51
|
Jiang JM, Zong Y, Chuang DY, Lei W, Lu CH, Gu Z, Fritsche KL, Thomas AL, Lubahn DB, Simonyi A, Sun GY. Effects of Elderberry Juice from Different Genotypes on Oxidative and Inflammatory Responses in Microglial Cells. ACTA ACUST UNITED AC 2015; 1061:281-288. [PMID: 27158184 DOI: 10.17660/actahortic.2015.1061.31] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Many species of berries are nutritious food and offer health benefits. However, among the different types of berries, information on health effects of American elderberries (Sambucus nigra subsp. canadensis) has been lacking and little is known about whether elderberry consumption can confer neuroprotective effects on the central nervous system. Microglial cells constitute a unique class of immune cells and exhibit characteristic properties to carry out multifunctional duties in the brain. Activation of microglial cells has been implicated in brain injury and in many types of neurodegenerative diseases. Our recent studies demonstrated the ability for endotoxin (lipopolysaccharide, LPS) and interferon gamma (IFNγ) to induce reactive oxygen species (ROS) and nitric oxide (NO) in murine microglial cells (BV-2) through activating NADPH oxidase and the MAPK pathways. In this study, BV-2 microglial cells were used to examine effects of elderberry juice obtained from different genotypes on oxidative and inflammatory responses induced by LPS and IFNγ. Results show that 'Wyldewood' extract demonstrated antioxidant properties by inhibiting IFNγ-induced ROS production and p-ERK1/2 expression. On the other hand, most juice extracts exerted small effects on LPS-induced NO production and some extracts showed an increase in NO production upon stimulation with IFNγ. The disparity of responses on ROS and NO production from different extracts suggests possible presence of unknown endogenous factor(s) in the extract in promoting the IFNγ-induced iNOS synthesis pathway.
Collapse
|
52
|
Luo Z, Hu M, Hong M, Li C, Gu Q, Gu Z, Liao C, Zhao M, Wu H. Outbreeding avoidance as probable driver of mate choice in the
A
siatic toad. J Zool (1987) 2014. [DOI: 10.1111/jzo.12183] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
53
|
Jiang J, Yu T, Yan Y, Du W, Tan T, Hua L, Gu J, Yang X, Liu Z, Ye X, Gu Z. 154 Drug response database with PDX tumor models in biomarker-driven multi-drug multi-arm clinical trial settings. Eur J Cancer 2014. [DOI: 10.1016/s0959-8049(14)70280-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
54
|
Gu Z, Bao Q, Taschereau R, Wang H, Bai B, Chatziioannou AF. Optimization of the Energy Window for PETbox4, a Preclinical PET Tomograph With a Small Inner Diameter. IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2014; 61:1164-1173. [PMID: 25774063 PMCID: PMC4356993 DOI: 10.1109/tns.2014.2321326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Small animal positron emission tomography (PET) systems are often designed by employing close geometry configurations. Due to the different characteristics caused by geometrical factors, these tomographs require data acquisition protocols that differ from those optimized for conventional large diameter ring systems. In this work we optimized the energy window for data acquisitions with PETbox4, a 50 mm detector separation (box-like geometry) pre-clinical PET scanner, using the Geant4 Application for Tomographic Emission (GATE). The fractions of different types of events were estimated using a voxelized phantom including a mouse as well as its supporting chamber, mimicking a realistic mouse imaging environment. Separate code was developed to extract additional information about the gamma interactions for more accurate event type classification. Three types of detector backscatter events were identified in addition to the trues, phantom scatters and randoms. The energy window was optimized based on the noise equivalent count rate (NECR) and scatter fraction (SF) with lower-level discriminators (LLD) corresponding to energies from 150 keV to 450 keV. The results were validated based on the calculated image uniformity, spillover ratio (SOR) and recovery coefficient (RC) from physical measurements using the National Electrical Manufacturers Association (NEMA) NU-4 image quality phantom. These results indicate that when PETbox4 is operated with a more narrow energy window (350-650 keV), detector backscatter rejection is unnecessary. For the NEMA NU-4 image quality phantom, the SOR for the water chamber decreases by about 45% from 15.1% to 8.3%, and the SOR for the air chamber decreases by 31% from 12.0% to 8.3% at the LLDs of 150 and 350 keV, without obvious change in uniformity, further supporting the simulation based optimization. The optimization described in this work is not limited to PETbox4, but also applicable or helpful to other small inner diameter geometry scanners.
