300 resultados para Negative resistance


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Efficient transformation of barley cv. Schooner was achieved using Agrobacterium delivery, hygromycin or bialaphos selection and embryogenic callus. Using this system, transgenic plants were generated that contained either the green fluorescent protein gene, or transgenes derived from barley yellow dwarf (BYDV) and cereal yellow dwarf (CYDV) viruses. Many of these plants contained 1-3 transgene copies that were inherited in a simple Mendelian manner. Some plants containing BYDV and/or CYDV derived transgenes showed reduced virus symptoms and rates of viral replication when challenged with the appropriate virus. The ability to transform Schooner is a significant advance for the Australian barley industry, as this elite malting variety is, and has for the last 15 years been, the most widely grown barley variety in eastern Australia.

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On occasion, virus-derived transgenes in plants can be poorly expressed and yet provide excellent virus resistance, and transgene constructs designed to supplement the expression of endogenous genes can have the effect of co-suppressing themselves and the endogenous genes. These two phenomena appear to result from the same post-transcriptional silencing mechanism, which operates by targeted-RNA degradation. Recent research into RNA-mediated virus resistance and co-suppression has provided insights into the interactions between plant viruses and their hosts, and spawned several models to explain the phenomenon.

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A very simple leaf assay is described that rapidly and reliably identifies transgenic plants expressing the hygromycin resistance gene, hph or the phosphinothricin resistance gene, bar. Leaf tips were cut from plants propagated either in the glasshouse or in tissue culture and the cut surface embedded in solid medium containing the appropriate selective agent. Non-transgenic barley or rice leaf tips had noticeable symptoms of either bleaching or necrosis after three days on the medium and were completely bleached or necrotic after one week. Transgenic leaf tips remained green and healthy over this period. This gave unambiguous discrimination between transgenic and non-transgenic plants. The leaf assay was also effective for dicot plants tested (tobacco and peas).

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For the last decade, one question has haunted me: what helps people to cope with large-scale organisational change in their workplace? This study explores the construct of personal change resilience, and its potential for identifying solutions to the problems of change fatigue and change resistance. The thesis has emerged from the fields of change management, leadership, training, mentoring, evaluation, management and trust within the context of higher education in Australia at the beginning of the twenty-first century. In this thesis I present a theoretical model of the factors to consider in increasing peoples’ personal change resilience as they navigate large-scale organisational change at work, thereby closing a gap in the literature on the construct of change resilience. The model presented is based on both the literature in the realms of business and education, and on the findings of the research. In this thesis, an autoethnographic case study of two Australian university projects is presented as one narrative, resulting in a methodological step forward in the use of multiple research participants’ stories in the development of a single narrative. The findings describe the experiences of workers in higher education and emphasise the importance of considerate management in the achievement of positive experiences of organisational change. This research makes a significant contribution to new knowledge in three ways. First, it closes a gap in the literature in the realm of change management around personal change resilience as a solution to the problem of change fatigue by presenting models of both change failure and personal change resilience. Second, it is methodologically innovative in the use of personae to tell the stories of multiple participants in one coherent tale presented as a work of ethnographic fiction seen through an autoethnographic lens. By doing so, it develops a methodology for giving a voice to those to whom change is done in the workplace. Third, it provides a perspective on organisational change management from the view of the actual workers affected by change, thereby adding to the literature that currently exists, which is based on the views of those with responsibility for leading or managing change rather than those it affects. This thesis is intended as a practical starting point for conversations by actual change managers in higher education, and it is written in such a way as to help them see how theory can be applied in real life, and how empowering and enabling the actual working staff members, and engaging with them in a considerate way before, during and even after the change process, can help to make them resilient enough to cope with the change, rather than leaving them burned out or disengaged and no longer a well-functioning member of the institution. This thesis shows how considerately managed large-scale organisational change can result in positive outcomes for both the organisation and the individuals who work in it.

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In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than what the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the subpopulation that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, that is, increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors and to develop strategies to minimize their effect.

