Forwarding and optical indices of 4-regular circulant networks

An all-to-all routing in a graph $G$ is a set of oriented paths of $G$, with exactly one path for each ordered pair of vertices. The load of an edge under an all-to-all routing $R$ is the number of times it is used (in either direction) by paths of $R$, and the maximum load of an edge is denoted by $\pi(G,R)$. The edge-forwarding index $\pi(G)$ is the minimum of $\pi(G,R)$ over all possible all-to-all routings $R$, and the arc-forwarding index $\overrightarrow{\pi}(G)$ is defined similarly by taking direction into consideration, where an arc is an ordered pair of adjacent vertices. Denote by $w(G,R)$ the minimum number of colours required to colour the paths of $R$ such that any two paths having an edge in common receive distinct colours. The optical index $w(G)$ is defined to be the minimum of $w(G,R)$ over all possible $R$, and the directed optical index $\overrightarrow{w}(G)$ is defined similarly by requiring that any two paths having an arc in common receive distinct colours. In this paper we obtain lower and upper bounds on these four invariants for $4$-regular circulant graphs with connection set $\{\pm 1,\pm s\}$, $1<s<n/2$. We give approximation algorithms with performance ratio a small constant for the corresponding forwarding index and routing and wavelength assignment problems for some families of $4$-regular circulant graphs.Comment: 19 pages, no figure in Journal of Discrete Algorithms 201

A TREATMENT SYSTEM FOR LANDFILL LEACHATE

Landfill leachate is a potential source of ground and surface water contamination and causes extensive pollution if it is not properly collected, treated and disposed of. The objective of the research was to study a combined advanced oxidation process (AOP) with sequencing batch reactor (SBR) system for treatment of mature landfill leachate so as to meet the discharge standard, particularly in terms of COD, BOD5 and suspended solids. Fenton and photo-Fenton processes were applied to the preliminary treated (adjusted to pH 3 and 1-h settling) leachate and response surface methodology (RSM) was used to optimize the processes for removal of COD, colour and ammonia nitrogen (NH3-N). The optimum operating conditions for Fenton treatment were at about H2O2/COD molar ratio 2.25, H2O2/Fe2+ molar ratio 10.0 and 1.5 h reaction time for 51% COD removal, 77% colour removal and 84% NH3-N removal, whereas the optimum operating conditions for photo-Fenton treatment were H2O2/COD molar ratio 3.75, H2O2/Fe2+ molar ratio 10.0 and 1.5 h irradiation time for 68% COD removal, 81% colour removal and 80% NH3-N removal. The biodegradability (BOD5/COD ratio) of the Fenton and photo-Fenton treated leachate were 0.21 and 0.33, respectively under optimum operating conditions. Photo-Fenton treatment under Fenton process optimum operating conditions, i.e. H2O2/COD molar ratio 2.25, H2O2/Fe2+ molar ratio 10.0 (lower dosages of the Fenton reagent) and 1.5 h irradiation time, was conducted and 65% COD removal, 83% colour removal and 80% NH3-N removal were achieved, and the biodegradability was 0.35. Aerobic sequencing batch reactor (SBR) treatment of the photo-Fenton treated leachate resulted in soluble COD, BOD5 and NH3-N removal of 78, 81 and 94%, respectively. The final effluent characteristics were COD 92 mg/L, soluble COD 71 mg/L, BOD5 26 mg/L, NH3-N 7 mg/L, total phosphorus 6.4 mg/L, suspended solids 38 mg/L and colour 46 Pt-Co Units, and met the Malaysian discharge standard (B) (COD 100 mg/L, BOD5 50 mg/L and suspended solids 100 mg/L). The study shows that combined photo-Fenton-SBR provides effective treatment of a mature landfill leachate

Canine biphasic synovial sarcoma: case report and immunohistochemical characterization

The clinical, radiological and pathologic features of a biphasic synovial sarcoma in the left elbow joint of a two-year-old male Rottweiler are presented. The tumor showed positive immunoreactivity for vimentin, Epithelial Membrane Antigen (EMA), p53 and PCNA, while it was negative for the cytokeratin used, S-100, Rb and p21. Immunohistochemistry for EMA allowed the identification of epithelioid components of synovial sarcoma, and may, therefore, contribute in establishing a diagnosis of biphasic synovial sarcoma. Intratumoral variation in PCNA immunoreactivity was minimal, indicating that the various tumor components proliferate at more or less similar rates. Overall, the characterized immunohistochemical profile for canine synovial sarcoma, not defined previously, may provide clues to the histogenesis of the phenotypically mesenchymal and epithelial elements of the tumor, and may be of value in the differential diagnosis of challenging cases, decreasing the risk of under- and mis-diagnosis. Although more cases need to be studied to determine whether there is a consistent pattern of immunostaining in canine synovial sarcoma, its potential significance is discussed in relation to the histogenesis, molecular pathology and differential diagnosis of canine synovial sarcoma

Atmospheric pressure chemical ionisation mass spectrometry analysis linked with chemometrics for food classification – a case study: geographical provenance and cultivar classification of monovarietal clarified apple juices

In the present work, we have evaluated for first time the feasibility of APCI-MS volatile compound fingerprinting in conjunction with chemometrics (PLS-DA) as a new strategy for rapid and non-destructive food classification. For this purpose 202 clarified monovarietal juices extracted from apples differing in their botanical and geographical origin were used for evaluation of the performance of APCI-MS as a classification tool. For an independent test set PLS-DA analyses of pre-treated spectral data gave 100% and 94.2% correct classification rate for the classification by cultivar and geographical origin, respectively. Moreover, PLS-DA analysis of APCI-MS in conjunction with GC-MS data revealed that masses within the spectral ACPI-MS data set were related with parent ions or fragments of alkyesters, carbonyl compounds (hexanal, trans-2-hexenal) and alcohols (1-hexanol, 1-butanol, cis-3-hexenol) and had significant discriminating power both in terms of cultivar and geographical origin

