A new framework for solution of multidimensional population balance equations

A new framework is proposed in this work to solve multidimensional population balance equations (PBEs) using the method of discretization. A continuous PBE is considered as a statement of evolution of one evolving property of particles and conservation of their n internal attributes. Discretization must therefore preserve n + I properties of particles. Continuously distributed population is represented on discrete fixed pivots as in the fixed pivot technique of Kumar and Ramkrishna [1996a. On the solution of population balance equation by discretization-I A fixed pivot technique. Chemical Engineering Science 51(8), 1311-1332] for 1-d PBEs, but instead of the earlier extensions of this technique proposed in the literature which preserve 2(n) properties of non-pivot particles, the new framework requires n + I properties to be preserved. This opens up the use of triangular and tetrahedral elements to solve 2-d and 3-d PBEs, instead of the rectangles and cuboids that are suggested in the literature. Capabilities of computational fluid dynamics and other packages available for generating complex meshes can also be harnessed. The numerical results obtained indeed show the effectiveness of the new framework. It also brings out the hitherto unknown role of directionality of the grid in controlling the accuracy of the numerical solution of multidimensional PBEs. The numerical results obtained show that the quality of the numerical solution can be improved significantly just by altering the directionality of the grid, which does not require any increase in the number of points, or any refinement of the grid, or even redistribution of pivots in space. Directionality of a grid can be altered simply by regrouping of pivots.

Block-based feature detection and matching for mosaicing of camera-captured document images

In this paper, we present a new feature-based approach for mosaicing of camera-captured document images. A novel block-based scheme is employed to ensure that corners can be reliably detected over a wide range of images. 2-D discrete cosine transform is computed for image blocks defined around each of the detected corners and a small subset of the coefficients is used as a feature vector A 2-pass feature matching is performed to establish point correspondences from which the homography relating the input images could be computed. The algorithm is tested on a number of complex document images casually taken from a hand-held camera yielding convincing results.

DNA cleavage in red light promoted by copper(II) complexes of -amino acids and photoactive phenanthroline bases

Ternary copper(II) complexes [Cu(L-trp)(B)(H2O)](NO3) ( 1–3) and [Cu(L-phe)(B)(H2O)](NO3) ( 4–6) of L-tryptophan (L-trp) and L-phenylalanine (L-phe) having phenanthroline bases (B), viz. 1,10-phenanthroline (phen, 1 and 4), dipyrido[3,2-d:2,3-f]quinoxaline (dpq, 2 and 5) and dipyrido[3,2-a:2,3-c]phenazine (dppz, 3 and 6), were prepared and characterized by physico-chemical techniques. Complexes 3 and 6 were structurally characterized by X-ray crystallography and show the presence of a square pyramidal (4 + 1) CuN3O2 coordination geometry in which the N,O-donor amino acid (L-trp or L-phe) and N,N-donor phenanthroline base bind at the equatorial plane with an aqua ligand coordinated at the elongated axial site. Complex 3 shows significant distortion from the square pyramidal geometry and a strong intramolecular – stacking interaction between the pendant indole ring of L-trp and the planar dppz aromatic moiety. All the complexes display good binding propensity to the calf thymus DNA giving an order: 3, 6 (dppz) > 2, 5 (dpq) > 1, 4 (phen). The binding constant (Kb) values are in the range of 2.1 × 104–1.1 × 106 mol-1 with the binding site size (s) values of 0.17–0.63. The phen and dpq complexes are minor groove binders while the dppz analogues bind at the DNA major groove. Theoretical DNA docking studies on 2 and 3 show the close proximity of two photosensitizers, viz. the indole moiety of L-trp and the quinoxaline/phenazine of the dpq/dppz bases, to the complementary DNA strands. Complexes 2 and 3 show oxidative DNA double strand breaks (dsb) of supercoiled (SC) DNA forming a significant quantity of linear DNA along with the nicked circular (NC) form on photoexposure to UV-A light of 365 nm and red light of 647.1 nm (Ar–Kr laser). Complexes 1, 5 and 6 show only single strand breaks (ssb) forming NC DNA. The red light induced DNA cleavage involves metal-assisted photosensitization of L-trp and dpq/dppz base resulting in the formation of a reactive singlet oxygen (1O2) species.

