24 research outputs found
Koinzidente Detektion von Cherenkov Photonen für medizinische Anwendungen
No full textThe detection of higher energetic gamma rays (≥ 1 MeV) is of increasing importance in
medical imaging and nuclear medicine. Especially proton therapy treatment could benefit
from the ability to measure prompt gammas emitted subsequent to the irradiation of the
patient with high-energetic sub-atomic particles like protons. Such an imaging modality
would help monitor the treatment process and ensure correct particle range and optimal dose
delivery to the tumor while sparing surrounding healthy tissue.
One potential gamma detector for medical applications is the Compton camera – a two-layer
detection system, where an incoming gamma scatters in a first detection layer and is absorbed
in a second layer. In the first layer, a Compton electron is created, which carries a large part
of the momentum information about the incoming gamma. A coincidence measurement of
energy and position of both the electron and the absorbed gamma enables to reconstruct the
gamma source location to lie on the surface of a cone. Knowledge of the electron momentum
direction enables to confine the origin to an arc. The real reconstructed source position
is obtained by the measurement and superposition of many of these cones or arcs, respectively.
In this work, a novel detection concept for the Compton scattered electron is presented and
investigated, which is based on the coincident measurement of Cherenkov photons created
by that electron in an optically transparent radiator material. The photons are emitted
along the surface of a cone with a characteristic opening angle that mainly depends on the
refractive index of the material and the velocity of the electron. The intersection of this
Cherenkov cone with a photon sensitive detector area forms a ring or an ellipse, which can
be used to reconstruct the cone and the momentum direction of the electron. The number
of emitted photons yields information on the electron energy, while the size of the ellipse
contains information on the scattering vertex position.
A first proof of this concept is provided in this thesis. In a first test set-up, a successful
coincident measurement of Cherenkov photons on an array of Silicon-Photomultipliers (SiPMs)
was performed. The photons were created by electrons from a Sr-90 source inside radiator
materials of different types and thicknesses. A coincidence time resolution of 242 ps could be
achieved using signal read-out based on an application specific integrated circuit (ASIC). The
number of detected photons could be counted with a charge integrating measurement and
analysis method using an oscilloscope. The width of the distribution of the measured patterns
was quantified and was in good agreement with predictions. All results were compared
with calculations, which were performed under consideration of electron energy and range,
detection efficiency of the SiPM, detector geometry and absorption properties of the radiator.
A sensitivity of the measured pattern to the thickness of the sample and to the position of
the electron source was observed from accumulated coincident events. These patterns also
allowed for a reconstruction of the electron source position with an accuracy better than
1 mm. In the scope of the development of the set-up and measurement method, all detector
components were investigated to find the optimal parameter settings and the most suited
radiator materials.
With an improved set-up with a different ASIC and cooled detectors a coincident light
detection on single photon level was possible. An extensive correction algorithm allowed for
a compensation of time walk effects and inherent time differences between individual ASIC
channels. The ability to count the number of detected Cherenkov photons per event and per
Silicon Photomultiplier (SiPM) channel was implemented using the Time over Threshold
(TOT) information of the SiPM signals. The average number of detected photons per event
was measured for various sample thicknesses and the results were compared to calculations
and simulations performed with Geant4.
After these first successful coincidence measurements, the detection principle was applied
to the detection of Compton scattered electrons and photo electrons created by 511 keV
photons from a Na-22 source in UV transparent Polymethyl Metacrylate (PMMA). A detection
efficiency on the order of 0.001 was found. Simulations indicate a strong increase in the
efficiency to about 3 % for higher gamma energies. The number of detected Cherenkov
photons from Compton electrons was counted and compared with simulation results. The
measured coincidence pattern from accumulated events showed response to a shift of the
gamma source position.