Collapse
|
55
|
Gu Z, Fang W, Guo X, Ji C, Mao T. F-064 * COMPARISON OF PULMONARY FUNCTION AFTER VIDEO-ASSISTED THORACOSCOPIC LOBECTOMY AND LIMITED RESECTIONS FOR EARLY STAGE LUNG CANCER. Interact Cardiovasc Thorac Surg 2014. [DOI: 10.1093/icvts/ivu167.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
56
|
Yang B, Chen H, Gu Z, Tian F, Ross RP, Stanton C, Chen YQ, Chen W, Zhang H. Synthesis of conjugated linoleic acid by the linoleate isomerase complex in food-derived lactobacilli. J Appl Microbiol 2014; 117:430-9. [PMID: 24750362 DOI: 10.1111/jam.12524] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 04/11/2014] [Accepted: 04/11/2014] [Indexed: 12/20/2022]
Abstract
AIMS To assess strains of lactobacilli for their capacity to produce functional fatty acid-conjugated linoleic acid. To assess the linoleate isomerase for CLA production in the most efficient CLA producer. METHODS AND RESULTS In this study, strains of food-derived lactobacilli were cultured in media with linoleic acid and CLA production was assessed. Most of the selected strains produced CLA at different levels, with Lactobacillus plantarum ZS2058 being the most efficient CLA producer converting over 50% of linoleic acid to c9, t11-CLA and t9, t11-CLA. Some intermediates 10-hydroxy-cis-12-octadecenoic acid, 10-oxo-cis-12-octadecenoic acid and 10-oxo-trans-11-octadecenoic acid were determined via GC-MS. The genes coding the multicomponent linoleate isomerase containing myosin-cross-reactive antigen, short-chain dehydrogenase/oxidoreductase and acetoacetate decarboxylase for CLA production in Lact. plantarum ZS2058 were cloned and expressed in Escherichia coli. With the mixture of recombinant E. coli, c9, t11-CLA and three kinds of intermediates were produced from linoleic acid, which were in line with those in the lactobacilli. CONCLUSIONS The ability for CLA production by lactobacilli exhibited variation. Lactobacillus plantarum and Lact. bulgaricus were the most efficient producers in the selected strains. Lact. plantarum ZS2058 converted linoleic acid to CLAs with 10-hydroxy-cis-12-octadecenoic acid, 10-oxo-cis-12-octadecenoic acid and 10-oxo-trans-11-octadecenoic acid as intermediates. The multiple-step reactions for CLA production catalysed by multicomponent linoleate isomerase in Lact. plantarum ZS2058 were confirmed successfully. SIGNIFICANCE AND IMPACT OF THE STUDY Multicomponent linoleate isomerase provides important results for the illustration of the mechanism for CLA production in lactic acid bacteria. Food-derived lactobacilli with CLA production ability offers novel opportunities for functional foods development.
