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Kerr BA, McCabe NP, Feng W, Byzova TV. Platelets govern pre-metastatic tumor communication to bone. Oncogene 2013; 32:4319-24. [PMID: 23069656 PMCID: PMC3687027 DOI: 10.1038/onc.2012.447] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/07/2012] [Accepted: 08/09/2012] [Indexed: 12/22/2022]
Abstract
Although the survival rate for early detected cancers is high, once a cancer metastasizes to bone, it is incurable. Interestingly, patients without visible metastases display abnormal bone formation and resorption, suggesting a link between primary cancers and the bone microenvironment prior to metastasis, and this link likely facilitates preparation of the pre-metastatic niche. We hypothesized that communication with the primary tumor would result in bone remodeling alterations, and that platelets could facilitate this communication. By using three tumor models, we demonstrate that primary tumor growth stimulates bone formation measured by microcomputed tomography. Further, platelet depletion prevented tumor-induced bone formation, highlighting the importance of platelets in the communication between tumors and the bone microenvironment. Finally, we determine that platelets sequester a variety of tumor-derived proteins, TGF-β1 and MMP-1 in particular, which regulate bone formation. Thus, our data reveal that platelets function as mediators of tumor-bone communication prior to metastasis.
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Barve S, Rao R, Chaudhry K, Samak G, Gangwar R, Mir H, Bhargavi M, Isse T, Kawamoto T, Salaspuro M, Kaihovaara P, Kirpich I, Feng W, Wang Y, Liu Y, Barve S, McClain C, Zhou Z. S16 * GUT MICROBIOTA, INTESTINAL BARRIER FUNCTION, ENDOTOXEMIA AND ALCOHOLIC LIVER INJURY. Alcohol Alcohol 2013. [DOI: 10.1093/alcalc/agt087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Yang HX, Feng W, Wei JC, Zeng TS, Li ZD, Zhang LJ, Lin P, Luo RZ, He JH, Fu JH. Support vector machine-based nomogram predicts postoperative distant metastasis for patients with oesophageal squamous cell carcinoma. Br J Cancer 2013; 109:1109-16. [PMID: 23942069 PMCID: PMC3778272 DOI: 10.1038/bjc.2013.379] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/25/2013] [Accepted: 06/24/2013] [Indexed: 12/18/2022] Open
Abstract
Background: We aim to develop effective models for predicting postoperative distant metastasis for oesophageal squamous cell carcinoma (OSCC) for the purpose of guiding tailored therapy. Methods: We used data from two centres to establish training (n=319) and validation (n=164) cohorts. All patients underwent curative surgical treatment. The clinicopathological features and 23 immunomarkers detected by immunohistochemistry were involved for variable selection. We constructed eight support vector machine (SVM)-based nomograms (SVM1–SVM4 and SVM1'–SVM4'). The nomogram constructed with the training cohort was tested further with the validation cohort. Results: The outcome of the SVM1 model in predicting postoperative distant metastasis was as follows: sensitivity, 44.7% specificity, 90.9% positive predictive value, 81.0% negative predictive value, 65.6% and overall accuracy, 69.5%. The corresponding outcome of the SVM2 model was as follows: 44.7%, 92.1%, 82.9%, 65.9%, and 70.1%, respectively. The corresponding outcome of the SVM3 model was as follows: 55.3%, 93.2%, 87.5%, 70.7%, and 75.6%, respectively. The SVM4 model was the most effective nomogram in prediction, and the corresponding outcome was as follows: 56.6%, 97.7%, 95.6%, 72.3%, and 78.7%, respectively.Similar results were observed in SVM1', SVM2', SVM3', and SVM4', respectively. Conclusion: The SVM-based models integrating clinicopathological features and molecular markers as variables are helpful in selecting the patients of OSCC with high risk of postoperative distant metastasis.
