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Upper bound of tunnel face stability using asymmetric yielding

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Underground Space 2018年第4期3卷 288-296页

作者： Itai Elkayam assaf klar Technion–Israel Institute of Technology HaifaIsrael Technical University of Denmark LyngbyDenmark

Although significant advancement has been made over recent years with respect to three-dimensional upper bound calculations of tun-nel facing,a considerable difference still exists between analytically and empirically based stability *** current work suggests that the difference may well be the outcome of the traditional use of Tresca yield criterion for the upper bound calculations,which,by definition,does not distinguish among the shearing modes(compression,extension,plane strain).Consequently,this paper suggests and discusses a new yield function,which allows for asymmetric *** yielding is only beneficial in the case of three-dimensional and continuous velocity fields,and therefore a numerical procedure that generates relevant kinematically admissible fields for classical upper bound cal-culation is *** procedure involves conversion from a load controlled boundary value problem to a velocity controlled problem at the limit state of *** analysis results in significantly lower upper bound values than those presented earlier(for Tresca mate-rial),and the values are much closer to the stability curves of Kimura and Mair(1981),which are commonly used in design.

关键词： Tunnels Plasticity Stability Upper bound

A hardening load transfer function for rock bolts and its calibration using distributed fiber optic sensing

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第11期15卷 2816-2830页

作者： assaf klar Ori Nissim Itai Elkayam Faculty of Civil and Environmental Engineering Technion-Israel Institute of TechnologyHaifa32000Israel

Confinement of rock bolts by the surrounding rock formation has long been recognized as a positive contributor to the pull-out behavior,yet only a few experimental works and analytical models have been reported,most of which are based on the global rock bolt response evaluated in pull-out *** paper presents a laboratory experimental setup aiming to capture the rock formation effect,while using distributed fiber optic sensing to quantify the effect of the confinement and the reinforcement pull-out behavior on a more local *** is shown that the behavior along the sample itself varies,with certain points exhibiting stress drops with crack *** edge effects related to the kinematic freedom of the grout to dilate are also ***,it was found that the mid-level response is quite similar to the average response along the *** ability to characterize the variation of the response along the sample is one of the many advantages high-resolution fiber optic sensing allows in such *** paper also offers a plasticity-based hardening load transfer function,representing a"slice"of the *** paper describes in detail the development of the model and the calibration/determination of its *** suggested model captures well the coupled behavior in which the pull-out process leads to an increase in the confining stress due to dilative behavior.

关键词： Rock bolts Distributed fiber optic sensing Pull-out tests Load transfer function Hardening model

Combining Gprof and Event-Driven Monitoring for Analyzing Distributed Programs:A Rough View of NCSA Mosaic

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Journal of Computer Science & Technology 1996年第4期11卷 427-432页

作者：彭澄廉 R.klar DepartmentofComputerScienceFudanUniversity Shanghai200433 IMMDVII，UniversityofErlangen－Nuernbery Ger

There are several purposes of analyzing a program: functional or performance analysis, debugging or, more recently, mapping a program to a new parallel or distributed architecture. In this paper, we introduce an effective method leading to the Execution Graph (EG) from a program. First,the Unix profiling tool Gprof is used to get the Execution Model (EM) of a C-program. Then the event-driven monitoring tool AICOS-SIMPLE is used to get the EG which includes not only the call graph but also the execution time table of the program. This method is suitable for analyzing modern distributed programs. As the example of the analysis, the well known HTTP protocol under the NCSA Mosaic is chosen. An EG of NCSA Mosaic on the routing level is given.

关键词： Distributed monitoring performance analysis Gprof profiling

Bacteriolytic therapy of experimental pancreatic carcinoma

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World Journal of Gastroenterology 2010年第28期16卷 3546-3552页

作者： Claudia Maletzki Michael Gock Ulrike Klier Ernst klar Michael Linnebacher Department of General VascularThoracic and Transplantation SurgerySection of Molecular Oncology and ImmunotherapyUniversity of Rostock18057 RostockGermany

