209 research outputs found
Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere
Einstein realised that the fluctuations of a Brownian particle can be used to
ascertain properties of its environment. A large number of experiments have
since exploited the Brownian motion of colloidal particles for studies of
dissipative processes, providing insight into soft matter physics, and leading
to applications from energy harvesting to medical imaging. Here we use
optically levitated nanospheres that are heated to investigate the
non-equilibrium properties of the gas surrounding them. Analysing the sphere's
Brownian motion allows us to determine the temperature of the centre-of-mass
motion of the sphere, its surface temperature and the heated gas temperature in
two spatial dimensions. We observe asymmetric heating of the sphere and gas,
with temperatures reaching the melting point of the material. This method
offers new opportunities for accurate temperature measurements with spatial
resolution on the nanoscale, and a new means for testing non-equilibrium
thermodynamicsComment: 5 pages, 4 figures, supplementary material available upon reques
The vibration discomfort of standing persons: 0.5â16-Hz fore-and-aft, lateral, and vertical vibration
Communicating climate change: conduits, content, and consensus
Climate change has been the subject of increasing efforts by scientists to understand its causes and implications; it has been of growing interest to policymakers, international bodies, and a variety of nongovernment organizations; and it has attracted varied amounts of attention from traditional and, increasingly, online media. These developments have been aligned with shifts in the nature of climate change communication, with changes in how researchers study it and how a variety of actors try to influence it. This article situates the theory and practice of climate change communication within developments that have taken place since we first reviewed the field in 2009. These include the rise of new social media conduits for communication, research, and practice aimed at fine tuning communication content, and the rise to prominence of scientific consensus as part of that content. We focus in particular on continuing tensions between a focus on the part of communicators to inform the public and more dialogic strategies of public engagement. We also consider the tension between efforts to promote consensus and certainty in climate science and approaches that attempt to engage with uncertainty more fully. We explore the lessons to be learnt from climate communication since 2009, highlighting how the field remains haunted by the deficit model of science communication. Finally, we point to more fruitful future directions for climate change communication, including more participatory models that acknowledge, rather than ignore, residual uncertainties in climate science in order to stimulate debate and deliberation
Business angel exits: A theory of planned behaviour perspective
Although there are a handful of studies on business angel investment returns, the business angel literature has given little or no attention to exits and the exit strategy. This is surprising given that a primary objective of investing is to achieve a capital gain through some form of liquidity event. Using the theory of planned behaviour (TPB) as an interpretative heuristic, we examine how exits happen: specifically, what are the motivations to seek an exit and to what extent are they planned or opportunistic? Based on multiple case studies in which business angels were invited to tell the story of their most recent exit(s), the evidence suggests that the majority of liquidity events are the outcome of planned behaviour. We propose a typology of angel-backed investment exits as the basis for identifying future directions for research and developing practical advice to angels on effective business practices
Recommended from our members
Angel investor's selection criteria: a comparative institutional perspective
Despite the important role of angel investors as critical financial providers for new ventures, little is known regarding how institutions make their investment decisions. While angels make decisions based on selection criteria during the first stage, they are also embedded within and affected by different institutional settings and as a result weight these criteria differently than other investors. We compare angel investors' selection criteria in China and Denmark using the comparative institutional perspective. We use a policy capturing approach and hierarchy linear modeling, revealing that since Chinese angels are embedded within relationship-based institutional settings they tend to reply more on strong ties such as family and friends in management team, as well as weighting risks less compared to Danish angels operating within more rule-based institutional contexts
Product and process innovation in manufacturing firms: a 30-year bibliometric analysis
