bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cortical connections of the lateral mediodorsal thalamus in cynomolgus monkeys
Authors: Erickson Susan L. , Lewis David A. 
Published: March 2004

AbstractThe prefrontal cortex has been defined as that cortical territory that has “essential or sustaining” connections with the mediodorsal (MD) nucleus of the thalamus (Rose and Woolsey [1948] Publ Assoc Res Nerv Ment Dis 27:210–232). However, recent studies in the monkey have documented projections from MD to the more caudal, agranular regions of the frontal cortex, suggesting that the connections of MD may be characterized by a breadth of distribution and diversity of functional roles too great to be useful as a unifying and defining feature for a specific cortical territory. In this study, we placed tracer injections in the lateral divisions of MD in cynomolgus monkeys (Macaca fascicularis) to assess the relative proportions of connections devoted to diverse regions of the frontal cortex (FC). Three different patterns of label were observed in the cortex, associated with different locations within lateral MD. We have designated these as the ventrolateral MD‐arcuate FC circuit, having most label in areas 8 and 6; the caudoventral MD‐dorsomedial FC circuit, having most label in areas 24 and presupplementary motor area (SMA); and the anterodorsal MD‐anterior FC circuit, with the most label in areas 9, 46, 12, and 10. Only two of the nine cases injected in lateral MD were predominantly connected with the anterior FC. Thus, particular locales within lateral MD are connected with multiple, functionally diverse cortical regions, including several not classically recognized as “prefrontal” areas. This divergence may distinguish MD‐frontocortical and reciprocal corticothalamic pathways from the largely segregated pathways arising from the other thalamic nuclei that are interconnected with the frontal cortex, such as those from the ventrolateral nuclear group. J. Comp. Neurol. 473:107–127, 2004. © 2004 Wiley‐Liss, Inc.
Differential expression of γ‐aminobutyric acid type B receptor subunit mRNAs in the developing nervous system and receptor coupling to adenylyl cyclase in embryonic neurons
Authors: Martin Stella C. , Steiger Janine L. , Gravielle María Clara , Lyons Helen R. , Russek Shelley J. , Farb David H. 
Published: March 2004

Abstractγ‐Aminobutyric acid type B receptors (GABABRs) mediate both slow inhibitory synaptic activity in the adult nervous system and motility signals for migrating embryonic cortical cells. Previous papers have described the expression of GABABRs in the adult brain, but the expression and functional significance of these gene products in the embryo are largely unknown. Here we examine GABABR expression from rat embryonic day 10 (E10) to E18 compared with adult and ask whether embryonic cortical neurons contain functional GABABR. GABABR1 transcript levels greatly exceed GABABR2 levels in the developing neural tube at E11, and olfactory bulb and striatum at E17 but equalize in most regions of adult nervous tissue, except for the glomerular and granule cell layers of the main olfactory bulb and the striatum. Consistent with expression differences, the binding affinity of GABA for GABABRs is significantly lower in adult striatum compared with cerebellum. Multiple lines of evidence from in situ hybridization, RNase protection, and real‐time PCR demonstrate that GABABR1a, GABABR1b, GABABR1h (a subunit subtype, lacking a sushi domain, that we have identified in embryonic rat brain), GABABR2, and GABABL transcript levels are not coordinately regulated. Despite the functional requirement for a heterodimer of GABABR subunits, the expression of each subunit mRNA is under independent control during embryonic development, and, by E18, GABABRs are negatively coupled to adenylyl cyclase in neocortical neurons. The presence of embryonic GABABR transcripts and protein and functional receptor coupling indicates potentially important roles for GABABRs in modulation of synaptic transmission in the developing embryonic nervous system. J. Comp. Neurol. 473:16–29, 2004. © 2004 Wiley‐Liss, Inc.
Inverse relationship between the contents of neuromelanin pigment and the vesicular monoamine transporter‐2: Human midbrain dopamine neurons
Authors: Liang Chang‐Lin , Nelson Omar , Yazdani Umar , Pasbakhsh Parichehr , German Dwight C. 
Published: March 2004

