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Search Results: 1 - 10 of 1058 matches for " Hartmut Merz "
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Sensitive and reliable detection of Kit point mutation Asp 816 to Val in pathological material
Christian K?hler, Sabine Didlaukat, Alfred C Feller, Hartmut Merz
Diagnostic Pathology , 2007, DOI: 10.1186/1746-1596-2-37
Abstract: The Kit point mutation Asp 816 to Val is heterozygous which means a problem in detection by PCR because the wild-type allele is also amplified and the number of cells which bear the point mutation is in most of the cases low. Most PCR protocols use probes to block the wild-type allele during amplification with more or less satisfying result. This is why point-mutated forward primers were designed and tested for efficiency in amplification of the mutated allele.One primer combination (A) fits the most for the introduced PCR assay. It was able just to amplify the mutated allele with high specificity from different patient's materials (FFPE or blood) of varying quality and quantity. Moreover, the sensitivity for this assay was convincing because 10 ng of DNA which bears the point mutation could be detected in a total volume of 200 ng of DNA.The PCR assay is able to deal with different materials (blood and FFPE) this means quality and quantity of DNA and can be used for high-througput screening because of its robustness. Moreover, the method is easy-to-use, not labour-intensive, and easy to realise in a standard laboratory.1,000 to 8,000 incidences of human mastocytosis are reported every year in the US [1]. Human mastocytosis is characterised by accumulation of mast cells in different organs. It is a heterogenous group of disorders which can be divided into the categories cutaneous mastocytosis (CM) and systemic mastocytosis (SM) which is commonly seen in adults by histological lesions in the bone marrow and other non-cutaneous organs [2,3]. SM can be further divided into the categories indolent systemic mastocytosis (ISM), SM with an associated clonal hematologic non-mast cell lineage disease (AHNMD), aggressive sytemic mastocytosis (ASM), and mast cell leukemia (MCL). ISM is the most common form which involves skin, bone marrow, and GI tract with good prognosis for the patient. First relations between mastocytosis and activating mutations in the receptor tyrosine kin
Gastrointestinal stromal tumors with pseudocystic change mimicking a pancreatic tumor: two case reports
Ursula Pauser, Sebastian Hinz, Hartmut Merz, Alfred C Feller
Journal of Medical Case Reports , 2009, DOI: 10.1186/1752-1947-3-7592
Abstract: A 51-year-old woman and a 65-year-old man, both German, presented with abdominal cystic lesions suspected to be pancreatic pseudocysts. Both tumors were classified as gastrointestinal stromal tumors, epithelioid subtype. In one case, tumor origin in the gastric wall was confirmed by relaparotomy. In the other case, a point mutation in PDGFRalpha gene, exon 18 proved the diagnosis of gastrointestinal stromal tumor. The tumors were resected and both patients are still alive and disease-free.The differential diagnosis of cystic lesions in the upper abdomen must include gastrointestinal stromal tumors with pseudocystic change. The origin of a large cystic gastrointestinal stromal tumor may be difficult to determine. Epithelioid tumor pattern, weak or absent KIT expression and detection of PDGFRalpha mutation are typical diagnostic parameters of gastric gastrointestinal stromal tumors.Cystic lesions of the pancreas are usually pseudocysts, related to chronic pancreatitis. Some are inflammatory pseudotumors with regressive cystic change; others are solid-pseudopapillary tumors or serous or mucinous cystic neoplasms of the pancreas.The diagnostic spectrum of pancreatic cystic lesions has been well investigated. Recently, we introduced a new entity entitled solid and cystic pancreatic hamartomas with a review of the literature [1]. The diagnoses and malignant potential of cystic lesions are sometimes difficult to predict, but in general, they are simply classified by their histology. The following cases demonstrate pancreatic cystic lesions that secondarily involved the pancreas. The histological, immunohistochemical and molecular investigation led to the diagnosis of gastrointestinal stromal tumor (GIST) with pseudocystic change. The difficulties of tumor diagnosis and tumor origin are discussed.A 51-year-old woman presented with a palpable abdominal mass on physical examination. From a computed tomography (CT) scan, a cystic tumor, 20 cm in diameter, was notes to be prese
Primary NK/T cell lymphoma nasal type of the stomach with skin involvement: a case report
Sebastian Kobold,Hartmut Merz,Markus Tiemann,Carolina Mahuad
Rare Tumors , 2009, DOI: 10.4081/rt.2009.e58
Abstract: Since nasal NK/T cell lymphoma and NK/T cell lymphoma nasal type are rare diseases, gastric involvement has seldom been seen. We report a unique case of a patient with a primary NK/T cell lymphoma nasal type of the stomach with skin involvement. The patient had no history of malignant diseases and was diagnosed with hematemesis and intense bleeding from his gastric primary site. Shortly after this event, exanthemic skin lesions appeared with concordant histology to the primary site. Despite chemotherapy, the patient died one month after the first symptomatic appearance of disease.