The ability to detect Cherenkov photons from Compton electrons in coincidence could be
successfully demonstrated. In future works, the patterns of individual events need to be used
to reconstruct the Cherenkov cone and the electron momentum direction. The achievements
in this thesis constitute a vital step towards an application of this electron detection principle
for medical purposes and could help realize prompt gamma detection in particle therapy
treatment using a Compton camera.Die Detektion höherenergetischer Gammastrahlung (≥ 1 MeV) ist von wachsender Bedeutung
für die medizinische Bildgebung und die Nuklearmedizin. Besonders die Partikeltherapie
könnte von der Möglichkeit profitieren, prompte Gammastrahlen zu messen, welche in Folge
der Bestrahlung des Patienten mit hochenergetischen, subatomaren Teilchen wie Protonen
emittiert werden. Solch ein Bildgebungsverfahren würde die Überwachung des Behand-
lungsprozesses unterstützen und dabei helfen, die korrekte Teilchenreichweite und die opti-
male Dosisverabreichung im Tumor sicherzustellen und dabei umliegendes Gewebe zu schonen.
Ein Kandidat für einen Gammadetektor in medizinischen Anwendungen ist die Compton
Camera – ein zweilagiges Detektorsystem, bei welchem ein einfallendes Gamma in einer ersten
Detektorschicht streut und in einer zweiten absorbiert wird. In der ersten Schicht wird ein
Compton-Elektron erzeugt, welches einen großen Teil der Impulsinformation des einfallenden
Gammas trägt. Eine koinzidente Messung von Energie und Position des Elektrons als auch
des gestreuten Gammas ermöglicht es, die Ursprungsrichtung des Gammas auf die Oberfläche
eines Kegels einzuschränken. Kenntnis des Elektronenimpulses ermöglicht eine Einschränkung
des Usprungs auf einen Kreisbogen. Die tatsächliche rekonstruierte Quellposition wird durch
Messung und Überlagerung vieler dieser Kegel beziehungsweise Kreisbögen gewonnen.
In dieser Arbeit wird ein neues Messkonzept für Compton-gestreute Elektronen präsentiert
und untersucht, welches auf der koinzidenten Messung von Cherenkovphotonen basiert, die
durch das Elektron in einem optisch transparenten Radiatormaterial abgestrahlt werden. Die
Photonen werden entlang der Oberfläche eines Kegels mit charakteristischem Öffnungswinkel
emittiert, welcher hauptsächlich vom Brechungsindex des Materials und der Geschwindigkeit
des Elektrons abhängt. Der Schnitt des Cherenkovkegels mit einer lichtsensitiven Detek-
torebene erzeugt einen Ring oder eine Ellipse, welche dazu verwendet werden kann, den
Kegel und die Impulsinformation des Elektrons zu rekonstruieren. Die Anzahl der emittierten
Photonen gibt Aufschluss über die Energie des Elektrons, während die Größe der Ellipse
Informationen über die Position des Compton-Streuvertex enthält.
Ein erster Machbarkeitsnachweis wird in dieser Dissertation vorgestellt. Eine erfolgreiche
Koinzidenzmessung von Cherenkovphotonen auf einem Array von Silizium-Photomultipliern
(SiPMs) wurde mit einem ersten Testaufbau durchgeführt. Die Photonen wurden von Elek-
tronen aus einer Sr-90-Quelle in Radiatormaterialien unterschiedlicher Typen und Stärken
erzeugt. Unter Verwendung einer Ausleseelektronik basierend auf einem Application Specific
Integrated Circuit (ASIC) konnte eine Koinzidenzzeitauflösung von 242 ps erreicht werden.
Die Anzahl der detektierten Photonen konnte mit einem Oszilloskop mittels Ladungsinte-
gration gezählt werden. Die Breite der Verteilung der aufgenommenen Pattern (Hitmuster
koinzidenter Photonen) wurde quantifiziert und war in guter Übereinstimmung mit Vorher-
sagen. Alle Ergebnisse wurden mit Berechnungen verglichen, welche unter Berücksichtigung
von Elektronenenergie und -reichweite, Detektionseffizienz des SiPM, Detektorgeometrie und Absorptionseigenschaften des Radiators angestellt worden waren. Es wurde eine Sensi-
tivität der gemessenen Pattern von akkumulierten Ereignissen hinsichtlich Radiatorstärke
und Quellposition beobachtet. Diese Pattern ermöglichten es des Weiteren, die Position der
Elektronenquelle mit einer Genauigkeit von unter 1 mm zu rekonstruieren. Im Rahmen der
Entwicklung des Messaufbaus und der Messmethode wurden alle Detektorkomponenten un-
tersucht, um die optimalen Einstellungen und die am besten geeigneten Radiatormaterialien
zu finden.
