Range-Free Localization with the Radical Line

Due to hardware and computational constraints, wireless sensor networks (WSNs) normally do not take measurements of time-of-arrival or time-difference-of-arrival for rangebased localization. Instead, WSNs in some applications use rangefree localization for simple but less accurate determination of sensor positions. A well-known algorithm for this purpose is the centroid algorithm. This paper presents a range-free localization technique based on the radical line of intersecting circles. This technique provides greater accuracy than the centroid algorithm, at the expense of a slight increase in computational load. Simulation results show that for the scenarios studied, the radical line method can give an approximately 2 to 30% increase in accuracy over the centroid algorithm, depending on whether or not the anchors have identical ranges, and on the value of DOI.Comment: Proc. IEEE ICC'10, Cape Town, South Africa, May, 201

Modulation of 5-Aminolevulinic acid mediated photodynamic therapy induced cell death in a human lung adenocarcinoma cell line

Photodynamic therapy (PDT) is a cancer treatment involving the administration of a photosensitising drug which selectively accumulates in tumor tissue, followed by irradiation with appropriate wavelength light. It triggers photochemical reactions inducing reactive oxygen species (ROS) production with the consequent cellular damage, which ultimately leads to cell death. Porphyrins are the only photosensitizers (PSs) endogenously synthesized by means of administration of the biological precursor, 5- aminolevulinic acid (ALA). Several antioxidants and ROS scavenger agents: reduced glutathione (GSH), mannitol (Man), l-tryptophan (Trp), ascorbate (Asc) and trolox (Trx), were assayed to determine their ability to modulate ALA-based PDT (ALA-PDT); it was performed on A549 human lung adenocarcinoma cells, by incubating with 1mM ALA for 3 hr and followed by irradiation with or without 1 hr pre-incubation with the modulators. They were previously tested for possible cytotoxicity/ photoactivity in concentrations ranging from 0.01 to 20 mM. The ratio between cell survival after ALA-PDT in the presence and in the absence of the scavenger agent (protection grade: PG) was determined, and the concentration showing no cytotoxicity/ photoactivity and providing the highest PG was used in the subsequent experiments. ALA-PDT alone induced a high percentage of apoptotic cell death (98.4 ± 3.5%) as revealed by acridine orange/ethidium bromide staining and AnnexinV-FITC/propidium iodide labelling. Pre-incubation with the modulators at their highest PG concentration significantly reduced apoptotic cells to 48.3 ± 2.7% (Asc), 58.8 ± 4.2 (Trx), 78.5 ± 3.1% (GSH), 64.3 ± 1.6% (Man), 74.6 ± 2.3% (Trp). ROS involvement in early cell death induction after ALA-PDT was tested by flow cytometry using the fluorescent probes dihydro-dichlorofluorescein diacetate (H2-DCFDA) and methoxyvinylpyrene (MVP) for detection of peroxides and singlet oxygen, respectively. ROS production increased after ALA-PDT (H2-DCFDA positive cells, control: 1.1 ± 0.1 %; 10 min-PDT: 69.3 ± 5.6%; MVP positive cells, control: 0.65 ± 0.35%; 10 min-PDT: 83.5 ± 1.9%). Asc prevented peroxide formation (H2-DCFDA positive cells: 50.7 ± 2.8%) and mostly prevented singlet oxygen increase (MVP positive cells: 25.4 ± 5.2%) whereas Trx limited peroxides formation (H2-DCFDA positive cells: 20.8 ± 0.5%), but did not significantly affected singlet oxygen production (MVP positive cells: 73.6 ± 3.4%). Selective scavenger mediated protection against PDT-induced cell death, and direct detection of specific pro-oxidative agents, entail the strong involvement of ROS in ALA-PDT-mediated tumor eradication, suggesting that undesired photodamage to normal tissue might be attenuated by administration of antioxidant agents.Fil: Teijo, Maria Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Diez, Berenice Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Battle, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Fukuda, Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Investigaciones sobre Porfirinas y Porfirias. Universidad de Buenos Aires. Centro de Investigaciones sobre Porfirinas y Porfirias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin

Beyond gauge theory: Hilbert space positivity and causal localization in the presence of vector mesons