Collapse
|
57
|
Liu S, Ma L, Tan R, Lu Q, Geng Y, Wang G, Gu Z. Safe and efficient local gene delivery into skeletal muscle via a combination of Pluronic L64 and modified electrotransfer. Gene Ther 2014; 21:558-65. [PMID: 24694536 DOI: 10.1038/gt.2014.27] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/25/2013] [Accepted: 01/24/2014] [Indexed: 11/09/2022]
Abstract
Efficient DNA electrotransfer into muscles can be achieved by combining two types of electronic pulses sequentially: short high-voltage (HV) pulse for the cell electropermeabilization and long low-voltage (LV) pulse for the DNA electrophoresis into cells. However, the voltages currently applied can still induce histological and functional damages to tissues. Pluronic L64 has been considered as a molecule possessing cell membrane-disturbing ability. For these reasons, we hope that L64 can be used as a substitute for the HV pulse in cell membrane permeabilization, and a safe LV pulse may still keep the ability to drive plasmid DNA across the permeabilized membrane. In this work, we optimized the electrotransfer parameters to establish a safe and efficient procedure using a clinically applied instrument, and found out that the critical condition for a successful combination of electrotransfer with L64 was that the injection of plasmid/L64 mixture should be applied 1 h before the electrotransfer. In addition, we revealed that the combined procedure could not efficiently transfer plasmid into solid tumor because the uncompressed plasmid may rapidly permeate the leaky tumor vessels and flow away. Altogether, the results demonstrate that the combined procedure has the potential for plasmid-based gene therapy through safe and efficient local gene delivery into skeletal muscles.
Collapse
|
58
|
Hayden M, Banks W, Shah G, Gu Z, Sowers J. Cardiorenal metabolic syndrome and diabetic cognopathy. Cardiorenal Med 2013; 3:265-82. [PMID: 24474955 PMCID: PMC3901619 DOI: 10.1159/000357113] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 11/01/2013] [Indexed: 12/22/2022] Open
Abstract
The prevalence of the cardiorenal metabolic syndrome (CRS) is increasing in parallel with obesity, type 2 diabetes mellitus, Alzheimer's disease, and other forms of dementia. Along with metabolic, inflammatory, and immunological abnormalities, there is maladaptive structural remodeling of the heart, kidney, and brain. The term 'diabetic cognopathy' (DC) may be used when discussing functional and structural changes in the brain of the diabetic patient. DC likely represents an advanced form of these changes in the brain that evolve with increasing duration of the CRS and subsequent clinical diabetes. We posit that DC develops due to a convergence of aging, genetic and lifestyle abnormalities (overnutrition and lack of exercise), which result in multiple injurious metabolic and immunologic toxicities such as dysfunctional immune responses, oxidative stress, inflammation, insulin resistance, and dysglycemia (systemically and in the brain). These converging abnormalities may lead to endothelial blood-brain barrier tight junction/adherens junction (TJ/AJ) complex remodeling and microglia activation, which may result in neurodegeneration, impaired cognition, and dementia. Herein, we describe the brain ultrastructural changes evolving from a normal state to maladaptive remodeling in rodent models of CRS including microglia activation/polarization and attenuation and/or loss of the TJ/AJ complexes, pericytes and astrocytes of the neurovascular unit. Further, we discuss the potential relationship between these structural changes and the development of DC, potential therapeutic strategies, and future directions.
