Automatic white blood cell segmentation using stepwise merging rules and gradient vector flow snake

This study aims at proposing a new stained WBC (white blood cell) image segmentation method using stepwise merging rules based on mean-shift clustering and boundary removal rules with a GVF (gradient vector flow) snake. This paper proposes two different schemes for segmenting the nuclei and cytoplasm of WBCs, respectively. For nuclei segmentation, a probability map is created using a probability density function estimated from samples of WBC's nuclei and sub-images cropped to include a nucleus based on the fact that nuclei have a salient color against the background and red blood cells. Mean-shift clustering is then performed for region segmentation, and a stepwise merging scheme applied to merge particle clusters with a nucleus. Meanwhile, for cytoplasm segmentation, morphological opening is applied to a green image to boost the intensity of the granules and canny edges detected within the sub-image. The boundary edges and noise edges are then removed using removal rules, while a GVF snake is forced to deform to the cytoplasm boundary edges. When evaluated using five different types of stained WBC, the proposed algorithm produced accurate segmentation results for most WBC types.     

Selective and sensitive chromo-fluorogenic sensing of anionic surfactants in water using functionalised silica nanoparticles

A new chromo-fluorogenic sensing protocol for anionic surfactants in aqueous environments using silica functionalised nanoparticles containing imidazolium and thiol groups has been developed.     

Pressure-induced magnetic switching and linkage isomerism in K0.4Fe4[Cr(CN)6]2.8 x 16 H2O: X-ray absorption and magnetic circular dichroism studies

The effect of applied pressure on the magnetic properties of the Prussian blue analogue K0.4Fe4[Cr(CN)6]2.8 x 16 H2O (1) has been analyzed by dc and ac magnetic susceptibility measurements. Under ambient conditions, 1 orders ferromagnetically at a critical temperature (T(C)) of 18.5 K. Under application of pressure in the 0-1200 MPa range, the magnetization of the material decreases and its critical temperature shifts to lower temperatures, reaching T(C) = 7.5 K at 1200 MPa. Pressure-dependent Raman and Mossbauer spectroscopy measurements show that this striking behavior is due to the isomerization of some Cr(III)-C[triple bond]N-Fe(II) linkages to the Cr(III)-N[triple bond]C-Fe(II) form. As a result, the ligand field around the iron(II) centers increases, and the diamagnetic low-spin state is populated. As the number of diamagnetic centers in the cubic lattice increases, the net magnetization and critical temperature of the material decrease considerably. The phenomenon is reversible: releasing the pressure restores the magnetic properties of the original material. However, we have found that under more severe pressure conditions, a metastable sample containing 22% Cr(III)-N[triple bond]C-Fe(II) linkages can be obtained. X-ray absorption spectroscopy and magnetic circular dichroism of this metastable sample confirm the linkage isomerization process.     

Changeover during in situ compositional modulation of hexacyanoferrate (Prussian Blue) material

This paper describes the importance of (H2O)6 clusters in controlling the properties of hexacyanoferrate (Prussian Blue) materials. A careful in situ study of compositional changes by using electrogravimetric techniques (in ac and dc modes) in hexacyanoferrates containing K+ alkali metals reveals the existence of a changeover in the properties of these films in a narrow potential range. Control of the compositional variation of the changeover is dependent on the K+ stoichiometric number in the compound structure. However, a specific K+ occupation in the compound structure activates the occupation of the (H2O)6 cluster by H3O+ and/or H+, causing the changeover in the properties of hexacyanoferrate film. Thus, the information thus obtained is very useful for understanding the mechanisms involved in the electrochemical reversible switch between ferrimagnetism/paramagnetism, "semiconductor/metal" and electroluminescence/nonelectroluminescence properties of molecular cyanide materials.     

High-resolution confocal detection of nanometric displacement by use of a 2 x 1 optical fiber coupler

A novel high-resolution confocal measurement of nanometric displacement that uses a simple 2 x 1 optical fiber coupler is presented. The basic principle is to detect interferometrically the change in the phase difference between two adjacent input fibers of the coupler that results from the nonuniform wave-front curvature of the reflected light. Measurement of subnanometer axial modulation, which permits high-resolution displacement sensing by optical means, is demonstrated.     

