618 research outputs found
A biobibliometric study on Prof. B. N. Koley, an eminent physiologist
No full text74-82This biobibliometric study is based on 251 papers of Prof. B. N. Koley published during 1958-2001. On the basis of collecteddata, this study examines year-wise distribution of papers, research group of the scientist and scattering of papers in differentcommunication channels. In addition, it finds out author productivity, spectrum of research activity through analysis of the titlekeywords, and productivity of Koley's research group. Finally, it shows that the data set does not follow Bradford distribution
DS_10.1177_0022034518809086 – Supplemental material for A Chemical Approach to Optimizing Bioactive Glass Dental Composites
No full textSupplemental material, DS_10.1177_0022034518809086 for A Chemical Approach to Optimizing Bioactive Glass Dental Composites by S. Aponso, J.G. Ummadi, H. Davis, J. Ferracane and D. Koley in Journal of Dental Research</p
Social Capital as Engagement and Belief Revision
No full textSocial Capital or “goodwill” is an essential ingredient of any collective activity – be it commercial, cultural or administrative activity. In online environments, several models have been pursued for recording and utilizing social capital based on signals including likes or upvotes. Such explicitly stated signals are susceptible to impulsive behavior and hyperinflation. In this paper, we develop an implicit model for social capital based on the extent of engagement generated by any participant’s activities, and the way this engagement leads to a belief revision about the participant from other members of the community. Two kinds of social capital measures are proposed: an authority score that indicates engagement, and a citizenship score that calibrates value-addition made by a user as a result of engaging with others’ content. The proposed model is implemented in two online communities showing different kinds of content authorities, supported by a strong community of engaged citizens
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Electrochemical advancement of solid state ion selective electrodes
No full textThe general theme of this dissertation is the development of new analytical sensors to quantitatively study biological and environmental samples in aqueous and non-aqueous environments. A platinum ultramicroelectrode (UME) and a unique carbon-based pH microprobe were used to design a new SECM-based electrochemical bioassay. The Pt UME was used to distinguish between different strains of acid-producing Streptococcus mutans oral bacteria based on height and morphological features. The pH microprobe was used to quantitatively measure the pH above the three different S.Mutans biofilms as a biomarker to study dental caries disease. This dissertation focuses on precisely controlling electrochemically deposited ethylenedioxythiophene (EDOT) copolymerized with an alkoxysulfonate derivative of EDOT as a stable and tunable self-doped PEDOT/PEDOT-S copolymer to select for different properties. PEDOT/PEDOT-S copolymer was used as a solid contact material for new monovalent and divalent calibration free ion-selective electrodes. PEDOT/PEDOT-S was also used to fabricate a new solid-state reference electrode with a unique in situ PTFE-AF coating for both aqueous and nonaqueous electroanalytical measurements while satisfying the need for true reference electrode nonaqueous solutions.
A two-probe scanning electrochemical microscopy (SECM)-based bioassay was used to characterize the height, morphology, and pH above three live bacterial biofilms. A 25 μm Pt electrode was used as an SECM probe to quantitatively map the morphology, height, and volume of the biofilm surface. A second probe, a unique carbon-based fast response pH microprobe, was used to quantify the local metabolic activity by quantitively measuring the pH profile above the three different biofilms when fed with sucrose. S. mutans B04Sm5 wild-type (WT) was recently isolated from early childhood dental caries patients and was found to produce a new N-acyl tetramic acid called mutanocyclin. An SECM characterization of the WT immediately after sucrose feeding found that the pH of the acidic environment 50 μm above the biofilm was 4.42 ± 0.54 (N=5). A laboratory strain S. mutans UA 159 had a pH of 5.21 ± 0.22 (N=4), and a variant of S. mutans B04Sm5 (MUTD) produced a local environment pH of 4.51 ± 0.40 (N=7). The change in the pH of the local environment normalized by height for the three strains showed the WT: 0.09 ± 0.02 (ΔpH ⁄ μm) (N=3), MUTD 0.05 ± 0.01 (ΔpH ⁄ μm) (N=7), and UA 159: 0.03 (ΔpH ⁄ μm) (N=2). A comparison of WT with the laboratory strain UA 159 showed that the pH of the local environment for WT was more acidic than UA 159 (p=0.043, 95%). There was no statistical deference between the WT and MUTD strains.