Collapse
|
59
|
Gu Z, Jiang J, Xia Y, Yue X, Yan M, Tao T, Cao X, Da Z, Liu H, Liu H, Miao Y, Li L, Wang Z. p21 is Associated with the Proliferation and Apoptosis of Bone Marrow-derived Mesenchymal Stem Cells from Non-obese Diabetic Mice. Exp Clin Endocrinol Diabetes 2013; 121:607-13. [PMID: 24277484 DOI: 10.1055/s-0033-1354380] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
60
|
Jiang DC, Tan Y, Shi S, Xu Q, Dong W, Gu Z, Zou RX. Research on new method of electron beam candle melting used for removal of P from molten Si. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/1433075x11y.0000000026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
61
|
Wu M, Xu T, Zhou Y, Lu H, Gu Z. Pressure and inflammatory stimulation induced increase of cadherin-11 is mediated by PI3K/Akt pathway in synovial fibroblasts from temporomandibular joint. Osteoarthritis Cartilage 2013; 21:1605-12. [PMID: 23916685 DOI: 10.1016/j.joca.2013.07.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/12/2013] [Accepted: 07/24/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The goal of the study was to investigate the expression of cadherin-11 in synovial fibroblasts (SFs) under mechanical or inflammatory stimuli, and its potential relationship with PI3K/Akt signaling pathway. METHODS SFs separated from rat temporomandibular joint (TMJ) were treated with hydrostatic pressures (HP) of 30, 60, 90, and 120 kPa, as well as tumor necrosis factor-α (TNF-α) for 12, 24, 48, and 72 h. The location of cadherin-11 was observed by immunofluorescence microscopy, and its expression was detected by real-time PCR and Western blot. We also studied the activation of PI3K/Akt signaling pathway in SFs with HP or TNF-α stimulation. RESULTS The results showed that increased expression of cadherin-11 could be found in the cell-cell contact site of SFs in response to HP and inflammatory stimulation. The mRNA and protein expression of cadherin-11 was positively correlated with the intensity of HP and the duration time of TNF-α treatment. Increased expression of vascular endothelial growth factor-D (VEGF-D) and activation of Akt were also found. Treatment with PI3K inhibitor LY294002 attenuated the pressure or inflammatory cytokine induction increases of cadherin-11, VEGF-D, and FGF-2 both in mRNA and protein levels. CONCLUSIONS These findings suggest that cadherin-11 may play important roles in SFs following exposure to mechanical loading and inflammatory stimulation. In addition, PI3K/Akt pathway was associated with pressure or inflammation-induced cadherin-11 expression, which may involve in the pathogenesis of temporomandibular diseases.
Collapse
|
62
|
Fang W, Guo X, Mao T, Gu Z. Radically resected node-negative squamous cell carcinoma of thoracic esophagus: recurrence pattern and indication for adjuvant therapy. J Cardiothorac Surg 2013. [PMCID: PMC3845860 DOI: 10.1186/1749-8090-8-s1-o88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
63
|
Zhang Y, Gu Z, Qiu G. Association of the polymorphism of MMP2 with the risk and severity of lumbar disc degeneration in the Chinese Han population. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2013; 17:1830-1834. [PMID: 23852912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE The present study aimed to determine whether the -735 C/T polymorphism of the Matrix Metalloproteinase 2 (MMP2) gene is associated with the risk and severity of lumbar disc degeneration (LDD) in the Chinese Han population. PATIENTS AND METHODS A total of 1008 patients with LDD and 906 healthy controls were enrolled in this study. The grade of disc degeneration was determined according to Schneiderman's classification for Magnetic Resonance Imaging (MRI). The -735 C/T polymorphism of MMP2 was genotyped using polymerase chain reaction and the restriction fragment length polymorphism method. RESULTS The genotype frequency of the -735 C/T polymorphism was in agreement with the Hardy-Weinberg equilibrium (p = 0.087). The frequencies of the -735CT and TT genotypes were significantly lower among LDD patients compared with normal controls (p < 0.001); CT and TT genotype were significantly associated with a decreased risk of LDD compared with the CC genotype (for TT genotype, p = 0.031; OR 0.413; 95% CI 0.184-0.924; for CT genotype, p < 0.001, OR 0.645, 95% CI 0.506-0.822). Patients with LDD showed significantly higher frequencies of the C allele than normal controls (p < 0.001), T allele was significantly associated with a decreased risk of LDD compared with the C allele (p < 0.001; OR 0.631; 95% CI 0.508-0.783). In addition, the -735TT and CT genotypes, as well as the T allele were associated with lower degenerative grades of LDD compared with CC genotype and the C allele, respectively (both p < 0.001). CONCLUSIONS The -735 C/T polymorphism of MMP2 may be associated with the risk and severity of LDD in the Chinese Han population.
