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Weber CE, Kothari AN, Wai PY, Li NY, Driver J, Zapf MAC, Franzen CA, Gupta GN, Osipo C, Zlobin A, Syn WK, Zhang J, Kuo PC, Mi Z. Osteopontin mediates an MZF1-TGF-β1-dependent transformation of mesenchymal stem cells into cancer-associated fibroblasts in breast cancer. Oncogene 2014; 34:4821-33. [PMID: 25531323 PMCID: PMC4476970 DOI: 10.1038/onc.2014.410] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 10/20/2014] [Accepted: 11/08/2014] [Indexed: 12/18/2022]
Abstract
Interactions between tumor cells and cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TMEN) significantly influence cancer growth and metastasis. Transforming growth factor-β (TGF-β) is known to be a critical mediator of the CAF phenotype, and osteopontin (OPN) expression in tumors is associated with more aggressive phenotypes and poor patient outcomes. The potential link between these two pathways has not been previously addressed. Utilizing in vitro studies using human mesenchymal stem cells (MSCs) and MDA-MB231 (OPN+) and MCF7 (OPN−) human breast cancer cell lines, we demonstrate that OPN induces integrin-dependent MSC expression of TGF-β1 to mediate adoption of the CAF phenotype. This OPN-TGF-β1 pathway requires the transcription factor, myeloid zinc finger 1 (MZF1). In vivo studies with xenotransplant models in NOD-scid mice showed that OPN expression increases cancer growth and metastasis by mediating MSC-to-CAF transformation in a process that is MZF1- and TGF-β1-dependent. We conclude that tumor-derived OPN engenders MSC-to-CAF transformation in the microenvironment to promote tumor growth and metastasis via the OPN-MZF1-TGF-β1 pathway.
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Mi Z, Novitzky D, Collins JF, Cooper DK. The optimal hormonal replacement modality selection for multiple organ procurement from brain-dead organ donors. Clin Epidemiol 2014; 7:17-27. [PMID: 25565890 PMCID: PMC4278733 DOI: 10.2147/clep.s71403] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The management of brain-dead organ donors is complex. The use of inotropic agents and replacement of depleted hormones (hormonal replacement therapy) is crucial for successful multiple organ procurement, yet the optimal hormonal replacement has not been identified, and the statistical adjustment to determine the best selection is not trivial. Traditional pair-wise comparisons between every pair of treatments, and multiple comparisons to all (MCA), are statistically conservative. Hsu's multiple comparisons with the best (MCB) - adapted from the Dunnett's multiple comparisons with control (MCC) - has been used for selecting the best treatment based on continuous variables. We selected the best hormonal replacement modality for successful multiple organ procurement using a two-step approach. First, we estimated the predicted margins by constructing generalized linear models (GLM) or generalized linear mixed models (GLMM), and then we applied the multiple comparison methods to identify the best hormonal replacement modality given that the testing of hormonal replacement modalities is independent. Based on 10-year data from the United Network for Organ Sharing (UNOS), among 16 hormonal replacement modalities, and using the 95% simultaneous confidence intervals, we found that the combination of thyroid hormone, a corticosteroid, antidiuretic hormone, and insulin was the best modality for multiple organ procurement for transplantation.
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Djavid M, Liu X, Mi Z. Improvement of the light extraction efficiency of GaN-based LEDs using rolled-up nanotube arrays. OPTICS EXPRESS 2014; 22 Suppl 7:A1680-A1686. [PMID: 25607481 DOI: 10.1364/oe.22.0a1680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this paper, we have investigated the effect of rolled-up nanotubes on the light extraction efficiency of GaN-based LEDs using two-dimensional finite element method simulation. The light extraction involves two successive steps, including the coupling from the light source to the tube and the subsequent emission from the tube to the air. Significantly enhanced light extraction efficiency is observed for both TE and TM waves by optimizing the nanotube geometry and dimension as well as the separation between the nanotube and light source. We have further shown that densely packed nanotube arrays can be integrated with GaN-based LEDs to achieve unequivocal improvement of light extraction efficiency over a large surface area. With recent advances in rolled-up micro- and nanotubes, it is expected that this study can offer a potentially flexible, low cost approach to enhance the light extraction of various LED devices.
