151
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Tress M, Erber M, Mapesa EU, Huth H, Müller J, Serghei A, Schick C, Eichhorn KJ, Voit B, Kremer F. Glassy Dynamics and Glass Transition in Nanometric Thin Layers of Polystyrene. Macromolecules 2010. [DOI: 10.1021/ma102031k] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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152
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Androsch R, Di Lorenzo ML, Schick C, Wunderlich B. Mesophases in polyethylene, polypropylene, and poly(1-butene). POLYMER 2010. [DOI: 10.1016/j.polymer.2010.07.033] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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153
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Emel’yanenko VN, Verevkin SP, Schick C, Stepurko EN, Roganov GN, Georgieva MK. The thermodynamic properties of S-lactic acid. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2010. [DOI: 10.1134/s0036024410090074] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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154
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Yang B, Gao Y, Zou C, Zhai Q, Zhuravlev E, Schick C. Size-dependent undercooling of pure Sn by single particle DSC measurements. CHINESE SCIENCE BULLETIN-CHINESE 2010. [DOI: 10.1007/s11434-010-3041-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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155
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Kearns KL, Whitaker KR, Ediger MD, Huth H, Schick C. Observation of low heat capacities for vapor-deposited glasses of indomethacin as determined by AC nanocalorimetry. J Chem Phys 2010; 133:014702. [DOI: 10.1063/1.3442416] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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156
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Weber T, Cammerer G, Schick C, Solbach C, Hillenbrand A, Barth TF, Henne-Bruns D, Blagieva R, Böhm BO, Reske SN, Luster M. C-11 methionine positron emission tomography/computed tomography localizes parathyroid adenomas in primary hyperparathyroidism. Horm Metab Res 2010; 42:209-14. [PMID: 20013649 DOI: 10.1055/s-0029-1243185] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In patients with primary hyperparathyroidism (pHPT), positive preoperative localization studies enable to perform a minimally invasive approach for parathyroid surgery. However, current imaging techniques are not always successful. We therefore conducted a study to determine the sensitivity of C-11 methionine positron emission tomography/computed tomography (Met-PET/CT) in localizing parathyroid adenomas in pHPT. Met-PET/CT scans of the neck and mediastinum of 33 patients undergoing parathyroidectomy for primary HPT were compared with intraoperative and histological findings. Primary HPT was caused by a single gland adenoma in 30 patients, while another 3 patients had multiglandular disease. Met-PET/CT scan correctly located a single gland adenoma in 25 out of 30 (83%) patients with pHPT, among them 2 patients with persistent disease, 7 patients with prior neck surgery, and 8 patients with concomitant thyroid nodules. In 3 patients with multiglandular disease, Met-PET/CT showed only one enlarged parathyroid gland in two individuals and was negative in the third patient. Statistical analysis found a significant correlation between true-positive results and the weight (2.42+/-4.05 g) and diameter (2.0+/-1.18 cm) of parathyroid adenomas while the subgroup with false negative findings had significantly smaller (0.98+/-0.54 cm) and lighter (0.5+/-0.38 g) glands. Sensitivity was 83% for single gland adenomas and 67% for multiglandular disease. Met-PET/CT correctly localized 83% of single gland parathyroid adenomas in patients with pHPT. However, preoperative localization of multiglandular disease due to double adenomas or parathyroid hyperplasia remained difficult.