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Zhou X, Gao Q, Feng W, Pan K. Immobilization of Yarrowia lipolyticaLipase on Bamboo Charcoal to Resolve ( R, S)-Phenylethanol in Organic Medium. Chem Eng Technol 2013. [DOI: 10.1002/ceat.201200672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Min S, Xiaoyan X, Fanghui P, Yamei W, Xiaoli Y, Feng W. The glioma-associated oncogene homolog 1 promotes epithelial--mesenchymal transition in human esophageal squamous cell cancer by inhibiting E-cadherin via Snail. Cancer Gene Ther 2013; 20:379-85. [PMID: 23788111 DOI: 10.1038/cgt.2013.36] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 05/19/2013] [Indexed: 02/06/2023]
Abstract
The glioma-associated oncogene homolog 1 (GLI1) family of zinc finger transcription factors is the nuclear mediator of the Hedgehog pathway that regulates genes essential for various stages of tumor development and progression. However, the role and mechanism by which high expression of GLI1 contributes to the invasion and metastasis of human esophageal squamous cell cancer (ESCC) has not been fully elucidated. In the present study, we demonstrated that GLI1 was over-expressed in human ESCC tissues, especially in ESCC tissues with deep invasion and lymph-node metastasis. Moreover, GLI1 was also over-expressed in ESCC cell lines and correlated with the aggressiveness of ESCC cell lines. In addition, GLI signaling pathway agonist purmorphamine could increase the invasion and metastasis ability of ESCC cells in vitro. There is increasing evidence for the contribution of epithelial-mesenchymal transition (EMT) to ESCC invasion and metastasis, therefore we investigated GLI1's role in EMT. Our results showed that high expression of GLI1 dampened expression of E-cadherin and enhanced the expression of Vimentin, and it also improved the expression of Snail, indicative of its role in EMT occurrence. Mechanistic studies showed that down-expression of Snail reversed GLI1 activation-regulated expression of EMT markers, suggesting the role of Snail in GLI1-mediated EMT. Taken together, our results had revealed that GLI1 could participate in the invasion and metastasis of ESCC through EMT. These studies indicated that in ESCC, GLI1 could be a useful target for cancer prevention and therapy.
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Feng W, Meyerheim HL, Mohseni K, Brovko O, Stepanyuk VS, Jedrecy N, Felici R, Kirschner J. Misfit-induced modification of structure and magnetism in O/Fe(001)-p(1×1). PHYSICAL REVIEW LETTERS 2013; 110:235503. [PMID: 25167511 DOI: 10.1103/physrevlett.110.235503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/08/2013] [Indexed: 06/03/2023]
Abstract
The geometry of oxygen atoms in hollow sites of Fe nanoislands (⊘≈1-2 nm) on Fe(001) is modified by mesoscopic misfit-induced relaxations of the island atoms. Surface x-ray diffraction, scanning tunneling microscopy, and ab initio calculations indicate a 0.3 Å increased adsorption height [0.7 Å versus 0.4 Å in O/Fe(001)-p(1×1)] of O atoms going in parallel with a reduced Fe-Fe layer spacing inducing a reduction of the surface magnetic moment (2.85μ(B) versus 3.2μ(B)). Our results demonstrate the importance of the mesoscopic misfit for surface physical properties in general.
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Chu A, Feng W, Lincoln H, Su F, Nath R. SU-E-T-118: Small Dynamic Field Dosimetry by Gfachromic Film (EBT3) and 2D-Array Diode. Med Phys 2013. [DOI: 10.1118/1.4814553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Chu A, Deng J, Feng W, Chen Z, Ahmad M, Nath R. SU-E-T-100: The Influence Edge Electrons in Small Fields: Emphasis by the Difference of Copper-Cerrobend Cutout. Med Phys 2013. [DOI: 10.1118/1.4814535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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134
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Feng W, Xuan Y, Chu A, Hu J. WE-C-116-12: Camer-Rao Lower Bound Analysis of 1H Magnetic Resonance Spectroscopic Imaging for Breast with Singular Value Decomposition, LCModel and QUEST. Med Phys 2013. [DOI: 10.1118/1.4815574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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135
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Chang J, Newman G, DeWyngaert K, Feng W. TH-C-116-01: Managing Treatment Planning Systems. Med Phys 2013. [DOI: 10.1118/1.4815794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Cai B, Zhang J, Zhang M, Li L, Feng W, An Z, Wang L. Micro-inflammation Characterized by Disturbed Treg/Teff Balance with Increasing sIL-2R in Patients with Type 2 Diabetes. Exp Clin Endocrinol Diabetes 2013; 121:214-9. [PMID: 23595796 DOI: 10.1055/s-0033-1333687] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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137
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Feng W, Lee A, Fang F, Shang Q, Wang J, Liu M, Yu C. Comparing the mitral leaflet geometric differences between ischemic mitral regurgitation associated with anterior and inferior myocardial infarction. Int J Cardiol 2013. [DOI: 10.1016/s0167-5273(13)70566-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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138
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Wang J, Fang F, Feng W, Yu C, Lam Y. Characterization of changes of left ventricular performance in patients with heart failure and normal ejection fraction by exercise echocardiography. Int J Cardiol 2013. [DOI: 10.1016/s0167-5273(13)70590-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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139