Collapse
|
64
|
Gu Z, Taschereau R, Vu NT, Wang H, Prout DL, Silverman RW, Bai B, Stout DB, Phelps ME, Chatziioannou AF. NEMA NU-4 performance evaluation of PETbox4, a high sensitivity dedicated PET preclinical tomograph. Phys Med Biol 2013; 58:3791-814. [PMID: 23666034 DOI: 10.1088/0031-9155/58/11/3791] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PETbox4 is a new, fully tomographic bench top PET scanner dedicated to high sensitivity and high resolution imaging of mice. This manuscript characterizes the performance of the prototype system using the National Electrical Manufacturers Association NU 4-2008 standards, including studies of sensitivity, spatial resolution, energy resolution, scatter fraction, count-rate performance and image quality. The PETbox4 performance is also compared with the performance of PETbox, a previous generation limited angle tomography system. PETbox4 consists of four opposing flat-panel type detectors arranged in a box-like geometry. Each panel is made by a 24 × 50 pixelated array of 1.82 × 1.82 × 7 mm bismuth germanate scintillation crystals with a crystal pitch of 1.90 mm. Each of these scintillation arrays is coupled to two Hamamatsu H8500 photomultiplier tubes via a glass light guide. Volumetric images for a 45 × 45 × 95 mm field of view (FOV) are reconstructed with a maximum likelihood expectation maximization algorithm incorporating a system model based on a parameterized detector response. With an energy window of 150-650 keV, the peak absolute sensitivity is approximately 18% at the center of FOV. The measured crystal energy resolution ranges from 13.5% to 48.3% full width at half maximum (FWHM), with a mean of 18.0%. The intrinsic detector spatial resolution is 1.5 mm FWHM in both transverse and axial directions. The reconstructed image spatial resolution for different locations in the FOV ranges from 1.32 to 1.93 mm, with an average of 1.46 mm. The peak noise equivalent count rate for the mouse-sized phantom is 35 kcps for a total activity of 1.5 MBq (40 µCi) and the scatter fraction is 28%. The standard deviation in the uniform region of the image quality phantom is 5.7%. The recovery coefficients range from 0.10 to 0.93. In comparison to the first generation two panel PETbox system, PETbox4 achieves substantial improvements on sensitivity and spatial resolution. The overall performance demonstrates that the PETbox4 scanner is suitable for producing high quality images for molecular imaging based biomedical research.
Collapse
|
65
|
Gu Z, Chhabra AY, Alard P, Warner DR, Kosiewicz MM. FcγRI is required for TGFβ2-treated macrophage-induced tolerance. Immunobiology 2013; 218:1200-6. [PMID: 23643295 DOI: 10.1016/j.imbio.2013.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 03/04/2013] [Accepted: 04/07/2013] [Indexed: 11/29/2022]
Abstract
Macrophages treated with TGFβ2 (TGFβ2-Mϕ) and antigen are highly tolerogenic in vivo, and induce antigen-specific and long-lasting tolerance in both naïve and primed mice via induction of suppressor/regulatory T cells. In this study, we examined the molecular pathways, including the requirements for Smad-dependent signaling, that are involved in the induction and function of tolerogenic TGFβ2-Mϕ. Treatment of murine macrophages with TGFβ2 induced translocation of Smad2/3 to the nucleus, and impairment of Smad3-, but not Smad2-, dependent signaling inhibited the tolerogenic function of a TGFβ2-treated murine macrophage cell line. Gene expression in murine macrophages treated with TGFβ2 was evaluated by microarray analysis. The FcγRI gene was one of a number of immune-related genes differentially expressed in TGFβ2-Mϕ, and appeared to be critical for tolerance in this system, since TGFβ2-Mϕ from FcγRI deficient mice were unable to induce tolerance. The role that FcγRI plays in TGFβ2-Mϕ-mediated tolerance is currently unclear. The results of this study provide important information about the factors that are critical for the induction of TGFβ2-Mϕ-mediated tolerance, and a better understanding of these mechanisms could lead to the development of more effective tolerance-inducing strategies for the treatment of autoimmune/inflammatory diseases.
