148 research outputs found
Calculation of the real part of the nuclear amplitude at high s and small t from the Coulomb amplitude
A new method for the determination of the real part of the elastic scattering
amplitude is examined for high energy proton-proton at small momentum transfer.
This method allows us to decrease the number of model assumptions, to obtain
the real part in a narrow region of momentum transfer and to test different
models. The possible non-exponential behavior of the real part was found on the
base of the analysis of the ISR experimental data.Comment: 5 pages, 3 figures, Talk on XIth International Conference on Elastic
and Diffractive Scatterin
Thermal Aware Design Method for VCSEL-Based On-Chip Optical Interconnect
Optical Network-on-Chip (ONoC) is an emerging technology considered as one of
the key solutions for future generation on-chip interconnects. However, silicon
photonic devices in ONoC are highly sensitive to temperature variation, which
leads to a lower efficiency of Vertical-Cavity Surface-Emitting Lasers
(VCSELs), a resonant wavelength shift of Microring Resonators (MR), and results
in a lower Signal to Noise Ratio (SNR). In this paper, we propose a methodology
enabling thermal-aware design for optical interconnects relying on
CMOS-compatible VCSEL. Thermal simulations allow designing ONoC interfaces with
low gradient temperature and analytical models allow evaluating the SNR.Comment: IEEE International Conference on Design Automation and Test in Europe
(DATE 2015), Mar 2015, Grenoble, France. 201
A natural fuzzyness of de Sitter space-time
A non-commutative structure for de Sitter spacetime is naturally introduced
by replacing ("fuzzyfication") the classical variables of the bulk in terms of
the dS analogs of the Pauli-Lubanski operators. The dimensionality of the fuzzy
variables is determined by a Compton length and the commutative limit is
recovered for distances much larger than the Compton distance. The choice of
the Compton length determines different scenarios. In scenario I the Compton
length is determined by the limiting Minkowski spacetime. A fuzzy dS in
scenario I implies a lower bound (of the order of the Hubble mass) for the
observed masses of all massive particles (including massive neutrinos) of spin
s>0. In scenario II the Compton length is fixed in the de Sitter spacetime
itself and grossly determines the number of finite elements ("pixels" or
"granularity") of a de Sitter spacetime of a given curvature.Comment: 16 page
Heisenberg's Universal (lns)**2 Increase of Total Cross Sections
The (lns)**2 behaviour of total cross-sections, first obtained by Heisenberg
50 years ago, receives now increased interest both on phenomenological and
theoretical levels. In this paper we present a modification of the Heisenberg's
model in connection with the presence of glueballs and we show that it leads to
a realistic description of all existing hadron total cross-section data.Comment: 6 pages, 3 figure
Increased Activity of Cell Surface Peptidases in HeLa Cells Undergoing UV-Induced Apoptosis Is Not Mediated by Caspase 3
We have previously shown that in HeLa cells treated with a variety of agents there is an increase in cell surface peptidase (CSP) activity in those cells undergoing apoptosis. The increase in CSP activity observed in UVB-irradiated cells undergoing apoptosis was unaffected when the cultures were treated with the aminopeptidase inhibitor bestatin, and matrix metalloprotease inhibitor BB3103, but greatly enhanced when treated with the caspase 3 inhibitor-DEVD, and reduced in the presence of the poly(ADP-ribose) polymerase (PARP) inhibitor-3-aminobenzamide (3AB). Neither 3AB nor DEVD had an effect on the gross morphology of the apoptotic cells observed under electron microscopy, nor did they have an effect on phosphatidylserine eversion on the cell membrane, or that of PARP cleavage. All the agents except for DEVD had no effect on the level of caspase 3 activity in the cells. The results suggest that other caspases may cleave PARP in these cells. Both 3AB and DEVD treatment reduced the level of actin cleavage seen in the apoptotic cells. The increase in CSP activity observed in cells undergoing UVB-induced apoptosis appears to involve PARP but not caspase 3
Pre-formulation and systematic evaluation of amino acid assisted permeability of insulin across in vitro buccal cell layers
The aim of this work was to investigate alternative safe and effective permeation enhancers for buccal peptide delivery. Basic amino acids improved insulin solubility in water while 200 and 400 ”g/mL lysine significantly increased insulin solubility in HBSS. Permeability data showed a significant improvement in insulin permeation especially for 10 ”g/mL of lysine (p < 0.05) and 10 ”g/mL histidine (p < 0.001), 100 ”g/mL of glutamic acid (p < 0.05) and 200 ”g/mL of glutamic acid and aspartic acid (p < 0.001) without affecting cell integrity; in contrast to sodium deoxycholate which enhanced insulin permeability but was toxic to the cells. It was hypothesized that both amino acids and insulin were ionised at buccal cavity pH and able to form stable ion pairs which penetrated the cells as one entity; while possibly triggering amino acid nutrient transporters on cell surfaces. Evidence of these transport mechanisms was seen with reduction of insulin transport at suboptimal temperatures as well as with basal-to-apical vectoral transport, and confocal imaging of transcellular insulin transport. These results obtained for insulin is the first indication of a possible amino acid mediated transport of insulin via formation of insulin-amino acid neutral complexes by the ion pairing mechanism
Insights into the Complex Formed by Matrix Metalloproteinase-2 and Alloxan Inhibitors: Molecular Dynamics Simulations and Free Energy Calculations
Matrix metalloproteinases (MMP) are well-known biological targets implicated in tumour progression, homeostatic regulation, innate immunity, impaired delivery of pro-apoptotic ligands, and the release and cleavage of cell-surface receptors. Hence, the development of potent and selective inhibitors targeting these enzymes continues to be eagerly sought. In this paper, a number of alloxan-based compounds, initially conceived to bias other therapeutically relevant enzymes, were rationally modified and successfully repurposed to inhibit MMP-2 (also named gelatinase A) in the nanomolar range. Importantly, the alloxan core makes its debut as zinc binding group since it ensures a stable tetrahedral coordination of the catalytic zinc ion in concert with the three histidines of the HExxHxxGxxH metzincin signature motif, further stabilized by a hydrogen bond with the glutamate residue belonging to the same motif. The molecular decoration of the alloxan core with a biphenyl privileged structure allowed to sample the deep S1âČ specificity pocket of MMP-2 and to relate the high affinity towards this enzyme with the chance of forming a hydrogen bond network with the backbone of Leu116 and Asn147 and the side chains of Tyr144, Thr145 and Arg149 at the bottom of the pocket. The effect of even slight structural changes in determining the interaction at the S1âČ subsite of MMP-2 as well as the nature and strength of the binding is elucidated via molecular dynamics simulations and free energy calculations. Among the herein presented compounds, the highest affinity (pIC50â=â7.06) is found for BAM, a compound exhibiting also selectivity (>20) towards MMP-2, as compared to MMP-9, the other member of the gelatinases
Software countermeasures for control flow integrity of smart card C codes
International audienceFault attacks can target smart card programs in order to disrupt an execution and gain an advantage over the data or the embedded functionalities. Among all possible attacks, control flow attacks aim at disrupting the normal execution flow. Identifying harmful control flow attacks as well as designing countermeasures at software level are tedious and tricky for developers. In this paper, we propose a methodology to detect harmful intra-procedural jump attacks at source code level and to automatically inject formally-proven countermeasures. The proposed software countermeasures defeat 100% of attacks that jump over at least two C source code statements or beyond. Experiments show that the resulting code is also hardened against unexpected function calls and jump attacks at assembly level
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