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Ferreira JA, Nguyen HPT, Mi Z, Leonelli R, Stafford L. Improvement of the emission properties from InGaN/GaN dot-in-a-wire nanostructures after treatment in the flowing afterglow of a microwave N₂ plasma. NANOTECHNOLOGY 2014; 25:435606. [PMID: 25299752 DOI: 10.1088/0957-4484/25/43/435606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nominally pure GaN nanowires (NWs) and InGaN/GaN dot-in-a-wire heterostructures were exposed to the flowing afterglow of a N2 microwave plasma and characterized by photoluminescence (PL) spectroscopy. While the band-edge emission from GaN NWs and the GaN matrix of the InGaN/GaN NWs strongly decreased due to the creation of non-radiative recombination centers in the near-surface region, the emission from the InGaN dots strongly increased. PL excitation measurements indicate that such an increase cannot be explained by a plasma-induced shift of the GaN absorption edge. It is rather ascribed to the passivation of grown-in defects and dynamic annealing due to the presence of plasma-generated N atoms and N2 metastables without excessive introduction of ion-induced damage.
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Wang Q, Liu X, Kibria MG, Zhao S, Nguyen HPT, Li KH, Mi Z, Gonzalez T, Andrews MP. p-Type dopant incorporation and surface charge properties of catalyst-free GaN nanowires revealed by micro-Raman scattering and X-ray photoelectron spectroscopy. NANOSCALE 2014; 6:9970-9976. [PMID: 25074362 DOI: 10.1039/c4nr01608d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Micro-Raman scattering and X-ray photoelectron spectroscopy were employed to investigate Mg-doped GaN nanowires. With the increase of Mg doping level, pronounced Mg-induced local vibrational modes were observed. The evolution of longitudinal optical phonon-plasmon coupled mode, together with detailed X-ray photoelectron spectroscopy studies, show that the near-surface region of nanowires can be transformed from weakly n-type to p-type with the increase of Mg doping.
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Salehzadeh O, Tran NH, Liu X, Shih I, Mi Z. Exciton kinetics, quantum efficiency, and efficiency droop of monolayer MoS₂ light-emitting devices. NANO LETTERS 2014; 14:4125-30. [PMID: 24905765 DOI: 10.1021/nl5017283] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We have investigated the quantum efficiency of monolayer MoS2 light-emitting devices through detailed temperature and power-dependent photoluminescence studies and rate equation analysis. The internal quantum efficiency can reach 45 and 8.3% at 83 and 300 K, respectively. However, efficiency droop is clearly measured with increasing carrier injection due to the unusually large Auger recombination coefficient, which is found to be ∼10(-24) cm(6)/s at room temperature, nearly 6 orders of magnitude higher than that of conventional bulk semiconductors. The significantly elevated Auger recombination in the emerging two-dimensional (2D) semiconductors is primarily an indirect process and is attributed to the abrupt bounding surfaces and the enhanced correlation, mediated by magnified Coulomb interactions, between electrons and holes confined in a 2D structure.
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Kibria MG, Zhao S, Chowdhury FA, Wang Q, Nguyen HPT, Trudeau ML, Guo H, Mi Z. Tuning the surface Fermi level on p-type gallium nitride nanowires for efficient overall water splitting. Nat Commun 2014; 5:3825. [DOI: 10.1038/ncomms4825] [Citation(s) in RCA: 205] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 04/08/2014] [Indexed: 12/23/2022] Open
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Novitzky D, Mi Z, Collins J, Cooper D. Thyroid Hormone Therapy in 63,593 Donors: A Retrospective Review of Heart and Lung Procurement. J Heart Lung Transplant 2014. [DOI: 10.1016/j.healun.2014.01.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Driver J, Mi Z, Callaci J, Mascarenhas J, Franzen C, Gupta G, Wai P, Zhang J, Kuo P. Alcohol Inhibits Osteopontin Induced Expression of TGF-β1 in Human Mesenchymal Stem Cells: Implications for Fracture Healing in Intoxicated Patients. J Surg Res 2014. [DOI: 10.1016/j.jss.2013.11.360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zhao S, Le BH, Liu DP, Liu XD, Kibria MG, Szkopek T, Guo H, Mi Z. p-Type InN nanowires. NANO LETTERS 2013; 13:5509-5513. [PMID: 24090401 DOI: 10.1021/nl4030819] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this Letter, we demonstrate that with the merit of nanowire structure and a self-catalytic growth process p-type InN can be realized for the first time by "direct" magnesium (Mg) doping. The presence of Mg acceptor energy levels in InN is confirmed by photoluminescence experiments, and a direct evidence of p-type conduction is demonstrated unambiguously by studying the transfer characteristics of InN nanowire field effect transistors. Moreover, the near-surface Fermi-level of InN can be tuned from nearly intrinsic to p-type degenerate by controlling Mg dopant incorporation, which is in contrast to the commonly observed electron accumulation on the grown surfaces of Mg-doped InN films. First-principle calculation using the VASP electronic package further shows that the p-type surface formed on Mg-doped InN nanowires is highly stable energetically.