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Cisplatin is one of the most potent anticancer agents, displaying significant clinical activity against a variety of solid tumours. To date, cisplatin-based combination treatment remains the most effective systemic chemotherapy for non-small cell lung cancer (NSCLC) patients. Unfortunately, the outcome of cisplatin therapy in NSCLC has reached a plateau due to the development of both intrinsic and acquired resistance that have become a major obstacle in the use of cisplatin in the clinical setting. The molecular mechanisms that underlie chemoresistance are largely unknown. Mechanisms of acquired resistance to cisplatin include reduced intracellular accumulation of the drug, enhanced drug inactivation by metallothionine and glutathione, increased repair activity of DNA damage, and altered expression of oncogenes and regulatory proteins. Cisplatin-induced cytotoxicity is mediated through the induction of apoptosis and cell cycle arrest as a result of cisplatin-DNA adduct formation, which in turn, activates multiple signaling pathways and mediators. These include p53, Bcl-2 family, caspases, cyclins, CDKs, MAPK and PI3K/Akt. Increased expression of anti-apoptotic genes and mutations in the intrinsic apoptotic pathway may also contribute to the inability of cells to detect DNA damage or to induce apoptosis. This chapter will provide an insight into the mechanisms involved in cisplatin resistance and a better understanding of the molecular basis of the cellular response to cisplatin-based chemotherapy in lung cancer.

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Intrinsic or acquired resistance to chemotherapeutic agents is a common phenomenon and a major challenge in the treatment of cancer patients. Chemoresistance is defined by a complex network of factors including multi-drug resistance proteins, reduced cellular uptake of the drug, enhanced DNA repair, intracellular drug inactivation, and evasion of apoptosis. Pre-clinical models have demonstrated that many chemotherapy drugs, such as platinum-based agents, antracyclines, and taxanes, promote the activation of the NF-κB pathway. NF-κB is a key transcription factor, playing a role in the development and progression of cancer and chemoresistance through the activation of a multitude of mediators including anti-apoptotic genes. Consequently, NF-κB has emerged as a promising anti-cancer target. Here, we describe the role of NF-κB in cancer and in the development of resistance, particularly cisplatin. Additionally, the potential benefits and disadvantages of targeting NF-κB signaling by pharmacological intervention will be addressed.

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The article discusses the issues of resistance; that is resistance by prisoners to the various manifestations of power operating in high security prisons, as well as that of attempted shifts in the regime from physical to psychological control. Other topics highlighted include legitimacy and 'official discourse', mourning and the construction of 'ungrievable lives' and the importance of finding a way out of the cycle of violence, which high security regimes perpetuate.

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This chapter focuses on ‘intergenerational collaborative drawing’, a particular process of drawing whereby adults and children draw at the same time on a blank paper space. Such drawings can be produced for a range of purposes, and based on different curriculum or stimulus subjects. Children of all ages, and with a range of physical and intellectual abilities are able to draw with parents, carers and teachers. Intergenerational collaborative drawing is a highly potent method for drawing in early childhood contexts because it brings adults and children together in the process of thinking and theorizing in order to create visual imagery and this exposes in deep ways to adults and children, the ideas and concepts being learned about. For adults, this exposure to a child’s thinking is a far more effective assessment tool than when they are presented with a finished drawing they know little about. This chapter focuses on drawings to examine wider issues of learning independence and how in drawing, preferred schema in the form of hand-out worksheets, the suggestive drawings provided by adults, and visual material seen in everyday life all serve to co-opt a young child into making particular schematic choices. I suggest that intergenerational collaborative drawing therefore serves to work as a small act of resistance to that co-opting, in that it helps adults and children to collectively challenge popular creativity and learning discourses.

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We examine the security of the 64-bit lightweight block cipher PRESENT-80 against related-key differential attacks. With a computer search we are able to prove that for any related-key differential characteristic on full-round PRESENT-80, the probability of the characteristic only in the 64-bit state is not higher than 2−64. To overcome the exponential (in the state and key sizes) computational complexity of the search we use truncated differences, however as the key schedule is not nibble oriented, we switch to actual differences and apply early abort techniques to prune the tree-based search. With a new method called extended split approach we are able to make the whole search feasible and we implement and run it in real time. Our approach targets the PRESENT-80 cipher however,with small modifications can be reused for other lightweight ciphers as well.