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157
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Gotzen NA, Huth H, Schick C, Van Assche G, Neus C, Van Mele B. Phase separation in polymer blend thin films studied by differential AC chip calorimetry. POLYMER 2010. [DOI: 10.1016/j.polymer.2009.10.062] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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158
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Guns S, Kayaert P, Martens JA, Van Humbeeck J, Mathot V, Pijpers T, Zhuravlev E, Schick C, Van den Mooter G. Characterization of the copolymer poly(ethyleneglycol-g-vinylalcohol) as a potential carrier in the formulation of solid dispersions. Eur J Pharm Biopharm 2010; 74:239-47. [DOI: 10.1016/j.ejpb.2009.09.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/17/2009] [Accepted: 09/20/2009] [Indexed: 11/28/2022]
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159
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Wurm A, Ismail M, Kretzschmar B, Pospiech D, Schick C. Retarded Crystallization in Polyamide/Layered Silicates Nanocomposites caused by an Immobilized Interphase. Macromolecules 2010. [DOI: 10.1021/ma902175r] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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160
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Wurm A, Minakov AA, Schick C. Combining X-ray scattering with dielectric and calorimetric experiments for monitoring polymer crystallization. Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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161
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Mileva D, Androsch R, Zhuravlev E, Schick C. Temperature of Melting of the Mesophase of Isotactic Polypropylene. Macromolecules 2009. [DOI: 10.1021/ma901797b] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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162
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Chen W, Zhou D, Xue G, Schick C. Chip calorimetry for fast cooling and thin films: a review. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11458-009-0090-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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163
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Wurm A, Minakov A, Schick C. Simultaneous Calorimetric, Dielectric, and SAXS/WAXS Experiments During Polymer Crystallization. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/978-3-540-95968-7_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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164
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Zhou D, Huth H, Gao Y, Xue G, Schick C. Calorimetric Glass Transition of Poly(2,6-dimethyl-1,5-phenylene oxide) Thin Films. Macromolecules 2008. [DOI: 10.1021/ma8012543] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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165
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Krumme A, Lehtinen A, Adamovsky S, Schick C, Roots J, Viikna A. Crystallization behavior of some unimodal and bimodal linear low‐density polyethylenes at moderate and high supercooling. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/polb.21494] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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166
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Emel'yanenko VN, Verevkin SP, Heintz A, Schick C. Ionic liquids. Combination of combustion calorimetry with high-level quantum chemical calculations for deriving vaporization enthalpies. J Phys Chem B 2008; 112:8095-8. [PMID: 18547098 DOI: 10.1021/jp802112m] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work, the molar enthalpies of formation of the ionic liquids [C2MIM][NO3] and [C4MIM][NO3] were measured by means of combustion calorimetry. The molar enthalpy of fusion of [C2MIM][NO3] was measured using differential scanning calorimetry. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the G3MP2 theory. We have used a combination of traditional combustion calorimetry with modern high-level ab initio calculations in order to obtain the molar enthalpies of vaporization of a series of the ionic liquids under study.
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167
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Serghei A, Huth H, Schick C, Kremer F. Glassy Dynamics in Thin Polymer Layers Having a Free Upper Interface. Macromolecules 2008. [DOI: 10.1021/ma702381t] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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168
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De Santis F, Adamovsky S, Titomanlio G, Schick C. Isothermal Nanocalorimetry of Isotactic Polypropylene. Macromolecules 2007. [DOI: 10.1021/ma071491b] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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169
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Sargsyan A, Tonoyan A, Davtyan S, Schick C. The amount of immobilized polymer in PMMA SiO2 nanocomposites determined from calorimetric data. Eur Polym J 2007. [DOI: 10.1016/j.eurpolymj.2007.05.011] [Citation(s) in RCA: 301] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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170
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Minakov AA, Schick C. Ultrafast thermal processing and nanocalorimetry at heating and cooling rates up to 1 MK/s. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:073902. [PMID: 17672768 DOI: 10.1063/1.2751411] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
To generate artificial materials with advanced physical and chemical properties and to study phase transition kinetics on submillisecond time scale, an ultrafast nonadiabatic membrane nanocalorimeter was constructed. A set of commercially available membrane gauges for ultrafast nanocalorimetry has been developed. The gauges placed in a thermostat with controlled helium gas pressure and temperature can be utilized as devices for thermal processing and calorimetry with resolution of 1 nJ/K. Controlled ultrafast cooling, as well as heating, up to 10(6) K/s can be attained for nanogram samples. The maximum cooling rate is inversely proportional to the radius of the heated region of the gauge, which was in the range of 10-100 microm depending on the gauge. The minimum addenda heat capacity was 3 nJ/K. The dynamic heat-transfer problem for the temperature distribution in the membrane-gas system at ultrafast processing has been solved. The characteristic rate R(0) corresponding to quasistatic limit of the temperature change in the membrane-gas system has been found to be equal to 10(5) K/s for a 1 microm thick silicon nitride membrane in helium gas. Calorimeter performance at ultrafast rates has been verified by a set of test experiments. The method was applied for thermal processing and calorimetric measurements in a set of linear polymers. It has been established that nearly amorphous polyethylene can be obtained at a cooling rate of 10(6) K/s.