Collapse
|
66
|
|
67
|
Nyakiti LO, Lee RG, Gu Z, Edgar JH, Chaudhuri J. Polarity determination of rough and smooth surface grains in AlN crystals. CRYSTAL RESEARCH AND TECHNOLOGY 2012. [DOI: 10.1002/crat.201200005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
68
|
Zhou Y, Cheng Z, Wu M, Hong Z, Gu Z. Trepanation and curettage treatment for acute implant periapical lesions. Int J Oral Maxillofac Surg 2011; 41:171-5. [PMID: 22000955 DOI: 10.1016/j.ijom.2011.09.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 07/06/2011] [Accepted: 09/20/2011] [Indexed: 10/16/2022]
Abstract
Six dental implants in six patients with periapical lesions were inserted and underwent trepanation and thorough curettage. During surgery, the lesion area was irrigated with copious natural saline and chlorhexidine and the bone defects were treated with tetracycline paste. The six implants were stable and asymptomatic postoperatively. The implants were loaded after 3 months. Radiologically, the radiolucency in the apical part disappeared gradually. These prostheses have functioned satisfactorily with no further complication during the follow-up period. For cases in which small lesions initially appear soon after implant placement, trepanation and curettage of the periapical lesion without resection of the apical part of the implant or bone substitute material and/or autogenous bone grafting is an effective management option. A rapid and exact diagnosis is important for treating implant periapical lesions.
Collapse
|
69
|
Edgar J, Gu Z, Taggart K, Chaudhuri J, Nyakiti L, Lee R, Witt R. Oxidation of Aluminum Nitride for Defect Characterization. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-0892-ff21-02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe thermal oxidation of aluminum nitride was developed as a means to study defects in bulk aluminum nitride crystals. The oxidation kinetics was established for the dry oxidation of highly textured AlN polycrystals produced by sublimation-recombination crystal growth in a tungsten furnace. Despite seeding on polycrystalline tungsten, the grains were predominantly [0001] oriented as verified by electron backscattering diffraction (EBSD). The oxidation rate is dependent on the crystal’s orientation, polarity, stress, and surface condition, thus oxidation decorates grain boundaries, polishing scratches, and inversion domains by producing oxide layers of different thicknesses. The initial oxidation rate of nitrogen polar (0001) AlN is approximately 25% faster than on aluminum polar crystals. Low temperature (800 °C) dry oxidation produced an amorphous oxide layer and generated a high density of defects (vacancies, stacking faults, and dislocations) in the nitride near the oxide/nitride interface, as observed by cross-sectional transmission electron microscopy. In contrast, high temperature oxidation (1000 °C) produced a crystalline oxide layer, and left the nitride free of observable defects.
Collapse
|
70
|
Ngim KK, Green J, Cuzzi J, Ocampo M, Gu Z. Optimized Derivatization Procedure for Characterizing (Aminomethyl)phosphonic Acid Impurities by GC-MS. J Chromatogr Sci 2011. [DOI: 10.1093/chrsci/49.1.8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
71
|
Gravani S, Polychronopoulou K, Stolojan V, Cui Q, Gibson PN, Hinder SJ, Gu Z, Doumanidis CC, Baker MA, Rebholz C. Growth and characterization of ceria thin films and Ce-doped γ-Al2O3 nanowires using sol-gel techniques. NANOTECHNOLOGY 2010; 21:465606. [PMID: 20975211 DOI: 10.1088/0957-4484/21/46/465606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
γ-Al(2)O(3) is a well known catalyst support. The addition of Ce to γ-Al(2)O(3) is known to beneficially retard the phase transformation of γ-Al(2)O(3) to α-Al(2)O(3) and stabilize the γ-pore structure. In this work, Ce-doped γ-Al(2)O(3) nanowires have been prepared by a novel method employing an anodic aluminium oxide (AAO) template in a 0.01 M cerium nitrate solution, assisted by urea hydrolysis. Calcination at 500 °C for 6 h resulted in the crystallization of the Ce-doped AlOOH gel to form Ce-doped γ-Al(2)O(3) nanowires. Ce(3+) ions within the nanowires were present at a concentration of < 1 at.%. On the template surface, a nanocrystalline CeO(2) thin film was deposited with a cubic fluorite structure and a crystallite size of 6-7 nm. Characterization of the nanowires and thin films was performed using scanning electron microscopy, transmission electron microscopy, electron energy loss spectroscopy, x-ray photoelectron spectroscopy and x-ray diffraction. The nanowire formation mechanism and urea hydrolysis kinetics are discussed in terms of the pH evolution during the reaction. The Ce-doped γ-Al(2)O(3) nanowires are likely to find useful applications in catalysis and this novel method can be exploited further for doping alumina nanowires with other rare earth elements.