A unique back contact made of 3,4-Ethylenedioxythiophene (EDOT) and 4-(2,3-dihydrothieno [3,4-b][1,4]dioxin-2-yl-methoxy)-1-butanesulfonic acid, sodium salt (EDOT-S) was designed as a back contact for calibration free monovalent and divalent solid state ion selective electrodes (ISEs). The calibration free ISEs showed near Nernstian responses of 57.2 ± 0.2 mV/log [K+] and 28.5 ± 0.3 mV/log [Ca2+] while maintaining their respective selectivity against major interfering ions. The detection limits for Ca2+ and K+ ISEs were 0.45 ± 0.01 mM and 1.68 ± 0.18 mM, respectively. The charging cycles of the PEDOT/PEDOT-S back contact allowed us to fix the background potential at a desired fixed intercept value across different ionophores (K+, Ca2+). This protocol was used to determine the content of K+ and Ca2+ in creek water samples. The concentration of [Ca2+] and [K+] in a local creek was 257 ± 7.3 mM (N=6) and 28.1± 1.1 mM (N=3), respectively.
Currently, there is no reference electrode that is adequate for both aqueous and organic solutions. Silver-silver chloride (Ag/AgCl) is the most widely used reference for aqueous potentiometry and amperometry experiments. This reference is particularly robust due to the half-reaction of Ag/AgCl, but the stability of the potential can change with wire strain and requires a cumbersome liquid salt bridge or complex polymer membranes. The leaching of ions can contaminate the samples, rendering them unsuitable for applications requiring a limited sample volume (e.g., wearable sensors). In nonaqueous solutions, a liquid junction of unknown potential occurs due to an unmissable aqueous salt bridge and a nonaqueous sample. Water and ion leakage into the organic phase plague Ag/AgCl electrodes in nonaqueous solutions. A self-doped PEDOT/PEDOT-S solid state reference electrode with high mechanical and chemical durability and in situ PTFE-AF coating was designed to maintain a fixed potential based on the ratio of oxidized species to reduced species in the polymer as indicated by the Nernst equation. The PEDOT/PEDOT-S reference characterized versus ferrocene in acetonitrile with 0.1 M TBAPF6 had a stable potential of 0.411 V ± 0.008 V versus ferrocene over 14 days (N=3). The single junction PTFE-AF coated PEDOT/PEDOT-S electrode showed a potential of 0.397 V ± 0.009 V characterized versus ferrocene (2100 cycles) (N=3). For nonaqueous applications where size is not limited, we designed a double junction form of the PEDOT/PEDOT-S solid state reference electrode with a potential of 0.384 V versus ferrocene that did not change over four days (3100 cycles)
Creighton Law Review
No full textFIRST PARAGRAPH(S)|When the Omaha World-Herald Foundation, John Gottschalk and other members of the World-Herald management team contributed funds to Creighton University School of Law to establish The James L. Koley '54 Scholarship in Constitutional Law, I was both honored and deeply humbled by their generosity. As a 1954 graduate of the Creighton University School of Law, I have fond memories from my time as a student at Creighton and great respect for the quality of education provided to so many fine people who have become outstanding members of the legal profession...2004-2005741383
Students group with Thomas S. Bowdern, SJ.
No full textStudents group with Thomas S. Bowdern, SJ., Back Row; Don Bruckner. Tex O'Neil, Lee Bloomingdale, Front Row: Bob Klein, Fr. Bowdern, Jim Koley
RGe(I)Ge(I)R compound (R = PhC(NtBu)2) with a Ge−Ge single bond and a comparison with the gauche conformation of hydrazine.