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171
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Minakov AA, Wurm A, Schick C. Superheating in linear polymers studied by ultrafast nanocalorimetry. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2007; 23:43-53. [PMID: 17510749 DOI: 10.1140/epje/i2007-10173-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 04/25/2007] [Indexed: 05/15/2023]
Abstract
To study phase transition kinetics on submillisecond time scale a sensitive ultrafast nanocalorimeter was constructed. Controlled ultrafast cooling, as well as heating, up to 10(6) K/s was attained. The method was applied for the measurements of the superheating phenomenon in a set of linear polymers: iPS, PBT, PET, and iPP. A power law relation between the superheating and the heating rate holds in the heating rate range 10(-2) - 10(4) K/s. A limiting superheating of about 10% of the melting temperature was observed at rates above 10(4) - 10(5) K/s. This limit depends on annealing conditions before sample melting. The observed superheating limit, as well as the power law, can be accounted for the internal stresses near the crystalline amorphous interface in semicrystalline polymers induced by heating, which are related to the thermal expansion gradients inherent in a semicrystalline material.
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172
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Silvestre C, Cimmino S, Duraccio D, Schick C. Isothermal Crystallization of Isotactic Poly(propylene) Studied by Superfast Calorimetry. Macromol Rapid Commun 2007. [DOI: 10.1002/marc.200600844] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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173
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Huth H, Wang LM, Schick C, Richert R. Comparing calorimetric and dielectric polarization modes in viscous 2-ethyl-1-hexanol. J Chem Phys 2007; 126:104503. [PMID: 17362071 DOI: 10.1063/1.2539105] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dielectric relaxation and dynamic heat capacity measurements are compared for 2-ethyl-1-hexanol near its glass transition temperature Tg in order to further clarify the origin of the prominent Debye-type loss peak observed in many monohydroxy alcohols and other hydrogen-bonding liquids. While the dielectric spectrum epsilon" displays two distinct polarization processes that are separated by a factor of 2000 in terms of the peak frequency, the heat capacity cp" shows only a single peak. The dielectric process with lower amplitude and higher peak frequency coincides with the calorimetric signal, whereas the large dielectric Debye signal is not associated with calorimetric modes. The authors conclude that the Debye process corresponds to a transition among states which differ in energy only in the case of an external electric field.
