Experiments on quantum phases in InAs/GaSb bilayers: Topological insulator and exciton condensation

Du, Lingjie ProQuest Dissertations & Theses Rice University 2016 해외박사(DDOD)

Recent developments in Quantum Spin Hall (QSH) effect have triggered much attention in inverted InAs/GaSb Quantum wells (QWs), which are the leading material in QSH systems. Inverted InAs/GaSb QWs are a type II heterostructure with the broken gap, where two dimensional (2D) electrons and holes are confined in spatially separated QWs. From the 1970s until now, the ground state of this structure has been discussed between two candidates: exciton insulator (BCS type exciton condensation) and hybridization gap. The QSH effect was theoretically proposed in the bulk hybridization gap. Although pioneer works about QSH effect have been performed, the conductive hybridization gap limits further exploration. For example, the existence of the QSH effect in this system is still not conclusive. In this thesis, through double-gate modulation, we investigated the whole phase in the inverted band of this structure. We observed two distinct quantum phases: time reversal symmetry (TRS) QSH insulator in the deeply inverted regime and exciton insulator in the shallowly inverted regime. In the deeply inverted regime, with the strain effect in InGaSb QW, we realized the insulating hybridization gap for the first time, which gave us the opportunity to observe TRS QSH effect in this system for the first time. With the largest bulk gap in known QSH systems, we observed the helical edges had the longest coherence length (nearly 13mum) and were more stable against temperature, compared with previous results, which paved the way to construct the room temperature topological circuit. In the shallowly inverted regime, the quantized plateau of QSH effect was observed in mesoscopic devices for the first time. Surprisingly, this helical edge mode was robust under the high magnetic field, demonstrating the first TRS broken QSH insulator. This novel quantum phase could not be understood in the single particle topological theory. Further studies showed that the bulk gap was dominated by exciton gap instead of hybridization gap. We performed the low temperature transport and Terahertz transmission measurement on the bulk exciton gap, and observed the solid evidence for the existence of BCS-like exciton condensation, which was under search for more than fifty years. Furthermore, we performed one dimensional Coulomb drag experiments in the topological circuit. We observed positive and negative drag results dependent on the temperature, indicating the charge symmetry and many-body correlation.

Far-infrared irradiation inhibits proliferation of human upper airway epithelial cells by protein phosphatase 2A-promoted dephosphorylation of p70 S6 kinase

Na-Young, Lee 영남대학교 대학원 2024 국내석사

Far-infrared (FIR) ray is an invisible electromagnetic radiation with a wavelength of 3‒1000 μm and conveys photon energy range of 12.4 meV to 1.7 eV. When living organisms and cells are exposed to FIR rays, they elicit various biological effects, including vasorelaxation and inhibition of cell proliferation. Functional dysregulation of airway epithelial cells caused by pathogen infections (such as viruses), toxicants, and allergens contributes to the development and exacerbation of chronic rhinosinusitis, asthma, and nasal polyposis, ultimately resulting in airway narrowing caused by epithelial hyperplasia and/or hypertrophy. Although these otolaryngological diseases are common worldwide, the effect of FIR irradiation remains to be elucidated. Therefore, in the present study, I investigated the molecular mechanisms through which FIR irradiation inhibits the proliferation of upper airway epithelial cells. FIR irradiation for 30 min significantly inhibited the proliferation of NCI-H292 cells with no alteration in cell death. The anti-proliferative effect of FIR radiation was accompanied by decreased phosphorylation of p70S6K at Thr389 (p-p70S6K-Thr389), with no changes in the phosphorylation of mTOR at Ser2448 (p-mTOR-Ser2448) and AMPK at Thr172 (p-AMPK-Thr172). As hypothesized, ectopic expression of dn-AMPKα1 gene did not affect FIR irradiation-decreased cell proliferation and p-p70S6K-Thr389. Overexpression of p70S6K-T389E mutant gene significantly reversed FIR irradiation-inhibited p-p70S6K-Thr389 and cell proliferation. Furthermore, cotreatment with okadaic acid, a specific PP2A inhibitor, significantly restored p-p70S6K-Thr389, and knockdown of PP2Ac gene expression by siRNA almost completely reversed p-p70S6K-Thr389 and cell proliferation. I examined whether FIR irradiation enhanced the binding of p70S6K and PP2Ac because total PP2Ac expression was not altered in FIR-irradiated cells. Coimmunoprecipitation assay results showed that 30 min of FIR irradiation remarkably promoted the physical association of p70S6K and PP2Ac. Hyperthermal stimulus (39 ℃) did not alter the level of p-p70S6K-Thr389 and cell proliferation. Similar to NCI-H292 cells, FIR irradiation for 30 min decreased p-p70S6K-Thr389 and cell proliferation in HNEpCs and HNPEpCs. Furthermore, hyperthermal stimulus (39 ℃) did not affect p-p70S6K-Thr389 and cell proliferation in these cells. My results demonstrated that FIR irradiation for 30 min decreased the proliferation of upper airway epithelial cells through PP2A-mediated inhibition of p70S6K phosphorylation, independent of the hyperthermal effect of FIR radiation. These results suggest that FIR therapy can be used to prevent and treat nasal narrowing diseases including chronic rhinosinusitis, nasal polyposis, and hypertrophy of the nasal turbinate.