No full textThis article reports the reduction of the chloride [PhC(NtBu)(2)]GeCl with potassium in THF to afford the reddish crystals of [PhC(NtBu)(2)](2)Ge-2 (2). The molecule of 2 contains a Ge-Ge bond. The X-ray structure and DFT calculation indicate that the Ge-Ge bond possesses an unusual gauche-bent geometry. The Ge-Ge bond length in 2 is 2.570 angstrom, which is very close to the single Ge-Ge interaction (2.61 angstrom) but significantly longer than that for typical digermenes, R2GeGeR2 (2.21-2.51 angstrom) and the two structurally characterized digermynes (2.2850 angstrom and 2.2060 angstrom), which proves that there is no multiple bond character in 2
Neutral, Cationic, and Anionic Low-Spin Iron(III) Complexes Stabilized by Amidophenolate and Iminobenzosemiquinonate Radical in N,N,O Ligands
No full textA brownish-black complex [Fe-III(L)(2)] (1) (S = 0), supported by two tridentate redox-active azo-appended o-amidophenolates [H2L = 2-(2-phenylazo)-anilino-4,6-di-tert-butylphenol], has been synthesized and structurally characterized. In CH2Cl2 1 displays two oxidative and two reductive 1e(-) redox processes at E-1/2 values of 0.48 and 1.06 V and -0.42 and -1.48 V vs SCE, respectively. The one-electron oxidized form [1](+) isolated as a green solid [Fe-III(L)(2)][BF4] (2) (S = 1/2) has been structurally characterized. Isolation of a dark ink-blue one-electron reduced form [1](-) has also been achieved [Co-III(eta(5)-C10H15)(2)][Fe-III(L)(2)] (3) (S = 1/2). Mossbauer spectral parameters unequivocally establish that 1 is a low-spin (LS) Fe-III complex. Careful analysis of Mossbauer spectral data of 2 and 3 at 200 and 80 K reveal that each complex has a major LS Fe-III and a minor LS Fe-II component (redox isomers): [Fe-III{(L-ISQ)(-center dot)}(2)](+) and [Fe-II{(L-IBQ)(0)}{(L-ISQ)(-center dot)}](+) (2) and [Fe-III{(L-AP)(2-)}(2)](-) and [Fe-II{(L-ISQ)(-center dot)}{(L-AP)(2-)}](-) (3). Notably, for both at 8 K mainly the major component exists. Broken-Symmetry (BS) Density Functional Theory (DFT) calculations at the B3LYP level reveals that in 1 the unpaired electron of LS Fe-III is strongly antiferromagnetically coupled with a pi-radical of o-iminobenzosemiquinonate(1-) (L-ISQ)(-center dot) form of the ligand, delocalized over two ligands providing 3- charge (X-ray structure). DFT calculations reveal that the unpaired electron in 2 is due to (L-ISQ)(-center dot) [LS Fe-III (S-Fe = 1/2) is strongly coupled to one of the (L-ISQ)(-center dot) radicals (S-rad = 1/2)] and 3 is primarily a LS Fe-III complex, supported by two o-amidophenolate(2-) ligands. Time-Dependent-DFT calculations shed light on the origin of UV-vis-NIR spectral absorptions for 1-3. The collective consideration of Mossbauer, variable-temperature (77-298 K) electron paramagnetic resonance (EPR), and absorption spectral behavior at 298 K, and DFT results reveals that in 2 and 3 the valence-tautomerism is operative in the temperature range 80-300 K
Addition Reactions of Me3SiCN with Aldehydes Catalyzed by Aluminum Complexes Containing in their Coordination Sphere O, S, and N Ligands
No full textThe reaction of oneequivalent of LAlH2 (1; L=HC(CMeNAr)(2), Ar=2,6-iPr(2)C(6)H(3), -diketiminate ligand) with twoequivalents of 2-mercapto-4,6-dimethylpyrimidine hydrate resulted in LAl[(-S)(m-C4N2H)(CH2)(2)](2) (2) in good yield. Similarly, when N-2-pyridylsalicylideneamine, N-(2,6-diisopropylphenyl)salicylaldimine, and ethyl 3-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylate were used as starting materials, the corresponding products LAl[(-O)(o-C6H4)CN(C5NH4)](2) (3), LAlH[(-O)(o-C4H4)CN(2,6-iPr(2)C(6)H(3))] (4), and LAl[(-NH)(o-C8SH8)(COOC2H5)](2) (5) were isolated. Compounds 2-5 were characterized by H-1 and (CNMR)-C-13 spectroscopy as well as by single-crystal X-ray structural analysis. Surprisingly, compounds 2-5 exhibit good catalytic activity in addition reactions of aldehydes with trimethylsilyl cyanide (TMSCN)
Reactivity Studies of a Disilene with N<sub>2</sub>O and Elemental Sulfur
No full textIn a previous contribution, we have reported on a convenient and high yield synthesis of the disilene trans-[(TMS)(2)N(eta(1)-Me5C5)-Si=Si(eta(1)-Me5C5)N(TMS)(2)] (2). Herein, we show the reactions of 2 with N2O and S-g. The former reaction affords two isomeric (cis- and trans-) dioxadisiletane ring compounds. To the best of our knowledge, this is the first report where both cis- and trans-isomers are isolated from the same disilene precursor and characterized structurally by single-crystal X-ray diffraction (XRD) studies. The reaction of 2 with elemental sulfur yields only the trans-isomer. To investigate this dissimilar reaction pattern exhibited by 2, computational studies were performed. Density functional theory (DFT) calculations showed that the two dioxadisiletane ring isomers are isoenergetic, with the trans isomer being slightly more stable than the cis counterpart, by 3.3 kcal/mol, while that is not the case with sulfur. All the isolated compounds are characterized by single-crystal XRD studies, multinuclear NMR spectroscopy, and electron ionization mass spectrometry (EI-MS)
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