An intelligent trust sensing scheme with metaheuristic based secure routing protocol for Internet of Things

Cluster Computing - The Internet of Things (IoT) defines the network of physical objects, commonly used to interconnect and communicate with other devices through the internet. Security is highly...     

Pilocarpine-induced status epilepticus in rats involves ischemic and excitotoxic mechanisms

The neuron loss characteristic of hippocampal sclerosis in temporal lobe epilepsy patients is thought to be the result of excitotoxic, rather than ischemic, injury. In this study, we assessed changes in vascular structure, gene expression, and the time course of neuronal degeneration in the cerebral cortex during the acute period after onset of pilocarpine-induced status epilepticus (SE). Immediately after 2 hr SE, the subgranular layers of somatosensory cortex exhibited a reduced vascular perfusion indicative of ischemia, whereas the immediately adjacent supragranular layers exhibited increased perfusion. Subgranular layers exhibited necrotic pathology, whereas the supergranular layers were characterized by a delayed (24 h after SE) degeneration apparently via programmed cell death. These results indicate that both excitotoxic and ischemic injuries occur during pilocarpine-induced SE. Both of these degenerative pathways, as well as the widespread and severe brain damage observed, should be considered when animal model-based data are compared to human pathology.     

Isolation and characterization of poly- and oligosaccharides from the red microalga Porphyridium sp.

The current study forms part of an ongoing research effort focusing on the elucidation of the chemical structure of the sulfated extracellular polysaccharide of the red microalga Porphyridium sp. (UTEX 637). We report here on the chemical structure of a fraction separated from an acidic crude extract of the polysaccharide, as investigated by methylation analysis, carboxyl reduction-methylation analysis, desulfation-methylation analysis, partial acid hydrolysis, Smith degradation, together with 1D and 2D ¹H and ¹³C NMR spectroscopy. This fraction with a molar mass of 2.39 × 10⁵ g mol⁻¹ comprised d- and l-Gal, d-Glc, d-Xyl, d-GlcA, and sulfate groups in a molar ratio of 1.0:1.1:2.1:0.2:0.7. The almost linear backbone of the fraction is composed of (1→2)- or (1→4)-linked d-xylopyranosyl, (1→3)-linked l-galactopyranosyl, (1→3)-linked d-glucopyranosyl, and (1→3)-linked d-glucopyranosyluronic acid and comprises a possible acidic building unit:

[(2 or 4)-β-d-Xylp-(l→3)]_m-α-d-Glcp-(1→3)-α-d-GlcpA-(1→3)-l-Galp(l→

Attached to the backbone are sulfate groups and nonreducing terminal d-xylopyranosyl and galactopyranosyl residues, which occur at the O-6 positions of Glc-derived moieties in the main chain.     

Dual role of nNOS in ischemic injury and preconditioning

Background  

Nitric oxide (NO) is cardioprotective and a mediator of ischemic preconditioning (IP). Endothelial nitric oxide synthase (eNOS) is protective against myocardial ischemic injury and a component of IP but the role and location of neuronal nitric oxide synthase (nNOS) remains unclear. Therefore, the aims of these studies were to: (i) investigate the role of nNOS in ischemia/reoxygenation-induced injury and IP, (ii) determine whether its effect is species-dependent, and (iii) elucidate the relationship of nNOS with mitoK_ATP channels and p38MAPK, two key components of IP transduction pathway.     

Purification and Characterization of Thermophilic Xylanase Isolated from the Xerophytic-<Emphasis Type="Italic">Cereus pterogonus</Emphasis> sp.

A thermo stable xylanase was purified and characterized from the cladodes of Cereus pterogonus plant species. The enzyme was purified to homogeneity by ammonium sulfate (80%) fractionation, ion exchange and size exclusion chromatography. The enzyme showed a final specific activity of 216.2 U/mg and the molecular mass of the protein was 80 KDa. The optimum pH and temperature for xylanase activity were 5.0 and 80 °C, respectively,. With oat spelt xylan as a substrate the enzyme yielded a Km value of 2.24 mg/mL and a Vmax of 5.8 μmol min⁻¹ mg⁻¹. In the presence of metal ions (1 mM) such as Co²⁺,Mn²⁺, Ni²⁺, Ca²⁺ and Fe³⁺ the activity of the enzyme increased, where as strong inhibition of the enzyme activity was observed with the use of Hg²⁺, Cd²⁺, Cu²⁺, while partial inhibition was noted with Zn²⁺ and Mg²⁺. The substrate specificity of the xylanase yielded maximum activity with oat spelt xylan.     