Caracterisation et transfert des magmas felsiques dans la croute moyenne a profonde. Exemple: Le Mont Hay en Australie centrale (French text)

Bonnay, Marianne Universite du Quebec a Chicoutimi (Canada) 2001 해외박사(DDOD)

Le lien entre la source du magma dans la croûte moyenne à profonde et son site d'accumulation dais la croûte supérieure, est illustré par le massif du Mont Hay, lequel représente une portion de la Croûte moyenne à profonde protérozoïque constituée de roches supracrustales felsiques et mafiques de composition MORB (<italic>Middle Ocean Ridge Basalt</italic>) et MORB contaminée. Selon des calculs basés sur la composition des roches résiduelles et des fondus solidifiés, la contamination du N-MORB (<italic>Normal Middle Ocean Ridge Basalt</italic>) par les éléments lithophiles serait en effet le résultat de 82% de magma mafique N-MORB contamin par 18% de métasédiments. Le massif du Mont Hay représente une zone de transfert optimale exhumée pour les magmas produits <italic> in situ</italic> et/ou injectés, qui ont pu être transférés et se mélanger dans un milieu suffisamment chaud pour éviter leur solidification. La caractérisation et le transfert de ces magmas felsiques dans la croûte sont orchestrés par la tectonique et le métamorphisme. Ainsi, le massif du Mont Hay subit une première hybridation lors de la formation du protolithe igné vers 1820 Ma (phase prédéformationnelle) puis une seconde hybridation pendant la déformation subséquente vers 1770 Ma (phase syndéformationnelle). La fermeture du bassin d'arrière-arc marque le début d'un événement contractionnel qui commence au nord et induit le métamorphisme et l'anatexie du protolithe au faciès granulitique à 825–875°C et 6–7 kbar. La fusion partielle <italic>in situ</italic> de la granulite mafique produit les leucosomes tonalitiques (cm) qui correspondent à la source 1 de fondu, tandis que les métasédiments produisent beaucoup de leucogranites (cm à m) qui correspondent à la source 3. Ce réseau de transfert, qui crée un lien entre le lieu de production et d'accumulation de magmas, est constitué de dykes et sa structure est déterminée par leur distribution statistique normale ou log-normale. Les observations de terrain tendent à prouver que les dykes deviennent plus larges et moins denses en s'éloignant de la source; alors le processus de drainage de l'échelle du grain à l'échelle régionale pourrait être consistant et le lien entre la source et le magma est un réseau interconnecté s'élargissant du grain au pluton. (Abstract shortened by UMI.).

