Integrated multiplexed capillary electrophoresis system

The present invention provides an integrated multiplexed capillary electrophoresis system for the analysis of sample analytes. The system integrates and automates multiple components, such as chromatographic columns and separation capillaries, and further provides a detector for the detection of analytes eluting from the separation capillaries. The system employs multiplexed freeze/thaw valves to manage fluid flow and sample movement. The system is computer controlled and is capable of processing samples through reaction, purification, denaturation, pre-concentration, injection, separation and detection in parallel fashion. Methods employing the system of the invention are also provide

Are All Successful Communities Alike? Characterizing and Predicting the Success of Online Communities

The proliferation of online communities has created exciting opportunities to study the mechanisms that explain group success. While a growing body of research investigates community success through a single measure -- typically, the number of members -- we argue that there are multiple ways of measuring success. Here, we present a systematic study to understand the relations between these success definitions and test how well they can be predicted based on community properties and behaviors from the earliest period of a community's lifetime. We identify four success measures that are desirable for most communities: (i) growth in the number of members; (ii) retention of members; (iii) long term survival of the community; and (iv) volume of activities within the community. Surprisingly, we find that our measures do not exhibit very high correlations, suggesting that they capture different types of success. Additionally, we find that different success measures are predicted by different attributes of online communities, suggesting that success can be achieved through different behaviors. Our work sheds light on the basic understanding of what success represents in online communities and what predicts it. Our results suggest that success is multi-faceted and cannot be measured nor predicted by a single measurement. This insight has practical implications for the creation of new online communities and the design of platforms that facilitate such communities.Comment: To appear at The Web Conference 201

Edge Detection by Cost Minimization

Edge detection is cast as a problem in cost minimization. This is achieved by the formulation of two cost functions which evaluate the quality of edge configurations. The first is a comparative cost function (CCF), which is a linear sum of weighted cost factors. It is heuristic in nature and can be applied only to pairs of similar edge configurations. It measures the relative quality between the configurations. The detection of edges is accomplished by a heuristic iterative search algorithm which uses the CCF to evaluate edge quality. The second cost function is the absolute cost function (ACF), which is also a linear sum of weighted cost factors. The cost factors capture desirable characteristics of edges such as accuracy in localization, thinness, and continuity. Edges are detected by finding the edge configurations that minimize the ACF. We have analyzed the function in terms of the characteristics of the edges in minimum cost configurations. These characteristics are directly dependent of the associated weight of each cost factor. Through the analysis of the ACF, we provide guidelines on the choice of weights to achieve certain characteristics of the detected edges. Minimizing the ACF is accomplished by the use of Simulated Annealing. We have developed a set of strategies for generating next states for the annealing process. The method of generating next states allows the annealing process to be executed largely in parallel. Experimental results are shown which verify the usefulness of the CCF and ACF techniques for edge detection. In comparison, the ACF technique produces better edges than the CCF or other current detection techniques

Crystal structure of (4,4′-bipyridyl-κN)bis[N-(2-hydroxyethyl)-N-isopropyldithiocarbamato-κ2 S,S′]zinc(II)–4,4′-bipyridyl (2/1) and its isostructural cadmium(II) analogue

The title structures, [M(C6H12NOS2)2(C10H8N2)]·0.5C10H8N2, for M = Zn, (I), and Cd, (II), feature terminally bound 4,4′-bipyridyl ligands and non-coordinating 4,4′-bi­pyridyl mol­ecules, with the latter disposed about a centre of inversion. The coordination geometry about the metal atom is defined by two non-symmetrically chelating di­thio­carbamate ligands and a pyridyl N atom. The NS4 donor sets are distorted but, approximate to trigonal bipyramidal in each case. In the crystal, hy­droxy-O—H...O(hy­droxy) and hy­droxy-O—H...N(pyrid­yl) hydrogen bonds between the zinc-containing mol­ecules lead to a supra­molecular layer parallel to (100). The three-dimensional architecture arises as the layers are linked via methine-C—H...S, pyridyl-C—H...O(hy­droxy) and π–π [inter-centroid distance between coordinated pyridyl rings = 3.6246 (18) Å] inter­actions. Channels along the c-axis direction are occupied by the non-coordinating 4,4′-bipyridine mol­ecules, which are held in place by C—H...π(chelate ring) contacts

Crystal structure of bis(μ-N-i-propyl-N-n-propyldithiocarbamato-κ2S:S′) bis(N-i-propyl-N-n-propyldithiocarbamato-κ2S,S′)dizinc(II), C28H56N4S8Zn2

C28H56N4S8Zn2, monoclinic, P21/n (no. 14), a=9.4123(2) Å, b=19.2708(4) Å, c=11.5228(3) Å, β=107.202(2)°, V= 1996.54(8) Å3, Z=2, Rgt(F)=0.0254, wRref(F2)=0.0572, T=100(2)

A 1:2 co-crystal of 2,2′-thiodibenzoic acid and triphenylphosphane oxide: crystal structure, Hirshfeld surface analysis and computational study

