Naresuan University Journal
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Inhibition of cathepsin B by caspase-3 inhibitors blocks programmed cell death in Arabidopsis
No full textAbstract Programmed cell death (PCD) is used by plants for development and survival to biotic and abiotic stresses. The role of caspases in PCD is well established in animal cells. Over the past 15 years, the importance of caspase-3-like enzymatic activity for plant PCD completion has been widely documented despite the absence of caspase orthologues. In particular, caspase-3 inhibitors blocked nearly all plant PCD tested. Here, we affinity-purified a plant caspase-3-like activity using a biotin-labelled caspase-3 inhibitor and identified Arabidopsis thaliana cathepsin B3 (AtCathB3) by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Consistent with this, recombinant AtCathB3 was found to have caspase-3-like activity and to be inhibited by caspase-3 inhibitors. AtCathepsin B triple-mutant lines showed reduced caspase-3-like enzymatic activity and reduced labelling with activity-based caspase-3 probes. Importantly, AtCathepsin B triple mutants showed a strong reduction in the PCD induced by ultraviolet (UV), oxidative stress (H2O2, methyl viologen) or endoplasmic reticulum stress. Our observations contribute to explain why caspase-3 inhibitors inhibit plant PCD and provide new tools to further plant PCD research. The fact that cathepsin B does regulate PCD in both animal and plant cells suggests that this protease may be part of an ancestral PCD pathway pre-existing the plant/animal divergence that needs further characterisation.Cell Death and Differentiation advance online publication, 8 April 2016; doi:10.1038/cdd.2016.3
New End Markets, Supermarket Expansion, and Shifting Social Standards
No full textIn recent years, Northern supermarket chains have internationalized rapidly and Southern supermarket chains have expanded their footprint in emerging markets. As they have done so, questions have arisen about the impact of such supermarkets and the extent of consumer demand for social standards (labour standards and fair trade). While standards have been more (or less) codified in their Northern counterparts over recent decades, it remains an empirical question whether –and if so how—they will take hold in the rapidly expanding markets of the global South. The paper analyses the extent to which social standards are applied by Northern lead firms as well as regional supermarkets operating in the global South. It questions the view that Southern consumers and civil society actors are uninterested in social standards, and suggests a more differentiated and complex process driving their selective application in the global South. Value chain concepts of governance help analyse how lead firms are shifting from regimes of control and coordination towards practices of normalization and convergence. We draw on the notion of multi-polar governance to explore emerging pressures for social standards extended to Southern consumer markets and differential channels for convergence emerging across the global North and South. Three case studies highlight diverse channels of convergence on social standards: (i) led by transnational retailers; (ii) led by standards initiatives; and (iii) linking private with public governance. These illustrate that socially responsible consumption is only one element in more complex multi-polar governance processes that reveal trends towards both divergence and convergence in the drivers of social standards within emerging economies
High Power Picosecond Laser Surface Micro-texturing of H13 Tool Steel and Pattern Replication onto ABS Plastics via Injection Moulding
No full textMidwives experiences of asking the Whooley questions to assess current mental health: a qualitative interpretive study
No full textBackgound: Perinatal Mental Illness (PMI) is a key cause of maternal mortality and morbidity in the UK, with one goal of midwives to identify those at risk during pregnancy. At present, the system of preliminary identification of existing PMI in the UK involves the midwife asking pregnant women the Whooley questions at the antenatal booking interview. Aim: To explore midwives experiences of asking the Whooley questions with pregnant women. Method: A qualitative interpretive study explored midwives’ (n = 8) experiences of asking the Whooley questions in one maternity unit in England (UK). Data were gathered through semistructured interviews and analysed using Framework Analysis (FWA). Findings: Themes and subthemes identified included: (1) no clear understanding of purpose, (1a) discomfort when disclosure occurs, (2) feeling pressurised for time, (3) resultant dissatisfaction and frustration; (3a) lack of knowledge and how to refer, (3b) lack of training around PMI, (3c) relying on experience and use of intuition. Discussion: The development and evaluation of an education curriculum to prepare midwives to effectively use case-finding instruments such as the Whooley questions to identify pregnant women at risk is required
Debt Maturity and Initial Public Offerings
No full textWe investigate the effect of initial public offerings (IPOs) on the evolution of debt maturity by tracking a sample of US firms that went public over the period 1998–2011. Our findings reveal a significant and permanent increase in debt maturity post-IPO. The short-term debt ratio drops by nearly a fifth in the first 2 years after the IPO. These findings are economically significant and robust to controlling for the endogeneity in the listing decision. However, the lengthening of the post-IPO debt maturity is only evident in small, high-growth, and highly levered firms. This finding lends greater support to asymmetric information models than theories based on the agency costs of debt. There is some support for the argument based on the agency costs of equity as the IPO effect on debt maturity is only significant for firms with a high dilution ratio. Finally, the IPO effect varies with macroeconomic conditions as the increase in debt maturity post-IPO was most pronounced during the recent financial crisis of 2007–2008
Epistemologies of Rehearsal:Crow Indianist Reflections on Re-enactment as Research Practice
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Non-Gaussian Berkson Errors in Bioassay
No full textThe experimental design plays an important role in every experimental study. However, if errors in the settings of the studied factors cannot be avoided, i.e. Berkson errors occur, the estimates of the model parameters may be biased and the variability in the study increased. Correction methods for the effect of Berkson errors are compared. The emphasis is on the study of correlated Berkson errors which follow non-Gaussian distribution as this appears to have been a neglected, yet important, area. It is shown that the regression calibration approach bias correction methods are useful when the Berkson errors are independent. However, when these errors are dependent, the newly proposed method B-SIMEX clearly outperforms the other methods
Single integrodifferential wave equation for a Lévy walk
No full textWe derive the single integrodifferential wave equation for the probability density function of the position of a classical one-dimensional Lévy walk with continuous sample paths. This equation involves a classical wave operator together with memory integrals describing the spatiotemporal coupling of the Lévy walk. It is valid at all times, not only in the long time limit, and it does not involve any large-scale approximations. It generalizes the well-known telegraph or Cattaneo equation for the persistent random walk with the exponential switching time distribution. Several non-Markovian cases are considered when the particle's velocity alternates at the gamma and power-law distributed random times. In the strong anomalous case we obtain the asymptotic solution to the integrodifferential wave equation. We implement the nonlinear reaction term of Kolmogorov-Petrovsky-Piskounov type into our equation and develop the theory of wave propagation in reaction-transport systems involving Lévy diffusion