P53 expression is significantly correlated with high risk of malignancy and epithelioid differentiation in GISTs. An immunohistochemical study of 104 cases
Ursula Pauser, Nina Schmedt auf der Günne, Günter Kl?ppel, Hartmut Merz, Alfred C Feller
BMC Cancer , 2008, DOI: 10.1186/1471-2407-8-204
Abstract: We investigated 104 KIT positive GISTs from various tumor sites in immunoassays on CD34, Ki67 and particularly on P53, BCL-2 and Cyclin D1. The results were compared with tumor size, mitotic rate, proliferative activity, histological subtype, nuclear atypia and risk assessment according to Fletcher and Miettinen. Occurrence of metastases and survival were also taken into account.The expression of P53 was significantly correlated with high risk criteria towards malignancy and epithelioid differentiation in GISTs. Likewise P53 label correlated significantly with the established prognostic indicators: tumor size, mitotic rate, nuclear atypia and proliferative activity. Regarding the site of tumor presentation, P53 was not a decisive factor. BCL-2 and Cyclin D1 expression was not related to any of the prognostic indicators.The present data identified P53 being a recommendable marker for predicting the risk of malignancy in GISTs. In addition, we found P53 significantly correlated with epithelioid tumor differentiation, independent of tumor site. BCL-2 and Cyclin D1, however, did not prove to be deciding markers for diagnosis and prognosis.In recent years, progress has been achieved in establishing accurate diagnoses of gastrointestinal stromal tumors (GISTs), elucidating their molecular pathogenesis and developing a specific treatment. GISTs are defined as mesenchymal tumors of stomach and intestine that express KIT (CD117) and show either a c-kit mutation or a mutation in the gene that encodes the platelet-derived growth factor receptor alpha (PDGFRα) [1-3]. Mutations in both genes lead to ligand independent dimerization of transmembrane tyrosine kinase receptor type III and to intracytoplasmic signal transduction via phosphorylation of tyrosine kinase [4-7]. The tyrosine kinase receptor inhibitor imatinib (Glivec ?) has proven to be highly successful for the treatment of metastasized GISTs. Currently, (neo-) adjuvant imatinib therapy is being tested in order to minimi
Self-repairing material systems―a dream or a reality?  [PDF]
Hartmut Fischer
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.28110
Abstract: Currently, most industrial materials rely entirely on passive protection mechanisms; such me chanisms are readily applicable and universal for many different materials systems. However, they will always stay passive, and therefore their lifetime and functionality is limited and related to the amount of protective additives and the intensity of their consumption. Therefore, better, and preferentially active process for the protection/repair of damaged materials―selfrepairing processes―were developed and need to be developed further. Although it sounds futuristic or like a fiction in the modern, trendy times, which in many ways affects also directions of research; self healing of material systems exists already for a long time in all sorts of systems of materials or functionalities. The aim of this work is to go beyond the scope of a classical review the ones published recently in this field which almost entirely focused only onto polymeric systems. In this work, an analysis of the underlying functional and constructional principles of existing natural and synthetically selfhealing systems spanning over a range of classes of materials is given leading to general rules and principles for the design of new and application tailored selfhealing material systems.
Gen(de)red power: Die Macht des Genres im Streit um die Frauenrolle in Pastoralbriefen und Paulusakten
Annette Merz
HTS Theological Studies/Teologiese Studies , 2012, DOI: 10.4102/hts.v68i1.1185
Abstract: Gen(de)red power: The power of genre in the debate about women’s roles in the Pastoral Letters and the Acts of Paul. Two texts that contributed to the discussion on gender roles in formative Christianity, 1 Timothy and the Acts of Paul, are investigated. In both cases the emphasis is on the much-disputed role of women. Power plays a role on different levels. On the one hand power relations between the sexes are depicted or directly addressed by the text (‘gendered’ power), while on the other hand the power of persuasion is brought to bear on both male and female readers to legitimize the patriarchal, videlicet the encratitic model of gender. This is done by rhetorical means that are text-specific, but also make use of genre-specific persuasion strategies. This ‘genred power’ is still mostly unchartered territory in exegetical discussions and is therefore the focus of my investigation. Especially important in both genres are intertextual allusions to authoritative texts. Fictive self-references which enable the author (’Paul’) to correct himself are one focus of interest. Narrative strategies (i.e. character and plot development) which also have an intertextual dimension are a second focal point. The take-over of the role of Peter who denies Jesus and repents by Paul in the Acts of Thecla turns out to be of major rhetorical significance. How to cite this article: Merz, A., 2012, ‘Gen(de)red power: Die Macht des Genres im Streit um die Frauenrolle in Pastoralbriefen und Paulusakten‘, HTS Teologiese Studies/Theological Studies 68(1), #Art. 1185, 9 pages. http://dx.doi.org/10.4102/hts.v68i1.1185
Discharge Measurements In Low Flow Conditions With ADCP Technology – First Experiences In Nepal
J Merz
Journal of Hydrology and Meteorology , 2010, DOI: 10.3126/jhm.v7i1.5615