Mit einem verbesserten Aufbau unter Verwendung eines anderen ASICs und gekühlten
Detektoren war eine koinzidente Lichtdetektion auf Einzelphotonenniveau möglich. Ein
aufwändiger Korrekturalgorithmus ermöglichte die Kompensation von Time-Walk-Effekten
und inherenten Zeitunterschieden zwischen einzelnen Kanälen des ASICs. Die Möglichkeit,
die Anzahl detektierter Cherenkovphotonen zu zählen, wurde unter Verwendung der Time-
over-Threshold-Information der SiPM-Signale umgesetzt. Die mittlere Anzahl detektierter
Photonen pro Ereignis wurde für unterschiedliche Materialstärken gemessen und mit Berech-
nungen und Geant4-Simulationen verglichen.
Nach diesen ersten erfolgreichen Koinzidenzmessungen wurde das Detektionsprinzip für
den Nachweis von Compton- und Photoelektronen verwendet, welche in UV-transparentem
Polymethylmethacrylat (PMMA) von Photonen mit einer Energie von 511 keV aus einer
Na-22 Quelle erzeugt wurden. Es wurde eine Detektionseffizienz in der Größenordnung von
0,001 ermittelt. Simulationen deuten auf einen starken Anstieg der Effizienz auf etwa 3 % für
höherenergetische Gammas hin. Die Anzahl der detektierten Cherenkovphotonen von Comp-
tonelektronen wurde gezählt und mit Simulationsergebnissen verglichen. Die gemessenen
Koinzidenzmuster von akkumulierten Ereignissen sprachen auf eine Änderung der Position
der Gammaquelle an.
Die Möglichkeit, Cherenkovphotonen vom Comptonelektronen in Koinzidenz zu detektieren,
konnte erfolgreich nachgewiesen werden. In zukünftigen Arbeiten müssen die Pattern einzelner
Ereignisse verwendet werden, um den Cherenkovkegel und den Elektronenimpuls zu rekon-
struieren. Die Erfolge in dieser Dissertation stellen einen wesentlichen Schritt in Richtung
einer Anwendung für medizinische Zwecke dar und könnten dazu beitragen, Prompt-Gamma-
Detektion in der Partikeltherapie mittels Compton Cameras zu realisieren
Use of silicon photomultipliers for detection of Cherenkov light from Compton scattered electrons for medical imaging
No full textConflicting Choreographies? Dance as Doctrinal Expression in Ignatius’ Ephesians 19 and Acts of John 94-96
No full textIgnatius of Antioch’s epistle to the Ephesians 19 has long puzzled interpreters. In a polemical context the author pulls together different Christological topics and offers a “mythic” narration, which presents a circular dance of heavenly bodies, involving sun, moon and stars. Focusing on this enigmatic passage, the present contribution compares it to another intriguing text, namely Acts of John 94-96, which depicts a ritual dance supposedly performed by Jesus with His disciples prior to His execution. It is worth noting that each of these descriptions conveys a particular Christological message. In this contribution similarities and differences are be pointed out with the aim of bringing these two puzzling dance scenes into dialogue. It is argued that the two passages represent conflicting Christological views but, at the same time, both can be situated in the Johannine tradition. This all taken into consideration, the two pericopes can illuminate each other as well as offer valuable material for the study of the development and conflict within Johannine Christianity
Contribution of arbuscular mycorrhiza and exoenzymes to nitrogen acquisition of sorghum under drought