Software Tool for Brain Connectivity Analysis

Structural magnetic resonance imaging (MRI) is a constitutive part of the clinical assessment of neurodegenerative patients. The routine neuroimaging evaluation of structural markers from preclinical to conspicuous stage is a key figure of how the disease is conceptualized, and will determine its imminent diagnosis and treatment to dementia. Atrophy, a late feature in the progression of the disease, is now a valid diagnostic marker to the neurodegenerative diseases. At the mild cognitive impairment stage of the Alzheimer disease (AD), the valid diagnostic marker is the atrophy of medical temporal structure [33]. In temporal lobe epilepsy (TLE), the atrophy of the subcortical brain structures specifically the size of the hippocampus is observed [34]. Apart from these neurodegenerative diseases, there is a significant evidence showing that the long-term ‘Ketum’ drug abuse also causes dementia which are profound impairments of learning and memory. These cognitive-impairing effects are revealed by the analysis of electroencephalogram (EEG) that shows a significant decline of delta power in the hippocampus [35]. Additionally, in the electrocorticography (ECoG) of the frontal cortex, it is found out that there is a complete suppression of the delta and theta bands [35]

Phase Reversal Diffraction in incoherent light

Phase reversal occurs in the propagation of an electromagnetic wave in a negatively refracting medium or a phase-conjugate interface. Here we report the experimental observation of phase reversal diffraction without the above devices. Our experimental results and theoretical analysis demonstrate that phase reversal diffraction can be formed through the first-order field correlation of chaotic light. The experimental realization is similar to phase reversal behavior in negatively refracting media.Comment: 8 pages, 5 figure

Core-Shell Assisted Bimetallic Assembly of Pt and Ru Nanoparticles by DNA Hybridization

We have discovered that the current protocols to assemble Au nanoparticles based on DNA hybridization do not work well with the small metal nanoparticles (e.g. 5 nm Au, 3.6 nm Pt and 3.2 nm Ru particles). Further investigations revealed the presence of strong interaction between the oligonucleotide backbone and the surface of the small metal nanoparticles. The oligonucleotides in this case are recumbent on the particle surface and are therefore not optimally oriented for hybridization. The nonspecific adsorption of oligonucleotides on small metal nanoparticles must be overcome before DNA hybridization can be accepted as a general assembly method. Two methods have been suggested as possible solutions to this problem. One is based on the use of stabilizer molecules which compete with the oligonucleotides for adsorption on the metal nanoparticle surface. Unfortunately, the reported success of this approach in small Au nanoparticles (using K₂BSPP) and Au films (using 6-mercapto-1-hexanol) could not be extended to the assembly of Pt and Ru nanoparticles by DNA hybridization. The second approach is to simply use larger metal particles. Indeed most reports on the DNA hybridization induced assembly of Au nanoparticles have made use of relatively large particles (>10 nm), hinting at a weaker non-specific interaction between the oligonucleotides and large Au nanoparticles. However, most current methods of nanoparticle synthesis are optimized to produce metal nanoparticles only within a narrow size range. We find that core-shell nanoparticles formed by the seeded growth method may be used to artificially enlarge the size of the metal particles to reduce the nonspecific binding of oligonucleotides. We demonstrate herein a core-shell assisted growth method to assemble Pt and Ru nanoparticles by DNA hybridization. This method involves firstly synthesizing approximately 16 nm core-shell Ag-Pt and 21 nm core-shell Au-Ru nanoparticles from 9.6 nm Ag seeds and 17.2 nm Au seeds respectively by the seed-mediated growth method. The core-shell nanoparticles were then functionalized by complementary thiolated oligonucleotides followed by aging in 0.2 M PBS buffer for 6 hours. The DNA hybridization induced bimetallic assembly of Pt and Ru nanoparticles could then be carried out in 0.3 M PBS buffer for 10 hours.Singapore-MIT Alliance (SMA

Shedding light on the pion production in heavy-ion collisions for constraining the high-density symmetry energy

Within the framework of the quantum molecular dynamics transport model, the pion production and constraint of the high-density symmetry energy in heavy-ion collisions near threshold energy have been thoroughly investigated. The energy conservation in the decay of resonances and reabsorption of pions in nuclear medium are taken into account. The density profile of pion production, energy conservation and pion potential are analyzed by the model. The isospin diffusion in the low-density region (0.2$\rho_{0}$ - 0.8$\rho_{0}$) and high-density region (1.2$\rho_{0}$ - 1.8$\rho_{0}$) is investigated by analyzing the neutron/proton and $\pi^{-}/\pi^{+}$ ratios in the isotopic reactions of $^{132}$Sn + $^{124}$Sn and $^{108}$Sn + $^{112}$Sn at the incident energy of 270 MeV/nucleon, in which the symmetry energy manifests the opposite contribution. The controversial conclusion of the $\pi^{-}/\pi^{+}$ ratio for constraining the high-density symmetry energy by different transport models is clarified. A soft symmetry energy with the slope parameter of $L(\rho_{0}) = 42\pm 25$ MeV by using the standard error analysis within the range of $1\sigma$ is obtained by analyzing the experimental data from the S$\pi$RIT collaboration.Comment: 8 pages, 7 figure