The asymmetric unit of the title co-crystal, 2,20-thiodibenzoic acid–triphenylphosphane oxide (1/2), C14H10O4S2C18H15OP, comprises two molecules of 2,20 -thiodibenzoic acid [TDBA; systematic name: 2-[(2-carboxyphenyl)sulfanyl]benzoic acid] and four molecules of triphenylphosphane oxide [TPPO;systematic name: (diphenylphosphoryl)benzene]. The two TDBA molecules are twisted about their disulfide bonds and exhibit dihedral angles of 74.40 (5) and 72.58 (5) between the planes through the two SC6H4 residues. The carboxylic acid groups are tilted out of the planes of the rings to which they are attached forming a range of CO2/C6 dihedral angles of 19.87 (6)–60.43 (8). Minor conformational changes are exhibited in the TPPO molecules with the range of dihedral angles between phenyl rings being �2.1 (1) to �62.8 (1). In the molecular packing, each TDBA acid molecule bridges two TPPO molecules via hydroxy-O—HO(oxide) hydrogen bonds to form two three-molecule aggregates. These are connected into a three-dimensional architecture by TPPO-C—HO(oxide, carbonyl) and TDBA-C—H(oxide, carbonyl) interactions. The importance of HH, OH/HO and CH/HC contacts to the calculated Hirshfeld surfaces has been demonstrated. In terms of individual molecules, OH/HO contacts are more important for the TDBA (ca 28%) than for the TPPO molecules (ca 13%), as expected from the chemical composition of these species. Computational chemistry indicates the four independent hydroxy-O—HO(oxide) hydrogen bonds in the crystal impart about the same energy (ca 52 kJ mol-1), with DTBA-phenyl-C—HO(oxide) interactions being next most stabilizing (ca 40 kJ mol-1)

Crystal structure of [μ2-1,1′-bis(diphenylphosphanyl)ferrocene-κ2P:P′]bis[(pyrrolidine-1-carbodithioato-κS)gold(I)]

The asymmetric unit of the title compound, {(C34H28FeP2)[Au(C5H8NS2)]2}, comprises half a molecule, with the full molecule being generated by the application of a centre of inversion. The independent AuI atom is coordinated by thiolate S and phosphane P atoms that define an approximate linear geometry [S—Au—P = 169.35 (3)°]. The deviation from the ideal linear is traced to the close approach of the (intramolecular) non-coordinating thione S atom [Au...S = 3.1538 (8) Å]. Supramolecular layers parallel to (100) feature in the crystal packing, being sustained by phenyl–thione C—H...S interactions, with the non-coordinating thione S atom in the role of a dual acceptor. Layers stack with no specific interactions between them

Crystal structure of bis(μ-N-i-propyl-N-n-propyldithiocarbamato-κ3S,S′:S)bis(N-i-propyl-N-n-propyldithiocarbamato-κ2S,S′)dicadmium(II), C28H56Cd2N4S8

C28H56Cd2N4S8, monoclinic, P21/n (no. 14), a=9.9003(3) Å, b=11.7373(3) Å, c=17.4539(5) Å, β=102.999(3)°, V =1976.22(10) Å3, Z =2, Rgt(F)=0.0243, wRref(F2)=0.0582, T =100 K

Crystal structure, Hirshfeld surface analysis and computational study of the 1:2 co-crystal formed between N,N′-bis(pyridin-4-ylmethyl)ethanediamide and 4-chlorobenzoic acid

The asymmetric unit of the title 1:2 co-crystal, C14H14N4O22C7H5ClO2,comprises two half molecules of oxalamide (4LH2), as each is disposed about a centre of inversion, and two molecules of 4-chlorobenzoic acid (CBA), each in general positions. Each 4LH2 molecule has a (+)antiperiplanar conformation with the pyridin-4-yl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angles between the respective central core and the pyridyl rings being 68.65 (3) and 86.25 (3), respectively, representing the major difference between the independent 4LH2 molecules. The anti conformation of the carbonyl groups enables the formation of intramolecular amide-N—HO(amide) hydrogen bonds, each completing an S(5) loop. The two independent CBA molecules are similar and exhibit C6/CO2 dihedral angles of 8.06 (10) and 17.24 (8), indicating twisted conformations. In the crystal, two independent, three-molecule aggregates are formed via carboxylic acid-O—HN(pyridyl) hydrogen bonding. These are connected into a supramolecular tape propagating parallel to [100] through amide-N—HO(amide) hydrogen bonding between the independent aggregates and ten-membered {HNC2O}2 synthons. The tapes assemble into a three-dimensional architecture through pyridyl- and methylene-C—HO(carbonyl) and CBA-C—HO(amide) interactions. As revealed by a more detailed analysis of the molecular packing by calculating the Hirshfeld surfaces and computational chemistry, are the presence of attractive and dispersive ClC O interactions which provide interaction energies approximately one-quarter of those provided by the amideN—HO(amide) hydrogen bonding sustaining the supramolecular tape