XIV homelies du IXe siecle

Ambrose Editions du Cerf 1970 국내박사

The Effect of Virtual Reality Immersion on Balance in Stroke Patients

Du-ri Jeong 청주대학교 보건의료대학원 2022 국내석사

This study investigated the effect of virtual reality (VR) immersion on balance in stroke patients using a VR program for balance training. This study measured the balance ability of 30 subjects who were randomly assigned to perform full-immersion VR (FVR, n=15) or semi-immersion VR (SVR, n=15). The interventions were performed for approximately 30 minutes; the immediate effect on balance was then measured using a force plate (Balancia program), Berg Balance Scale (BBS), Tinetti Performance Oriented Mobility Assessment (POMA), and Functional Reach Test (FRT). Paired t-tests were used to compare differences in values before and after within groups, while independent sample t-tests were icant improvements in force plate, BBS, POMA, and FRT measurements (p<0.05) in the before-and-after comparison within the group, while SVR only showed a difference in functional balance assessment (BBS, POMA, FRT) (p <0.05) Comparisons of balance ability between the groups showed differences in average displacement (p<0.05) Considering the improvement of balance ability and the other positive effects of FVR in stroke patients, FVR is recommended over SVR. 본 연구는 가상현실프로그램을 사용하여 뇌졸중 환자에게 균형 훈련을 진행했을 때 가상현실의 몰입도가 균형에 어떠한 영향을 미치는지 알아보고자 하였다. 연구의 대상자들은 총 30명 선정하였으며 측정도구를 이용하여 대상자들의 균형능력을 측정하였다 제비뽑기를 실시하여 완전몰입군(FVR, n=15), 반몰입군(SVR, n=15)에 무작위로 각각 배정하였다. 30분가량 중재를 하였으며 이후 즉각적으로 균형에 미치는 영향을 힘판(Balancia program), 버그균형척도(BBS), 실행지향 움직임평가(POMA), 기능적 뻗기 검사(FRT)을 이용해 측정하였다. 그룹 내 전후를 비교하기 위해 paired t-test을 실시, 그룹 간 차이를 비교하기 위해 independent sample t-test를 사용하였다 (p<0.05) 그룹 내 전후 비교에서 FVR은 유의한 개선을 보였으며(Force plate, BBS, POMA, FRT)(p<0.05), SVR은 기능적인 균형평가(BBS, POMA, FRT) 에서만 차이를 보였다(p<0.05) 그룹 간 균형능력의 차이 비교는 평균변위에서 차이를 보였다(p<0.05) 따라서 FVR이 가져오는 뇌졸중 환자들의 균형 능력 향상과 그 외 다양한 긍정적인 영향을 볼 때, SVR보다 FVR을 이용하는 것을 추천한다.

A research on synthesis and luminescent properties of rare-earth ions activated nanomaterials for versatile applications

