59 research outputs found
Collaboration among humanitarian relief organizations and volunteer technical communities : identifying research opportunities and challenges through a systematic literature review
Collaboration is the foundation to strengthen disaster preparedness and for effective emergency response actions at all levels. Some studies have highlighted that remote volunteers, i.e., volunteers supported by Web 2.0 technologies, possess the potential to strengthen humanitarian relief organizations by offering information regarding disaster-affected people and infrastructure. Although studies have explored various aspects of this topic, none of those provided an overview of the state-of-the-art of researches on the collaboration among humanitarian organizations and communities of remote volunteers. With the aim of overcoming this gap, a systematic literature review was conducted on the existing research works. Therefore, the main contribution of this work lies in examining the state of research in this field and in identifying potential research gaps. The results show that most of the research works addresses the general domain of disaster management, whereas only few of them address the domain of humanitarian logistics.
Collaboration among Humanitarian Relief Organizations and Volunteer Technical Communities: Identifying Research Opportunities and Challenges through a Systematic Literature Review (PDF Download Available). Available from: https://www.researchgate.net/publication/315790817_Collaboration_among_Humanitarian_Relief_Organizations_and_Volunteer_Technical_Communities_Identifying_Research_Opportunities_and_Challenges_through_a_Systematic_Literature_Review [accessed May 26, 2017]
Comparison of Gene-Transfer Efficiency in Human Embryonic Stem Cells
Technologies designed to allow manipulation and modification of human embryonic stem (hES) cells are numerous and vary in the complexity of their methods, efficiency, reliability, and safety. The most commonly studied and practiced of these methods include electroporation, lipofection, nucleofection, and lentiviral transduction. However, at present, it is unclear which protocol offers the most efficient and reliable method of gene transfer to hES cells. In this study, a bi-fusion construct with ubiquitin promoter driving enhanced green fluorescent protein reporter and the firefly luciferase (pUb-eGFP-Fluc) along with neomycin selection marker was used for in vitro and in vivo studies. In vitro studies examined the transfection efficiency and viability of each technique using two hES cell lines (male H1 and female H9 cells). Lentiviral transduction demonstrated the highest efficiency (H1: 25.3 ± 4.8%; H9: 22.4 ± 6.5%) with >95% cell viability. Nucleofection demonstrated transfection efficiency of 16.1 ± 3.6% (H1) and 5.8 ± 3.2% (H9). However, minimal transfection efficiency was observed with electroporation (2.1 ± 0.4% (H1) and 1.9 ± 0.3% (H9)) and lipofection (1.5 ± 0.5% (H1) and 1.3 ± 0.2% (H9); P < 0.05 vs. lentiviral transduction). Electroporation also demonstrated the highest cell death (62 ± 11% (H1) and 42 ± 10% (H9)) followed by nucleofection (25 ± 9% (H1) and 30 ± 15 (H9)). Importantly, lentiviral transduction generated a greater number of hES cell lines stably expressing the double-fusion reporter gene (hES-DF) compared to other transfection techniques. Finally, following subcutaneous transplantation into immunodeficient nude mice, the hES-eGFP-Fluc cells showed robust proliferation as determined by longitudinal bioluminescence imaging. In summary, this study demonstrates that lentiviral transduction and nucleofection are efficient, simple, and safe techniques for reliable gene transfer in hES cells. The double-fusion construct provides an attractive approach for generating stable hES cell lines and monitoring engraftment and proliferation in vitro and in vivo
SLO-2 Is Cytoprotective and Contributes to Mitochondrial Potassium Transport
Mitochondrial potassium channels are important mediators of cell protection against stress. The mitochondrial large-conductance “big” K+ channel (mBK) mediates the evolutionarily-conserved process of anesthetic preconditioning (APC), wherein exposure to volatile anesthetics initiates protection against ischemic injury. Despite the role of the mBK in cardioprotection, the molecular identity of the channel remains unknown. We investigated the attributes of the mBK using C. elegans and mouse genetic models coupled with measurements of mitochondrial K+ transport and APC. The canonical Ca2+-activated BK (or “maxi-K”) channel SLO1 was dispensable for both mitochondrial K+ transport and APC in both organisms. Instead, we found that the related but physiologically-distinct K+ channel SLO2 was required, and that SLO2-dependent mitochondrial K+ transport was triggered directly by volatile anesthetics. In addition, a SLO2 channel activator mimicked the protective effects of volatile anesthetics. These findings suggest that SLO2 contributes to protection from hypoxic injury by increasing the permeability of the mitochondrial inner membrane to K+
Quantitative Comparison of Constitutive Promoters in Human ES cells
BACKGROUND: Constitutive promoters that ensure sustained and high level gene expression are basic research tools that have a wide range of applications, including studies of human embryology and drug discovery in human embryonic stem cells (hESCs). Numerous cellular/viral promoters that ensure sustained gene expression in various cell types have been identified but systematic comparison of their activities in hESCs is still lacking. METHODOLOGY/PRINCIPAL FINDINGS: We have quantitatively compared promoter activities of five commonly used constitutive promoters, including the human β-actin promoter (ACTB), cytomegalovirus (CMV), elongation factor-1α, (EF1α), phosphoglycerate kinase (PGK) and ubiquitinC (UbC) in hESCs. Lentiviral gene transfer was used to ensure stable integration of promoter-eGFP constructs into the hESCs genome. Promoter activities were quantitatively compared in long term culture of undifferentiated hESCs and in their differentiated progenies. CONCLUSION/SIGNIFICANCE: The ACTB, EF1α and PGK promoters showed stable activities during long term culture of undifferentiated hESCs. The ACTB promoter was superior by maintaining expression in 75-80% of the cells after 50 days in culture. During embryoid body (EB) differentiation, promoter activities of all five promoters decreased. Although the EF1α promoter was downregulated in approximately 50% of the cells, it was the most stable promoter during differentiation. Gene expression analysis of differentiated eGFP+ and eGFP- cells indicate that promoter activities might be restricted to specific cell lineages, suggesting the need to carefully select optimal promoters for constitutive gene expression in differentiated hESCs
Collaboration Among Humanitarian Relief Organizations and Volunteer Technical Communities: Identifying Research Opportunities and Challenges Through a Systematic Literature Review
Collaboration is the foundation to strengthen disaster preparedness and for effective emergency response actions at all levels. Some studies have highlighted that remote volunteers, i.e., volunteers supported by Web 2.0 technologies, possess the potential to strengthen humanitarian relief organizations by offering information regarding disaster-affected people and infrastructure. Although studies have explored various aspects of this topic, none of those provided an overview of the state-of-the-art of researches on the collaboration among humanitarian organizations and communities of remote volunteers. With the aim of overcoming this gap, a systematic literature review was conducted on the existing research works. Therefore, the main contribution of this work lies in examining the state of research in this field and in identifying potential research gaps. The results show that most of the research works addresses the general domain of disaster management, whereas only few of them address the domain of humanitarian logistics
Low-frequency gravity waves in blue supergiants revealed by high-precision space photometry
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