No full textIntroduction For low-fertile and degraded soils of sub-Saharan Africa, nitrogen (N) is often the most growth-limiting factor restricting crop yields. The often-suggested exploitation of advantageous rhizosphere traits such as enzyme secretion and/or the symbiosis with arbuscular mycorrhizal fungi (AMF) remains to be validated as a potential strategy to overcome N limitation, especially when N deficiency co-occurs with further abiotic stresses such as water scarcity. Methods Three sorghum genotypes were cultivated in soil mesocosms with a root-exclusion compartment, where only AMF could scavenge for nutrients under drought and optimal conditions. Plant carbon (C) investment into the rhizosphere and N uptake were tracked by 15 N application coupled with 13 CO 2 labeling Results Under drought, uptake of mineral 15 N by AMF from the root-exclusion compartment increased 4–12 times compared to well-watered conditions. In addition, water stress enhanced below-ground allocation of recently assimilated C into microbial biomass. Drought reduced the enzymatic potential (Vmax) of chitinase while increasing leucine aminopeptidase (LAP) activity. This suggests that N acquisition via protein mineralization in soil was relatively enhanced compared to that of chitin following moisture limitation. LAP substrate affinity (Km) was reduced by drought compared to that of chitinase with genotype-specific shifts in the rhizosphere enzyme systems observed. Conclusion Our findings suggest that below-ground C allocation activated AMF symbiosis and its associated microbiome. This not only led to a shift in enzyme-driven exploitation of distinct organic N sources but also induced a strong increase in AMF-based mineral N acquisition from the mycosphere. This trait plasticity in response to drought may be harnessed to stabilize food production from low-fertile soil under the increasingly negative impacts of droughts due to climate change
Conflicting Choreographies? Dance as Doctrinal Expression in Ignatius’ Ephesians 19 and Acts of John 94-96
No full textIgnatius of Antioch’s epistle to the Ephesians 19 has long puzzled interpreters. In a polemical context the author pulls together different Christological topics and offers a “mythic” narration, which presents a circular dance of heavenly bodies, involving sun, moon and stars. Focusing on this enigmatic passage, the present contribution compares it to another intriguing text, namely Acts of John 94-96, which depicts a ritual dance supposedly performed by Jesus with His disciples prior to His execution. It is worth noting that each of these descriptions conveys a particular Christological message. In this contribution similarities and differences are be pointed out with the aim of bringing these two puzzling dance scenes into dialogue. It is argued that the two passages represent conflicting Christological views but, at the same time, both can be situated in the Johannine tradition. This all taken into consideration, the two pericopes can illuminate each other as well as offer valuable material for the study of the development and conflict within Johannine Christianity
“… striving for the prize”: The Theological Significance of Athletic Language in Philippians 3:12-16
No full textThis study focuses on potential athletic language in Phil 3:12-16. The main focus is the question what the assumption of the presence of athletic language in this text contributes to understanding it and especially its theological meaning better. The study consists of three parts. In part 1, the author analyses the preceding and the subsequent context of Phil 3:12-16 joining the defenders of a concentric structure: 3:1-11 (A), 3:12-16 (B), 3:17-4:1 (A’). The two framing sections (A and A’) focus on the opposition between Paul and his opponents, but the main point is Paul’s command to the Philippian addressees to “stand firm in the Lord”. Part 2 contains a brief exegetical analysis of 3:12-16. Our analysis focuses on the most important words (gaining/attaining; movement; thinking) and the goal of heavenly perfection with which they are connected. In the third part we analyse the potential athletic images in 3:12-16 which finds its “anchor point” in