DU PENG The Graduate School of Kyung Hee Univeristy 2018 국내박사

With the rapid development of science and technique, the interest in developing novel materials, particularly, the trivalent rare-earth ions activated nanoparticles, for multifunctional applications is increasing. Nowadays, the applications of the trivalent rare-earth activated nanoparticles for non-contact optical thermometry by means of the fluorescence intensity ratio (FIR) based on the thermally coupled levels of rare-earth ions have received considerable attention because of their noble and impressive characteristics of real-time monitoring, fast response, high special resolution, and so on. Apart from the optical thermometer, the phosphor converted white light-emitting diodes (WLEDs) were also intensively studied as the next generation lighting source on account of their favorite merits including energy saving, ecofriendly and long working lifetime. To fulfill these applications, the rare-earth ions activated nanoparticles should have the characteristics of high thermal stability, high luminescence efficiency and can be pumped by near-ultraviolet (NUV) or near-infrared light. In comparison with other host matrixes, the rare-earth ions activated molybdate and tungstate, which possessed strong absorption in ultraviolet region and can shift the energy to activators, have been extensively researched for optical temperature sensors and solid-state lighting. However, the previous achievements are still far away from the requirement of the industry manufacture. Hence, there is still a huge challenge to search for novel rare-earth ions activated nanoparticles with splendid stability and high efficiency for non-invasion optical thermometry and indoor lighting. On the other hand, the scientists also paid much attention to develop the rare-earth ion activated nanoparticles with homogenous shape and nontoxicity so as to extend their applications in the fields of bioimaing, plant growth and latent fingerprint detection. Up to date, since the fluorides have low phonon energy, they were considered as excellent luminescent matrixes for rare-earth ions. Currently, some routes, such as sol-gel method, hydrothermal method, solvothermal method and co-precipitation method, were proposed to prepare the rare-earth ions activated fluorides. Unfortunately, these techniques suffer from some deadly drawbacks including high calcination temperature, long reaction time, insufficient product and complex experimental process. Thus, an ultra-rapid facile preparation technology, which can be carried out at low temperature, is expected to be developed to synthetic the uniform rare-earth ions activated fluoride nanoparticles. In this dissertation, the Er3+/Yb3+-coactivated Na0.5Gd0.5MoO4 and Eu3+-activated La2MoO6-La2WO6 nanoparticles were sintered by utilizing the critic acid assistant sol-gel route. The field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and the X-ray diffraction were employed to characterize the microstructure and phase compositions of the prepared nanoparticles. Under 980 nm light irradiation, the Er3+/Yb3+-coactivated Na0.5Gd0.5MoO4 nanoparticles emitted glaring upconverison (UC) emissions originating from the 4f-4f transitions of Er3+ ions and the UC emission intensities were dependent on the dopant content. With the help of the temperature dependent green UC emission spectra as well as the FIR route, the temperature sensing behaviors of the resultant nanoparticles were studied. Likewise, the Eu3+-activated La2MoO6-La2WO6 nanoparticles had broad absorption in the NUV region and were found to be efficiently excited by 379 nm light. Under NUV (379 nm) light excitation, the visible red lights were seen in the Eu3+-activated La2MoO6-La2WO6 nanoparticles and the photoluminescence (PL) emission intensities were also dependent on the doping concentration. Furthermore, through mixing the Eu3+-activated La2MoO6-La2WO6 nanoparticles with commercial blue-emitting and green-emitting phosphors, a novel WLEDs device, which can emit bright white light with proper color rending index (CRI) and correlated color temperature (CCT) values, was fabricated. These achieved results suggested that the Er3+/Yb3+-coactivated Na0.5Gd0.5MoO4 and Eu3+-activated La2MoO6-La2WO6 nanoparticles had promising applications for optical thermometer and solid-state lighting, respectively. By the hydrothermal method, series of Ho3+-activated NaYbF4 and Er3+/Yb3+-coactivated NaYF4 nanoparticles were sintered. The TEM images revealed that all the compounds were composed of homogenous nanoparticles with regular shape. Under 980 nm excitation, these obtained nanoparticles exhibited intense UC emission properties. The Ho3+-activated NaYbF4 nanoparticles did not only possess low toxicity but also exhibited potential application in bioimaging. The feasibility of the Ho3+-activated NaYbF4 nanoparticles for the latent fingerprint detection application was confirmed. By means of the FIR route, the optical thermometric behaviors of the Er3+/Yb3+-coactivated NaYF4 nanoparticles were investigated. In addition, the sensor sensitivities of the designed nanoparticles were determined to be dependent on the calcination temperature. These achievements demonstrated that the rare-earth ions activated fluoride nanoparticles, which were prepared by hydrothermal method, can be applied in the fields of bioimaging, latent fingerprint detection and optical thermometry. In the other side, a new ultrafast reaction, which can be operated at room temperature, was proposed to rare-earth ions activated fluoride nanoparticles. After one minute reaction at ambient temperature, the Er3+/Yb3+-coactivated NaBiF4 and Eu3+-activated NaBiF4 nanoparticles were prepared. Through tuning the content of NH4F, the phase structure and morphology of the Er3+/Yb3+-coactivated NaBiF4 nanoparticles were modified. When the 14 mmol of NH4F was added, the Er3+/Yb3+-coactivated NaBiF4 compounds did not only exhibit pure phase structure but also consisted of uniformly spherical nanoparticles. Through analyzing the temperature dependent UC emission spectra, the optical thermometric behaviors of the synthesized nanoparticles were studied. Furthermore, the prepared Er3+/Yb3+-coactivated NaBiF4 nanoparticles were also revealed to have the ability to convert the incident energy into heat. Likewise, under NUV (394 nm) light excitation, the Eu3+-activated NaBiF4 nanoparticles exhibited dazzling red light with high color purity. The Eu3+ ion concentration shows significant effect on the PL emission performance of the resultant nanoparticles. With the aid of the Judd-Oflet theory, the estimated optical intensity parameters confirmed that the dopants occupied the low symmetry sites in the host lattices. Through integrating the NUV chip, Eu3+-activated NaBiF4 nanoparticles, commercial blue-emitting and green-emitting compounds, a new WLEDs device that can emit white light with suitable CCT and CRI values was developed. Additionally, the Eu3+-activated NaBiF4 nanoparticles can also be used as fluorescence probe to track the transportation process of the studied nanoparticles in plant cells. These results suggested that rare-earth ions activated fluoride nanoparticles, which were synthesized by the one minute reaction process at room temperature, were promising candidates for optical thermometer, optical heater, WLEDs and fluorescence probe in plant cells.

