5,329 research outputs found
Dynamic disorder in receptor-ligand forced dissociation experiments
Recently experiments showed that some biological noncovalent bonds increase
their lifetimes when they are stretched by an external force, and their
lifetimes will decrease when the force increases further. Several specific
quantitative models have been proposed to explain the intriguing transitions
from the "catch-bond" to the "slip-bond". Different from the previous efforts,
in this work we propose that the dynamic disorder of the force-dependent
dissociation rate can account for the counterintuitive behaviors of the bonds.
A Gaussian stochastic rate model is used to quantitatively describe the
transitions observed recently in the single bond P-selctin glycoprotein ligand
1(PSGL-1)P-selectin force rupture experiment [Marshall, {\it et al.}, (2003)
Nature {\bf 423}, 190-193]. Our model agrees well to the experimental data. We
conclude that the catch bonds could arise from the stronger positive
correlation between the height of the intrinsic energy barrier and the distance
from the bound state to the barrier; classical pathway scenario or {\it a
priori} catch bond assumption is not essential.Comment: 4 pages, 2 figure
Adaptive online deployment for resource constrained mobile smart clients
Nowadays mobile devices are more and more used as a platform for applications. Contrary to prior generation handheld devices configured with a predefined set of applications, today leading edge devices provide a platform for flexible and customized application deployment. However, these applications have to deal with the limitations (e.g. CPU speed, memory) of these mobile devices and thus cannot handle complex tasks. In order to cope with the handheld limitations and the ever changing device context (e.g. network connections, remaining battery time, etc.) we present a middleware solution that dynamically offloads parts of the software to the most appropriate server. Without a priori knowledge of the application, the optimal deployment is calculated, that lowers the cpu usage at the mobile client, whilst keeping the used bandwidth minimal. The information needed to calculate this optimum is gathered on the fly from runtime information. Experimental results show that the proposed solution enables effective execution of complex applications in a constrained environment. Moreover, we demonstrate that the overhead from the middleware components is below 2%
Do topology and ferromagnetism cooperate at the EuS/BiSe interface?
We probe the local magnetic properties of interfaces between the insulating
ferromagnet EuS and the topological insulator BiSe using low energy
muon spin rotation (LE-SR). We compare these to the interface between EuS
and the topologically trivial metal, titanium. Below the magnetic transition of
EuS, we detect strong local magnetic fields which extend several nm into the
adjacent layer and cause a complete depolarization of the muons. However, in
both BiSe and titanium we measure similar local magnetic fields,
implying that their origin is mostly independent of the topological properties
of the interface electronic states. In addition, we use resonant soft X-ray
angle resolved photoemission spectroscopy (SX-ARPES) to probe the electronic
band structure at the interface between EuS and BiSe. By tuning the
photon energy to the Eu anti-resonance at the Eu pre-edge we are able to
detect the BiSe conduction band, through a protective AlO
capping layer and the EuS layer. Moreover, we observe a signature of an
interface-induced modification of the buried BiSe wave functions and/or
the presence of interface states
No-cloning theorem and teleportation criteria for quantum continuous variables
We discuss the criteria presently used for evaluating the efficiency of
quantum teleportation schemes for continuous variables. Using an argument based
upon the difference between 1-to-2 quantum cloning (quantum duplication) and
1-to-infinity cloning (classical measurement), we show that a fidelity value
larger than 2/3 is required for successful quantum teleportation of coherent
states. This value has not been reached experimentally so far.Comment: 4 pages, 1 figure, submitted to Phys. Rev.
Co-translational protein targeting facilitates centrosomal recruitment of PCNT during centrosome maturation in vertebrates.
As microtubule-organizing centers of animal cells, centrosomes guide the formation of the bipolar spindle that segregates chromosomes during mitosis. At mitosis onset, centrosomes maximize microtubule-organizing activity by rapidly expanding the pericentriolar material (PCM). This process is in part driven by the large PCM protein pericentrin (PCNT), as its level increases at the PCM and helps recruit additional PCM components. However, the mechanism underlying the timely centrosomal enrichment of PCNT remains unclear. Here, we show that PCNT is delivered co-translationally to centrosomes during early mitosis by cytoplasmic dynein, as evidenced by centrosomal enrichment of PCNT mRNA, its translation near centrosomes, and requirement of intact polysomes for PCNT mRNA localization. Additionally, the microtubule minus-end regulator, ASPM, is also targeted co-translationally to mitotic spindle poles. Together, these findings suggest that co-translational targeting of cytoplasmic proteins to specific subcellular destinations may be a generalized protein targeting mechanism
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Aerosol-Jet Printed Fine-Featured Triboelectric Sensors for Motion Sensing
Triboelectric motion sensors, based on the generation of a voltage across two dissimilar materials sliding across each other as a result of the triboelectric effect, have generated interest due to the relative simplicity of the typical grated device structures and materials required. However, these sensors are often limited by poor spatial and/or temporal resolution of motion due to limitations in achieving the required device feature sizes through conventional lithography or printing techniques. Furthermore, the reliance on metallic components that are relatively straightforward to pattern into fine features limits the possibility to develop transparent sensors. Polymers would allow for transparent devices, but these materials are significantly more difficult to pattern into fine features when compared to metals. Here, we use an aerosol-jet printing (AJP) technique to develop triboelectric sensors using a wide variety of materials, including polymers, which can be directly printed into finely featured grated structures for enhanced sensitivity to displacement and speed of motion. We present a detailed investigation highlighting the role of material selection and feature size in determining the overall resolution of the resulting motion sensor. A 3-channel rotary sensor is also presented, demonstrating the versatility of the AJP technique in developing more complex triboelectric motion sensors.European Research Council (ERC-2014-STG-639526, NANOGEN)
Marie Sklodowska Curie Fellowship (H2020-MSCA-IF-2015-702868
Exposure to fine aerosols in sleeping environments of Lisbon dwellings
Trabalho apresentado em European Aerosol Conference 2023 (EAC2023), September 3−8, 2023, Malaga, SpainN/
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