926 resultados para In situ high pressure 129Xe NMR spectroscopy


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Hepatitis A virus (HAV) replicates relatively slowly in cell culture without a cytopathic effect, a fact that limits the use of tissue culture assays. The radioimmunofocus assay is the standard method for HAV titration, although it is labor intensive and requires the use of radioisotopes. A simple, rapid and objective infectivity assay based on an in situ enzyme immunoassay (EIA) is described here for a Brazilian cell culture-adapted HAV strain (HAF-203). The assay uses a peroxidase-labeled polyclonal antibody to fixed monolayers as an indicator of infection. EIA may be completed within 7 days using serial 5-fold dilutions of the virus, yielding a titer of 5.024 log 50% tissue culture infective dose (TCID50)/ml for HAF-203. This technique had a detection limit of 1.1 log TCID50/ml and the specificity was demonstrated by detecting no reaction on the columns of uninfected wells. The reproducibility (with intra- and inter-assay coefficients of variation ranging from 1.9 to 3.8% and from 3.5 to 9.9%, respectively) and quantitation of the assay were demonstrated by close agreement in virus infectivity titers among different assays of the same amount of virus and between assays of different amounts of virus. Furthermore, this assay does not require the use of radiolabeled antibodies. We describe here an efficient EIA that is highly reproducible and that could be used to monitor HAV growth in cell culture and to determine the quantity of HAV antigen needed for diagnostic assays. This is the first report of the infectious titer of the Brazilian cell culture-adapted HAV strain (HAF-203).

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Over the last 30 years, new technologies and globalization have radically changed the way in which marketing is conducted. However, whereas their effects on business in general have been widely discussed, the focus of the effects on marketing remains without clear recognition. Global research has been made to shed light onto the issue, but it has widely concentrated on the views of executives as well as the consumer markets. In addition, a research gap is existent in applying the concept of marketing change in a specific business-to-business (B2B) industry. Therefore, the main research question this study seeks to answer is: “How is contemporary marketing conducted in the high-technology industry?” In this research, the researcher considers the specific industry of high-technology. However, as the industry is comprised of differing markets, the focus will be given to one of the industry’s prime sectors – the information technology (IT) markets, where companies offer other firms products or services manufactured with advanced technology. The growing IT-market is considered of critical importance in the economies of technologically ready countries such as Finland, where this research is also conducted. Through multiple case studies the researcher aims to describe how the changes in technology, customer engagement and future trends have shaped the way in which successful high-tech marketing is conducted in today’s marketplace. Then, results derived from the empirical research are presented to the reader with links to existing literature. As a conclusion, a generalized framework is constructed to depict and ideal marketer-customer relationship, with emphasis on dynamic, two-way communication and its supporting elements of customer analytics, change adaptation, strategic customer communication and organizational support. From a managerial point of view, the research may provide beneficial information as contemporary marketing can yield profitable outcomes if managed correctly. As a new way to grasp competitive advantage, strategic marketing is much more data-driven and customer-focused than ever before. The study can also prove to be relevant for the academic communities, while its results may act as inspiring for new focus on the education trends of future marketers. This study was limited to the internal activities done at the high-tech industry, leaving out the considerations for co-marketing, marketing via business partners or marketing at other B2B-industries.

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Human epidermal growth factor receptor 2 (HER2) has been evaluated in breast cancer patients to identify those most likely to benefit from herceptin-targeted therapy. HER2 amplification, detected in 20-30% of invasive breast tumors, is associated with reduced survival and metastasis. The most frequently used technique for evaluating HER2 protein status as a routine procedure is immunohistochemistry (IHC). HER2 copy number alterations have also been evaluated by fluorescence in situ hybridization (FISH) in moderate immunoexpression (IHC 2+) cases. An alternative procedure to evaluate gene amplification is chromogenic in situhybridization (CISH), which has some advantages over FISH, including the correlation between HER2 status and morphological features. Other methodologies have also been used, such as silver-enhanced in situ hybridization (SISH) and quantitative real-time RT-PCR, to determine the number of HER2 gene copies and expression, respectively. Here we will present a short and comprehensive review of the current advances concerning HER2 evaluation in human breast cancer.

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We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT2R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT2R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca2+-free medium or the subsequent tonic constrictions induced by the addition of Ca2+ in the absence of agonists. Thus, the contractions induced by Ca2+ release from intracellular stores and Ca2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca2+. Neither levels of angiotensins nor of AT2R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca2+ entry.

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Finnish Defence Studies is published under the auspices of the War College, and the contributions reflect the fields of research and teaching of the College. Finnish Defence Studies will occasionally feature documentation on Finnish Security Policy. Views expressed are those of the authors and do not necessarily imply endorsement by the War College.

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The purpose of this qualitative research is to study how international new ventures change internally during initial internationalization. Based on the analysis of seven INV firms, a framework illustrating this change process, will be developed. This research will also develop earlier theories, and create a solid combination of existing theories to explain the phenomenon. INV firms internationalize more rapidly and aggressively than traditional MNEs. At the same, external and internal drivers cause changes in INVs culture, resources, capabilities, strategic management, and output decisions inside the company. Organizational learning and resource acquisition through international business networks explain how INVs are able to cope with the dynamic high-technology industry and be able to adapt. Internationalization of INVs proceeds through several phases, which may be gone through rapidly due to the network effects and INVs’ special characteristics. The results of this research revealed that INVs internal change process proceeds through four phases; pre-incorporation phase, product development phase, internationalization and growth phase, and maturation phase. INVs culture, resources, capabilities, strategic management, and outputs change significantly during initial internationalization, and INVs develop from small start-ups into fully established companies.