Option pricing under habit formation and event risks

Du, Du The University of Chicago 2007 해외박사(DDOD)

This paper proposes a new structural option pricing model, which is estimated using the method of simulated moments (MSM) based on the joint data of stocks and options. The estimated model explains well the observed unconditional and conditional volatility smirks in option pricing. The driving forces are a slow moving external habit and i.i.d. consumption jumps which induce jumps in stock prices. Habit formation generates excess return volatility, which is tightly linked to the price levels of ATM (at-the-money) options quoted in terms of Black-Scholes implied volatility (B/S-vol), while jumps generate the observed variations in B/S-vol across varying degrees of moneyness. The model also has predictions about the term structure of option pricing, historical smirk premia backed out of historical consumption, and a wide variety of stock pricing features which are all verified by the data. The model's asset pricing implications are robust to more realistic assumptions about the dividend process.

(La)signification de la mort a travers "Les Thibault" de Roger Martin du Gard

신승섭 韓國外國語大學校 大學院 1975 국내석사

IPA를 이용한 문화유산관광지 개선방안에 관한 연구: 청두(成都) 무후사(武侯祠)박물관을 중심으로

Du, Linhong 세종대학교 대학원 2024 국내석사

오늘날 관광 산업이 급속하게 성장함에 따라 관광객들의 관광방식도 다양해지고 있다. 관광객들은 문화유산 관광을 통해 다양한 역사를 배우고 문화를 습득하게 되어 즐거운 경험을 얻을 수 있을 뿐만 아니라 문화유산관광지는 지역의 경제 성장에 기여할 수 있는 중요한 영역이다. 그리고 지역이나 국가의 문명과 사회적 진보의 상징으로서 문화유산지를 찾고 있는 관광객들은 점점 많아지며, 문화유산지는 관광에 없어서는 안 된다는 명소로 간주되어 있으나 IPA를 이용한 청두 무후사박물관에 관한 문화유산관광의 연구는 부족한 실정이다. 따라서 본 연구는 청두 무후사박물관에 방문한 관광객을 대상으로 설문조사를 통해 문화유산관광의 선택속성을 파악하고 전통 IPA와 2가지의 수정 IPA기법을 이용해서 도출된 연구결과를 비교하여 관광객의 만족도를 높이고 시사점 및 향후의 연구 방향을 제시하고자 한다. 본 연구의 설문조사는 2023년 07월 27일부터 08월 10일까지 2주간의 온라인 설문조사와 현장 설문조사를 통해 진행하였다. 온라인 설문조사는 최근 2년 이내 청두 무후사박물관을 방문해 본 적이 있는 관광객을 대상으로 하였고, 현장 설문조사는 청두 무후사박물관에서 방문을 마치는 관광객을 대상으로 설문조사를 실시하였다. 