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Yang CX, Li CY, Feng W. Toll-like receptor 4 genetic variants and prognosis of breast cancer. ACTA ACUST UNITED AC 2013; 81:221-6. [PMID: 23510418 DOI: 10.1111/tan.12096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/02/2013] [Accepted: 02/15/2013] [Indexed: 12/24/2022]
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Fenli S, Feng W, Ronghua Z, Huande L. Biochemical mechanism studies of venlafaxine by metabonomic method in rat model of depression. EUROPEAN REVIEW FOR MEDICAL AND PHARMACOLOGICAL SCIENCES 2013; 17:41-48. [PMID: 23329522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND Venlafaxine is a new antidepressant that has a chemical structure and neuropharmacologic profile distinct from those of existing antidepressants. The studies about the mechanism of pharmacological action of venlafaxine mostly investigated the effects of venlafaxine on 5-hydroxytryptamine (5-HT), norepinephrine (NE) and dopamine (DA) levels, while only few studies examined the effects on the metabolites levels and ratio of these monoamines neurotransmitters. AIM To study the biochemical mechanism of venlafaxine through determining the metabolism of monoamine neurotransmitters in brain tissues of rat model of depression after administration of venlafaxine using metabonomic method. MATERIALS AND METHODS The rat model of depression was established by using the methods of separation and chronic unpredictable stress. We have determined 5-HT, NE, DA and their metabolites, i.e., 5-hydroxyindole-3-acetic acid (5-HIAA), 4-hydroxy-3-methoxyphenylglycol (MHPG) sulfate, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in rat brain tissues by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) following chronic administration of different venlafaxine doses (8, 16, 32 mg·kg-1) and saline solution for 14 days. Linear discriminant analysis (LDA) and principal components analysis (PCA) were used in data analysis of metabonomic. RESULTS Compared with saline, venlafaxine could significantly increase brain 5-HT and NE levels at middle dose (16 mg·kg-1) or high dose (32 mg·kg-1), especially at middle dose. These increases were greater than those seen with the comparable dose of selective serotonin reuptake inhibitor (SSRI), fluoxetine, under the same experimental conditions. CONCLUSIONS Venlafaxine lowers brain neurotransmitter metabolite levels by decreasing brain neurotransmitters turnover. Venlafaxine could correct the disorder of neurotransmitters' metabolism and coordinate the balance of 5-HT, NE and DA to reach the anti-depressed function.
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Ng J, Horowitz D, Yan P, Schweizer M, Feng W, Chao K, Brenner D, Hei T, Shuryak I, Cheng S. Comparing Lung Dosimetry and Secondary Malignancy Risks Associated With Stereotactic Body Radiation Therapy (SBRT) Using Intensity Modulated Radiation Therapy (IMRT), Coplanar Volumetric Modulated Arc Therapy (VMAT), and Noncoplanar Volumetric Modulated Arc Therapy Techniques. Int J Radiat Oncol Biol Phys 2012. [DOI: 10.1016/j.ijrobp.2012.07.1568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Feng W, Wu B, Phan J, Dale J, Wang M, Young A. An integrated cancer biomarker information system. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2012; 2005:2851-4. [PMID: 17282837 DOI: 10.1109/iembs.2005.1617068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rapid progress in functional genomics is yielding unparalleled opportunities for cancer biomarker discovery. Several procedures including data collection, analysis, verification, and visualization are necessary to identify cancer biomarkers from continuously updated microarray data, which are derived from multiple tissue sources using various methods. BioMarker is designed to integrate these procedures in a user-friendly manner, for practical application by cancer researcher and clinicians. From the feedback of clinical and research application, BioMarker is the first effort to provide a system that facilitates all aspects of biomarker discovery from microarray datasets.
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Chen X, Chen Q, Zhang P, Feng W, Blackall PJ. Evaluation of a PCR test for the detection of Haemophilus paragallinarum in China. Avian Pathol 2012; 27:296-300. [PMID: 18484001 DOI: 10.1080/03079459808419339] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The application of a recently described PCR test for the detection of Haemophilus paragallinarum in China is described. The test was used to examine a total of 127 chickens sourced from a challenge trial (38 chickens), a respiratory disease-free experimental chicken farm (50 chickens) and eight farms with suspect infectious coryza (IC) outbreaks (39 chickens). The PCR results were compared with traditional culture. The PCR detected 14/14 infected birds in the challenge trial as compared with 13/14 for culture. The 50 chickens from the disease-free experimental farm were all negative by both PCR and culture. PCR yielded 15/39 birds and 6/8 commercial farms positive as compared with 8/39 birds and 4/8 farms positive by culture. All farms positive by PCR had chickens showing the typical clinical signs of IC, indicating that culture failed to confirm coryza on two farms that had the typical clinical signs of the disease. Although chickens on two commercial farms were thought initially to be suffering from coryza, detailed clinical examination yielded no birds with typical clinical signs. The 12 chickens examined from these two farms were negative by both PCR and culture. The results suggest that the PCR test for H. paragallinarum is a suitable alternative to culture even under the typical field and laboratory conditions that operate in China.