Resolution of overlapped peaks in liquid chromatography by use of derivative spectrophotometry and multivariate analysis and its application in the determination of active components in insecticide formulations

Two procedures for the determination of active components in insecticide formulations have been devised. The first is based in the use of derivative spectra of the components obtained by a diode-array spectrophotomer around the maxima signal of the chromatographic peak. In the second method, mixtures are resolved by the partial least-squares (PLS) regression method from standard spectra of the pure components; spectra of the components were also registered around the maxima signal of the peak. Both procedures have been applied to the analysis of diverse mixtures of active components (piperonyl butoxide, neopynamine and fenitrothion) in insecticide formulations with satisfactory results.     

Capillary electrophoresis and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry for analysis of the novel erythropoiesis-stimulating protein (NESP)

NESP (novel erythropoiesis-stimulating protein) is a recently approved hyperglycosylated analogue of human erythropoietin (EPO) with a long-lasting effect. In this work, the capillary electrophoresis (CE) methodology proposed by the European Pharmacopoeia for the separation of EPO glycoforms has been modified for the separation of NESP glycoforms. Optimization of pH of the separation electrolyte has been fundamental in order to achieve baseline resolution of seven peaks corresponding to NESP glycoforms. Intact NESP has also been characterized by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). An accurate approximation to an average molecular mass of the NESP molecule has been obtained, taking into account the strong influence of laser intensity upon the MALDI-TOF mass spectra found.     

Aluminium complexes with thio-phosphorus ligands: syntheses and characterisations of [Al(2)(CyPS(3))(2)(CyPHS(2))(2)] and [Al(S(2)PPh(2))(3)

The novel aluminium complexes [Al(2)(CyPS(3))(2)(CyPHS(2))(2)] and [Al(S(2)PPh(2))(3)] have been prepared as potential models for alumino-thiophosphonate based materials; [Al(2)(CyPS(3))(2)(CyPHS(2))(2)] is the first example of a primary dithiophosphinate to be characterised in the solid state.     

Experimental Determination of the Burning Velocity of Mixtures of n-Heptane and Toluene in Engine-like Conditions

Although the burning velocities of fuel-air mixtures have been extensively studied at room temperature and pressure, there is relatively little experimental information available for elevated temperatures and pressures (the so-called engine like conditions). Therefore, the main aim of the present work is to generate accurate experimental burning velocities valid over a range of high unburned gas temperatures and pressures of a variety of mixtures of n-heptane and toluene, varying its proportion by 25% in volume each time. Two experimental combustion facilities have been used and their results compared. One facility consists of a constant volume cylindrical bomb in which Schlieren images can be recorded and used to calculate the flame front development. The second facility is a spherical combustion bomb with centred ignition in which burning velocities are calculated from pressure records by means of a two-zone model. In order to check that the pressure method is reliable, experiments with n-heptane at room temperature and pressure for different equivalence ratios carried out in the spherical combustion bomb were compared with the ones obtained at the same conditions in the cylindrical vessel equipped with the Schlieren technique. Once the validity has been checked, extensive experiments have been carried out for widely varying initial conditions of pressure between 0.3 and 0.7?MPa, temperature between 363?K and 453?K and equivalence ratios from 0.8 to 1.1. Over the ranges studied, by removing the influence of the ignition energy at the earliest stages of combustion and the quenching effects at the later ones, the burning velocities are fitted by a correlation of type $ Cc=Cc_{r}\cdot (T_{ub}/T_{r})^{\varepsilon }\cdot (P/P_{r})^{\beta } $ , where Cc _r , ?? and ?? depend on the equivalence ratio. The ranges of validity of the correlations obtained cover from 370?K to 700?K, from 0.3?MPa to 4.5?MPa, and from 0.8 to 1.1 equivalence ratio. A comparison with previous predicted values is also given.     

<Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">K</Emphasis></Subscript> from the lattice with Wilson quarks

We report our results for the bag parameter B _K obtained from the quenched simulations on the lattice with Wilson fermions for three values of the lattice spacing. We implemented the method by which no subtraction of the mixing with other four-fermion operators is needed. Our final result, in terms of the renormalization group invariant bag parameter, is .Received: 9 July 2004, Revised: 27 July 2004, Published online: 21 September 2004