Simulation of wavelength/time multiple-pulses-per-row fiber-optic CDMA network

Passive wavelength/time fiber-optic code division multiple access (WIT FO-CDMA) network is a viable option for highspeed access networks. Constructions of 2-D codes, suitable for incoherent WIT FO-CDMA, have been proposed to reduce the time spread of the 1-D sequences. The 2-D constructions can be broadly classified as 1) hybrid codes and 2) matrix codes. In our earlier work [141, we had proposed a new family of wavelength/time multiple-pulses-per-row (W/T MPR) matrix codes which have good cardinality, spectral efficiency and at the same time have the lowest off-peak autocorrelation and cross-correlation values equal to unity. In this paper we propose an architecture for a WIT MPR FO-CDAM network designed using the presently available devices and technology. A complete FO-CDMA network of ten users is simulated, for various number of simultaneous users and shown that 0 --> 1 errors can occur only when the number of interfering users is at least equal to the threshold value.

Primary Structural Documentation of the Major Urinary Protein of the Indian Commensal Rat (Rattus rattus) Using a Proteomics Platform

Purpose: A number of proteome studies have been performed recently to identify pheromone-related protein expression and their molecular function using genetically modified rodents' urine. However, no such studies have used Indian commensal rodents; interestingly, in a previous investigation, we confirmed the presence of volatile molecules in commensal rodents urine and these molecules seem to be actively involved in pheromonal communication. Therefore, the present study aims to identify the major urinary protein [MUP] present in commensal rat urine, which will help us to understand the protein's expression pattern and intrinsic properties among the rodents globally. Experimental Design: Initially, the total urinary proteins were separated by 1-D and 2-D electrophoresis and then subsequently analyzed by Matrix Assisted Laser Desorption Ionization-Time of Flight and Mass Spectrometer (MALDI-TOF/MS). Furthermore, they were then fragmented with the aid of a Tandem Mass Spectrometer (TOF/TOF) and the identified sequences aligned and confirmed using similarity with the deduced primary structures of members of the lipocalin superfamily.Results: The SDS-PAGE protein profiles showed distinct proteins with molecular masses of 15, 22.4, 25, 28, 42, 50, 55, 68, and 91 kDa. Of these proteins, the 22.4 kDa protein was considered to be target candidate. When 2D electrophoresis was carried out, about similar to 50 spots were detected with different masses and various pI ranges. The 22.4 kDa protein was found to have a pI of about 4.9. This 22.4 kDa protein spot was digested and subjected to mass spectrometry; it was identified as rat MUP. The fragmented peptides from the rat MUP at 935, 1026, 1192, and 1303 m/z were further fragmented with the aid of MS/MS and generated de novo sequence and this confirmed this protein to be the MUP present in the urine of commensal rats.Conclusion: The present investigation confirms the presence of MUP with a molecular mass of 22.4 kDa in the urine of commensal rats. This protein may be involved in the binding of volatile molecules and opens up a discussion about how volatile and non-volatile molecules in the commensal rats' urine may contribute chemo-communication.

Photocytotoxicity and DNA cleavage activity of L-arg and L-lys Schiff base oxovanadium(IV) complexes having phenanthroline bases