the noun τὸ βραβεῖον in 3:14. Based on the acceptance of this noun as an agonistic terminus technicus, other verbs and nouns which are not in and of themselves referring to athletics are interpreted as having an thletic meaning in our context. The study concludes with the caution that Paul counterbalances the “effort-reward scheme” of athletic language with the “giving-receiving scheme” of his call language. In this way, Paul introduces an emphasis on the future-orientedness of the message which is characteristic of his preaching and living.Tematem niniejszego artykułu jest potencjalny język atletyki w Flp 3,12-16. Główny akcent skupia się na pytaniu, jak przyjęcie istnienia w nim języka atletyki przyczynia się do lepszego zrozumienia tego tekstu, a przede wszystkim jego teologicznej treści. Artykuł składa się z trzech części. W części pierwszej autor analizuje poprzedzający i następujący kontekst Flp 3,12-16. Przychyla się przy tym ku poglądowi zwolenników struktury koncentrycznej: 3,1-11 (A), 3,12-16 (B), 3,17-4,1 (A’). W częściach obramowania (A i A’) chodzi o polemikę Pawła z jego przeciwnikami, przy czym głównym zamiarem Pawła jest wezwanie Filipian do tego, by „mocno stali w wierze”. Część druga artykułu zawiera krótką analizę egzegetyczną tekstu 3,12-16, która jest skoncentrowana na najważniejszych pojęciach (zdobyć, ruch, myślenie) oraz na celu niebiańskiej doskonałości, z którymi te pojęcia są związane. W części trzeciej zostają zanalizowane potencjalne atletyczne obrazy w 3,12-16. W oparciu o powszechną akceptację rzeczownika τὸ βραβεῖον w 3,14 jako agonistycznego terminus technicus, inne rzeczowniki i czasowniki, które same w sobie nie mają znaczenia atletycznego, zostają zinterpretowane jako odnoszące się do atletyki w kontekście tej perykopy. Na zakończenie autor artykułu zauważa, że Paweł jako przeciwwagi dla schematu „wysiłek-nagroda”, typowego dla języka atletycznego, używa języka powołania, wprowadzając schemat „dawanie-otrzywanie”. W ten sposób Paweł podkreśla ukierunkowanie na przyszłość, które jest charakterystyczne dla przesłania, które głosi i którym żyje.Dieser Aufsatz hat die potentielle athletische Sprache in Phil 3,12-16 zum Thema. Das Hauptinteresse liegt auf der Frage, was die Annahme des Vorliegens von athletischer Sprache in diesem Text dazu beiträgt, ihn und insbesondere seinen theologischen Inhalt besser zu verstehen. Diese Untersuchung besteht aus drei Teilen. In Teil 1 analysiert der Autor den vorausgehenden und den folgenden Kontext von Phil 3,12-16. Dabei schließt sich diese Untersuchung den Vertretern einer konzentrischen Struktur an: 3,1-11 (A), 3,12-16 (B), 3,17-4,1 (A‘). In den beiden Rahmenteilen (A und A‘) geht es um die Polemik des Paulus gegenüber seinen Gegnern, wobei allerdings der Aufruf des Paulus an die Adresse der Philipper, „fest im Herrn zu stehen“, der Hauptpunkt des Paulus ist. Teil 2 enthält eine kurze exegetische Analyse von 3,12-16, welche sich auf die wichtigsten Begriffe (erreichen; Bewegung; denken) und auf das Ziel der himmlischen Vollkommenheit, mit dem sie verbunden sind, konzentriert. Im dritten Teil werden die potentiellen athletischen Bilder in 3,12-16 analysiert. Ausgehend von dem Substantiv τὸ βραβεῖον in 3,14, das allgemein als agonistischer terminus technicus akzeptiert wird, werden andere Verben und Substantive, dieals solche keine athletische Bedeutung haben, in diesem Kontext als athletisch interpretiert. Die Untersuchung schließt mit dem Hinweis, dass Paulus zum „Werke-Lohn-Schema“ der athletischen Sprache mit dem Gebrauch der Sprache der Berufung das „Geben-Empfangen-Schema“ als Gegengewicht einführt. So unterstreicht Paulus die Ausrichtung auf die Zukunft, die der Botschaft eigen ist, die er verkündet und lebt
