885 resultados para Inducers of resistance


Relevância:

90.00% 90.00%

Publicador:

Resumo:

We investigate the dielectric dispersion of water, specially in the low-frequency range, by using the impedance spectroscopy technique. The frequency dependencies of the real R and imaginary Z parts of the impedance Could not be explained by means of the Usual description of the dielectric properties of the water as all insulating liquid containing ions. This is due to the incomplete knowledge of the parameters entering in the fundamental equations describing the evolution of the system, and oil the mechanisms regulating the exchange of charge of the cell with the external circuit. We propose a simple description of our experimental data based on the model of Debye, by invoking a dc conductivity of the cell, related to the nonblocking character of the electrodes. A discussion on the electric Circuits able to simulate the cell under investigation, based oil bulk and Surface elements, is also reported. We find that the simple circuit formed by a series of two parallels of resistance and capacitance is able to reproduce the experimental data concerning the real and imaginary part of the electrical impedance of the cell for frequency larger than 1 Hz. According to this description, one of the parallels takes into account the electrical properties of interface between the electrode and water, and the other of the bulk. For frequency lower than 1 Hz, a good agreement with the experimental data is obtained by simulating the electrical properties of the interface by means of the constant phase element.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The urban landscapes of Yangon and Mandalay in Burma (Myanmar) exhibit a rich cultural layering and complex blending of urban forms and architectural styles. But while both cities today are shaped by contemporary economic and political realities, they also clearly reflect
their historical origins—Yangon as the British colonial capital and Mandalay as the last seat of the monarchy. Burma’s ancient religious monuments, monarchical and colonial heritage on the one hand, and new religious edifices, international standard hotels, commercial enterprises, new public buildings and satellite towns on the other hand, represent the two poles of the dialectic of tradition and modernity. The landscapes, as symbolic representations, have been appropriated by
the authoritarian military regime, the State Peace and Development Council (SPDC) for nation building purposes. But the urban landscapes are also contested and appropriated in symbolic ways and invested with meanings as sites of resistance and struggle by those in opposition, and
are thus contested sites where the power relations of domination and resistance intersect. The paper illustrates these themes with examples drawn from Yangon and Mandalay.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Fabric pilling is a serious problem for the apparel industry, causing an unsightly appearance and premature wear. Woolen products are particularly prone to pilling. Recently, a process for production of woolen nonwoven apparel fabrics has been commercialized in Australia, and may lead to new markets for Australian wool. However, the success of such nonwoven fabrics will partly rely on their propensity to pill. A key element in the control of fabric pilling is the evaluation of resistance to pilling by testing. Resistance to pilling is normally tested in the laboratory by processes that simulate accelerated wear, followed by a manual assessment of the degree of pilling by an expert based on a visual comparison of the sample to a set of test images. To bring more objectivity into the pilling rating process, a number of automated systems based on image analysis have been developed. The authors previously proposed a new method of image analysis based on the two-dimensional discrete wavelet transform to objectively measure the pilling intensity for woven fabrics. This paper presents preliminary work in extending this method to nonwoven fabrics.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

To investigate the in vivo effects of resistance exercise on translational control in human skeletal muscle, we determined the phosphorylation of AMP-activated kinase (AMPK), eukaryotic initiation factor 4E-binding protein (4E-BP1), p70/p85-S6 protein kinase (S6K1), and ribosomal S6 protein (S6). Furthermore, we investigated whether changes in the phosphorylation of S6K1 are muscle fiber type specific. Eight male subjects performed a single high-intensity resistance exercise session. Muscle biopsies were collected before and immediately after exercise and after 30 and 120 min of postexercise recovery. The phosphorylation statuses of AMPK, 4E-BP1, S6K1, and S6 were determined by Western blotting with phospho-specific and pan antibodies. To determine fiber type-specific changes in the phosphorylation status of S6K1, immunofluorescence microscopy was applied. AMPK phosphorylation was increased approximately threefold immediately after resistance exercise, whereas 4E-BP1 phosphorylation was reduced to 27 ± 6% of preexercise values. Phosphorylation of S6K1 at Thr421/Ser424 was increased 2- to 2.5-fold during recovery but did not induce a significant change in S6 phosphorylation. Phosphorylation of S6K1 was more pronounced in the type II vs. type I muscle fibers. Before exercise, phosphorylated S6K1 was predominantly located in the nuclei. After 2 h of postexercise recovery, phospho-S6K1 was primarily located in the cytosol of type II muscle fibers. We conclude that resistance exercise effectively increases the phosphorylation of S6K1 on Thr421/Ser424, which is not associated with a substantial increase in S6 phosphorylation in a fasted state.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