Abstract: Low flows prevail during about nine months of the year in Himalayan rivers as a result of the influence of the monsoon climate. They account for a large portion of the annual water balance and accurate information about these flows is therefore critical for water resources planning, development, management and hydropower design. Issues that occur with the neighbouring country India are often related to low flows and make exact information on low flows a prerequisite for successful transboundary water management. However, reliable and long-term information on low flows are generally not available as most basins are ungauged. In addition low flow measurements are often associated with measurement errors as measurement cross-sections change during the flood season. Changes in measurement cross-sections are natural, but need frequent re-surveying of the sections in order to obtain good quality discharge measurements. This is often done on in-frequent basis and changes between big flood events are not recorded. The equipment used for discharge measurements is rarely recalibrated leading to additional errors. Internationally, in the last two decades river and stream discharge measurements have been improved with the introduction of Acoustic Doppler Current Profiler (ADCP) technology. This new technology for hydrologic data acquirement has so far not been used extensively in the Himalayan region. First experiences with a StreamPro ADCP in Nepal as a part of a technology evaluation confirmed the commonly stated advantages of this technology compared to current-meter measurements, and showed its promising potential for various future applications including the application for accurate low flow measurements. Keywords: Discharge measurement; ADCP; low flow DOI: http://dx.doi.org/10.3126/jhm.v7i1.5615 JHM 2010; 7(1): 40-48
Designing and Verifying Communication Protocols Using Model Driven Architecture and Spin Model Checker  [PDF]
Prabhu Kaliappan, Hartmut Koenig
Journal of Software Engineering and Applications (JSEA) , 2008, DOI: 10.4236/jsea.2008.11003
Abstract: The need of communication protocols in today’s environment increases as much as the network explores. Many new kinds of protocols, e.g. for information sharing, security, etc., are being developed day-to-day which often leads to rapid, premature developments. Many protocols have not scaled to satisfy important properties like deadlock and livelock freedom, since MDA focuses on the rapid development rather than on the quality of the developed models. In order to fix the above, we introduce a 2-Phase strategy based on the UML state machine and sequence diagram. The state machine is converted into PROMELA code as a protocol model and its properties are derived from the sequence diagram as Linear Temporal Logic (LTL) through automation. The PROMELA code is interpreted through the SPIN model checker, which helps to simulate the behavior of protocol. Later the automated LTL properties are supplemented to the SPIN for the verification of protocol properties. The results are compared with the developed UML model and SPIN simulated model. Our test results impress the designer to verify the expected results with the system design and to identify the errors which are unnoticed during the design phase.
A Methodology to Assess the Safety of Aircraft Operations When Aerodrome Obstacle Standards Cannot Be Met  [PDF]
Hartmut Fricke, Christoph Thiel
Open Journal of Applied Sciences (OJAppS) , 2015, DOI: 10.4236/ojapps.2015.52007
Abstract: When Aerodrome Obstacle Standards cannot be met as a result of urban or technical development, an aeronautical study can be carried out with the permission of EASA, in conjunction with ICAO, to prove how aircrafts can achieve an equivalent level of safety. However currently, no detailed guidance for this procedure exists. This paper proposes such a safety assessment methodology in order to value obstacle clearance violations around airports. This method has already been applied to a safety case at Frankfurt Airport where a tower elevating 4 km out of threshold 25R severely violates obstacle limitation surfaces. The model data refers to a take-off and landing performance model (TLPM) computing precisely aircraft trajectories for both standard and engine out conditions at ground proximity. The generated tracks are used to estimate collision risk incrementally considering EASA/FAA, EU-OPS & ICAO clearance criteria. Normal operations are assessed with a probabilistic analysis of empirical take-off/landing track data generating the local actual navigation performance (ANP) on site. The ANP shows integration to collision risk for an aircraft with any obstacle. The obstacle is tested for clearance within a “5-step-plan” against all performance requirements for landing climb and take-off climb. The methodology thereby delivers a comprehensive risk picture: The presented safety case for Frankfurt Airport showed an equivalent safety level despite the violation of standards. The collision risk during both normal and degraded performance operations was still found to be within ICAO Collision Risk Model (CRM) limits, requiring only limited risk mitigation measures. The presented work should complement ICAO Doc 9774 Appendix 3.
Local existence result of the single dopant diffusion including cluster reactions of high order
R. Bader,W. Merz
Abstract and Applied Analysis , 2001, DOI: 10.1155/s108533750100046x
Abstract: We consider the pair diffusion process which includes clusterreactions of high order. We are able to prove a local (in time)existence result in arbitrary space dimensions. The modelincludes a nonlinear system of reaction-drift-diffusion equations,a nonlinear system of ordinary differential equations in Banachspaces, and a nonlinear elliptic equation for the electrochemicalpotential. The local existence result is based on the fixed pointtheorem of Schauder.
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