• Title/Summary/Keyword: Group ring

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Wilson's Disease in Bangladeshi Children: Analysis of 100 Cases

  • Rukunuzzaman, Md.
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.18 no.2
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    • pp.121-127
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    • 2015
  • Purpose: To evaluate clinical and laboratory profile of Wilson's disease (WD) in children. Methods: This cross sectional study was conducted at Bangabandhu Sheikh Mujib Medical University Hospital. Bangladesh, over a period of 3 years. One hundred consecutive children of WD between 3 to 18 years of age were evaluated. Results: Mean age was $8.5{\pm}1.5years$. Male female ratio was 2:1. Ninety-one percent of patients were Muslim and 9% Hindu. A total of 53% cases of hepatic WD presented between 5 to 10 years of age and most of the neurologic WD manifested in 10-15 years age group. Sixty-nine children presented only with hepatic manifestations, 6 only with neurological manifestations, 14 with both hepatic and neurological manifestation, 10 children was asymptomatic and 1 patient presented with psychiatric features. WD presented as chronic liver disease (CLD) in 42%, CLD with portal hypertension in 34%, acute hepatitis in 20% and fulminant hepatic failure in 4% cases. Stigmata of CLD were found in 18% patients. Keiser-Fleischser ring was found in 76% total patients. Elevated serum transaminase was found in 85% cases, prolonged prothrombin time in 59% cases and hypoalbuminaemia in 53% cases. A total of 73% patients had low serum ceruloplasmin, basal urinary copper of >$100{\mu}g/day$ was found in 81% cases and urinary copper following penicillamine challenge of >$1,200{\mu}g/day$ was found in 92% cases. Conclusion: Majority of studied WD children presented with hepatic manifestation of which 76% presented with CLD. Any child presented with jaundice after the age of 3 years should be investigated for WD.

Steric and Electronic Effects of Tetradentate Nickel(II) and Palladium(II) Complexes toward the Vinyl Polymerization of Norbornene

  • Lee, Dong-Hwan;Lee, Jung-Hwan;Eom, Geun-Hee;Koo, Hyo-Geun;Kim, Cheal;Lee, Ik-Mo
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1884-1890
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    • 2011
  • A series of Ni(II) and Pd(II) complexes bearing N4-type tetradentate ligands, [Ni($X^1X^2$-6-$Me_2bpb$) 1] and [Pd($X^1X^2$-6-$Me_2bpb$) 2]; 6-$Me_2bpb$ = N,N'-(o-phenylene)bis(6-methylpyridine-2-carboxamidate), $X^1$ = Cl, H, or $CH_3$, $X^2$ = $NO_2$, Cl, F, H, $CH_3$, or $OCH_3$) were designed, synthesized, and characterized to investigate electronic and steric effects of ligand on the norbornene polymerization catalysts. Using modified methylaluminoxanes as an activator, the complexes exhibited high catalytic activities for the polymerization of norbornene and the nickel complexes exhibited better catalytic activity the palladium complexes. Ni complex 1a with $NO_2$ group on the benzene ring showed the highest catalytic activity of $4.9{\times}10^6$ g of PNBEs/$mol_{Ni}{\cdot}h$ and molecular weight of $15.28{\times}10^5$ g/mol with PDI < 2.30. Complexes with electron-withdrawing groups are more thermally stable (> 100 $^{\circ}C$), and tend to afford higher polymerization productivities than the ones having electron-donating groups. Amorphous polynorbornenes were obtained with good solubility in halogenated aromatic solvents. A vinyl addition mechanism has been proposed for the catalytic polymerization.