Oxovanadium(IV) complexes [VO(sal-argH)(B)] Cl (1-3) and [VO(sal-lysH)(B)] Cl (4-6), where sal-argH2 and sal-lysH(2) are N-salicylidene-L-arginine and N-salicylidene-L-lysine Schiff bases and B is a phenanthroline base, viz. 1,10-phenanthroline (phen in 1 and 4); dipyrido[3,2-d: 2', 3'-f] quinoxaline (dpq in 2 and 5) and dipyrido[3,2-a: 2', 3'-c] phenazine (dppz in 3 and 6), have been prepared, characterized and their DNA photocleavage activity studied. Complex 1, characterized by X-ray crystallography, shows the presence of a vanadyl group in VIVO3N3 coordination geometry with a tridentate Schiff base having a pendant guanidinium moiety and bidentate phen ligand. The complexes exhibit a d-d band at similar to 715 nm in 20% DMF-Tris-HCl buffer. The complexes are redox active showing cathodic and anodic responses near -1.0 V and 0.85 V (vs. SCE) for the V(IV)-V(III) and V(V)-V(IV) couples, respectively, in DMF-Tris-HCl buffer. The complexes bind to calf thymus DNA giving Kb values in the range of 3.8 x 10(4) to 1.6 x 10(5) M-1. Thermal denaturation and viscosity data suggest DNA groove binding nature of the complexes. The complexes do not show any `chemical nuclease'' activity in dark in the presence of 3-mercaptopropionic acid or H2O2. The dpq and dppz complexes are efficient photocleavers of plasmid DNA in UV-A (365 nm) and red light (676 nm) via singlet oxygen pathway. The dppz complexes exhibit photocytotoxicity in HeLa cancer cells giving IC50 values of 15.4 mu M for 3 and 17.5 mu M for 6 in visible light while being non-toxic in dark giving IC50 values of > 100 mu M.

Kinetic theory for the density plateau in the granular flow down an inclined plane

The striking lack of observable variation of the volume fraction with height in the center of a granular flow down an inclined plane is analysed using constitutive relations obtained from kinetic theory. It is shown that the rate of conduction in the granular energy balance equation is O(delta(2)) smaller than the rate of production of energy due to mean shear and the rate of dissipation due to inelastic collisions, where the small parameter delta = (d/(1 - e(n))H-1/2), d is the particle diameter, en is the normal coefficient of restitution and H is the thickness of the flowing layer. This implies that the volume fraction is a constant in the leading approximation in an asymptotic analysis in small delta. Numerical estimates of both the parameter delta and its pre-factor are obtained to show that the lack of observable variation of the volume fraction with height can be explained by constitutive relations obtained from kinetic theory.

Photocytotoxic and anaerobic DNA cleavage activity of binuclear 3,3 '-dithiodipropionic acid cobalt(II) complexes having phenanthroline bases

Dicobalt(II) complexes [{(B)Co-11)(2)(mu-dtdp)(2)] (1-3) of 3,3'-dithiodipropionic acid (dtdp) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 2) and dipyrido13,2-a:2',3'-clphenazine (dppz in 3), have been prepared, characterized and their photo-induced anaerobic DNA cleavage activity studied. The elemental analysis and mass spectral data suggest binuclear formulation of the complexes. The redox inactive complexes have magnetically non-interacting dicobalt(II) core showing magnetic moment of similar to 3.9 p per cobalt(II) center. The complexes show good binding propensity to calf thymus DNA giving K-b values within 4.3 x 10(5)-4.0 x 10(6) M-1. Thermal melting and viscosity data predict DNA groove binding and/or partial intercalative nature of the complexes. The complexes show significant anaerobic DNA cleavage activity in green light under argon atmosphere possibly involving radical species generated from the disulfide moiety in a type-I pathway. The DNA cleavage reaction under aerobic medium in green light is found to involve hydroxyl radical species. The dppz complex 3 exhibits significant photocytotoxicity in HeLa cervical cancer cells with an IC50 value of 2.31 mu M in UV-A light of 365 nm, while it is essentially non-toxic in dark giving an IC50 value of >200 mu M. A significant reduction of the dark toxicity of the organic dppz base (IC50 = 8.3 mu M in dark) is observed on binding to the cobalt(II) center while essentially retaining its photocytotoxicity in UV-A light (IC50 = 0.4 mu M). (C) 2010 Elsevier Ltd. All rights reserved.

Structure of L-Arginyl-L-aspartie Acid Dihydrate

C~0H~gN5Os.2H20, Mr=325.32, monoclinic,P2~, a = 12.029 (2), b=4.904 (2), c=13.215 (2) A, fl= 107.68 (2) ° , F= 743 (1) A 3, Z= 2,D m = 1-45, D x = 1.45 Mg m -3, Cu Ka, 2 = 1.54184 A,fl= 1.01mm -1, F(000)=348, T=293K. The final R value for 1277 observed reflections 110 >_ 3tr(Io)l is 0.031. The dipeptide exists as a zwitterion. The arginyl side-chain conformation is similar to that found in arginyl-glutamic acid [Pandit, Seshadri & Viswamitra (1983). Acta Cryst. C39, 1669-16721. The guanidyl group forms a pair of hydrogen bonds with oxygen atoms of the backbone carboxyl group. The crystal structure is also stabilized by -bonding interactions involving both water molecules.

