2,842 research outputs found
Targeted microbubbles: a novel application for the treatment of kidney stones
Kidney stone disease is endemic. Extracorporeal shockwave lithotripsy was the first major technological breakthrough where focused shockwaves were used to fragment stones in the kidney or ureter. The shockwaves induced the formation of cavitation bubbles, whose collapse released energy at the stone, and the energy fragmented the kidney stones into pieces small enough to be passed spontaneously. Can the concept of microbubbles be used without the bulky machine? The logical progression was to manufacture these powerful microbubbles ex vivo and inject these bubbles directly into the collecting system. An external source can be used to induce cavitation once the microbubbles are at their target; the key is targeting these microbubbles to specifically bind to kidney stones. Two important observations have been established: (i) bisphosphonates attach to hydroxyapatite crystals with high affinity; and (ii) there is substantial hydroxyapatite in most kidney stones. The microbubbles can be equipped with bisphosphonate tags to specifically target kidney stones. These bubbles will preferentially bind to the stone and not surrounding tissue, reducing collateral damage. Ultrasound or another suitable form of energy is then applied causing the microbubbles to induce cavitation and fragment the stones. This can be used as an adjunct to ureteroscopy or percutaneous lithotripsy to aid in fragmentation. Randall's plaques, which also contain hydroxyapatite crystals, can also be targeted to pre-emptively destroy these stone precursors. Additionally, targeted microbubbles can aid in kidney stone diagnostics by virtue of being used as an adjunct to traditional imaging methods, especially useful in high-risk patient populations. This novel application of targeted microbubble technology not only represents the next frontier in minimally invasive stone surgery, but a platform technology for other areas of medicine
From partners to populations:A hierarchical Bayesian account of coordination and convention
Languages are powerful solutions to coordination problems: they provide
stable, shared expectations about how the words we say correspond to the
beliefs and intentions in our heads. Yet language use in a variable and
non-stationary social environment requires linguistic representations to be
flexible: old words acquire new ad hoc or partner-specific meanings on the fly.
In this paper, we introduce CHAI (Continual Hierarchical Adaptation through
Inference), a hierarchical Bayesian theory of coordination and convention
formation that aims to reconcile the long-standing tension between these two
basic observations. We argue that the central computational problem of
communication is not simply transmission, as in classical formulations, but
continual learning and adaptation over multiple timescales. Partner-specific
common ground quickly emerges from social inferences within dyadic
interactions, while community-wide social conventions are stable priors that
have been abstracted away from interactions with multiple partners. We present
new empirical data alongside simulations showing how our model provides a
computational foundation for several phenomena that have posed a challenge for
previous accounts: (1) the convergence to more efficient referring expressions
across repeated interaction with the same partner, (2) the gradual transfer of
partner-specific common ground to strangers, and (3) the influence of
communicative context on which conventions eventually form.Comment: In press at Psychological Revie
Mechanical and thermal properties of crab chitin reinforced carboxylated SBR composites
The addition of small amounts (up to 9 wt%) of chitin microsized particles, originating from shellfish waste, to carboxylated styrene-butadiene rubber (XSBR) matrix (as received and annealed to 100°C) has been studied. In particular, this study concentrated on their mechanical (creep investigation by nanoindentation and dynamical-mechanical analysis), thermal (differential scanning calorimetry and thermogravimetry) and swelling behaviour (toluene absorption) and was completed by morphological characterisation by scanning electron microscopy and atomic force microscopy. The results show that annealing has a limited effect on materials properties, effects which are further reduced by the addition of growing amounts of crab chitin. It should be noted that the limited filler content used in the study does not substantially modify the linear creep behaviour of XSBR for sufficiently long loading times. The thermal stability of the system does also appear to be preserved even with the maximum chitin content added, while it serves sufficiently as an effective barrier against aromatic solvent absorption
Revalorization of sunflower stalks as novel sources of cellulose nanofibrils and nanocrystals and their effect on wheat gluten bionanocomposite properties
[EN] Novel gluten based bionanocomposites reinforced with cellulose nanofibrils (CNF) and cellulose
nanocrystals (CNC) extracted from sunflower stalks by respectively a steam explosion treatment and
a hydrolysis procedure, were prepared by casting/evaporation. The extracted cellulose nanomaterials,
both CNC and CNF, were embedded in gluten matrix and their effect was investigated. Morphological
investigations highlighted that gluten based bionanocomposites showed a homogenous morphology,
the absence of visible cellulose nanoreinforcements, and the presence of holes for Gluten CNF nanocomposites.