Collapse
|
72
|
Sharif MAR, Gu Z. Turbulent flow simulation behind a V-shaped flame stabilizer using a nonlinear K-E model and a smoothing algorithm. CHEM ENG COMMUN 2010. [DOI: 10.1080/00986440212092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
73
|
Gu Z, Akiyama K, Ma X, Zhang H, Feng X, Yao G, Hou Y, Lu L, Gilkeson GS, Silver RM, Zeng X, Shi S, Sun L. Transplantation of umbilical cord mesenchymal stem cells alleviates lupus nephritis in MRL/lpr mice. Lupus 2010; 19:1502-14. [PMID: 20647254 DOI: 10.1177/0961203310373782] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease, which, despite the advances in immunosuppressive medical therapies, remains potentially fatal in some patients, especially in treatment-refractory patients. This study found that transplantation of umbilical cord mesenchymal stem cells (UC-MSCs) has the same therapeutic effect as transplantation of bone marrow mesenchymal stem cells (BM-MSCs), which has been reported to be efficient in treating SLE-related symptoms in MRL/lpr mice. Multi-treatment (at the 18th, 19th, and 20th weeks of age) of 1 × 10(6) UC-MSCs was able to decrease the levels of 24-h proteinuria, serum creatinine, and anti-double-stranded DNA (dsDNA) antibody, and the extent of renal injury such as crescent formation in MRL/lpr mice. A lower, but still significant, reduction in these parameters was also observed in mice receiving a single dose of UC-MSCs (at the 18th week). UC-MSCs treatment also inhibited expression of monocyte chemotactic protein-1 (MCP-1) and high-mobility group box 1 (HMGB-1) expression in a similar fashion. UC-MSCs labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) were found in the lungs and kidneys 1 week post infusion. In addition, after 11 weeks post UC-MSCs infusion, human cells were found in kidney of UC-MSCs-treated mice. These findings indicated that UC-MSCs transplantation might be a potentially promising approach in the treatment of lupus nephritis, possibly by inhibiting MCP-1 and HMGB-1 production.
Collapse
|
74
|
Balbuena PB, Calvo SR, Callejas-Tovar R, Gu Z, Ramirez-Caballero GE, Hirunsit P, Ma Y. Challenges in the Design of Active and Durable Alloy Nanocatalysts for Fuel Cells. MODERN ASPECTS OF ELECTROCHEMISTRY 2010. [DOI: 10.1007/978-1-4419-5594-4_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
75
|
Chan P, Qin Z, Zheng Z, Zhang L, Fang X, Sun F, Gu Z, Chen S, Ma J, Meng C, Langston J, Tanner C. P2.204 A randomized, double-blind, placebo-controlled, delayed start study to assess safty, tolerability and efflcacy of green tea polyphenols in Parkinson's disease. Parkinsonism Relat Disord 2009. [DOI: 10.1016/s1353-8020(09)70555-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|