Broiler Farms' Organization, Management, and Performance
No full textThis study provides a comprehensive view of the organization, management, and financial performance of U.S. broiler farms. Using data from USDA's Agricultural Resource Management Study (ARMS, formerly known as the Farm Costs and Returns Survey), we examine farm size, financial structure, household income, management practices, and spousal participation in decision-making. We compare broiler operations with other farming enterprises and their earnings with that of the average U.S. household. Because most of the 7 billion broilers produced in the United States in 1995 were raised under contract, we also explore the use of contracts and the effects of contracting on the broiler sector.contracting, broilers, poultry, farm characteristics, farm income, farm operator characteristics, risk management strategies, Livestock Production/Industries,
Numerical investigation reveals challenges in measuring the contrast recovery coefficients in PET
No full textObjective.Contrast recovery coefficient (CRC) is essential for image quality (IQ) assessment in positron emission tomography (PET), typically measured according to the National Electrical Manufacturers Association (NEMA) NU 2 standard. This study quantifies systematic uncertainties of the CRC measurement by a numerical investigation of the effects from scanner-independent parameters like voxel size, region-of-interest (ROI) misplacement, and sphere position on the underlying image grid.Approach.CRC measurements with 2D and 3D ROIs were performed on computer-generated images of a NEMA IQ-like phantom, using voxel sizes of 1-4 mm for sphere diameters of 5-40 mm-first in absence of noise and blurring, then with simulated spatial resolution and image noise with varying noise levels. The systematic uncertainties of the CRC measurement were quantified from above variations of scanner-independent parameters. Subsampled experimental images of a NEMA IQ phantom were additionally used to investigate the impact of ROI misplacement at different noise levels.Main results.In absence of noise and blurring, systematic uncertainties were up to 28.8% and 31.0% with 2D and 3D ROIs, respectively, for the 10 mm sphere, with the highest impact from ROI misplacement. In all cases, smaller spheres showed higher uncertainties with larger voxels. Contrary to prior assumptions, the use of 3D ROIs did not exhibit less susceptibility for parameter changes. Experimental and computer-generated images both demonstrated considerable variations on individual CRC measurements when background coefficient-of-variation exceeded 20%, despite negligible effects on mean CRC.Significance.This study underscores the effect of scanner-independent parameters on reliability, reproducibility, and comparability of CRC measurements. Our findings highlight the trade-off between the benefits of smaller voxel sizes and noise-induced CRC fluctuations, which is not considered in the current version of the NEMA IQ standards. The results furthermore warrant adjustments to the standard to accommodate the advances in sensitivity and spatial resolution of current-generation PET scanners
Morphological and biochemical alterations in the jejunum following iodoacetamide-induced colitis in rats