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This pilot study developed a climate instrument which was administered in a sample of high schools in one board of education. Several tests were conducted i n order to determine the reliability and internal consistency of the instrument . The ability of the instrument to identify the demographic differences of school and gender was also tested. The relationship between leadership styles and an effective use of authority in creating a productive and rewarding work environment was the f ocus of t his study. Attitudes to leadership and perceived school morale were investigated in a demographic study, a climate survey, as well as a body of related literature. In light of the empirical research, an attempt was made to determine the extent to which the authority figure's behaviour and adopted leadership style contributed to a positive school climate : one in which t eachers were motivated to achieve to t he best of their abilities by way of their commitment and service. The tone of authority assumed by t he leader not only shapes the mood of the school environment but ultimately determines the efficiency and morale of t he teaching staff.

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Student enrolment rates in optional health and physical education (HPE) classes have been steadily declining, to the point where most Ontario students stop taking HPE after completion of their one required credit, typically taken in grade nine. This study looked at factors that could contribute to HPE enrolment, sampling 227 grade ten students from five schools. These factors included selfefficacy (SE), perceived autonomy support (PAS), task value (TV), motivational regulation (autonomous, AR; controlled, CR), HPE grade average and body size discrepancy (BSD). Qualitative information was also gathered from students regarding likes and dislikes ofHPE, as well as reasons for their HPE enrolment choice. Cronbach Alpha values of each scale fell within acceptable values. ANOVA analysis revealed differences between enrolment groups in SE, TV, AR, HPE grade average, and BSD (p < .05). Reasons students reported for not taking HPE included a dislike of health classes, scheduling challenges, not needing HPE for future endeavors, concerns about social self-presentation, and a dislike of sports and/or competition. This research shows important differences between students and their HPE class choices and calls for a re-evaluation of how HPE classes are structured, advertised and scheduled by high school practitioners. Future works should look toward what other factors could be at play in students' decisions for or against optional HPE and how those factors interact with the constructs that were found to be of significance in this study. Keywords: Health and physical education, high school students, participation.

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This qualitative study explored 4 former students' perceptions of the learning associated with their involvement in a high school theatre program and the contextual factors they linked to their perceived development. The study involved 4 adult participants, 2 male and 2 female, who had participated extensively in a high school theatre company from 1996 to 2001 when they were students in a large Ontario school board. Data were collected from January to August, 2007, when the 4 former students took part in two in-depth, open-ended interviews. The focus of investigation was participant perspectives. Data analysis revealed that the 4 participants' involvement in high school theatre produced both wide-ranging and enduring developmental benefits across personal, social, and cognitive domains. Participants achieved these benefits through interactions among 3 related contexts: (a) rehearsal and performance practices, (b) the world of the play, and (c) characteristics of the high school theatre company.

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Copper arsenite CuAs2O4 and Copper antimonite CuSb2O4 are S=1/2 (Cu2+ 3d9 electronic configuration) quasi-one-dimensional quantum spin-chain compounds. Both compounds crystallize with tetragonal structures containing edge sharing CuO6 octahedra chains which experience Jahn-Teller distortions. The basal planes of the octahedra link together to form CuO2 ribbon-chains which harbor Cu2+ spin-chains. These compounds are magnetically frustrated with competing nearest-neighbour and next-nearest-neighbour intrachain spin-exchange interactions. Despite the similarities between CuAs2O4 and CuSb2O4, they exhibit very different magnetic properties. In this thesis work, the physical properties of CuAs2O4 and CuSb2O4 are investigated using a variety of experimental techniques which include x-ray diffraction, magnetic susceptibility measurements, heat capacity measurements, Raman spectroscopy, electron paramagnetic resonance, neutron diffraction, and dielectric capacitance measurements. CuAs2O4 exhibits dominant ferromagnetic nearest-neighbour and weaker antiferromagnetic next-nearest-neighbour intrachain spin-exchange interactions. The ratio of the intrachain interactions amounts to Jnn/Jnnn = -4.1. CuAs2O4 was found to order with a ferromagnetic groundstate below TC = 7.4 K. An extensive physical characterization of the magnetic and structural properties of CuAs2O4 was carried out. Under the effect of hydrostatic pressure, CuAs2O4 was found to undergo a structural phase transition at 9 GPa to a new spin-chain structure. The structural phase transition is accompanied by a severe alteration of the magnetic properties. The high-pressure phase exhibits dominant ferromagnetic next-nearest-neighbour spin-exchange interactions and weaker ferromagnetic nearest-neighbour interactions. The ratio of the intrachain interactions in the high-pressure phase was found to be Jnn/Jnnn = 0.3. Structural and magnetic characterizations under hydrostatic pressure are reported and a relationship between the structural and magnetic properties was established. CuSb2O4 orders antiferromagnetically below TN = 1.8 K with an incommensurate helicoidal magnetic structure. CuSb2O4 is characterized by ferromagnetic nearest-neighbour and antiferromagnetic next-nearest-neighbour spin-exchange interactions with Jnn/Jnnn = -1.8. A (H, T) magnetic phase diagram was constructed using low-temperature magnetization and heat capacity measurements. The resulting phase diagram contains multiple phases as a consequence of the strong intrachain magnetic frustration. Indications of ferroelectricity were observed in the incommensurate antiferromagnetic phase.

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Tesis (Maestría en Ciencias con Especialidad en Biología Celular) UANL

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Tesis (Maestría en Ciencias con Especialidad en Recursos Alimenticios y Producción Agrícola) UANL

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Tesis (Maestría en Ciencias con Especialidad en Morfología) UANL