展有所启发。
ContributorsChu, Xiaoqing (Author) / Pei, Ker-Wei (Thesis advisor) / Cheng, Shijun (Thesis advisor) / Shen, Wei (Committee member) / Arizona State University (Publisher)
Created2019
Description近些年来，我国城市化进程不断加快，到2020年我国常住人口城镇化率将达到60%左右，户籍人口城镇化率将会达到45%左右。伴随着我国城市化进程的高速推进以及经济水平的不断提高，公共物品及服务的需求程度加大，政府单独出资建设公共项目会导致资金不足、经营管理效率低下等问题。与此同时，我国当前不同层级地方政府的政府性债务都达到了一个非常高的水平，截至2017年末，中国地方政府债务16.47万亿元，债务率（债务余额/综合财力）为76.5%，其中地方负有偿还责任的债务约12.9万亿，地方政府性债务的控制和转化成为经济新常态下重要特征之一。在地方债务压力较大的情况下，PPP将替代土地财政和地方政府融资，为我国新型城镇化建设提供可持续的资金支持，PPP模式成为当前城市建设领域融资的重要选项。
据此，本文基于实证研究方法探讨在债务约束的背景下，在地方政府债务约束下，PPP模式的引入，对城市规划中建设用地面积、人口规划规模与容量、建设用地属性等的城市规划变量的影响；与此同时，考虑到地方政府的政策很大程度上受到是由地方官员，特别是受到作为地方政府党政“一把手”的市委书记和市长的晋升压力和激励的影响，讨论市委书记/市长的晋升压力和激励对PPP模式引入效果的影响。研究发现，在地方政府债务约束下，PPP模式的引入，显著增加城市规划中建设用地面积、人口规划规模与容量、建设用地属性等的城市规划变量；同时，地方政府官员存在利用PPP放大城市建设和规划规模的行为，反映了PPP项目在引入和使用的过程中很大程度上受政府官员的激励的影响。
据此，本文基于实证研究方法探讨在债务约束的背景下，在地方政府债务约束下，PPP模式的引入，对城市规划中建设用地面积、人口规划规模与容量、建设用地属性等的城市规划变量的影响；与此同时，考虑到地方政府的政策很大程度上受到是由地方官员，特别是受到作为地方政府党政“一把手”的市委书记和市长的晋升压力和激励的影响，讨论市委书记/市长的晋升压力和激励对PPP模式引入效果的影响。研究发现，在地方政府债务约束下，PPP模式的引入，显著增加城市规划中建设用地面积、人口规划规模与容量、建设用地属性等的城市规划变量；同时，地方政府官员存在利用PPP放大城市建设和规划规模的行为，反映了PPP项目在引入和使用的过程中很大程度上受政府官员的激励的影响。
ContributorsXu, Ke (Author) / Chen, Pei-Yu (Thesis advisor) / Zhu, Qigui (Thesis advisor) / Chen, Xin (Committee member) / Arizona State University (Publisher)
Created2019
Description
The purpose of this study was to observe the effectiveness of the phenylalanyl arginine β-naphthylamide dihydrochloride inhibitor and Tween 20 when combined with an antibiotic against Escherichia. coli. As antibiotic resistance becomes more and more prevalent it is necessary to think outside the box and do more than just increase the dosage of currently prescribed antibiotics. This study attempted to combat two forms of antibiotic resistance. The first is the AcrAB efflux pump which is able to pump antibiotics out of the cell. The second is the biofilms that E. coli can form. By using an inhibitor, the pump should be unable to rid itself of an antibiotic. On the other hand, using Tween allows for biofilm formation to either be disrupted or for the biofilm to be dissolved. By combining these two chemicals with an antibiotic that the efflux pump is known to expel, low concentrations of each chemical should result in an equivalent or greater effect on bacteria compared to any one chemical in higher concentrations. To test this hypothesis a 96 well plate BEC screen test was performed. A range of antibiotics were used at various concentrations and with varying concentrations of both Tween and the inhibitor to find a starting point. Following this, Erythromycin and Ciprofloxacin were picked as the best candidates and the optimum range of the antibiotic, Tween, and inhibitor were established. Finally, all three chemicals were combined to observe the effects they had together as opposed to individually or paired together. From the results of this experiment several conclusions were made. First, the inhibitor did in fact increase the effectiveness of the antibiotic as less antibiotic was needed if the inhibitor was present. Second, Tween showed an ability to prevent recovery in the MBEC reading, showing that it has the ability to disrupt or dissolve biofilms. However, Tween also showed a noticeable decrease in effectiveness in the overall treatment. This negative interaction was unable to be compensated for when using the inhibitor and so the hypothesis was proven false as combining the three chemicals led to a less effective treatment method.
ContributorsPetrovich Flynn, Chandler James (Author) / Misra, Rajeev (Thesis director) / Bean, Heather (Committee member) / Perkins, Kim (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The inherent risk in testing drugs has been hotly debated since the government first started regulating the drug industry in the early 1900s. Who can assume the risks associated with trying new pharmaceuticals is unclear when looked at through society's lens. In the mid twentieth century, the US Food and Drug Administration (FDA) published several guidance documents encouraging researchers to exclude women from early clinical drug research. The motivation to publish those documents and the subsequent guidance documents in which the FDA and other regulatory offices established their standpoints on women in drug research may have been connected to current events at the time. The problem of whether women should be involved in drug research is a question of who can assume risk and who is responsible for disseminating what specific kinds of information. The problem tends to be framed as one that juxtaposes the health of women and fetuses and sets their health as in opposition. That opposition, coupled with the inherent uncertainty in testing drugs, provides for a complex set of issues surrounding consent and access to information.
ContributorsMeek, Caroline Jane (Author) / Maienschein, Jane (Thesis director) / Brian, Jennifer (Committee member) / School of Life Sciences (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05