총 422부를 배포된 후 불성실한 응답 102부를 제거한 후 320부가 최종적으로 연구에 사용되었다. 본 연구는 SPSS 27.0 프로그램을 이용하였다. 응답자의 인구 통계 학적 및 일반적인 특성에 대해 기술통계와 빈도 분석을, 설문지에서 도출된 측정항목에 대해 탐색적 요인분석 및 신뢰성분석을 수행하여 신뢰성과 타당성을, IPA분석하여 Martilla & James(1977)의 전통적 IPA에서는 대응표본 t-검정을, Vavra(1997)의 수정 IPA는 명시적 중요도로부터 내재적 중요도를 도출하기 위해 회귀분석을, Deng(2007)의 수정 IPA에서는 절대적 성취도로부터 상대적 중요도를 활용하여 편상관분석을 실시하여 다음과 같은 분석결과를 도출하였다. 무후사 선택속성의 중요도와 만족도에서 ‘무후사에서 삼국시대에 생활문화를 확인함’과 ‘문화유산에 대한 자부심’을 가장 중요하게 생각하는 것으로 나타났고, ‘기념품비’는 가장 중요하게 생각하지 않는 것으로 나타났다. 관광객들이 가장 만족스럽게 생각하는 속성은 ‘문화유산에 대한 자부심’으로 나타났고 가장 만족하지 못한 속성은 ‘기념품비’로 보였다. 청두 무후사박물관 선택속성에 대한 중요도와 만족도 간의 차이를 검증한 결과로 총 30개의 속성 중 10개 속성이 만족도보다 중요도가 높은 것으로 나타나 관광객의 만족도를 높이기 위해 노력할 필요가 있는 것으로 알 수 있다. 청두 무후사박물관 선택속성에 대한 전통적 IPA와 2가지의 수정 IPA의결과를 비교해보면 Martilla & James(1977)의 전통적 IPA 기법을 적용하여 분석한 결과는 I사분면에는 17개 속성이, II사분면에는 2개 속성이, III사분면에는 7개 속성이, IV사분면에는 4개 속성이 분포되었다. ‘음식점 서비스’, ‘숙박 위생(내부시설 포함)’, ‘금리거리 치안’, ‘입장료’는 만족도보다 중요도가 높기 때문에 집중적으로 개선할 필요가 있다. Vavra(1997)의 수정 IPA 기법을 적용하여 분석한 결과는 I사분면에는 5개 속성이, II사분면에는 1개 속성이, III사분면에는 8개 속성이, IV사분면에는 16개 속성이 분포되었다. ‘문화유산의 보전’, ‘자연경관’, ‘지역색채’, ‘문화자원의 독특성(건축물과 역사 보행자거리)’, ‘무후사에서 삼국시대의 생활 문화를 확인함’, ‘문화유산보호의 중요성’, ‘종사원의 태도(친절함)’, ‘모든 시설 편의성(주차장, 좌석 및 화장실 등)’, ‘관광지 환경위생(모든 시설포함)’, ‘교통의 편의성(역까지의 거리)’, ‘음식점이 청결함’, ‘음식맛’, ‘숙박 위생(내부시설 포함)’, ‘금리거리 치안’, ‘입장료’, ‘교통비’는 만족도보다 중요도가 높기 때문에 집중적으로 개선할 필요가 있다. Deng(2007)의 수정 IPA 기법을 적용하여 분석한 결과는 I사분면에는 4개 속성이, II사분면에는 15개 속성이, III사분면에는 7개 속성이, IV사분면에는 4개 속성이 분포되었다. 음식점 서비스’, ‘금리거리 치안’, ‘입장료’, ‘기념품비’는 만족도보다 중요도가 높기 때문에 집중적으로 개선할 필요가 있다. 청두 무후사박물관 선택속성의 3 가지 IPA 결과를 비교하면 제I사분면에는 3개 속성이, 제III사분면에는 6개 속성이, 제IV사분면에는 2개 속성이 모두 동일하게 분류되었다. 본 연구는 무후사 방문한 관광객을 대상으로 무후사 선택속성에 대해 Martilla & James(1977)의 전통적 IPA, Vavra(1997)의 수정 IPA와 Deng(2007)의 수정 IPA를 통해 관광객들의 중요도와 만족도를 비교하여 도출된 연구결과 시사점을 제시하였다. 이는 청두 무후사박물관을 방문한 관광객들의 만족도를 향상시켜 문화유산광광의 향후 개선하기 위한 방안을 제안하는 데에 본 연구의 의미가 있다.