No full textThis study aims to describe the morphological alterations in the small and large intestines as well as the expression of some enterocyte enzymes and carriers in a rat model of iodoacetamide-induced colitis. Biopsies from the large and small intestines were taken at 1, 2, 4, 8, and 16 days postinduction and studied by light microscopy. The expressions of lactase, sucrase, aminopeptidase, and Glut-5 in the jejunum were studied by immunohistochemistry. Gene expressions of enterocyte lactase and sucrase were determined by RT-PCR using specific oligonucleotides. Microscopic examination of the large intestines revealed manifestations concordant with inflammation. Such alterations peaked at 2 days, were maintained to a lesser extent for 4 days, regressed by 8 days, and healed by 16 days. In the jejunum, the expression of lactase, sucrase, and aminopeptidase decreased 2 days after colitis induction, and recovered 2 days later. Similarly, Glut-5 expression decreased transiently with partial recovery by day 8. Compared with sham, gene expression of jejunal brush border enzymes sucrase and lactase showed a 4-fold increase in lactase and a 9-fold increase in sucrase after 4 days. We conclude that colitis can induce significant functional abnormalities in distant noninflamed small bowel regions. © 2006 NRC.Abreu Maria T, 2002, Curr Gastroenterol Rep, V4, P481, DOI 10.1007-s11894-002-0024-0; ANDERSSO.H, 1971, ACTA MED SCAND, V190, P407; ANDREWS CW, 1992, HUM PATHOL, V23, P774, DOI 10.1016-0046-8177(92)90347-6; ARVANITAKIS C, 1979, DIGESTION, V19, P259; Aube AC, 1999, NEUROGASTROENT MOTIL, V11, P55; BARADA KA, 2004, GUT S6, V53, pA46; Barada KA, 2001, LIFE SCI, V69, P3121, DOI 10.1016-S0024-3205(01)01418-7; BINDER HJ, 1970, J LAB CLIN MED, V76, P915; Brown KA, 2002, AM J GASTROENTEROL, V97, P2603; BROYART JP, 1990, BIOCHIM BIOPHYS ACTA, V1087, P61, DOI 10.1016-0167-4781(90)90121-H; Carty E, 2000, GUT, V46, P487, DOI 10.1136-gut.46.4.487; CHAKRAVA.KR, 1973, AM J DIG DIS, V18, P191, DOI 10.1007-BF01071972; CHALFIN D, 1967, AM J DIG DIS, V53, P890; DANIELSEN EM, 1989, J BIOL CHEM, V264, P13726; Darakhshan F, 1998, BIOCHEM J, V336, P361; Dieleman LA, 1996, AM J PHYSIOL-GASTR L, V271, pG130; Duluc I, 1997, J CELL SCI, V110, P1317; FABIA R, 1993, SCAND J GASTROENTERO, V28, P155, DOI 10.3109-00365529309096063; Fries W, 1999, LAB INVEST, V79, P49; HIRATA I, 1986, DIGEST DIS SCI, V31, P593, DOI 10.1007-BF01318690; Jacobson K, 1997, GASTROENTEROLOGY, V112, P156, DOI 10.1016-S0016-5085(97)70230-0; JACOBSON K, 1995, GASTROENTEROLOGY, V109, P718, DOI 10.1016-0016-5085(95)90378-X; JANKEY N, 1969, GUT, V10, P267, DOI 10.1136-gut.10.4.267; JURJUS AR, 2000, J PHARM TOXICOL METH, V50, P81; Karlinger K, 2000, EUR J RADIOL, V35, P154, DOI 10.1016-S0720-048X(00)00238-2; Kishi K, 1999, J NUTR, V129, P953; LEEPER LL, 1990, AM J PHYSIOL, V258, pG52; LEVINE JB, 1995, GASTROENTEROL CLIN N, V24, P633; LIU T, 1992, AM J PHYSIOL, V263, pG538; Miampamba M, 1999, J AUTONOM NERV SYST, V77, P140, DOI 10.1016-S0165-1838(99)00048-X; MORRIS GP, 1989, GASTROENTEROLOGY, V96, P795; Mourad FH, 2006, AM J PHYSIOL-GASTR L, V290, pG262, DOI 10.1152-ajpgi.00271.2005; NEWCOMER AD, 1967, GASTROENTEROLOGY, V53, P890; Podolsky DK, 2002, NEW ENGL J MED, V347, P417, DOI 10.1056-NEJMra020831; RAO SSC, 1987, GASTROENTEROLOGY, V93, P934; RAUL F, 1978, ENZYME, V23, P89; Rayhorn Nancy, 2002, Nurse Pract, V27, P13, DOI 10.1097-00006205-200211000-00003; SALEM SN, 1965, BRIT MED J, V1, P827; Sanovic S, 1999, AM J PATHOL, V155, P1051, DOI 10.1016-S0002-9440(10)65207-8; Satoh H, 1997, JPN J PHARMACOL, V73, P299, DOI 10.1254-jjp.73.299; Schaeffer C, 2000, GUT, V47, P192, DOI 10.1136-gut.47.2.192; Schmitz H, 1999, GASTROENTEROLOGY, V116, P301, DOI 10.1016-S0016-5085(99)70126-5; Schwarz NT, 2004, GASTROENTEROLOGY, V126, P159, DOI 10.1053-j.gastro.2003.10.060; SOULE JC, 1984, GASTROEN CLIN BIOL, V8, P800; SYMONS LEA, 1978, J PARASITOL, V64, P958, DOI 10.2307-3279552; SZABO S, 1981, SCIENCE, V214, P200, DOI 10.1126-science.7280691; Tanaka M, 1999, SCAND J GASTROENTERO, V34, P55; Washington K, 2002, AM J SURG PATHOL, V26, P1441, DOI 10.1097-00000478-200211000-00006; Zetzel L, 1942, AM J DIG DIS, V9, P74; Ziambaras T, 1996, J BIOL CHEM, V271, P123768