To determine whether preexercise muscle glycogen content influences the transcription of several early-response genes involved in the regulation of muscle growth, seven male strength-trained subjects performed one-legged cycling exercise to exhaustion to lower muscle glycogen levels (Low) in one leg compared with the leg with normal muscle glycogen (Norm) and then the following day completed a unilateral bout of resistance training (RT). Muscle biopsies from both legs were taken at rest, immediately after RT, and after 3 h of recovery. Resting glycogen content was higher in the control leg (Norm leg) than in the Low leg (435 ± 87 vs. 193 ± 29 mmol/kg dry wt; P < 0.01). RT decreased glycogen content in both legs (P < 0.05), but postexercise values remained significantly higher in the Norm than the Low leg (312 ± 129 vs. 102 ± 34 mmol/kg dry wt; P < 0.01). GLUT4 (3-fold; P < 0.01) and glycogenin mRNA abundance (2.5-fold; not significant) were elevated at rest in the Norm leg, but such differences were abolished after exercise. Preexercise mRNA abundance of atrogenes was also higher in the Norm compared with the Low leg [atrogin: 14-fold, P < 0.01; RING (really interesting novel gene) finger: 3-fold, P < 0.05] but decreased for atrogin in Norm following RT (P < 0.05). There were no differences in the mRNA abundance of myogenic regulatory factors and IGF-I in the Norm compared with the Low leg. Our results demonstrate that 1) low muscle glycogen content has variable effects on the basal transcription of select metabolic and myogenic genes at rest, and 2) any differences in basal transcription are completely abolished after a single bout of heavy resistance training. We conclude that commencing resistance exercise with low muscle glycogen does not enhance the activity of genes implicated in promoting hypertrophy.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

A single bout of aerobic exercise can enhance insulin action, but whether a similar effect occurs after resistance exercise is unknown. Hyperinsulinemic-euglycemic clamps were performed on eight male subjects at rest and after a single bout and three repeated bouts of resistance exercise over 7 days. Skeletal muscle biopsies were taken before and after the clamp and immediately after a single exercise bout. Whole-body insulin action measured by glucose infusion rate decreased (P < 0.05) after a single exercise bout, whereas in response to repeated bouts of resistance exercise, the glucose infusion rate was similar to the rest trial. In skeletal muscle, Akt substrate of 160 kDa (AS160) phosphorylation, an Akt substrate implicated in the regulation of GLUT4 translocation, and its interaction with 14-3-3 was decreased (P < 0.05) only after a single exercise bout. Insulin increased (P < 0.05) phosphorylation of AS160 and its interaction with 14-3-3, but the insulin response was not influenced by resistance exercise. Phosphorylation of insulin receptor substrate-1 and Akt were similar to changes in AS160 phosphorylation after exercise and/or insulin. In conclusion, a single bout of resistance exercise impairs whole-body insulin action. Regulation of AS160 and interaction with 14-3-3 in skeletal muscle are influenced by resistance exercise and insulin but do not fully explain the effect of resistance exercise on whole-body insulin action.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The Gay Games is firmly established on the contemporary global sports calendar, but is seldom canvassed in mainstream sports media, or considered a model for sports administrators. This is regrettable, as the Games’ ethos offers many clues into the relationships between individual and communal empowerment for homosexual and heterosexual participants alike, while providing a site of resistance against entrenched norms of elitism, nationalism, victory and record-breaking indicative of the modern Olympic movement. Credit for this inclusive ethos rests with the vision of inaugural Gay Games organiser Dr. Tom Waddell. Drawing on Games archives, this paper outlines Waddell’s vision, then discusses the impact of a protracted legal dispute instigated by the United States Olympic Committee in 1982 over the use of the term ‘Olympics’ in association with Gay Games I and II. Four United States Federal court rulings are examined, with particular reference to the contrasting hierarchy of private intellectual property and public civil rights considered under United States law of the time. Domestic and international legacies of the dispute are also briefly examined, focusing on the inherent tensions between the state-sanctioned protection of Olympic terminology, the ideals of free speech, the ownership of common sporting terms, and the potential discriminatory effects of selective trademark enforcement. The paper concludes with a brief discussion of how Waddell’s vision superseded each of these legal technicalities to ensure the Games continues to provide a viable model for inclusive and engaged participation for all people.