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Recent research at the Queensland University of Technology has investigated the structural and thermal behaviour of load bearing Light gauge Steel Frame (LSF) wall systems made of 1.15 mm G500 steel studs and varying plasterboard and insulation configurations (cavity and external insulation) using full scale fire tests. Suitable finite element models of LSF walls were then developed and validated by comparing with test results. In this study, the validated finite element models of LSF wall panels subject to standard fire conditions were used in a detailed parametric study to investigate the effects of important parameters such as steel grade and thickness, plasterboard screw spacing, plasterboard lateral restraint, insulation materials and load ratio on their performance under standard fire conditions. Suitable equations were proposed to predict the time–temperature profiles of LSF wall studs with eight different plasterboard-insulation configurations, and used in the finite element analyses. Finite element parametric studies produced extensive fire performance data for the LSF wall panels in the form of load ratio versus time and critical hot flange (failure) temperature curves for eight wall configurations. This data demonstrated the superior fire performance of externally insulated LSF wall panels made of different steel grades and thicknesses. It also led to the development of a set of equations to predict the important relationship between the load ratio and the critical hot flange temperature of LSF wall studs. Finally this paper proposes a simplified method to predict the fire resistance rating of LSF walls based on the two proposed set of equations for the load ratio–hot flange temperature and the time–temperature relationships.

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We present a determination of Delta(f)H(298)(HOO) based upon a negative. ion thermodynamic cycle. The photoelectron spectra of HOO- and DOO- were used to measure the molecular electron affinities (EAs). In a separate experiment, a tandem flowing afterglow-selected ion flow tube (FA-SIFT) was used to measure the forward and reverse rate constants for HOO- + HCdropCH reversible arrow HOOH + HCdropC(-) at 298 K, which gave a value for Delta(acid)H(298)(HOO-H). The experiments yield the following values: EA(HOO) = 1.078 +/- 0.006 eV; T-0((X) over tilde HOO - (A) over tilde HOO) = 0.872 +/- 0.007 eV; EA(DOO) = 1.077 +/- 0.005 eV; T-0((X) over tilde DOO - (A) over tilde DOO) = 0.874 +/- 0.007 eV; Delta(acid)G(298)(HOO-H) = 369.5 +/- 0.4 kcal mol(-1); and Delta(acid)H(298)(HOO-H) = 376.5 +/- 0.4 kcal mol(-1). The acidity/EA thermochemical cycle yields values for the bond enthalpies of DH298(HOO-H) = 87.8 +/- 0.5 kcal mol(-1) and Do(HOO-H) = 86.6 +/- 0.5 kcal mol(-1). We recommend the following values for the heats of formation of the hydroperoxyl radical: Delta(f)H(298)(HOO) = 3.2 +/- 0.5 kcal mol(-1) and Delta(f)H(0)(HOO) = 3.9 +/- 0.5 kcal mol(-1); we recommend that these values supersede those listed in the current NIST-JANAF thermochemical tables.

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An experiment tested the hypothesis that individuals high in negative affectivity (NA) show increased stress reactivity to stressors. There were three predictor variables: NA (measured 1 week prior to experimental participation), and two manipulated variables—demand (high/low) and behavioral control (high/low). First-year psychology students (n=256) were randomly allocated to one of the four experimental conditions. Measures obtained were initial and post-task negative mood, coping strategies, task satisfaction, and performance (subjective and objective). Participants with high levels of NA reported more post-task negative mood in response to high demand conditions, compared to participants with low NA. A similar pattern of results emerged for task satisfaction, particularly in response to high demand-low behavioral control situations. Mediation analyses suggested this was because participants with high NA used more emotion-focused coping strategies. The study provides support for the stress reactivity role of NA in the stressor-strain process.