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AlOtaibi B, Nguyen HPT, Zhao S, Kibria MG, Fan S, Mi Z. Highly stable photoelectrochemical water splitting and hydrogen generation using a double-band InGaN/GaN core/shell nanowire photoanode. NANO LETTERS 2013; 13:4356-4361. [PMID: 23927558 DOI: 10.1021/nl402156e] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report on the first demonstration of stable photoelectrochemical water splitting and hydrogen generation on a double-band photoanode in acidic solution (hydrogen bromide), which is achieved by InGaN/GaN core/shell nanowire arrays grown on Si substrate using catalyst-free molecular beam epitaxy. The nanowires are doped n-type using Si to reduce the surface depletion region and increase current conduction. Relatively high incident-photon-to-current-conversion efficiency (up to ~27%) is measured under ultraviolet and visible light irradiation. Under simulated sunlight illumination, steady evolution of molecular hydrogen is further demonstrated.
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Wang Q, Connie AT, Nguyen HPT, Kibria MG, Zhao S, Sharif S, Shih I, Mi Z. Highly efficient, spectrally pure 340 nm ultraviolet emission from AlxGa₁-xN nanowire based light emitting diodes. NANOTECHNOLOGY 2013; 24:345201. [PMID: 23899873 DOI: 10.1088/0957-4484/24/34/345201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
High crystal quality, vertically aligned AlxGa1-xN nanowire based double heterojunction light emitting diodes (LEDs) are grown on Si substrate by molecular beam epitaxy. Such AlxGa1-xN nanowires exhibit unique core-shell structures, which can significantly suppress surface nonradiative recombination. We successfully demonstrate highly efficient AlxGa1-xN nanowire array based LEDs operating at ∼340 nm. Such nanowire devices exhibit superior electrical and optical performance, including an internal quantum efficiency of ∼59% at room temperature, a relatively small series resistance, highly stable emission characteristics, and the absence of efficiency droop under pulsed biasing conditions.
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Zhao S, Kibria MG, Wang Q, Nguyen HPT, Mi Z. Growth of large-scale vertically aligned GaN nanowires and their heterostructures with high uniformity on SiO(x) by catalyst-free molecular beam epitaxy. NANOSCALE 2013; 5:5283-5287. [PMID: 23661186 DOI: 10.1039/c3nr00387f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The catalyst-free molecular beam epitaxial growth of GaN nanowires and their heterostructures on a SiOx template is studied in detail. It was found that by optimizing the growth temperature, highly uniform and vertically aligned GaN nanowires and InGaN/GaN heterostructures with excellent optical properties can be obtained on a SiOx template in a large-scale. This work provides an entirely new avenue for GaN nanowire based optoelectronic devices.
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AlOtaibi B, Harati M, Fan S, Zhao S, Nguyen HPT, Kibria MG, Mi Z. High efficiency photoelectrochemical water splitting and hydrogen generation using GaN nanowire photoelectrode. NANOTECHNOLOGY 2013; 24:175401. [PMID: 23548782 DOI: 10.1088/0957-4484/24/17/175401] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have studied the photoelectrochemical properties of both undoped and Si-doped GaN nanowire arrays in 1 mol l(-1) solutions of hydrogen bromide and potassium bromide, which were used separately as electrolytes. It is observed that variations of the photocurrent with bias voltage depend strongly on the n-type doping in GaN nanowires in both electrolytes, which are analyzed in the context of GaN surface band bending and its variation with the incorporation of Si-doping. Maximum incident-photon-to-current-conversion efficiencies of ~15% and 18% are measured for undoped and Si-doped GaN nanowires under ~350 nm light illumination, respectively. Stable hydrogen generation is also observed at a zero bias potential versus the counter-electrode.