Relevância:

90.00% 90.00%

Publicador:

Resumo:

Clubroot, caused by Plasmodiophora brassicae, is the most devastating soil-borne disease of vegetable brassicas. It occurs all over the world and is responsible for crop losses of up to 10% every year. In Australia, the disease is being managed effectively with chemicals and cultural practices, but ideally control can be improved in the long term by the introduction of resistant cultivars. The life cycle ofP. brassicae and mode of action of plant resistance has not been fully elucidated because of the technical difficulties of working with an obligate, soil-borne plant pathogen. However, Arabidopsis thaliana, which is a host ofP. brassicae, has great potential as a model system for studying the life cycle, the infection process and development of resistance. We have developed a sand-liquid-culture system for growing Arabidopsis that allows easy observation of all life stages and, most importantly, the primary plasmodial stages within the root hair. The method was first optimised for observations of the lifecycle of the pathogen in a susceptible Arabidopsis ecotype (Col-3) where all stages of the lifecycle have now been observed and characterised. Further screening of Arabidopsis ecotypes for disease resistance has utilised one of the most virulent Australian pathotypes of brassica (ECD number 16/19/31). To date, Arabidopsis ecotype Ta-0 has shown a level of tolerance to the disease even though the roots get infected. It has been reported earlier that resistance toP. brassicae in Arabidopsis is due to one or a small number of genes. To examine changes in gene expression during the early, critical stages of infection, RNA was extracted from the susceptible and resistant ecotypes at two time points, 4 days and 17 days after inoculation. Microarray analysis will be used to investigate genome wide changes in gene expression during infection but also to identify candidate genes that may confer resistance to Australian isolates of the pathogen.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Owing to their sessile nature, plants have evolved mechanisms to minimise the damaging effects of abiotic and biotic stresses. Attack by pathogenic fungi, viruses and bacterium is a major type of biotic stress. To resist infection, plants recognise invading pathogens and induce disease resistance through multiple signal transduction pathways. In addition, appropriate stimulation can cause plants to increase their resistance to future pathogen attack. We have found that exposure to non-lethal doses of UV-C (254 nm) renders a normally susceptible ecotype of Arabidopsis thaliana resistant to the biotrophic Oomycete pathogen Hyaloperonospora parasitica. The UV treatment induces an incompatible response in a dose-dependent fashion, and is still effective upon pathogen inoculation up to seven days after UV exposure. The degree of resistance diminishes with time but higher doses result in greater levels of resistance, even after seven days. Furthermore, the effect is systemic, occurring in parts of the plant that have not been irradiated. Incubation in the dark post?irradiation and prior to infection reduces the UV dose required to generate a specific level of pathogen resistance without affecting the duration of resistance. These observations, plus the inability of plants to photoreactivate UV photoproducts in the dark, strongly suggest that DNA damage induces the resistance phenotype. Currently, we are assessing the influence of DNA repair defects on UV-induced resistance, following the expression of a number of defence?related genes post-UV-C irradiation, and assessing the effect of UV in plant mutants deficient in specific signalling molecules involved in resistance.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Lao PDR is one of the 50 countries included in the International Wellbeing Group study which uses Cummin's (2001) Personal Wellbeing Index (PWI) to draw cross-national comparisons of subjective wellbeing. Lau, Cummins & McPherson (2005) found a statistically significant difference in PWI scores between Australian & Hong Kong. They ask whether this is a real reflection of lower quality of life in Hong Kong or whether there exists a cultural response bias which predisposes the Hong Kong population to be less willing to admit to high levels of satisfaction in the seven domains of the index. If the difference reflects cultural response bias, what factors contribute to that bias & how common is this phenomenon in the countries of South-east Asia & IndoChina? The paper addresses these questions with particular attention to Lao PDR where responses to the PWI from both urban & rural populations suggest a similar reticence about expressing high levels of satisfaction. The paper explores the sources of resistance to reporting positive subjective wellbeing & what adaptations may be needed to the Index to allow for such bias.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Boron nitride (BN) nanotubes have the same nanostructure as carbon nanotubes but are found to exhibit significant resistance to oxidation at high temperatures. Our systematic study has revealed that BN nanotubes are stable at 700 °C in air and that some thin nanotubes (diameter less than 20 nm) with perfect multiwalled cylindrical structure can survive up to 900 °C. Thermogravimetric analysis reveals an onset temperature for oxidation of BN nanotubes of 800 °C compared with only 400 °C for carbon nanotubes under the same conditions. This more pronounced resistance of BN nanotubes to oxidation is inherited from the hexagonal BN and also depends on the nanocrystalline structure. This high level of resistance to oxidation allows promising BN nanotube applications at
high temperatures