A NOTE ON WITT RINGS OF 2-FOLD FULL RINGS

  • Cho, In-Ho;Kim, Jae-Gyeom
    • Bulletin of the Korean Mathematical Society
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    • v.22 no.2
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    • pp.121-126
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    • 1985
  • D.K. Harrison [5] has shown that if R and S are fields of characteristic different from 2, then two Witt rings W(R) and W(S) are isomorphic if and only if W(R)/I(R)$^{3}$ and W(S)/I(S)$^{3}$ are isomorphic where I(R) and I(S) denote the fundamental ideals of W(R) and W(S) respectively. In [1], J.K. Arason and A. Pfister proved a corresponding result when the characteristics of R and S are 2, and, in [9], K.I. Mandelberg proved the result when R and S are commutative semi-local rings having 2 a unit. In this paper, we prove the result when R and S are 2-fold full rings. Throughout this paper, unless otherwise specified, we assume that R is a commutative ring having 2 a unit. A quadratic space (V, B, .phi.) over R is a finitely generated projective R-module V with a symmetric bilinear mapping B: V*V.rarw.R which is nondegenerate (i.e., the natural mapping V.rarw.Ho $m_{R}$ (V, R) induced by B is an isomorphism), and with a quadratic mapping .phi.:V.rarw.R such that B(x,y)=(.phi.(x+y)-.phi.(x)-.phi.(y))/2 and .phi.(rx)= $r^{2}$.phi.(x) for all x, y in V and r in R. We denote the group of multiplicative units of R by U(R). If (V, B, .phi.) is a free rank n quadratic space over R with an orthogonal basis { $x_{1}$, .., $x_{n}$}, we will write < $a_{1}$,.., $a_{n}$> for (V, B, .phi.) where the $a_{i}$=.phi.( $x_{i}$) are in U(R), and denote the space by the table [ $a_{ij}$ ] where $a_{ij}$ =B( $x_{i}$, $x_{j}$). In the case n=2 and B( $x_{1}$, $x_{2}$)=1/2, we reserve the notation [ $a_{11}$, $a_{22}$] for the space.the space.e.e.e.

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Recent Advances in Di-$\pi$-methane Processes. Novel Reactions of 1,4-Unsaturated Compounds Promoted by Triplet Sensitization and Photoelectron Transfer

  • Armesto, Diego;Ortiz, Maria J.;Agarrabeitia, Antonia R.
    • Journal of Photoscience
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    • v.10 no.1
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    • pp.9-20
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    • 2003
  • Recent studies on the photoreactivity of l,4-unsaturated systems have changed some ideas that were firmly established in this area of research for many years. Thus, we have described the first examples of 2-aza-di-$\pi$-methane (2-ADPM) rearrangements promoted by triplet-sensitization and by single electron transfer (SET) using electron-acceptor sensitizers. These reactions afford N-vinylaziridine and cyclopropylimine photoproducts in the first examples of di-$\pi$-methane processes that yield three-membered ring heterocycles. l-Aza-1,4-dienes also undergo SET-promoted l-aza-di-$\pi$-methane (l-ADPM) rearrangements via radical-cation intermediates using electron acceptor sensitizers. In some cases, alternative cyclizations yielding different carbocycles and heterocycles have been observed. The l-ADPM and di-$\pi$-methane (DPM) reactions also occur via radical-anion intermediates on irradiation using electron donor sensitizers. On the other hand, the photoreactivity reported for $\beta$,${\gamma}$-unsaturated aldehydes for many years was decarbonylation to the corresponding alkenes. However, our studies demonstrate that these compounds undergo the oxa-di-$\pi$-methane (ODPM) rearrangement with high chemical and quantum efficiency. A comparison of the photochemical reactivity of $\beta$,${\gamma}$-unsaturated aldehydes and corresponding methyl ketones has shown that the ketones do not undergo the ODPM rearrangement while the corresponding aldehydes are reactive by this pathway. Monosubstituted $\beta$,${\gamma}$-unsaturated aldehydes at C-2 undergo the ODPM rearrangement yielding the corresponding cyclopropane carbaldehydes diastereoselectively. Finally, we have described the first examples of reactions, similar to the well know Norrish Type I process, which take place in the triplet excited state of $\beta$,${\gamma}$-unsaturated carbonyl compounds by excitation of the C-C double bond instead of the carbonyl group.

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Synthesis and Characterization of Poly(L-lactic acid-co-glycine-L-lactic acid) and Poly - ( L-1actic acid-co-gl ycine-L-methyl 1actic acid) (생체분해성 고분자의 합성 및 물성에 관한 연구(II) -Poly (L-lactic acid-co-glycine-L-lactic acid) 와 Poly- (L-lactic acid-co-glycine-L-methyl lactic acid))