Functional implication of thioredoxin and Carotenoid cleavage dioxygenases in soybean nodulation

Du Hui 숙명여자대학교 대학원 2014 국내박사

During symbiotic nodule development in legume roots, early signaling events between host and rhizobia serve critical determinants for the proper onset of nodule morphogenesis, nitrogen fixation and assimilation. Previously we isolated thioredoxin from soybean nodules as one of differentially expressed genes during nodulation and noted its positive role in nitrogen fixation. To identify the target proteins of thioredoxin in nodules, we used thioredoxin affinity chromatography followed by mass spectrometry. N-35, a subunit of uricase, was found to be a target of thioredoxin. Their interaction was confirmed by pull-down assay and by bimolecular fluorescent complementation. With an increased uricase activity observed also in the presence of thioredoxin, these results appear to implicate a novel role of thioredoxin in the regulation of enzyme activities involved in nodule development and nitrogen fixation. As a disulfide reductase ubiquitously present in all taxa of organisms, the importance of thioredoxins as regulators of cellular redox state has long been recognized, and even redox-independent, chaperone function of some thioredoxins has also been reported recently. Previously, we identified N-35, the subunit of soybean uricase, as an interacting target of GmTRX, which is a cytosolic thioredoxin. Here we report further characterization of the interaction, which turns out to be independent of the disulfide reductase function of GmTRX and results in colocalization of the GmTRX and N-35 in peroxisomes, suggesting a possible chaperone function of GmTRX. The chaperone function of GmTRX was demonstrated in in vitro molecular chaperone activity assays including thermal denaturation assay and malate dehydrogenase aggregation assay. Our results show that the target of GmTRX is not only confined to the N-35, but many other peroxisomal proteins, such as catalase (AtCAT), transthyretin-like protein 1 (AtTTL1), acyl-coenzyme A oxidase 4 (AtACX4), also interact with GmTRX. Together with the increased uricase activity of N-35 and decreased ROS accumulation observed in the presence of GmTRX in our results, especially under heat shock and oxidative stress conditions, it appears that GmTRX represents a novel thioredoxin acting as a cytosolic chaperone whose function is essential in facilitating translocation of the peroxisomal proteins as well as in preserving their functional integrity. Carotenoid cleavage dioxygenases are a family of enzymes involved in the biosynthesis of diverse and important apocarotenoid metabolites that have a range of biological functions in plants such as phytohormones, pigments and aromatic volatile compounds. Previously, we found two carotenoid cleavage dioxygenases genes in soybean (Glycine max): GmCCD7 and GmCCD8, showed high expression in root and root nodules and they were also involved in the cleavage of carotenoids in nodules. Here we showed that GmCCD7 was located in chloroplast and GmCCD8 seemed to localize in cytosol. We made transgenic lines repressing GmCCD7 and GmCCD8 to examine their role in nodule development. GmCCD7- and GmCCD8-RNAi plants displayed defective root and nodule development and greatly reduced total nodule fresh weights. Moreover, nitrogenase activities were also dramatically decreased in GmCCD7 and GmCCD8-RNAi transgenic plants indicating impaired nitrogen fixation. In the meantime, overexpression of these two GmCCDs genes showed increased nitrogen fixation activity. Expression patterns of GmCCD7 and GmCCD8 in transgenic root and nodules were confirmed by the expression of β-glucuronidase (GUS) gene driven by the endogenous promoters of GmCCD7 and GmCCD8. These results suggest that the GmCCD7 and GmCCD8 may have essential roles in determining root and nodule development in soybean (Glycine max) plant.