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Kundu M, Mi Z, Weber C, Li N, Lynch T, Kuo P, Wai P. Activation of Tumor-Associated Macrophages is Required for Hepatocyte Growth Factor Enhanced Invasiveness and Predicts Survival in Hepatocellular Carcinoma. J Surg Res 2013. [DOI: 10.1016/j.jss.2012.10.618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Li N, Weber C, Wai P, Cuevas B, Kuo P, Mi Z. A MAPK Dependent Pathway Induces Epithelial Mesenchymal Transition (EMT) Via Twist Activation in Human Breast Cancer Cell Lines. J Surg Res 2013. [DOI: 10.1016/j.jss.2012.10.486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Armstrong FD, Elkin TD, Brown RC, Glass P, Rana S, Casella JF, Kalpatthi RV, Pavlakis S, Mi Z, Wang WC. Developmental function in toddlers with sickle cell anemia. Pediatrics 2013; 131:e406-14. [PMID: 23296434 PMCID: PMC3557401 DOI: 10.1542/peds.2012-0283] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/01/2012] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Neurocognitive impairment occurs in children and adults with sickle cell anemia, but little is known about neurodevelopment in very young children. We examined the neurodevelopmental status of infants participating in the Pediatric Hydroxyurea Phase III Clinical Trial (Baby Hug) to determine relationships with age, cerebral blood flow velocity, and hemoglobin concentration. METHODS Standardized measures of infant neurodevelopment were administered to 193 infants with hemoglobin SS or hemoglobin S-β(0) thalassemia between 7 and 18 months of age at the time of their baseline evaluation. Associations between neurodevelopmental scores and age, family income, parent education, hemoglobin concentration, and transcranial Doppler velocity were examined. RESULTS Mean functioning on the baseline neurodevelopment scales was in the average range. There were no mental development scores <70 (impaired); 22 children had scores in the clinically significant range, 11 with impaired psychomotor scores and 11 with problematic behavior rating scores. Significantly poorer performance was observed with older age at baseline. Behavior rating scores were an average of 2.82 percentile points lower per month of age, with similar patterns observed with parent report using adaptive behavior scales. Parent-reported functional abilities and hemoglobin were negatively associated with higher transcranial Doppler velocities. CONCLUSIONS Whereas overall functioning was in the normal range, behavioral and adaptive function was poorer with older age, even in this very young group of children. Explanatory mechanisms for this association between poorer developmental function and older age need to be identified.
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Cardin V, Dion-Bertrand LI, Grégoire P, Nguyen HPT, Sakowicz M, Mi Z, Silva C, Leonelli R. Recombination dynamics in InGaN/GaN nanowire heterostructures on Si(111). NANOTECHNOLOGY 2013; 24:045702. [PMID: 23299780 DOI: 10.1088/0957-4484/24/4/045702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have performed room-temperature time-resolved photoluminescence measurements on samples that comprise InGaN insertions embedded in GaN nanowires. The decay curves reveal non-exponential recombination dynamics that evolve into a power law at long times. We find that the characteristic power-law exponent increases with emission photon energy. The data are analyzed in terms of a model that involves an interplay between a radiative state and a metastable charge-separated state. The agreement between our results and the model points towards an emission dominated by carriers localized on In-rich nanoclusters that form spontaneously inside the InGaN insertions.
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Zhao S, Wang Q, Mi Z, Fathololoumi S, Gonzalez T, Andrews MP. Observation of phonon sideband emission in intrinsic InN nanowires: a photoluminescence and micro-Raman scattering study. NANOTECHNOLOGY 2012; 23:415706. [PMID: 23018196 DOI: 10.1088/0957-4484/23/41/415706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work, photoluminescence and micro-Raman scattering experiments were performed on undoped InN nanowires. It was found that, besides the main photoluminescence peak, a clear phonon sideband emission peak, with an extremely narrow linewidth ~9 meV, was measured. The phonon spectrum revealed by micro-Raman scattering indicates only uncoupled LO phonons are involved in such phonon sideband emission. The clearly resolved phonon sideband emission peak with a narrow linewidth, together with the uncoupled LO phonon modes, suggests the superior quality of the presented InN nanowires, i.e., extremely low residual electron density and the absence of surface electron accumulation, which is consistent with the physical properties of intrinsic InN nanowires as in the previous studies. The detailed phonon sideband properties are also discussed in the text.