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174
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Merzlyakov M, Wurm A, Zorzut M, Schick C. Frequency and temperature amplitude dependence of complex heat capacity in the melting region of polymers. J MACROMOL SCI B 2006. [DOI: 10.1080/00222349908248158] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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175
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Wurm A, Merzlyakov M, Schick C. Crystallization of polymers studied by temperature-modulated techniques (TMDSC, TMDMA). J MACROMOL SCI B 2006. [DOI: 10.1080/00222349908248132] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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176
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Majumder TP, Meißner D, Schick C, Roy SK. Phase transition phenomena and the corresponding relaxation process of wheat starch–water polymer matrix studied by dielectric spectroscopic method. Carbohydr Polym 2006. [DOI: 10.1016/j.carbpol.2005.12.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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177
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Grunewald M, Ketelsen D, Heckemann RA, Zenk J, Schick C, Bison B, Anders D, Knickenberg I, Wagner M, Neuhuber W, Bickel A, Bautz W, Greess H. www.tnt-radiology.de: Teach and be taught radiology: implementation of a web-based training program based on user preferences as determined by survery. Acad Radiol 2006; 13:461-8. [PMID: 16554226 DOI: 10.1016/j.acra.2005.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 12/18/2005] [Accepted: 12/19/2005] [Indexed: 11/29/2022]
Abstract
RATIONALE AND OBJECTIVES To create a Web-based training program addressing the needs of a large, heterogeneous audience of users. MATERIALS AND METHODS We defined our target group as consisting of medical professionals who teach radiology, or who, by their own perception, would benefit from improving their radiologic image interpretation skills. We interviewed 483 members of this group, eliciting their preferences with regard to layout, interactivity, contents, and other categories (11 in total). Considering majority preferences as recommendations and using the help of a special interest group of medical students, we assembled 500 teaching cases over a 1-year period into an interactive training program and made it available on the World Wide Web. RESULTS Important preferences expressed by majorities of interviewees were: high levels of interactivity, clear layout, intuitive usability, short page load times, permissibility of saving content locally, cost-free access, consideration of user input in the site development. To our knowledge, our web program TNT-Radiology, accessible at , is the first to implement all of these recommendations simultaneously. CONCLUSIONS We have created a Web-based program usable for teaching and learning radiologic image interpretation that meets the needs of a heterogeneous target audience to an unprecedented extent.
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178
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De Santis F, Adamovsky S, Titomanlio G, Schick C. Scanning Nanocalorimetry at High Cooling Rate of Isotactic Polypropylene. Macromolecules 2006. [DOI: 10.1021/ma052525n] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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179
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Tol R, Minakov A, Adamovsky S, Mathot V, Schick C. Metastability of polymer crystallites formed at low temperature studied by ultra fast calorimetry: Polyamide 6 confined in sub-micrometer droplets vs. bulk PA6. POLYMER 2006. [DOI: 10.1016/j.polymer.2006.01.052] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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180
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Huth H, Minakov AA, Schick C. Differential AC-chip calorimeter for glass transition measurements in ultrathin films. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/polb.20921] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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181
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Pyda M, Nowak-Pyda E, Heeg J, Huth H, Minakov AA, Di Lorenzo ML, Schick C, Wunderlich B. Melting and crystallization of poly(butylene terephthalate) by temperature-modulated and superfast calorimetry. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/polb.20789] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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182
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Jansen MAG, Goossens JGP, de Wit G, Bailly C, Schick C, Koning CE. Poly(butylene terephthalate) Copolymers Obtained via Solid-State Polymerization and Melt Polymerization. A Study on the Microstructure via 13C NMR Sequence Distribution. Macromolecules 2005. [DOI: 10.1021/ma051440j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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183
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Weyer S, Huth H, Schick C. Application of an extended Tool–Narayanaswamy–Moynihan model.Part 2. Frequency and cooling rate dependence of glass transition from temperature modulated DSC. POLYMER 2005. [DOI: 10.1016/j.polymer.2005.10.097] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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184
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Serghei A, Mikhailova Y, Huth H, Schick C, Eichhorn KJ, Voit B, Kremer F. Molecular dynamics of hyperbranched polyesters in the confinement of thin films. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2005; 17:199-202. [PMID: 15912265 DOI: 10.1140/epje/i2005-10009-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Accepted: 04/05/2005] [Indexed: 05/02/2023]
Abstract
Broadband Dielectric Spectroscopy is employed to investigate the molecular dynamics in thin films of hyperbranched polyesters (type AB(1)B(2), with -OH and -OCOCH(3) as terminal groups). Three relaxation processes are detected: alpha, beta and gamma. While the latter two are not influenced by the confinement, a pronounced effect is observed on the alpha relaxation: with decreasing film thickness the slower relaxation modes of the dynamic glass transition are gradually suppressed, resulting in an increase of the average relaxation rate and in a linear decrease of the dielectric strength. This is attributed to an immobilization in confinement of the polymeric segments located at the periphery of the hyperbranched macromolecular structures.