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Carvalho D, Bjerke L, Bax D, Chen L, Kozarewa I, Baker S, Grundy R, Ashworth A, Lord C, Hargrave D, Reis RM, Jones C, Bender S, Feng W, Jones DT, Kool M, Cin H, Pleier S, Hutter S, Sturm D, Liu HK, Korshunov A, Lichter P, Pfister SM, Alimova I, Birks DK, Harris P, Venkataraman S, Marquez VE, Foreman NK, Vibhakar R, Whiteway S, Harris P, Venkataraman S, Birks DK, Donson A, Foreman NK, Vibhakar R, Xipell E, Jauregui P, Gonzalez M, tejada-solis S, Diez-Valle R, Tunon T, Zazpe I, Zazpe I, Mora J, Carcaboso AM, Gomez-MAnzano C, Fueyo J, Alonso M, Dorris K, Sobo M, Holden P, Panditharatna E, Li S, Margol A, Stephenson C, Miles L, Goldman S, Asgharzadeh S, Onar A, Fouladi M, Drissi R, Erdreich-Epstein A, Ren X, Zhou H, Snyder K, Stamper M, Perez J, Nazarian J, Gershon T, Crowther A, Garcia I, Gama V, Yuan H, Chang S, Deshmukh M, Hutt M, Goldstein W, Nazarian J, Price A, Lim KJ, Warren K, Chang H, Eberhart CG, Raabe EH, Karakoula K, Phipps KP, Harkness W, Hayward R, Thompson D, Jacques TS, Darling JL, Warr TJ, Guldal C, Potts C, Rotenberry R, Kenney AM, Amani V, Griesinger AM, Donson AM, Bemis LT, Birks DK, Schittone SK, Morgan M, Thorburn A, Foreman NK, Mulcahy-Levy J, Kolkowitz I, Andor N, Jensen T, Banerjee A, Gupta N, Petritsch C, Taylor M, Hashizume R, Tom M, Haas-Kogan D, Mueller S, Stearns D, Ma N, Eberhart CG, Levy R, Gate D, Rodriguez J, Breunig J, Danielpour M, Town T. LAB-PEDIATRICS LABORATORY RESEARCH. Neuro Oncol 2012; 14:vi116-vi119. [PMCID: PMC3488789 DOI: 10.1093/neuonc/nos235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023] Open
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Wu H, Liu M, Wang S, Zhao H, Yao W, Feng W, Yan M, Tang Y, Wei M. Comparative fasting bioavailability and pharmacokinetic properties of 2 formulations of glucosamine hydrochloride in healthy Chinese adult male volunteers. ARZNEIMITTEL-FORSCHUNG 2012; 62:367-371. [PMID: 22791244 DOI: 10.1055/s-0032-1312650] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Glucosamine (CAS 66-84-2) hydrochloride is an amino monosaccharide indicated for the treatment of arthrosis, especially osteoarthritis of the knee joint. This study was conducted to assess and compare the pharmacokinetic (PK) properties, bioavailability of a newly developed dispersible tablet formulation (test) of glucosamine hydrochloride with those of an established branded capsule formulation (reference) in healthy Chinese adult male volunteers.This single-dose, randomized, open-label, 2-period crossover study was conducted in 18 healthy Chinese adult male volunteers under fasting condition. Plasma samples were collected at pre-specified times over a 12-h period following administration in each period and analyzed the plasma glucosamine concentrations by Liquid Chromatography coupled with Tandem Mass Spectrometry (LC/MS/MS) method. The mean (SD) PK parameters of Cmax, Tmax, AUC0-12, and AUC0-∞ after administration of the test and reference formulations were, respectively, as follows: Cmax, 907.01 (444.22) vs. 944.40 (429.89) ng/mL, Tmax, 3.03 (0.95) vs. 3.30 (0.99) hours, AUC0-12, 2891.41 (1352.30) vs. 2889.69 (925.48) ng/mL/h, and AUC0-∞, 3029.90 (1321.36) vs. 3091.87 (870.36) ng/mL/h. The mean (SD) t1/2 was 1.10 (0.52) hours for the test formulation and 1.50 (1.17) hours for the reference formulation. On ANOVA, neither period nor sequence effects were observed for any PK properties. The relative bioavailability of the test formulation was 98.3% assessed by AUC0-12. The 90% CIs of glucosamine for the log-transformed ratios of Cmax, AUC0-12, and AUC0-∞ were 78.4-113.9%, 80.8-108.5% and 80.8-105.8%, respectively, meeting the predetermined criteria for bioequivalence of SFDA.