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Plant innate immunity to pathogenic microorganisms is activated in response to recognition of extracellular or intracellular pathogen molecules by transmembrane receptors or resistance proteins, respectively. The defense signaling pathways share components with those involved in plant responses to UV radiation, which can induce expression of plant genes important for pathogen resistance. Such intriguing links suggest that UV treatment might activate resistance to pathogens in normally susceptible host plants. Here, we demonstrate that pre-inoculative UV (254 nm) irradiation of Arabidopsis (Arabidopsis thaliana) susceptible to infection by the biotrophic oomycete Hyaloperonospora parasitica, the causative agent of downy mildew, induces dose- and time-dependent resistance to the pathogen detectable up to 7 d after UV exposure. Limiting repair of UV photoproducts by postirradiation incubation in the dark, or mutational inactivation of cyclobutane pyrimidine dimer photolyase, (6-4) photoproduct photolyase, or nucleotide excision repair increased the magnitude of UV-induced pathogen resistance. In the absence of treatment with 254-nm UV, plant nucleotide excision repair mutants also defective for cyclobutane pyrimidine dimer or (6-4) photoproduct photolyase displayed resistance to H. parasitica, partially attributable to short wavelength UV-B (280–320 nm) radiation emitted by incubator lights. These results indicate UV irradiation can initiate the development of resistance to H. parasitica in plants normally susceptible to the pathogen and point to a key role for UV-induced DNA damage. They also suggest UV treatment can circumvent the requirement for recognition of H. parasitica molecules by Arabidopsis proteins to activate an immune response.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Activation of the transcription factor signal transducers and activators of transcription (STAT) 3 is common to many inflammatory cytokines and growth factors, with recent evidence of involvement in skeletal muscle regeneration. The purpose of this study was to determine whether STAT3 signaling activation is regulated differentially, at rest and following intense resistance exercise, in aged human skeletal muscle. Skeletal muscle biopsies were harvested from healthy younger (n = 11, 20.4 ± 0.8 years) and older men (n = 10, 67.4 ± 1.3 years) under resting conditions and 2 h after the completion of resistance exercise. No differences were evident at rest, whereas the phosphorylation of STAT3 was significantly increased in old (23-fold) compared to young (5-fold) subjects after exercise. This correlated with significantly higher induction of the STAT3 target genes including; interleukin-6 (IL-6), JUNB, c-MYC, and suppressor of cytokine signaling (SOCS) 3 mRNA in older subjects following exercise. Despite increased SOCS3 mRNA, cellular protein abundance was suppressed. SOCS3 protein is an important negative regulator of STAT3 activation and cytokine signaling. Thus, in aged human muscle, elevated responsiveness of the STAT3 signaling pathway and suppressed SOCS3 protein are evident following resistance exercise. These data suggest that enhanced STAT3 signaling responsiveness to proinflammatory factors may impact on mechanisms of muscle repair and regeneration.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Critical commentary on Australian artist Bill Henson’s work including the series Untitled 1994-1995 which represented Australia at the Venice Biennale is frequently framed within the discourse of the ‘white cube’. Its contextualisation in predominantly art historical and formalist perspectives tends to operate as a mechanism that denies affective and embodied dimensions of meaning making. Much the same could be said of the work of Marian Drew who uses road kill in her photographic still life works. However, the ‘distancing’ in these works is also achieved through historical allusion, which at the same time reactivates the fl ow of emotional empathy and desire. In this paper, I ask the question: “What distinguishes the work of these two artists with media images of torture?”