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185
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Serghei A, Huth H, Schellenberger M, Schick C, Kremer F. Pattern formation in thin polystyrene films induced by an enhanced mobility in ambient air. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:061801. [PMID: 16089755 DOI: 10.1103/physreve.71.061801] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2004] [Revised: 02/11/2005] [Indexed: 05/03/2023]
Abstract
Thin polystyrene films (prepared in a sandwich geometry between two aluminum electrodes) develop a characteristic pattern in ambient air when kept above the glass-transition temperature, whereas they remain unchanged in vacuum or in a pure nitrogen atmosphere. Measurements by broadband dielectric spectroscopy, capacitive dilatometry, and AC calorimetry reveal that the pattern formation is initiated in ambient air by an increase in the average relaxation rate of the dynamic glass transition, which results in a corresponding reduction of the glass-transition temperature. Infrared measurements evidence that this is caused by a shift of the molecular weight distribution to lower values as a consequence of oxygen-induced chain scissions.
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186
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Minakov AA, Mordvintsev DA, Schick C. Isothermal reorganization of poly(ethylene terephthalate) revealed by fast calorimetry (1000 K s−1; 5 ms). Faraday Discuss 2005; 128:261-70. [PMID: 15658778 DOI: 10.1039/b403441d] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reorganization of semicrystalline polymers on heating is a fast process. For poly(ethylene terephthalate) (PET) heating rates of several thousand Kelvin per second are needed to prevent reorganization of unstable crystals. Utilizing a thin film vacuum gauge as a fast calorimeter we are able to extend the scanning rate range of commercial DSC's (microK s(-1) to 10 K s(-1)) to rates as high as 10000 K s(-1) on heating and cooling. Because of the fast equilibration time isothermal experiments can be performed after scanning at several thousand Kelvin per second. The dead time after such a quench is in the order of 10 ms and the time resolution is in the order of milliseconds. These ultra fast calorimeters allow us to study the kinetics of extremely fast processes in semicrystalline polymers like reorganization. For PET crystallized at 130 degrees C reorganization needs less than 40 ms between 150 degrees C and 200 degrees C. Isothermal reorganization at 223 degrees C is about two orders of magnitude faster than isothermal crystallization from the isotropic melt at the same temperature. The melt memory for the remaining structures needed for reorganization is removed 25 K above the equilibrium melting temperature of PET.
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187
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Leis S, Drenkhahn S, Schick C, Arnolt C, Schmelz M, Birklein F, Bickel A. Catecholamine release in human skin--a microdialysis study. Exp Neurol 2004; 188:86-93. [PMID: 15191805 DOI: 10.1016/j.expneurol.2004.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2003] [Revised: 02/02/2004] [Accepted: 03/10/2004] [Indexed: 10/26/2022]
Abstract
Dermal microdialysis might be a promising tool to investigate properties of sympathetic neurons in the skin as investigation of peripheral noradrenergic neurons in humans usually relies on highly variable vasoconstrictor reflexes or on indirect measurements like skin temperature recordings. To evaluate this technique, 21 experiments were performed in 15 healthy subjects with four intracutaneous microdialysis fibers (diameter, 200 microm; cutoff, 5 kDa) at hands or feet. After 60 min, saline perfusion tyramine at concentrations of 0.195 to 200 microg/ml was applied for 15 min followed by a 15-min saline perfusion again. Catecholamine concentrations were detected through high-performance liquid chromatography with electrochemical detection. Control experiments were performed in human skin homogenates with and without tyramine incubation. In vivo, norepinephrine (NE) concentration increased from 36.3 +/- 10.2 pg/ml to 84.4 +/- 18.4 pg/ml (P < 0.001) during stimulation with tyramine, dialysate dopamine (DA) concentration increased from 105.2 +/- 36.5 pg/ml to 7162.4 +/- 3972.4 pg/ml (P < 0.001). Both tyramine-induced NE and DA release were dose-dependent (NE: r = 0.438, P < 0.05; DA: r = 0.894, P < 0.001). In skin homogenates, tyramine incubation led to a significant increase of DA concentrations (387.0 +/- 34.8 pg/ml, controls: 13.2 +/- 2.4 pg/ml; P < 0.05), while NE and epinephrine levels remained unchanged. In conclusion, our experiments show that dermal microdialysis is capable of locally measuring catecholamines in human skin. This offers the opportunity to investigate the function of the peripheral sympathetic nervous system. Additional to non-enzymatic oxidation, DA increase probably reflects metabolic degradation of tyramine by non-neuronal pathways and therefore does not reflect local sympathetic innervation.