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Shen K, Rice SD, Gingrich DA, Wang D, Mi Z, Tian C, Ding Z, Brower SL, Ervin PR, Gabrin MJ, Tseng G, Song N. Distinct genes related to drug response identified in ER positive and ER negative breast cancer cell lines. PLoS One 2012; 7:e40900. [PMID: 22815861 PMCID: PMC3397945 DOI: 10.1371/journal.pone.0040900] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 06/14/2012] [Indexed: 11/18/2022] Open
Abstract
Breast cancer patients have different responses to chemotherapeutic treatments. Genes associated with drug response can provide insight to understand the mechanisms of drug resistance, identify promising therapeutic opportunities, and facilitate personalized treatment. Estrogen receptor (ER) positive and ER negative breast cancer have distinct clinical behavior and molecular properties. However, to date, few studies have rigorously assessed drug response genes in them. In this study, our goal was to systematically identify genes associated with multidrug response in ER positive and ER negative breast cancer cell lines. We tested 27 human breast cell lines for response to seven chemotherapeutic agents (cyclophosphamide, docetaxel, doxorubicin, epirubicin, fluorouracil, gemcitabine, and paclitaxel). We integrated publicly available gene expression profiles of these cell lines with their in vitro drug response patterns, then applied meta-analysis to identify genes related to multidrug response in ER positive and ER negative cells separately. One hundred eighty-eight genes were identified as related to multidrug response in ER positive and 32 genes in ER negative breast cell lines. Of these, only three genes (DBI, TOP2A, and PMVK) were common to both cell types. TOP2A was positively associated with drug response, and DBI was negatively associated with drug response. Interestingly, PMVK was positively associated with drug response in ER positive cells and negatively in ER negative cells. Functional analysis showed that while cell cycle affects drug response in both ER positive and negative cells, most biological processes that are involved in drug response are distinct. A number of signaling pathways that are uniquely enriched in ER positive cells have complex cross talk with ER signaling, while in ER negative cells, enriched pathways are related to metabolic functions. Taken together, our analysis indicates that distinct mechanisms are involved in multidrug response in ER positive and ER negative breast cells.
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Zhao S, Fathololoumi S, Bevan KH, Liu DP, Kibria MG, Li Q, Wang GT, Guo H, Mi Z. Tuning the surface charge properties of epitaxial InN nanowires. NANO LETTERS 2012; 12:2877-2882. [PMID: 22545811 DOI: 10.1021/nl300476d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have investigated the correlated surface electronic and optical properties of [0001]-oriented epitaxial InN nanowires grown directly on silicon. By dramatically improving the epitaxial growth process, we have achieved, for the first time, intrinsic InN both within the bulk and at nonpolar InN surfaces. The near-surface Fermi-level was measured to be ∼0.55 eV above the valence band maximum for undoped InN nanowires, suggesting the absence of surface electron accumulation and Fermi-level pinning. This result is in direct contrast to the problematic degenerate two-dimensional electron gas universally observed on grown surfaces of n-type degenerate InN. We have further demonstrated that the surface charge properties of InN nanowires, including the formation of two-dimensional electron gas and the optical emission characteristics can be precisely tuned through controlled n-type doping. At relatively high doping levels in this study, the near-surface Fermi-level was found to be pinned at ∼0.95-1.3 eV above the valence band maximum. Through these trends, well captured by the effective mass and ab initio materials modeling, we have unambiguously identified the definitive role of surface doping in tuning the surface charge properties of InN.
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Bhattacharya S, Mi Z, Talbot L, Guo H, Kuo P. Human Mesenchymal Stem Cell and Epithelial Hepatic Carcinoma Cell Lines in Admixture: A Novel Method Demonstrating Concurrent Stimulation of CAF and EMT Markers. J Surg Res 2012. [DOI: 10.1016/j.jss.2011.11.128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Weber C, Talbot L, Wai P, Mi Z, Kundu M, Kuo P. Transformation of Mesenchymal Stem Cells into Cancer Associated Fibroblasts Within the Tumor Microenvironment. J Surg Res 2012. [DOI: 10.1016/j.jss.2011.11.381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nguyen HPT, Zhang S, Cui K, Han X, Fathololoumi S, Couillard M, Botton GA, Mi Z. p-Type modulation doped InGaN/GaN dot-in-a-wire white-light-emitting diodes monolithically grown on Si(111). NANO LETTERS 2011; 11:1919-1924. [PMID: 21517080 DOI: 10.1021/nl104536x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Full-color, catalyst-free InGaN/GaN dot-in-a-wire light-emitting diodes (LEDs) were monolithically grown on Si(111) by molecular beam epitaxy, with the emission characteristics controlled by the dot properties in a single epitaxial growth step. With the use of p-type modulation doping in the dot-in-a-wire heterostructures, we have demonstrated the most efficient phosphor-free white LEDs ever reported, which exhibit an internal quantum efficiency of ∼56.8%, nearly unaltered CIE chromaticity coordinates with increasing injection current, and virtually zero efficiency droop at current densities up to ∼640 A/cm(2). The remarkable performance is attributed to the superior three-dimensional carrier confinement provided by the electronically coupled dot-in-a-wire heterostructures, the nearly defect- and strain-free GaN nanowires, and the significantly enhanced hole transport due to the p-type modulation doping.
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Lu S, Wang L, Wang Y, Mi Z. Kinetic Model of Gas-Liquid-Liquid Reactive Extraction for Production of Hydrogen Peroxide. Chem Eng Technol 2011. [DOI: 10.1002/ceat.201000094] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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