AIM:To investigate the effectiveness of Clostridium novyi(***)-NT spores for the treatment of established subcutaneous pancreatic tumor in the syngeneic,immunocompetent Panc02/C57Bl/6 model. METHODS:***-NT spores were applied intravenously to animals carrying established pancreatic tumors of three different *** immune responses in peripheral blood and spleen were examined by flow ***,cytotoxic activity of lymphocytes against syngeneic tumor targets was analyzed. RESULTS:Application of spores identified,that(1) small tumors(450 mm3)responded with substantial necrosis followed by shrinkage and significant lethality most likely due to tumor lysis syndrome (n=6);and(3)an optimal treatment window exists for tumors of approximately 250 mm 3 (n=21).In this latter group,all tumor-bearing animals had complete tu-mor regression and remained free of tumor recurrence. In subsequent tumor rechallenge experiments a significant delay in tumor growth compared to the initial tumor cell inoculation was observed(tumor volume at day 28:197.8±87.3 mm 3 vs 500.1±50.9 mm3,P<0.05). These effects were accompanied by systemic activation of immune response mechanisms predominantly mediated by the innate arm of the immune system. CONCLUSION:The observed complete tumor regression is encouraging and shows that immunotherapy with ***-NT is an interesting strategy for the treatment of pancreatic carcinomas of defined sizes.

关键词： Bacteriolytic immunotherapy Clostridium novyi-NT Immune response Pancreatic carcinoma

The effect of adenovirus expressing wild-type p53 on 5-fluorouracil chemosensitivity is related to p53 status in pancreatic cancer cell lines

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World Journal of Gastroenterology 2004年第24期10卷 3583-3589页

作者： Sven Eisold Michael Linnebacher EduardRyschich DaliborAntolovic UlfHinz Ernst klar Jan Schmidt Department of General Surgery Thoracic and Vascular SurgeryUniversity of RostockSchillingallee 35D-18057 RostockGermany Molecular Pathology University of HeidelbergINFD-68120 HeidelbergGermany Department of General Surgery University of HeidelbergINFD-69120 HeidelbergGermany

AIM:There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU). Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status. METHODS:Human pancreatic cancer cell lines Capan-1^(p53mut), Capan-2^(p53wt),FAMPAC^(p53mut),PANC1^(p53mut),and rat pancreatic cancer cell lines AS^(p53wt) and DSL6A^(p53null) were used for in vitro *** infection with different ratios of Ad- p53-particles (MOI) in combination with 5-FU,proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining).In addition,DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivo studies. Tumor size,apoptosis (TUNEL) and survival were determined. RESULTS:Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing *** vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus *** in vitro and in vivo analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU. CONCLUSION:Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 *** findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.

关键词： Adenoviridae Adult Animals Antimetabolites, Antineoplastic Apoptosis Cell Division Cell Line, Tumor Combined Modality Therapy Drug Resistance, Neoplasm Female Fluorouracil Gene Expression Regulation, Neoplastic Gene Therapy Humans In Vitro Male Pancreatic Neoplasms Rats Rats, Inbred Lew Transduction, Genetic Tumor Suppressor Protein p53

Identification of differentially expressed genes after partial rat liver ischemia/reperfusion by suppression subtractive hybridization

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World Journal of Gastroenterology 2005年第9期11卷 1303-1316页

作者： Christine Fallsehr Christina Zapletal Michael Kremer Resit Demir Magnus von Knebel Doeberitz Ernst klar Institute of Molecular Pathology Department of Surgery