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188
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Sch�nhals A, Goering H, Schick C, Frick B, Zorn R. Glass transition of polymers confined to nanoporous glasses. Colloid Polym Sci 2004. [DOI: 10.1007/s00396-004-1106-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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189
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Rastogi R, Vellinga WP, Rastogi S, Schick C, Meijer HEH. The three-phase structure and mechanical properties of poly(ethylene terephthalate). ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20096] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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190
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Schick C, Arbogast M, Lowka K, Rzepka R, Melchers I. Continuous enhanced expression of Hsc70 but not Hsp70 in rheumatoid arthritis synovial tissue. ACTA ACUST UNITED AC 2004; 50:88-93. [PMID: 14730603 DOI: 10.1002/art.11426] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To investigate the expression of constitutive and inducible members of the Hsp70 protein family in synovial tissue of patients with rheumatoid arthritis (RA) or osteoarthritis (OA). METHODS Frozen sections of synovial tissue and isolated synovial adherent cells obtained from 17 RA patients, 5 OA patients, and 1 patient with carpal tunnel syndrome (CTS) were analyzed with specific monoclonal antibodies, by immunohistochemistry, immunocytochemistry, and immunoblotting. RESULTS Expression of the constitutive chaperone Hsc70 was increased in synovial tissue from 9 of 9 patients with RA, but was faint or undetectable in 3 of 3 samples from patients with OA. In RA samples, cells mainly of the synovial lining stained intensely for Hsc70 as well as for HLA-DR, CD14, and CD68. Also, in vitro-cultured synovial adherent cells from 8 of 9 RA patients overexpressed Hsc70 (specimens from 1 RA patient were used in both the immunochemistry and the in vitro culture studies). On immunoblots of protein extracts, the synovial and HeLa cell molecules appeared identical in size. The inducible chaperone Hsp70 was not detected in samples from any of the same 17 RA patients, except for rare, isolated cells in 3. Samples from 4 of 5 OA patients also were negative for the inducible chaperone Hsp70, and the fifth was very weakly positive. In addition, tissue from 1 patient with CTS was analyzed 10 months before diagnosis of RA. Synovial tissue from this patient showed extreme overexpression of both Hsc70 and Hsp70. CONCLUSION In RA, synovial lining cells continuously overexpress Hsc70 but not Hsp70. Hsc70 may be up-regulated due to the high activity of these cells in several respects, including antigen processing and presentation.