Photocytotoxicity and near-IR light DNA cleavage activity of oxovanadium(IV) Schiff base complexes having phenanthroline bases

Oxovanadium(IV) complexes VO(L)(B)] (1-3), where H2L is a Schiff base ligand 2-(2-hydroxybenzylideneamino) phenol and B is 1,10-phenanthroline (phen for 1), dipyrido3,2-d:2',3'-f]quinoxaline (dpq for 2) or dipyrido3,2-a:2',3'-c]phenazine (dppz for 3), have been prepared, characterized and their DNA binding property and photo-induced DNA cleavage activity studied. Complex 3 which is structurally characterized by X-ray crystallography shows the presence of an oxovanadium(IV) moiety in a six coordinate VO3N3 coordination geometry. The complexes show a d-d band within 800-850 nm in DMF. The complexes display an oxidative response near 0.7 V versus SCE for V(V)-V(IV) and a reductive response within -1.1 to -1.3 V due to V(IV)-V(III) couple in DMF-0.1 M TBAP. The complexes are avid binders to calf thymus DNA giving binding constant values of 4.2 x 10(4) to 1.2 x 10(5) M (1). The complexes do not show any ``chemical nuclease'' activity in dark. The dpq and dppz complexes are photocleavers of plasmid DNA in UV-A light of 365 nm via O-1(2) pathway and in near-IR light (752.5 to 799.3 nm IR optics) by HO* pathway. Complex 3 exhibits significant photocytotoxicity in visible light in HeLa cells giving IC50 value of 13 mu M, while it is less toxic in dark (IC50 = 97 mu M). (C) 2010 Elsevier B.V. All rights reserved.

High-resolution methyl edited GFT NMR experiments for protein resonance assignments and structure determination

Three-dimensional (3D) structure determination of proteins is benefitted by long-range distance constraints comprising the methyl groups, which constitute the hydrophobic core of proteins. However, in methyl groups (of Ala, Ile, Leu, Met, Thr and Val) there is a significant overlap of C-13 and H-1 chemical shifts. Such overlap can be resolved using the recently proposed (3,2)D HCCH-COSY, a G-matrix Fourier transform (GFT) NMR based experiment, which facilitates editing of methyl groups into distinct spectral regions by combining their C-13 chemical shifts with that of the neighboring, directly attached, C-13 nucleus. Using this principle, we present three GFT experiments: (a) (4,3)D NOESY-HCCH, (b) (4,3)D H-1-TOCSY-HCCH and (c) (4,3)D C-13-TOCSY-HCCH. These experiments provide unique 4D spectral information rapidly with high sensitivity and resolution for side-chain resonance assignments and NOE analysis of methyl groups. This is exemplified by (4,3)D NOESY-HCCH data acquired for 17.9 kDa non-deuterated cytosolic human J-protein co-chaperone, which provided crucial long-range distance constraints for its 3D structure determination.

Computer modelling studies on the mechanism of action of ribonuclease T1

The mechanism of action of ribonuclease (RNase) T1 is still a matter of considerable debate as the results of x-ray, 2-D nmr and site-directed mutagenesis studies disagree regarding the role of the catalytically important residues. Hence computer modelling studies were carried out by energy minimisation of the complexes of RNase T1 and some of its mutants (His40Ala, His40Lys, and Glu58Ala) with the substrate guanyl cytosine (GpC), and of native RNase T1 with the reaction intermediate guanosine 2',3'-cyclic phosphate (G greater than p). The puckering of the guanosine ribose moiety in the minimum energy conformer of the RNase T1-GpC (substrate) complex was found to be O4'-endo and not C3'-endo as in the RNase T1-3'-guanylic acid (inhibitor/product) complex. A possible scheme for the mechanism of action of RNase T1 has been proposed on the basis of the arrangement of the catalytically important amino acid residues His40, Glu58, Arg77, and His92 around the guanosine ribose and the phosphate moiety in the RNase T1-GpC and RNase T1-G greater than p complexes. In this scheme, Glu58 serves as the general base group and His92 as the general acid group in the transphosphorylation step. His40 may be essential for stabilising the negatively charged phosphate moiety in the enzyme-transition state complex.