Cattle egrets are less able to cope with light refraction than are other herons

The majority of heron species (Aves, Ardeidae) forage on aquatic prey in shallow water. Prey detection, aiming and the beginning of the capture strikes are performed while the heron's eyes are above water. For most angles, as a result of air/water light refraction, the apparent image available to a heron is vertically displaced from the prey's real position. Herons must therefore correct for refraction. We tested the hypothesis that species that forage in aquatic habitats should be more able to correct for image disparity than those of terrestrial habitats. The ability of hand-reared herons of four species to capture stationary prey (fish) underwater (submerged) or in air (aerial) was tested. Three species (little egret Egretta garzetta, squacco heron Ardeola ralloides, and night heron Nycticorax nycticorax) normally forage in aquatic habitats while the fourth (cattle egret Bubulcus ibis) forages in terrestrial habitats. No individuals missed aerial prey. Success rates of little egrets and of squacco herons with submerged prey were high, while night herons became less successful with increased prey depth and/or distance. In cattle egrets, success rate was low and negatively correlated with prey depth. The observed interspecific differences may thus be related to (1) differential ability to correct for air/water light refraction and (2) the species' foraging behaviour. We suggest that cattle egrets are in the process of losing their ability to cope with submerged prey. Copyright 1999 The Association for the Study of Animal Behaviour.     

Occurrence of high-level mupirocin resistant coagulase-negative staphylococci in hospitals and their characterization

Occurrence of high-level mupirocin resistant coagulase-negative staphylococci in 5 hospitals in the region of Gdansk was determined. The study was carried out on 192 staphylococcal strains isolated from patients and medical staff. The mupirocin resistant strains were detected by 5 microgram mupirocin disc. The minimal inhibitory concentration (MIC) for mupirocin was estimated by E-tests. The mupirocin resistant strains were characterised by antibiotic sensitivity, including MIC for glycopeptides and oxacillin. Biotypes of resistant strains were also determined. Eight high-level mupirocin resistant strains (4.7%) were found. Only one strain expressed low-level resistance. All but one of high-level mupirocin resistant strains were resistant to methicillin. Six of them belonged to the S. epidermidis species but differences in the biotypes and antibiotic resistance patterns of these strains suggest they did not have a common origin.     

Radiochemical investigations of (99m)Tc-N(3)S-X-BBN[7-14]NH(2): an in vitro/in vivo structure-activity relationship study where X = 0-, 3-, 5-, 8-, and 11-carbon tethering moieties

Bombesin (BBN), a 14 amino acid peptide, is an analogue of human gastrin releasing peptide (GRP) that binds to GRP receptors (GRPr) with high affinity and specificity. The GRPr is overexpressed on a variety of human cancer cells, including prostate, breast, lung, and pancreatic cancers. The specific aim of this study was to develop (99m)Tc-radiolabeled BBN analogues that maintain high specificity for the GRPr in vivo. A preselected synthetic sequence via solid-phase peptide synthesis (SPPS) was designed to produce N(3)S-BBN (N(3)S = dimethylglycyl-l-seryl-l-cysteinylglycinamide) conjugates with the following general structure: DMG-S-C-G-X-Q-W-A-V-G-H-L-M-(NH(2)), where the spacer group, X = 0 (no spacer), omega-NH(2)(CH(2))(2)COOH, omega-NH(2)(CH(2))(4)COOH, omega-NH(2)(CH(2))(7)COOH, or omega-NH(2)-(CH(2))(10)COOH. The new BBN constructs were purified by reversed phase-HPLC (RP-HPLC). Electrospray mass spectrometry (ES-MS) was used to characterize the nonmetalated BBN conjugates. Re(V)-BBN conjugates were prepared by the reaction of Re(V)gluconate with N(3)S-X-BBN[7-14]NH(2) (X = 0 carbons, beta-Ala (beta-alanine), 5-Ava (5-aminovaleric acid), 8-Aoc (8-aminooctanoic acid), and 11-Aun (11-aminoundecanoic acid)) with gentle heating. Re-N(3)S-5-Ava-BBN[7-14]NH(2) was also prepared by the reaction of [Re(V)dimethylglycyl-l-seryl-l-cysteinylglycinamide] with 5-Ava-BBN[7-14]NH(2). ES-MS was used to determine the molecular constitution of the new Re(V) conjugates. The (99m)Tc conjugates were prepared at the tracer level by each the prelabeling, post-conjugation and pre-conjugation, postlabeling approaches from the reaction of Na[(99m)TcO(4)] with excess SnCl(2), sodium gluconate, and corresponding ligand. The (99m)Tc and Re(V) conjugates behaved similarly under identical RP-HPLC conditions. In vitro and in vivo models demonstrated biological integrity of the new conjugates.     

Structure of formamidopyrimidine-DNA glycosylase covalently complexed to DNA

Formamidopyrimidine-DNA glycosylase (Fpg) is a DNA repair enzyme that excises oxidized purines from damaged DNA. The Schiff base intermediate formed during this reaction between Escherichia coli Fpg and DNA was trapped by reduction with sodium borohydride, and the structure of the resulting covalently cross-linked complex was determined at a 2.1-A resolution. Fpg is a bilobal protein with a wide, positively charged DNA-binding groove. It possesses a conserved zinc finger and a helix-two turn-helix motif that participate in DNA binding. The absolutely conserved residues Lys-56, His-70, Asn-168, and Arg-258 form hydrogen bonds to the phosphodiester backbone of DNA, which is sharply kinked at the lesion site. Residues Met-73, Arg-109, and Phe-110 are inserted into the DNA helix, filling the void created by nucleotide eversion. A deep hydrophobic pocket in the active site is positioned to accommodate an everted base. Structural analysis of the Fpg-DNA complex reveals essential features of damage recognition and the catalytic mechanism of Fpg.