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Schick C, Ritter RG, Balzer JO, Thalhammer A, Vogl TJ. Hepatic artery aneurysm: treatment options. Eur Radiol 2004; 14:157-9. [PMID: 12692679 DOI: 10.1007/s00330-003-1881-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Accepted: 02/03/2003] [Indexed: 10/26/2022]
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Vogl T, Schick C, Mack M, Gstöttner W. Bildgebende Diagnostik und Differentialdiagnostik von pathologischen Prozessen des Sinus cavernosus. ROFO-FORTSCHR RONTG 2004. [DOI: 10.1055/s-2004-827447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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193
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Zahn S, Leis S, Schick C, Schmelz M, Birklein F. No alpha-adrenoreceptor-induced C-fiber activation in healthy human skin. J Appl Physiol (1985) 2003; 96:1380-4. [PMID: 14672966 DOI: 10.1152/japplphysiol.00990.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In healthy volunteers, flare responses induced by norepinephrine (NE) iontophoresis have been observed. However, as NE iontophoresis is a combined electrical and chemical stimulus axon, reflexes cannot be directly linked to pharmocological activity of NE. Different concentrations of NE, clonidine (CL), and phenylephrine (PE) (NE: 10(-10)-10(-3) M; CL and PE: 10(-8)-10(-3) M) were applied via intradermal microdialysis fibers into the skin of healthy volunteers. Simultaneously, skin blood flow was visualized by laser-Doppler imaging scans and quantified in a vasoconstriction skin area directly above the membranes to control drug effects and in expected axon reflex vasodilation areas that were 0.75 cm apart. NE, PE, and CL caused dose-dependent vasoconstriction. However, neither in the presumed axon reflex areas (quantitative analysis) nor on laser-Doppler imaging pictures (qualitative analysis) were any vasodilation observed. Even at concentrations causing maximum vasoconstriction (10(-3) M for any drug), no vasodilation was induced. Our results indicate that, in healthy human skin, exogenously supplied alpha-adrenoreceptor agonists alone do not activate nociceptors sufficiently to induce axon reflex flare.
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Schick C, Mack MG, Marzi I, Vogl TGJ. Lipohemarthrosis of the knee: MRI as an alternative to the puncture of the knee joint. Eur Radiol 2003; 13:1185-7. [PMID: 12695844 DOI: 10.1007/s00330-002-1375-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2002] [Accepted: 09/30/2002] [Indexed: 10/25/2022]
Abstract
Joint effusions are common after sports injuries. In a specific form they can be very accurate for the diagnosis of intraarticular fractures; however, assessment can be tricky. Several imaging means are compared which outline the advantages and disadvantages of each technique.
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195
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Vogl TJ, Schick C, Mack M, Gstöttner W. [Diagnostic imaging and differential diagnosis of pathological processes of the sinus cavernosus]. Radiologe 2003; 43:161-70. [PMID: 12624673 DOI: 10.1007/s00117-003-0861-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
To describe the different imaging modalities for the evaluation of pathological changes in the cavernous sinus as well as to compile criteria for differential diagnosis. Imaging of the cavernous sinus comprises the primary use of tomographic modalities such as CT or MRI. The continuing development of multislice-CT (MSCT) allows the depiction of bony structures of the cavernous sinus with a high resolution.Secondary reconstructions of the acquired data set allow a reliable evaluation especially of the bony topography including the foraminae of nerves and vessels. Uni- or bilateral structures can be visualized using contrast-enhanced CT.CT-angiography is capable of demonstrating the course of the internal carotid artery and its involvement in pathologies of the cavernous sinus, this recent achievement has only been made available by use of the current short scanning times. Contrast-enhanced MRI in axial and coronal orientation, optionally using fat saturation techniques as well as arterial and venous MRI-angiography (MRA) are used to depict the soft parts of the cavernous sinus. Care must be taken to cover all topographic detail including different signal intensities, as multiple inborn, neoplastic, infectious or traumatic changes can be present hampering the radiologic diagnosis of the cavernous sinus. Uni- and bilateral infiltration of the cavernous sinus as well as vascular involvement represent additional criteria leading to the differential diagnosis. The advent of dynamic sequences as well as diffusion and perfusion weighted MRI have broadened the spectrum of diagnostic modalities. Digital subtraction angiography as an invasive technique is used during therapeutic procedures such as the local treatment of aneurysms or carotid-cavernous fistulas.