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Feng W, Xuan Y, Chu A, Hu J. TU-G-217A-08: Camer-Rao Lower Bound Analysis of 1H Magnetic Resonance Spectroscopic Imaging for Breast With Singular Value Decomposition Method and Linear Combination Method. Med Phys 2012. [DOI: 10.1118/1.4736031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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147
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Chu A, Feng W, Chen Z, Nath R. SU-E-T-356: Dose Response of a 2D Diode Array for Non-Primary Photon Radiation from a Dynamic MLC. Med Phys 2012. [DOI: 10.1118/1.4735443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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148
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Chu A, Feng W, Ahmad M, Chen Z, Nath R. SU-E-T-269: The Evaluation of Copper as an Alternative for Cerrobend Electron Shielding. Med Phys 2012; 39:3765. [PMID: 28517300 DOI: 10.1118/1.4735336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate the replacement of Cerrobend by copper for electron beam cutouts. METHODS The dosimetric comparisons for circular copper-and Cerrobend-cutouts with diameters (1.0, 2.0, 3.0, 5.0, 7.5, 10.0, and 12.5 cm) were made using electron beams with energies (6, 9, 12, 16, and 20 MeV) from 3 Varian accelerators. A PTW Farmer chamber (0.125cc-volume) was used for larger cutouts (diameters > 2cm), and an electron-diode for the 2 smallest cutouts. Also a Markus parallel plate chamber was used. RESULTS (1) The tests showed little difference for the electron dosimetric characteristics, Eo, Eop, R50, Rp, and dmax. For larger cutout, the parameters were virtually the same for copper and Cerrobend. for smaller cutout (diameter = 3cm), small discrepancies were observed i.e. differences < 1mm for R50, Rp and dmax, =0.1MeV for Eop, and =0.3MeV for Eo. (2) The larger-cutout outputs at dmax were also virtually the same (difference = 0.6%). For smaller cutouts (diameters = 3cm), the copper outputs were 2.0%∼5.0% higher than Cerrobend. (3) For lower energy electrons (<12MeV), more larger-angle scattered electrons from higher-Z Cerrobend raise the Cerrobend percentage-depth-dose (PDD) curve at shallow-depths, and more forward scatter dose after dmax from lower-Z copper shifts the copper PDD slightly away from the one of Cerrobend. for higher energy electrons (= 12MeV), the shallow-dose difference becomes smaller for both cutouts, but even more forward-scattered dose from copper shifts copper's PDD further away from Cerrobend's. (4) The higher X-ray transmission through copper is also observable; i.e. 12%, 10%, and 7% for 20MeV, 16MeV, and 12MeV, respectively, but such small transmitted amount is clinically insignificant. CONCLUSIONS Except for a higher x-ray transmission, other dosimetric differences brought in by the replacement of Cerrobend by copper cutout are negligible.
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Meyerheim HL, Ernst A, Mohseni K, Maznichenko IV, Ostanin S, Klimenta F, Jedrecy N, Feng W, Mertig I, Felici R, Kirschner J. BaTiO3(001)-(2×1): surface structure and spin density. PHYSICAL REVIEW LETTERS 2012; 108:215502. [PMID: 23003278 DOI: 10.1103/physrevlett.108.215502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Indexed: 06/01/2023]
Abstract
Using surface x-ray diffraction and ab initio calculations we present a model of the BaTiO3(001)-(2×1) surface structure, which has not been considered so far. While the crystal is terminated by two TiO2 layers similarly to SrTiO3(001)-(2×1), we find that one out of two surface layer Ti-atoms resides in a tetragonal pyramidal oxygen environment. This peculiar geometry leads to a metallic and magnetic surface involving local magnetic moments up to 2μ(B) in magnitude located at surface Ti and O atoms. Our results are important for the understanding of the intrinsic surface metallicity of insulating oxides in general.
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Sidorov E, Reynolds M, Feng W, Selim M. Cost-Minimization Analysis of CT vs. MRI in the Evaluation of Patients with Transient Ischemic Attacks at a Large Academic Center (P05.224). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.p05.224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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