A multi-species synthesis of physiological mechanisms in drought-induced tree mortality

Widespread tree mortality associated with drought 92 has been observed on all forested continents, and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water, and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analyzed across species and biomes using a standardized physiological framework. Here we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function

Variational formulas and cocycle solutions for directed polymer and percolation models

We discuss variational formulas for the law of large numbers limits of certain models of motion in a random medium: namely, the limiting time constant for last-passage percolation and the limiting free energy for directed polymers. The results are valid for models in arbitrary dimension, steps of the admissible paths can be general, the environment process is ergodic under spatial translations, and the potential accumulated along a path can depend on the environment and the next step of the path. The variational formulas come in two types: one minimizes over gradient-like cocycles, and another one maximizes over invariant measures on the space of environments and paths. Minimizing cocycles can be obtained from Busemann functions when these can be proved to exist. The results are illustrated through 1+1 dimensional exactly solvable examples, periodic examples, and polymers in weak disorder

A multi-species synthesis of physiological mechanisms in drought-induced tree mortality

Widespread tree mortality associated with drought 92 has been observed on all forested continents, and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water, and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analyzed across species and biomes using a standardized physiological framework. Here we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function

Disruption of oncogenic pathways in mucoepidermoid carcinoma: CREB inhibitor 666.15 as a potential therapeutic agent

Objectives: Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumour with around 50 % of cases carrying the CRTC1-MAML2 translocation. The CREB pathway has been associated with the transforming activity of this translocation. The aim of this study was to determine the effects of CREB inhibition on MEC cell behaviour in vitro. Material and Methods: Two translocation-positive (UM-HMC-2 and H292) and one translocation-negative (H253) MEC cell lines were treated with 666.15, a CREB inhibitor. Drug IC50 doses were determined for each cell line. Clonogenic and spheroid assays were used to assess survival, including percentage of cancer stem cells, and transwell and scratch assays evaluated invasive and migratory capacities, respectively. Immunofluorescence staining was used to determine E-cadherin expression. Results: CREB inhibition significantly reduced the number of surviving colonies and spheroids and delayed cell invasion in all cell lines, but this was more significant in the fusion positive, UM-HMC-2 cells. The expression of E-cadherin was significantly higher in treated UM-HMC-2 and H292 cells. Conclusion: CREB inhibition with 666.15 impaired key MEC oncogenic behaviours associated with metastasis and drug resistance, including cell invasion and survival

TrkB-targeted therapy for mucoepidermoid carcinoma

The brain-derived neurotrophic factor (BDNF)/tyrosine receptor kinase B (TrkB) pathway was previously associated with key oncogenic outcomes in a number of adenocarcinomas. The aim of our study was to determine the role of this pathway in mucoepidermoid carcinoma (MEC). Three MEC cell lines (UM-HMC-2, H253 and H292) were exposed to Cisplatin, the TrkB inhibitor, ANA-12 and a combination of these drugs. Ultrastructural changes were assessed through transmission electron microscopy; scratch and Transwell assays were used to assess migration and invasion; and a clonogenic assay and spheroid-forming assay allowed assessment of survival and percentage of cancer stem cells (CSC). Changes in cell ultrastructure demonstrated Cisplatin cytotoxicity, while the effects of ANA-12 were less pronounced. Both drugs, used individually and in combination, delayed MEC cell migration, invasion and survival. ANA-12 significantly reduced the number of CSC, but the Cisplatin effect was greater, almost eliminating this cell population in all MEC cell lines. Interestingly, the spheroid forming capacity recovered, following the combination therapy, as compared to Cisplatin alone. Our studies allowed us to conclude that the TrkB inhibition, efficiently impaired MEC cell migration, invasion and survival in vitro, however, the decrease in CSC number, following the combined treatment of ANA-12 and Cisplatin, was less than that seen with Cisplatin alone; this represents a limiting factor

Application of compact laser-driven accelerator X-ray sources for industrial imaging

X-rays generated by betatron oscillations of electrons in a laser-driven plasma accelerator were characterised and applied to imaging industrial samples. With a 125TW laser, a low divergence beam with 5.2±1.7 × 107photonsmrad−2 per pulse was produced with a synchrotron spectrum with a critical energy of 14.6±1.3keV. Radiographs were obtained of a metrology test sample, battery electrodes, and a damage site in a composite material. These results demonstrate the suitability of the source for non-destructive evaluation applications. The potential for industrial implementation of plasma accelerators is discussed

Avaliação de parentais e híbridos experimentais de melão rendilhado

Objetivou-se, neste trabalho, avaliar o desempenho de 38 genótipos de melão rendilhado, sendo seis parentais, 30 híbridos experimentais (15 híbridos e 15 recíprocos) e dois híbridos padrões de mercado (Bônus nº2 e Louis), quanto às características produtivas. O experimento foi conduzido no setor de Olericultura e Plantas Aromático-Medicinais da Faculdade de Ciências Agrárias e Veterinárias, UNESP-Jaboticabal, em casa de vegetação, em delineamento em blocos casualizados, com três repetições, e 38 tratamentos, contendo uma única fileira de cinco plantas, com espaçamento ente si de 0,5 m e 1 m entrelinhas. A semeadura foi realizada em 01 de agosto de 2007, utilizando bandejas de poliestireno expandido de 128 células, e quando as mudas apresentaram a primeira folha não cotiledonar, realizou-se o transplante. As plantas foram cultivadas em substrato de fibra da casca de coco, sendo a irrigação e adubação realizadas conjuntamente por fertirrigação. A colheita foi realizada durante o mês de dezembro, sendo avaliados: produção total, diâmetro médio transversal e longitudinal do fruto, índice de formato de fruto, diâmetro médio transversal e longitudinal do lóculo, índice de formato do lóculo, diâmetro médio da inserção do pedúnculo dos frutos, precocidade e concentração de colheita. Realizou-se análise de variância para cada característica e comparação entre as médias pelo teste de Scott-Knott, ao nível de 5% de probabilidade. Com base nos resultados obtidos, concluiu-se que os genótipos (híbridos) experimentais 4, 23, 24, 26 e 28 obtiveram os melhores desempenhos sendo semelhantes aos híbridos comerciais.The objective of this study was to evaluate the performance of 38 net melon genotypes, six parents, 30 experimental hybrids (15 hybrids and 15 reciprocals) and two standard hybrid market, on the characteristics productive. The experiment was conducted in the experimental area of the Sector of Vegetable Crops and Aromatic Medicinal Plants, Faculty of Agricultural and Veterinary Sciences, UNESP-Jaboticabal, in a greenhouse, with three replications, each with 38 plots, contained a single row of five plants with spacing between them of 0.5 m and 1 m between lines. The seedlings were performed on August 1st, 2007, in expanded polystyrene trays with 128 pyramidal cells. Transplanting was done when the seedlings showed the first non-cotyledon leaf. The plants were grown on the substrate of the shell of coconut fiber, and the irrigation and fertilization carried out jointly by fertirrigation. The harvest was conducted during December, and the following factors were evaluated: total production, transverse and longitudinal diameters of fruit, format index of fruit, transverse and longitudinal diameters of locule, format index of locule, insertion diameters, earliness, concentration of harvest. There was performed an analysis of variance to each feature and comparison between the average test of Scott-Knott at 5% probability. Based on the findings it was concluded that the experimental hybrids 4, 23, 24, 26 and 28 have the best performance and were similar to commercial hybrids