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Schick C, Wurm A, Mohammed A. Vitrification and Devitrification of the Rigid Amorphous Fraction in Semicrystalline Polymers Revealed from Frequency Dependent Heat Capacity. POLYMER CRYSTALLIZATION 2003. [DOI: 10.1007/3-540-45851-4_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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197
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Rödel F, Hoffmann J, Haas J, Grabenbauer G, Schick C, Günther K, Sauer R, Rödel C. Expression of survivin in rectal cancer is inversely correlated to apoptosis in-vitro and in-vivo and may predict tumor response to neoadjuvant radiochemotherapy. Int J Radiat Oncol Biol Phys 2002. [DOI: 10.1016/s0360-3016(02)03229-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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198
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Schick C, Thalhammer A, Balzer JO, Abolmaali N, Vogl TJ. Cystic lymph node enlargement of the neck: filariasis as a rare differential diagnosis in MRI. Eur Radiol 2002; 12:2349-51. [PMID: 12195494 DOI: 10.1007/s00330-001-1222-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2001] [Accepted: 09/28/2001] [Indexed: 10/25/2022]
Abstract
Cervical lymph node enlargement is a common feature of most inflammatory and neoplastic entities of the head and neck. Filariasis can lead to lymphangiectasis resembling lymph node enlargement; however, this is a rare differential diagnosis in European patients. As ethnic minorities are increasing throughout Europe and personal mobility, e.g. during holidays, is increasing, such rare differential diagnoses have to be taken into consideration. We present the case of an Iraqi patient referred to as for a suspected cystic lymph node mass that was verified histologically by open MRI biopsy and proved to be a cystic manifestation of filariasis.
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Rödel F, Hoffmann J, Grabenbauer GG, Papadopoulos T, Weiss C, Günther K, Schick C, Sauer R, Rödel C. High survivin expression is associated with reduced apoptosis in rectal cancer and may predict disease-free survival after preoperative radiochemotherapy and surgical resection. Strahlenther Onkol 2002; 178:426-35. [PMID: 12240548 DOI: 10.1007/s00066-002-1003-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Spontaneous apoptosis has been shown to predict tumor response to preoperative radiochemotherapy in rectal cancer. It remains to be elucidated, however, which genetic profile determines whether a tumor is more or less prone to apoptosis. Recently, a novel member of the inhibitor of apoptosis family, designated survivin, was identified. In the present study, we investigated the impact of survivin on tumor cell apoptosis and the risk to develop distant metastases or local failure after preoperative radiochemotherapy and surgical resection. PATIENTS AND METHODS The expression of survivin, p53, bcl-2 and the apoptotic index was evaluated by immunohistochemistry on pretreatment biopsies of 54 patients with locally advanced adenocarcinoma of the rectum. Survivin expression was correlated to clinical and histopathological markers, the levels of spontaneous apoptosis, p53 and bcl-2, as well as to disease-free survival, 5-year rates of local failure and distant disease after preoperative radiochemotherapy and surgical resection. RESULTS Survivin expression inversely correlated with the apoptotic index: High survivin expression was found in 56% of rectal carcinoma biopsies with a median apoptotic index of 1.22%. Conversely, low survivin expression in tumor cells was associated with a high median apoptotic index (2.29%, p = 0.0001). High survivin expression also segregated with bcl-2 overexpression (65% bcl-2+ in tumors with high survivin expression as compared to 35% bcl-2+ in tumors with low survivin expression), but the difference was not statistically significant (p = 0.1). Low survivin expression was significantly related to an increased disease-free survival rate (77% vs 18% at 5 years in tumors with high survivin expression, p = 0.02) and to a reduced risk for distant metastases (18% vs 78% at 5 years in tumors with high survivin expression, p = 0.05) and local failure (6% vs 37% at 5 years in tumors with high survivin expression, p = 0.07). CONCLUSION An inverse correlation between survivin expression and the level of spontaneous apoptosis in pretreatment biopsies suggests that survivin strongly inhibits tumor cell apoptosis in rectal cancer. Survivin expression may provide a novel predictive indicator for disease-free survival after preoperative radiochemotherapy and surgical resection in rectal cancer.
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Jacobi V, Thalhammer A, Schick C, Peters J, Vogl T. Notched ureter sign. Eur Radiol 2002; 12:2120-2. [PMID: 12211179 DOI: 10.1007/s00330-002-1348-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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