  • Sung, Yong-Kiel;Song, Dae-Kyung;Park, Kyung-Hee
    • Journal of Biomedical Engineering Research
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    • v.9 no.2
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    • pp.225-232
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    • 1988
  • Poly (L- lactic acid-co-glycine-L-lactic acid) and Poly (L-lactic acid-co-glycine-L- methyl lactic acid ) have been prepared by ring opening polymerization. The monomer 6, 6-dimethyl morpho-line-2, 5-dione was synthesized by the bromoisobutylation of 2-bromoisobutyryl bromide with glycin e. L-lactide, 6-methyl morpholine-2, 5-diode. and 6, 6-dimethyl morpholine-2, 5-diode have been used as starting materials for polydepsipeptides. The synthesized monomers and copolymers have been identified by NMR and FT-lR spa- ctrophotometer. The thermal propert ies and glass transition temperature(Tg) of the copolymers have been measured by differential scanning calorimetry. The Tg values of poly(L-lactic acid co-glycine-L-lactic acid) system are increased from $53^{\circ}C\; to\; 107^{\circ}C$ with increasing the mole fraction of 6-methyl morpholine-2, 5-diode. And the Tg values of poly(L-lactic acid co-glycine-L-methyl lactic acid) system are increased from $53^{\circ}C\;to\;138^{\circ}C$ with increasing the mole fraction of 6. 6-dimethyl morpholine-2, 5-diode The thermal stability of poly (L-lactic acid-co-glycine-L-methyl lactic acid) is slightly greta text than that of poly(L-lactic acid-co-glycine-L-lactic acid) due to the methyl group.

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Effects of 1,7-Substituted Methylxanthine Derivatives on LPS-Stimulated Expression of Cytokines and Chemokines in Raw 264.7 and HK-2 Cells

  • Kang, Joo-Yeon;Shin, Hea-Soon
    • Journal of Microbiology and Biotechnology
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    • v.25 no.2
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    • pp.296-301
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    • 2015
  • Chronic kidney diseases are based on uncontrolled immunological and inflammatory responses to pathophysiological renal circumstances such as glomerulonephritis, which is caused by immunological mechanisms of glomerular inflammation with increased production of renal pro-inflammatory cytokines. Pentoxifylline (PTX) exhibits anti-inflammatory properties by inhibiting cytokine and chemokine production through aggregation of erythrocytes and thrombocytes. We synthesized a series of 1,7-substituted methylxanthine derivatives by the Traube purine reaction, and the formation of purine ring was completed through nitrosation, a reduction of the nitroso to the amine by catalytic hydrogenation as derivatives of PTX. Then we studied biological activities such as renal anti-inflammatory effects of the synthesized compounds in the production of cytokines such as nitric oxide (NO), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) and of chemokines such as monocyte chemoattractant protein-1 and IL-8 in Raw 264.7 and HK-2 cells. Renal antiinflammatory activities of this novel series of N-1 and N-7-substituted methylxanthine showed that the N-7 methyl-group-substituted analogs (S7b) showed selective 61% and 77% inhibition of the production of NO and IL-8. The other replacement of the N-1-(CH2)4COCH3 roup, as in the case of compound S6c, also showed an effective 50% and 77% inhibition of TNF-α and IL-8 production in LPS-stimulated Raw 264.7 and HK-2 cells.

Preparation and Characterization of Cobalt(III) Complexes with N,N,N',N'-Tetrakis(2-aminoethyl)-1,2-ethanediamines Ligand (,N,N',N'-Tetrakis(2-aminoethyl)-1,2-ethanediamine형 리간드를 포함하는 코발트 (III) 착물의 합성과 특성)

  • Myung-ki Doh;Byeoung-Su Choi;Chang-Rok An;Junnosuke Fujita
    • Journal of the Korean Chemical Society
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    • v.26 no.5
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    • pp.310-319
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    • 1982
  • Cobalt(III) complexes with sexidentate ligands, N,N,N',N'-tetrakis(2-amino-ethyl)-1,2-ethanediamine (ten), -1,3-propanediamine (ttn), -1,4-butanediamine (ttmd), -(R,R)-and -(R,S)-2,4-pentanediamine (tptn) were prepared, and the characterization of d-d absorption band on the variation of chelate ring size and conformation of these complexes were studied by means of electronic spectra. The first d-d absorption bands of $[Co(L)]^{3+}$ complexes are shifted to smaller wave numbers in the order. ttn > (R,R)-tptn > ten > ttmd${\simeq}$(R,S)-tptn for (L). The UV, $^{13}C$ NMR, and Circular Dichroism studies indicate that the R,S-tptn ligand of $[Co(R,S-tptn)]^{3+}$ complex coodinates to cobalt(Ⅲ) ion as a sexidentate with one methyl group in axial position.