My attempt to address this question will involve a narrative re-reading of selected works of Henson and Drew incorporating notions of affect, identification, memory and desire as processes which operate non-discursively, but which are inseparable from memory and lived experiences. This will permit a double exposure of the work of these artists. Within a psychoanalytical context, my re-reading will be used to extend an understanding of the now familiar press and Internet images of the torture of Iraqi prisoners.

As a metaphor for desire and ideology, photography operates within manifest and latent registers. I will argue that certain forms of photographic practice may be understood in terms of a politics of abuse — instantiating an uneven differentiation of power between actants, the winning (forcefully or otherwise) of consent or complicity, the silencing of refusal of resistance and/or the incriminating of the ‘victim’ — whilst at the same time upholding the claim of verisimilitude and aesthetic or ethical intent. Critical engagement with such practices is crucial to an understanding of the relationship between institutional discourses, trauma and abuse in contemporary society.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

There is mounting evidence in support of the view that skeletal muscle hypertrophy results from the complex and coordinated interaction of numerous signalling pathways. Well characterised components integral to skeletal muscle adaptation include the transcriptional activity of the members of the myogenic regulatory factors, numerous secreted peptide growth factors, and the regenerative potential of satellite cells. Whilst studies investigating isolated components or pathways have enhanced our current understanding of skeletal muscle hypertrophy, our knowledge of how all of these components react in concert to a common stimulus remains limited. The broad aim of this thesis was to identify and characterise novel genes involved in skeletal muscle hypertrophy. We have created a customised human skeletal muscle specific microarray which contains ∼11,000 cDNA clones derived from a normalised human skeletal muscle cDNA library as well as 270 genes with known functional roles in human skeletal muscle. The first aspect of this thesis describes the production of the microarray and evaluates the robustness and reproducibility of this analytical technique. Study one aimed to use this microarray in the identification of genes that are differentially expressed during the forced differentiation of human rhabdomyosarcoma cells, an in vitro model of skeletal muscle development. Firstly using this unique model of aberrant myogenic differentiation we aimed to identify genes with previously unidentified roles in myogenesis. Secondly, the data from this study permitted the examination of the performance of the microarray in detecting differential gene expression in a biological system. We identified several new genes with potential roles in the myogenic arrest of rhabdomyosarcoma and further characterised the expression of muscle specific genes in rhabdomyosarcoma differentiation. In study two, the molecular responses of cell cycle regulators, muscle regulatory factors, and atrophy related genes were mapped in response to a single bout of resistance exercise in human skeletal muscle. We demonstrated an increased expression of MyoD, myogenin and p21, whilst the expression of myostatin was decreased. The results of this study contribute to the existing body of knowledge on the molecular regulation skeletal muscle to a hypertrophic stimulus. In study three, the muscle samples collected in study two were analysed using the human skeletal muscle specific microarray for the identification of novel genes with potential roles in the hypertrophic process. The analysis uncovered four interesting genes (TXNIP, MLP, ASB5, FLJ 38973) that have not previously been examined in human skeletal muscle in response to resistance exercise. The functions of these genes and their potential roles in skeletal muscle are discussed. In study four, the four genes identified in study three were examined in human primary skeletal muscle cell cultures during myogenic differentiation. Human primary skeletal muscle cells were derived from the vastus lateralis muscle of 8 healthy volunteers (6 males and 2 females). Cell cultures were differentiated using serum withdrawal and serum withdrawal combined with IGF-1 supplementation. Markers of the cell proliferation, cell cycle arrest and myogenic differentiation were examined to assess the effectiveness of the differentiation stimulus. Additionally, the expressions of TXNIP, MLP, ASB5 and FLJ 38973 measured in an attempt to characterise further their roles in skeletal muscle. The expression of TXNIP changed markedly in response to both differentiation stimuli, whilst the expression of the remaining genes were not altered. Therefore it was suggested that expression of these genes might be responsive to the mechanical strain or contraction induced by the resistance exercise. In order to examine whether these novel genes responded specifically to resistance type exercise, their expression was examined following a single bout of endurance exercise. The expression of TXNIP, MLP, and FLJ 38973 remained unchanged whilst ASB5 increased 30 min following the cessation of the exercise.