AIM: To identify potential diagnostic target genes in early reperfusion periods following warm liver ischemia before irreversible liver damage occurs. METHODS: We used two strategies (SSH suppression subtractive hybridization and hybridization of cDNA arrays) to determine early changes in gene expression profiles in a rat model of partial WI/R, comparing postischemic and adjacent nonischemic liver lobes. Differential gene expression was verified (WI/R; 1 h/2 h) and analyzed in more detail after warm ischemia (1 h) in a reperfusion time kinetics (0, 1, 2 and 6 h) and compared to untreated livers by Northern blot hybridizations. Protein expression was examined on Western blots and by immunohistochemistry for four differentially expressed target genes (Hsp70, Hsp27, Gadd45a and IL-1rI). RESULTS: Thirty-two individual WI/R target genes showing altered RNA levels after confirmation by Northern blot analyzes were identified. Among them, six functionally uncharacteristic expressed sequences and 26 known genes (12 induced in postischemic liver lobes, 14 with higher transcriptional expression in adjacent nonischemic liver lobes). Functional categories of the verified marker genes indicate on the one hand cellular stress and tissue damage but otherwise activation of protective cellular reactions (AP-1 transcription factors, apoptosis related genes, heat shock genes). In order to assign the transcriptional status to the biological relevant protein level we demonstrated that Hsp70, Hsp27, Gadd45a and IL-1rI were clearly up-regulated comparing postischemic and untreated rat livers, suggesting their involvement in the WI/R context. CONCLUSION: This study unveils a WI/R response gene set that will help to explore molecular pathways involved in the tissue damage after WI/R. In addition, these genes especially Hsp70 and Gadd45a might represent promising new candidates indicating WI/R liver damage.

关键词： Organ injury Liver ischemia AP-1 transcription factor Heat shock protein Gadd45A Suppression subtractive hybridization

Towards a Novel Super Current

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Journal of Applied Mathematics and Physics 2022年第7期10卷 2407-2414页

作者： Hubert klar Retired from University Freiburg Freiburg Germany

For nonrelativistic two-electron atoms, we employ a phase-amplitude method to derive an energy-dependent three-body force which controls the dynamics of the atom near the threshold for double escape. Its potential energy has been taken into account to derive beyond a static adiabatic basis a novel partial differential equation that replaces an adiabatic basis. That equation whose solutions span a Banach space has been solved exactly in the energy window near threshold. In that energy range, we find the formation of unstable electron pairs, comparable to Cooper pairs. In contrast to Cooper pairs, our pairs are bound by dominant correlation rather than by the coupling to a phonon field. These ingredients are suspected to allow for a super current independent of the temperature.

关键词： Correlation Wannier Theory Evolution Superconductivity

The Banach Space of Multiply Excited Atoms

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Journal of Applied Mathematics and Physics 2021年第12期9卷 3230-3239页

作者： Hubert klar University of Freiburg Freiburg Germany

We present, for the first time, a unified description of adiabatic collision channels and the Wannier channel in electron-atom scattering. We identify the Wannier channel as the solution of a recently presented partial differential equation of parabolic type. The kernel of that equation has been constructed near the ionization threshold. Its eigenstates are shown to be members of a Banach space. For the purpose of demonstration, this paper embeds one adiabatic channel into a Bannach space. The full set of an adiabatic spectrum will be embedded into the Wannier continuum of a Banach space in a forthcoming paper. This technique delivers amended non-adiabatic collision channnels with ebergy-dependent potentials. That dependence manifests itself as energy-dependent discontinuity at the threshold. The branch above threshold describes the double escape of electrons, whereas the branch below threshold replaces an infinity of strongly coupled adiabatic channels by one new channel. The present paper is restricted to two-electron atoms consisting only of s2 1S configurations. Our model shows new unexpected effects including an electron-electron attraction similar to a Cooper pair except that our electron pair couples only to one nucleus at rest rather than to a vibrating lattice. Our electron-electron attraction stems from a dynamic deformation of the potential surface.

关键词： Dominant Correlation Nonseparable Wave Equations Embedding of a Hilbert Space into a Banach Space

The Born-Oppenheimer Approximation Revisited

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Journal of Applied Mathematics and Physics 2020年第8期8卷 1507-1514页

作者： Hubert klar University of Freiburg Freiburg im Breisgau Germany

We present an improved Born-Oppenheimer method for the treatment of molecules. Our development is based on taking into account a portion of the kinetic energy which was inadvertently omitted by Born and Oppenheimer. Our theory replaces the set of standard atom-atom potentials by an evolution operator. In particular, in contrast to the traditional Born-Oppenheimer method our amended basis describes the so-called Wannier phenomenon which deforms potential surfaces, and traps one or more threshold electrons into an unstable equilibrium. Within our framework that trapping manifests itself as a Fresnel distribution. Finally we discover a π/2 phase jump in the evolution operator caused by the diffraction of a two-electron wave from a potential ridge.

关键词： Born-Oppenheimer Adiabaticity Wannier Phenomenon