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Kinetic Study on Nucleophilic Substitution Reaction of 5-Nitro-8-quinolyl Benzoate, Picolinate, Nicotinate and Isonicotinate with Alkali Metal Ethoxide: Effect of Nonleaving Group on Reactivity and Transition State Structure

  • Lee, Jieun;Kim, Min-Young;Um, Ik-Hwan
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1789-1793
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    • 2014
  • Pseudo-first-order rate constants ($k_{obsd}$) have been measured spectrophotometrically for the reactions of 5-nitro-8-quinolyl nicotinate (4) and 5-nitro-8-quinolyl isonicotinate (5) with alkali metal ethoxides (EtOM; M = K, Na and Li) in anhydrous ethanol at $25.0{\pm}0.1^{\circ}C$. The plots of $k_{obsd}$ vs. [EtOM] curve slightly upward for the reactions with EtOK and EtONa but are linear for the reactions with EtOLi and for those with EtOK in the presence of 18-crown-6-ether. Dissection of $k_{obsd}$ into $k_{EtO^-}$ and $k_{EtOM}$ (i.e., the second-order rate constants for the reactions with the dissociated $EtO^-$ and ion-paired EtOM, respectively) has revealed that the reactivity increases in the order $EtO^-{\approx}EtOLi$ < EtOK < EtONa for the reactions of 4 and EtOLi < $EtO^-$ < EtOK < EtONa for the reactions of 5. Comparison of the kinetic results for the reactions of 4 and 5 with those reported previously for the corresponding reactions of 5-nitro-8-quinolyl benzoate (2) and picolinate (3) has revealed that the esters possessing a pyridine ring (i.e., 3-5) are significantly more reactive than the benzoate ester 2 due to the presence of the electronegative N atom (e.g., 2 << 3 < 4 < 5). It has been concluded that $M^+$ ion catalyzes the reactions of 3-5 by increasing the electrophilicity of the reaction center through a five-membered cyclic transition state (TS) for the reaction of 3 and via a four-membered cyclic TS for the reactions of 4 and 5.

Glucosylation of Isoflavonoids in Engineered Escherichia coli

  • Pandey, Ramesh Prasad;Parajuli, Prakash;Koirala, Niranjan;Lee, Joo Ho;Park, Yong Il;Sohng, Jae Kyung
    • Molecules and Cells
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    • v.37 no.2
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    • pp.172-177
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    • 2014
  • A glycosyltransferase, YjiC, from Bacillus licheniformis has been used for the modification of the commercially available isoflavonoids genistein, daidzein, biochanin A and formononetin. The in vitro glycosylation reaction, using UDP-${\alpha}$-D-glucose as a donor for the glucose moiety and aforementioned four acceptor molecules, showed the prominent glycosylation at 4' and 7 hydroxyl groups, but not at the $5^{th}$ hydroxyl group of the A-ring, resulting in the production of genistein 4'-O-${\beta}$-D-glucoside, genistein 7-O-${\beta}$-D-glucoside (genistin), genistein 4',7-O-${\beta}$-D-diglucoside, biochanin A-7-O-${\beta}$-D-glucoside (sissotrin), daidzein 4'-O-${\beta}$-D-glucoside, daidzein 7-O-${\beta}$-D-glucoside (daidzin), daidzein 4', 7-O-${\beta}$-D-diglucoside, and formononetin 7-O-${\beta}$-D-glucoside (ononin). The structures of all the products were elucidated using high performance liquid chromatography-photo diode array and high resolution quadrupole time-of-flight electrospray ionization mass spectrometry (HR QTOF-ESI/MS) analysis, and were compared with commercially available standard compounds. Significantly higher bioconversion rates of all four isoflavonoids was observed in both in vitro as well as in vivo bioconversion reactions. The in vivo fermentation of the isoflavonoids by applying engineered E. coli $BL21(DE3)/{\Delta}pgi{\Delta}zwf{\Delta}ushA$ overexpressing phosphoglucomutase (pgm) and glucose 1-phosphate uridyltransferase (galU), along with YjiC, found more than 60% average conversion of $200{\mu}M$ of supplemented isoflavonoids, without any additional UDP-${\alpha}$-D-glucose added in fermentation medium, which could be very beneficial to large scale industrial production of isoflavonoid glucosides.

Effect of Chemical Stabilizers in Silver Nanoparticle Suspensions on Nanotoxicity

  • Bae, Eun-Joo;Park, Hee-Jin;Park, Jun-Su;Yoon, Je-Yong;Kim, Young-Hun;Choi, Kyung-Hee;Yi, Jong-Heop
    • Bulletin of the Korean Chemical Society
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    • v.32 no.2
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    • pp.613-619
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    • 2011
  • Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.