Efficient Dielectrophoretic Patterning of Embryonic Stem Cells in Energy Landscapes Defined by Hydrogel Geometries

In this study, we have developed an integrated microfluidic platform for actively patterning mammalian cells, where poly(ethylene glycol) (PEG) hydrogels play two important roles as a non-fouling layer and a dielectric structure. The developed system has an embedded array of PEG microwells fabricated on a planar indium tin oxide (ITO) electrode. Due to its dielectric properties, the PEG microwells define electrical energy landscapes, effectively forming positive dielectrophoresis (DEP) traps in a low-conductivity environment. Distribution of DEP forces on a model cell was first estimated by computationally solving quasi-electrostatic Maxwell’s equations, followed by an experimental demonstration of cell and particle patterning without an external flow. Furthermore, efficient patterning of mouse embryonic stem (mES) cells was successfully achieved in combination with an external flow. With a seeding density of 107 cells/mL and a flow rate of 3 μL/min, trapping of cells in the microwells was completed in tens of seconds after initiation of the DEP operation. Captured cells subsequently formed viable and homogeneous monolayer patterns. This simple approach could provide an efficient strategy for fabricating various cell microarrays for applications such as cell-based biosensors, drug discovery, and cell microenvironment studies

Climate variability of southern Chile since the Last Glacial Maximum : a continuous sedimentological record from Lago Puyehue (40°S)

Author Posting. © Springer, 2007. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Paleolimnology 39 (2008): 179-195, doi:10.1007/s10933-007-9117-y.This paper presents a multi-proxy climate record of an 11 m long core collected in Lago Puyehue (southern Chile, 40°S) and extending back to 18,000 cal yr BP. The multi-proxy analyses include sedimentology, mineralogy, grain size, geochemistry, loss-on-ignition, magnetic susceptibility and radiocarbon datings. Results demonstrate that sediment grain size is positively correlated with the biogenic sediment content and can be used as a proxy for lake paleoproductivity. On the other hand, the magnetic susceptibility signal is correlated with the aluminium and titanium concentrations and can be used as a proxy for the terrigenous supply. Temporal variations of sediment composition evidence that, since the last glacial maximum, the Chilean Lake District was characterized by 3 abrupt climate changes superimposed on a long-term climate evolution. These rapid climate changes are: (1) an abrupt warming at the end of the last glacial maximum at 17,300 cal yr BP; (2) a 13,100-12,300 cal yr BP cold event, ending rapidly and interpreted as the local counter part of the Younger Dryas cold period, and (3) a 3400-2900 cal yr BP climatic instability synchronous with a period of low solar activity. The timing of the 13,100-12,300 cold event is compared with similar records in both hemispheres and demonstrates that this southern hemisphere climate change lags behind the northern hemisphere Younger Dryas cold period by 500 to 1000 years.This research is supported by the Belgian OSTC project EV/12/10B "A continuous Holocene record of ENSO variability in southern Chile"

Pathways towards coexistence with large carnivores in production systems

Coexistence between livestock grazing and carnivores in rangelands is a major challenge in terms of sustainable agriculture, animal welfare, species conservation and ecosystem function. Many effective non-lethal tools exist to protect livestock from predation, yet their adoption remains limited. Using a social-ecological transformations framework, we present two qualitative models that depict transformative change in rangelands grazing. Developed through participatory processes with stakeholders from South Africa and the United States of America, the models articulate drivers of change and the essential pathways to transition from routine lethal management of carnivores towards mutually beneficial coexistence. The pathways define broad actions that incorporate multiple values in grazing systems including changes to livestock management practices, financial support, industry capacity building, research, improved governance and marketing initiatives. A key fnding is the new concept of ‘Predator Smart Farming’, a holistic and conscientious approach to agriculture, which increases the resilience of landscapes, animals (domesticated and wild) and rural livelihoods. Implementation of these multiple pathways would lead to a future system that ensures thriving agricultural communities, secure livelihoods, reduced violence toward animals, and landscapes that are productive and support species conservation and coexistence

Supportive and palliative care needs of families of children who die from cancer: An Australian study

Objective: To obtain feedback from parents of children who died from cancer about their understanding of palliative care, their experiences of palliative and supportive care received during their child\u27s illness, and their palliative and supportive care needs. Design: A qualitative study with semi-structured interviews. Participants: 24 parents from Perth (n = 10), Melbourne (n = 5), Brisbane (n = 5) and Sydney (n = 4). Setting: Five Australian tertiary paediatric oncology centres. Results: Parents whose children died from cancer live within a context of chronic uncertainty and apprehension. Parents construed palliative care negatively as an independent process at the end of their children\u27s lives rather than as a component of a wider and continuous process where children and their families are offered both curative and palliative care throughout the cancer trajectory. The concept of palliative care was perceived to be misunderstood by key health professionals involved in the care of the child and family. The importance and therapeutic value of authentic and honest relationships between health professionals and parents, and between health professionals and children were highlighted as a critical aspect of care. Also highlighted was the need to include children and adolescents in decision making, and for the delivery of compassionate end-of-life care that is sensitive to the developmental needs of the children, their parents and siblings. Conclusions: There is a need for health professionals to better understand the concept of palliative care, and factors that contribute to honest, open, authentic and therapeutic relationships of those concerned in the care of the dying child. This will facilitate a better understanding by both parents and their children with cancer, and acceptance of the integration of palliative and supportive care in routine cancer care

A Qualitative Exploration of the Experiences of People Living Alone and Receiving Community-Based Palliative Care

Background: It is projected that in Australia there will be between 28% and 48% of palliative care patients living alone by the year 2031. As such, it will become increasingly important to provide appropriate home-based care in order to support these patients to be cared for and die at home. Aim: This study explored the experiences of community-based palliative care cancer patients who live alone without a caregiver and what psychosocial issues they face. Methods: Face-to-face semistructured interviews were conducted with eight participants, and constant comparison was used for the analysis. Findings: Four main themes emerged: (1) loss of social networks; (2) maintaining independence; (3) balancing independence and the need for assistance; and (4) planning for the end of life. Discussion: Participants balanced independence with the need to accept help in order to maintain independence. Participants became more flexible about their preferred place of death. Conclusion: The practice implications for working with people close to death who are living alone are that supports and assistance may be needed to maintain social networks and also a sense of independence