The Hilbert space formulation of interacting $s=1$ vector-potentials stands in an interesting contrast with the point-local Krein space setting of gauge theory. Already in the absence of interactions the Wilson loop in a Hilbert space setting has a "topological property" which is missing in the gauge theoretic description (Haag duality, Aharonov-Bohm effect); the conceptual differences increase in the presence of interactions. The Hilbert space positivity weakens the causal localization properties if interacting fields which results in the replacement of the gauge-variant point-local matter fields in Krein space by string-local physical fields in Hilbert space. The gauge invariance of the perturbative S-matrix corresponds to its independence of the spacelike string direction of its interpolating.fields. In contrast to gauge theory, whose physical range is limited to gauge invariant perturbative S-matrix and local observables, its Hilbert space string-local counterpart in is a full-fledged quantum field theory. The new setting reveals that the Lie-structure of self-coupled vector mesons results from perturbative implementation of the causal localization principles of QFT.Comment: 38 page

Androgen receptor phosphorylation status at serine 578 predicts poor outcome in prostate cancer patients

Purpose: Prostate cancer growth is dependent upon androgen receptor (AR) activation, regulated via phosphorylation. Protein kinase C (PKC) is one kinase that can mediate AR phosphorylation. This study aimed to establish if AR phosphorylation by PKC is of prognostic significance. Methods: Immunohistochemistry for AR, AR phosphorylated at Ser-81 (pARS81), AR phosphorylated at Ser-578 (pARS578), PKC and phosphorylated PKC (pPKC) was performed on 90 hormone-naïve prostate cancer specimens. Protein expression was quantified using the weighted histoscore method and examined with regard to clinico-pathological factors and outcome measures; time to biochemical relapse, survival from biochemical relapse and disease-specific survival. Results: Nuclear PKC expression strongly correlated with nuclear pARS578 (c.c. 0.469, p=0.001) and cytoplasmic pARS578 (c.c. 0.426 p=0.002). High cytoplasmic and nuclear pARS578 were associated with disease-specific survival (p<0.001 and p=0.036 respectively). High nuclear PKC was associated with lower disease-specific survival when combined with high pARS578 in the cytoplasm (p=0.001) and nucleus (p=0.038). Combined high total pARS81 and total pARS578 was associated with decreased disease-specific survival (p=0.005) Conclusions: pARS578 expression is associated with poor outcome and is a potential independent prognostic marker in hormone-naïve prostate cancer. Furthermore, PKC driven AR phosphorylation may promote prostate cancer progression and provide a novel therapeutic target

Probing the mechanism of electron capture and electron transfer dissociation using tags with variable electron affinity

Electron capture dissociation (ECD) and electron transfer dissociation (ETD) of doubly protonated electron affinity (EA)-tuned peptides were studied to further illuminate the mechanism of these processes. The model peptide FQpSEEQQQTEDELQDK, containing a phosphoserine residue, was converted to EA-tuned peptides via β-elimination and Michael addition of various thiol compounds. These include propanyl, benzyl, 4-cyanobenzyl, perfluorobenzyl, 3,5-dicyanobenzyl, 3-nitrobenzyl, and 3,5-dinitrobenzyl structural moieties, having a range of EA from −1.15 to +1.65 eV, excluding the propanyl group. Typical ECD or ETD backbone fragmentations are completely inhibited in peptides with substituent tags having EA over 1.00 eV, which are referred to as electron predators in this work. Nearly identical rates of electron capture by the dications substituted by the benzyl (EA = −1.15 eV) and 3-nitrobenzyl (EA = 1.00 eV) moieties are observed, which indicates the similarity of electron capture cross sections for the two derivatized peptides. This observation leads to the inference that electron capture kinetics are governed by the long-range electron−dication interaction and are not affected by side chain derivatives with positive EA. Once an electron is captured to high-n Rydberg states, however, through-space or through-bond electron transfer to the EA-tuning tags or low-n Rydberg states via potential curve crossing occurs in competition with transfer to the amide π* orbital. The energetics of these processes are evaluated using time-dependent density functional theory with a series of reduced model systems. The intramolecular electron transfer process is modulated by structure-dependent hydrogen bonds and is heavily affected by the presence and type of electron-withdrawing groups in the EA-tuning tag. The anion radicals formed by electron predators have high proton affinities (approximately 1400 kJ/mol for the 3-nitrobenzyl anion radical) in comparison to other basic sites in the model peptide dication, facilitating exothermic proton transfer from one of the two sites of protonation. This interrupts the normal sequence of events in ECD or ETD, leading to backbone fragmentation by forming a stable radical intermediate. The implications which these results have for previously proposed ECD and ETD mechanisms are discussed