X-ray studies on crystalline complexes involving amino acids and peptides. XXV. Structures of DL-proline hemisuccinic acid and glycyl-L-histidinium semisuccinate monohydrate and a comparative study of amino-acid and peptide complexes of succinic acid

DL-Proline hemisuccinic acid, C5H9NO2.1/2C4H6O4, M(r) = 174.2, P2(1/c) a = 5.254 (1), b = 17.480 (1), c = 10.230 (i) angstrom, beta = 119.60 (6)-degrees Z = 4, D(m) = 1.41 (4), D(x) = 1.42 g cm-3, R = 0.045 for 973 observed reflections. Glycyl-L-histidinium semisuccinate monohydrate, C8H13N4O3+.C4H5O4-.H2O, M(r) = 348.4, P2(1), a = 4.864 (1), b = 17.071 (2), c = 9.397 (1) angstrom, beta = 90.58-degrees, Z = 2, D(m) = 1.45 (1), D(x) = 1.48 g cm-3, R = 0.027 for 1610 observed reflections. Normal amino-acid and dipeptide aggregation patterns are preserved in the structures in spite of the presence of succinic acid/semisuccinate ions. In both the structures, the amino-acid/dipeptide layers stack in such a way that the succinic acid molecules/semisuccinate ions are enclosed in voids created during stacking. Substantial variability in the ionization state and the stoichiometry is observed in amino-acid and peptide complexes of succinic acid. Succinic acid molecules and succinate ions appear to prefer a planar centro-symmetric conformation with the two carboxyl (carboxylate) groups trans with respect to the central C=C bond. Considerable variation is seen in the departure from and modification of normal amino-acid aggregation patterns produced by the presence of succinic acid. Some of the complexes can be described as inclusion compounds with the amino acid/dipeptide as the 'host' and succinic acid/semisuccinate/succinate as the 'guest'. The effects of change in chirality, though very substantial, are not the same in different pairs of complexes involving DL and L isomers of the same amino acid.

Detection of edges from projections

In a number of applications of computerized tomography, the ultimate goal is to detect and characterize objects within a cross section. Detection of edges of different contrast regions yields the required information. The problem of detecting edges from projection data is addressed. It is shown that the class of linear edge detection operators used on images can be used for detection of edges directly from projection data. This not only reduces the computational burden but also avoids the difficulties of postprocessing a reconstructed image. This is accomplished by a convolution backprojection operation. For example, with the Marr-Hildreth edge detection operator, the filtering function that is to be used on the projection data is the Radon transform of the Laplacian of the 2-D Gaussian function which is combined with the reconstruction filter. Simulation results showing the efficacy of the proposed method and a comparison with edges detected from the reconstructed image are presented

An electron-spin-resonance study of MN2+ doped calcium hydrazine carboxylate monohydrate

Single crystals of calcium hydrazine carboxylate, monohydrate have been studied by ESR of Mn2+ doped in the calcium sites. X-band ESR indicated a large crystal field splitting necessitating experiments at Q band. The analysis shows two magnetically inequivalent (but chemically equivalent) sites with g(xx) = 2.0042+/-0.0038, g(yy) = 2.0076 +/-00029, g(zz) =2.0314+/-0.001, A(zz) = 0.0099+/-0.0002 cm(-1), A(xx) = 0.0099+/-0.0002 cm(-1), A(yy) = 0.0082+/-0.0002cm(-1), D = 3/2D(zz) = 0.0558+/-0.0006cm(-1), and E = 1/2(D-xx-D-yy) = 0.0127+/-0.0002 cm(-1).One of the principal components of the crystal field, (D-zz), is found to be along the Ca<->Ca direction in the structure and a second one, (D-xx), along the perpendicular to the plane of the triangle formed by three neighbouring calciums. The A tensor is found to have an orientation different from that of the g and D tensors reflecting the low symmetry of the Ca2+ sites.