150 research outputs found
Multiscale Analysis of Metal Oxide Nanoparticles in Tissue: Insights into Biodistribution and Biotransformation
Metal oxide nanoparticles have emerged as exceptionally potent biomedical sensors and actuators due to their unique physicochemical features. Despite fascinating achievements, the current limited understanding of the molecular interplay between nanoparticles and the surrounding tissue remains a major obstacle in the rationalized development of nanomedicines, which is reflected in their poor clinical approval rate. This work reports on the nanoscopic characterization of inorganic nanoparticles in tissue by the example of complex metal oxide nanoparticle hybrids consisting of crystalline cerium oxide and the biodegradable ceramic bioglass. A validated analytical method based on semiquantitative Xâray fluorescence and inductively coupled plasma spectrometry is used to assess nanoparticle biodistribution following intravenous and topical application. Then, a correlative multiscale analytical cascade based on a combination of microscopy and spectroscopy techniques shows that the topically applied hybrid nanoparticles remain at the initial site and are preferentially taken up into macrophages, form apatite on their surface, and lead to increased accumulation of lipids in their surroundings. Taken together, this work displays how modern analytical techniques can be harnessed to gain unprecedented insights into the biodistribution and biotransformation of complex inorganic nanoparticles. Such nanoscopic characterization is imperative for the rationalized engineering of safe and efficacious nanoparticleâbased systems
Fracturing ranked surfaces
Discretized landscapes can be mapped onto ranked surfaces, where every
element (site or bond) has a unique rank associated with its corresponding
relative height. By sequentially allocating these elements according to their
ranks and systematically preventing the occupation of bridges, namely elements
that, if occupied, would provide global connectivity, we disclose that bridges
hide a new tricritical point at an occupation fraction , where
is the percolation threshold of random percolation. For any value of in the
interval , our results show that the set of bridges has a
fractal dimension in two dimensions. In the limit , a self-similar fracture is revealed as a singly connected line
that divides the system in two domains. We then unveil how several seemingly
unrelated physical models tumble into the same universality class and also
present results for higher dimensions
Evidence of detrimental effects of prenatal alcohol exposure on offspring birthweight and neurodevelopment from a systematic review of quasi-experimental studies
Background: Systematic reviews of prenatal alcohol exposure effects generally only include conventional observational studies. However, estimates from such studi
The labour supply effect of Education Maintenance Allowance and its implications for parental altruism
Education Maintenance Allowance (EMA) was a UK government cash transfer paid directly to children aged 16â18, in the first 2Â years of post-compulsory full-time education. This paper uses the labour supply effect of EMA to infer the magnitude of the transfer response made by the parent, and so test for the presence of an âeffectively altruisticâ head-of-household, who redistributes resources among household members so as to maximise overall welfare. Using data from the Longitudinal Study of Young People in England, an EMA payment of ÂŁ30 per week is found to reduce teenagersâ labour supply by 3Â h per week and probability of employment by 13Â % points from a base of 43Â %. We conclude that parents withdraw cash and in-kind transfers from their children to a value of between 22 and 86Â % of what the child receives in EMA. This means we reject the hypothesis of an effectively altruistic head-of-household, and argue that making this cash transfer directly to the child produces higher child welfare than if the equivalent transfer were made to parents
Testing spooky action at a distance
In science, one observes correlations and invents theoretical models that
describe them. In all sciences, besides quantum physics, all correlations are
described by either of two mechanisms. Either a first event influences a second
one by sending some information encoded in bosons or molecules or other
physical carriers, depending on the particular science. Or the correlated
events have some common causes in their common past. Interestingly, quantum
physics predicts an entirely different kind of cause for some correlations,
named entanglement. This new kind of cause reveals itself, e.g., in
correlations that violate Bell inequalities (hence cannot be described by
common causes) between space-like separated events (hence cannot be described
by classical communication). Einstein branded it as spooky action at a
distance. A real spooky action at a distance would require a faster than light
influence defined in some hypothetical universally privileged reference frame.
Here we put stringent experimental bounds on the speed of all such hypothetical
influences. We performed a Bell test during more than 24 hours between two
villages separated by 18 km and approximately east-west oriented, with the
source located precisely in the middle. We continuously observed 2-photon
interferences well above the Bell inequality threshold. Taking advantage of the
Earth's rotation, the configuration of our experiment allowed us to determine,
for any hypothetically privileged frame, a lower bound for the speed of this
spooky influence. For instance, if such a privileged reference frame exists and
is such that the Earth's speed in this frame is less than 10^-3 that of the
speed of light, then the speed of this spooky influence would have to exceed
that of light by at least 4 orders of magnitude.Comment: Preliminary version of Nature 454, 861-864 (14 August 2008). 5 pages
and 5 figure
Elite Influence? Religion, Economics, and the Rise of the Nazis
Adolf Hitler's seizure of power was one of the most consequential events of the twentieth century. Yet, our understanding of which factors fueled the astonishing rise of the Nazis remains highly incomplete. This paper shows that religion played an important role in the Nazi party's electoral success -- dwarfing all available socioeconomic variables. To obtain the first causal estimates we exploit plausibly exogenous variation in the geographic distribution of Catholics and Protestants due to a peace treaty in the sixteenth century. Even after allowing for sizeable violations of the exclusion restriction, the evidence indicates that Catholics were significantly less likely to vote for the Nazi Party than Protestants. Consistent with the historical record, our results are most naturally rationalized by a model in which the Catholic Church leaned on believers to vote for the democratic Zentrum Party, whereas the Protestant Church remained politically neutral
The stigma turbine:A theoretical framework for conceptualizing and contextualizing marketplace stigma
Stigmas, or discredited personal attributes, emanate from social perceptions of physical characteristics, aspects of character, and âtribalâ associations (e.g., race; Goffman 1963). Extant research emphasizes the perspective of the stigma target, with some scholars exploring how social institutions shape stigma. Yet the ways stakeholders within the socio-commercial sphere create, perpetuate, or resist stigma remain overlooked. We introduce and define marketplace stigma as the labeling, stereotyping, and devaluation by and of commercial stakeholders (consumers, companies and their employees, stockholders, institutions) and their offerings (products, services, experiences). We offer the Stigma Turbine (ST) as a unifying conceptual framework that locates marketplace stigma within the broader sociocultural context, and illuminates its relationship to forces that exacerbate or blunt stigma. In unpacking the ST, we reveal the critical role market stakeholders can play in (de)stigmatization, explore implications for marketing practice and public policy, and offer a research agenda to further our understanding of marketplace stigma and stakeholder welfare
- âŠ