Built upon a thirty-year dataset collected from the Web of Science database, the present research aims to offer a comprehensive overview of papers, authors, streams of research, and the most influential journals that discuss product and process innovation in the manufacturing environment. The dataset is composed of 418 papers from more than 150 journals from the period between 1985 and 2015. Homogeneity analysis by means of alternating least squares (HOMALS) and Social Network Analysis (SNA) are used to accomplish the objectives listed above through the keywords given by authors. Initially, the paper highlights and discusses the similarity between the topics debated by the main journals in this field. Subsequently, a wide-range map of topics is presented highlighting five main areas of interests; namely, performance, patent, small firm, product development, and organization. A SNA is also performed in order to validate the results that emerged from HOMALS. Finally, several insights about future research avenues in the manufacturing field are provided
Electroporation increases antitumoral efficacy of the bcl-2 antisense G3139 and chemotherapy in a human melanoma xenograft
<p>Abstract</p> <p>Background</p> <p>Nucleic acids designed to modulate the expression of target proteins remain a promising therapeutic strategy in several diseases, including cancer. However, clinical success is limited by the lack of efficient intracellular delivery. In this study we evaluated whether electroporation could increase the delivery of antisense oligodeoxynucleotides against bcl-2 (G3139) as well as the efficacy of combination chemotherapy in human melanoma xenografts.</p> <p>Methods</p> <p>Melanoma-bearing nude mice were treated i.v. with G3139 and/or cisplatin (DDP) followed by the application of trains of electric pulses to tumors. Western blot, immunohistochemistry and real-time PCR were performed to analyze protein and mRNA expression. The effect of electroporation on muscles was determined by histology, while tumor apoptosis and the proliferation index were analyzed by immunohistochemistry. Antisense oligodeoxynucleotides tumor accumulation was measured by FACS and confocal microscopy.</p> <p>Results</p> <p>The G3139/Electroporation combined therapy produced a significant inhibition of tumor growth (TWI, more than 50%) accompanied by a marked tumor re-growth delay (TRD, about 20 days). The efficacy of this treatment was due to the higher G3139 uptake in tumor cells which led to a marked down-regulation of bcl-2 protein expression. Moreover, the G3139/EP combination treatment resulted in an enhanced apoptotic index and a decreased proliferation rate of tumors. Finally, an increased tumor response was observed after treatment with the triple combination G3139/DDP/EP, showing a TWI of about 75% and TRD of 30 days.</p> <p>Conclusions</p> <p>These results demonstrate that electroporation is an effective strategy to improve the delivery of antisense oligodeoxynucleotides within tumor cells <it>in vivo </it>and it may be instrumental in optimizing the response of melanoma to chemotherapy. The high response rate observed in this study suggest to apply this strategy for the treatment of melanoma patients.</p
Implications of human performance and perception under tonal noise conditions on indoor noise criteria
Environmental, Dietary, Maternal, and Fetal Predictors of Bulky DNA Adducts in Cord Blood: A European MotherâChild Study (NewGeneris)
Background:Bulky DNA adducts reflect genotoxic exposures, have been associated with lower birth weight, and may predict cancer risk.Objective:We selected factors known or hypothesized to affect in utero adduct formation and repair and examined their associations with adduct levels in neonates.Methods:Pregnant women from Greece, Spain, England, Denmark, and Norway were recruited in 2006â2010. Cord blood bulky DNA adduct levels were measured by the 32P-postlabeling technique (n = 511). Diet and maternal characteristics were assessed via questionnaires. Modeled exposures to air pollutants and drinking-water disinfection by-products, mainly trihalomethanes (THMs), were available for a large proportion of the study population.Results:Greek and Spanish neonates had higher adduct levels than the northern European neonates [median, 12.1 (n = 179) vs. 6.8 (n = 332) adducts per 108 nucleotides, p < 0.001]. Residence in southern European countries, higher maternal body mass index, delivery by cesarean section, male infant sex, low maternal intake of fruits rich in vitamin C, high intake of dairy products, and low adherence to healthy diet score were statistically significantly associated with higher adduct levels in adjusted models. Exposure to fine particulate matter and nitrogen dioxide was associated with significantly higher adducts in the Danish subsample only. Overall, the pooled results for THMs in water show no evidence of association with adduct levels; however, there are country-specific differences in results with a suggestion of an association in England.Conclusion:These findings suggest that a combination of factors, including unknown country-specific factors, influence the bulky DNA adduct levels in neonates.Citation:Pedersen M, Mendez MA, Schoket B, Godschalk RW, Espinosa A, Landström A, Villanueva CM, Merlo DF, Fthenou E, Gracia-Lavedan E, van Schooten FJ, Hoek G, Brunborg G, Meltzer HM, Alexander J, Nielsen JK, Sunyer J, Wright J, KovĂĄcs K, de Hoogh K, Gutzkow KB, Hardie LJ, Chatzi L, Knudsen LE, Anna L, Ketzel M, Haugen M, Botsivali M, Nieuwenhuijsen MJ, Cirach M, Toledano MB, Smith RB, Fleming S, Agramunt S, Kyrtopoulos SA, LukĂĄcs V, Kleinjans JC, SegerbĂ€ck D, Kogevinas M. 2015. Environmental, dietary, maternal, and fetal predictors of bulky DNA adducts in cord blood: a European motherâchild study (NewGeneris). Environ Health Perspect 123:374â380;âhttp://dx.doi.org/10.1289/ehp.140861
- âŠ