Gluten CNF showed a reduction of water vapour permeability coefficients but the values are
higher respect to gluten reinforced with CNC. This behaviour could be related to the ability of CNC to
increase the tortuous path of gas molecules. Moreover, the results from thermal, mechanical and barrier
properties confirmed the strong interactions obtained between CNC and gluten matrix during the
process.
The study suggested the possibility to re-valorise agricultural wastes with potential applications as
reinforcement in polymer matrix bionanocomposites.
© 2016 Elsevier Ltd. All rights reservedFortunati, E.; Luzi, F.; Jiménez Marco, A.; Gopakumar, D.; Puglia, D.; Thomas, S.; Kenny, J.... (2016). Revalorization of sunflower stalks as novel sources of cellulose nanofibrils and nanocrystals and their effect on wheat gluten bionanocomposite properties. Carbohydrate Polymers. 149:357-368. doi:10.1016/j.carbpol.2016.04.120S35736814
The Pine Needle, May 1947
Libraries and archives collect materials from different cultures and time periods to preserve and make available the historical record. As a result, materials such as those presented here may reflect sexist, misogynistic, abusive, racist, or discriminatory attitudes or actions that some may find disturbing, harmful, or difficult to view.
Both a humor and literary magazine, The Pine Needle was a University of Maine student-produced periodical that began publication in the fall of 1946, the first post-World War II semester that saw GIs returning to campus.
The Needle reflected an edginess and rebellion not found in previous student publications. While past student publications relied on euphemisms for alcohol and dating on campus, The Needle openly promoted the sexualization of co-eds and the use of drugs, tobacco, and alcohol by students who experienced war.
In response to Alumni complaints that The Needle was ...filled with sex and drinking, the University Publications Committee instituted stricter controls. In this issue, the editorial staff announce that starting in Fall 1947, the publication would publish only four issues of the magazine each yearâFall, Christmas, Spring, and Graduation among other changes.
Cover art for this issue is an unsigned ink illustration of chatting university students lined up outside a shop bearing a sign that reads Jifty Cleaners-Dyers. Signs in the shop window reads We Specialize in Grass Stains. 24 Hour Service
Geographic Clusters of Primary Biliary Cirrhosis
Genetic and environmental factors have been widely suggested to contribute to the pathogenesis of primary biliary cirrhosis (PBC), an autoimmune disease of unknown etiology leading to destruction of small bile ducts. Interestingly, epidemiologic data indicate a variable prevalence of the disease in different geographical areas. The study of clusters of PBC may provide clues as to possible triggers in the induction of immunopathology. We report herein four such unique PBC clusters that suggest the presence of both genetic and environmental factors in the induction of PBC. The first cluster is represented by a family of ten siblings of Palestinian origin that have an extraordinary frequency of PBC (with 5/8 sisters having the disease). Second, we describe the cases of a husband and wife, both having PBC. A family in which PBC was diagnosed in two genetically unrelated individuals, who lived in the same household, represents the third cluster. Fourth, we report a high prevalence of PBC cases in a very small area in Alaska. Although these data are anedoctal, the study of a large number of such clusters may provide a tool to estimate the roles of genetics and environment in the induction of autoimmunity
On the effect of linear feedback and parametric pumping on a resonators frequency stability
Resonant sensors based on Micro- and Nano-Electro Mechanical Systems (M/NEMS)
are ubiquitous in many sensing applications due to their outstanding
performance capabilities, which are directly proportional to the quality factor
(Q) of the devices. We address here a recurrent question in the field: do
dynamical techniques that modify the effective Q (namely parametric pumping and
direct drive velocity feedback) affect the performance of said sensors? We
develop analytical models of both cases, while remaining in the linear regime,
and introduce noise in the system from two separate sources: thermomechanical
and amplifier (read-out) noise. We observe that parametric pumping enhances the
quality factor in the amplitude response, but worsens it in the phase response
on the resonator. In the case of feedback, we find that Q is enhanced in both
cases. Then, we establish a solution for the noisy problem with direct drive
and parametric pumping simultaneously. We also find that, in the case when
thermomechanical noise dominates, no benefit can be obtained from neither
artificial Q-enhancement technique. However, in the case when amplifier noise
dominates, we surprisingly observe that a significant advantage can only be
achieved using parametric pumping in the squeezing region
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