AbstractThe dopaminergic neurons in the ventral substantia nigra (SN) are significantly more vulnerable to degeneration in Parkinson's disease (PD) than the dopaminergic neurons in the ventral tegmental area (VTA). The ventral SN neurons also contain significantly more neuromelanin pigment than the dopaminergic neurons in the VTA. In vitro data indicate that neuromelanin pigment is formed from the excess cytosolic catecholamine that is not accumulated into synaptic vesicles by the vesicular monoamine transporter‐2 (VMAT2). By using quantitative immunohistochemical methods in human postmortem brain, we sought to examine the relative contents of VMAT2 within neurons that contain different amounts of neuromelanin pigment. The immunostaining intensity (ISI) was measured for VMAT2 and also for the rate‐limiting enzyme for the synthesis of dopamine, tyrosine hydroxylase (TH). ISI measures were taken from the ventral SN region where neurons are most vulnerable to degeneration in PD, nigrosome‐1 (N1); from the ventral SN region where cells are moderately vulnerable to degeneration in PD, the matrix (M); and from VTA neurons near the exit of the third nerve (subregion III). The data indicate that 1) subregion III neurons have significantly higher levels of VMAT2 ISI compared with N1 neurons (more than twofold) and M neurons (45%); 2) there is an inverse relationship between VMAT2 ISI and neuromelanin pigment in the N1 and III neurons; 3) there is an inverse relationship between VMAT2 ISI and the vulnerability to degeneration in PD in the N1, M, and III subregions; and 4) neurons with high VMAT2 ISI also have high TH ISI. These data support the hypothesis that midbrain dopaminergic neurons that synthesize greater amounts of dopamine have more vesicular storage capacity for action potential‐induced release of transmitter and that the ventral SN neurons accumulate the most neuromelanin pigment, in part because they have the least VMAT2 protein. J. Comp. Neurol. 473:97–106, 2004. © 2004 Wiley‐Liss, Inc.
Selective Reaction of Aminorhenium Complexes and the Formation of Cp‐N‐P Tridentate Complexes
Authors: Wang Tein‐Fu , Wang Tan‐Ching , Wen Yuh‐Sheng 
Published: March 2004

AbstractRhenium complexes containing cyclopentadienyl‐amino‐phosphanyl tridentate ligands have been prepared starting from a cyclopentadienyl‐amino bidentate complex in a controlled manner. Dehydrobromination of [η5:η1‐C5H4CH2CH2NH(CH3)Re(CO)2Br]+ (2) was carried out selectively at low temperature to give an exocyclic iminorhenium complex [η5:η1‐C5H4CH2CH2N(=CH2)Re(CO)2] (5). Selective N‐methylation provided a cationic heterocyclopropane complex 8 which reacted with various nucleophiles (tBuNH2, NaOCH3, KPPh2) to give precursors for tridentate complexes. A formal oxidation of the carbonyl ligand to a labile carbon dioxide ligand was accomplished by oxidation with peroxy acid. Intramolecular N ligand displacement furnished the Cp‐N‐P tridentate complex. The relative stability of the N, P and CO ligands was revealed when an η3‐allyl ligand was formed. The N ligand became detached from the metal rather than the P or CO ligands as the η1‐allyl was transformed to the corresponding η3‐allyl coordination mode. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Palladium Chemistry in Anhydrous HF/AsF5 Superacid Medium
Authors: Mazej Zoran , Benkič Primož , Tressaud Alain , Žemva Boris 
Published: March 2004

AbstractPd metal dissolves in anhydrous HF (aHF) acidified with AsF5 in the presence of F2 at ≈︁298 K to give a blue‐green solution from which green Pd(AsF6)2 can be isolated. The latter was also prepared by the interaction of PdF2 and AsF5 in aHF or by the reaction between PdO and F2 in aHF acidified with AsF5. Powdered Pd(AsF6)2 slowly loses AsF5 in a dynamic vacuum. It can therefore be isolated from solution at T < 253 K. Single‐crystals of Pd(AsF6)2 were prepared by solvothermal synthesis from a Pd/AsF5/F2/aHF mixture at 393 K. Pd(AsF6)2 is triclinic with a = 500.9(5), b = 538.3(5), c = 864.9(9) pm, α = 74.46(3), β = 89.97(4), γ = 62.47(2)°, V = 0.1972(3) nm3, and Z = 1, space group P$\bar 1$
(No. 2). The six‐coordinate Pd atoms (coordinated with fluorine) are well separated by isolated AsF6 units. In the 2−175 K temperature range Pd(AsF6)2 follows the Curie−Weiss law with μeff = 3.53 B.M., Tn = 8 K and θp= −13 K. Because of cation‐anion interactions, the AsF6− anions deviate from ideal Oh symmetry. The reduced symmetry can be seen in vibrational spectra, where splitting of the anion vibrational modes can be observed. The oxidation of Pd metal or PdO with F2 in neutral aHF yielded Pd2F6. No reaction was observed between Pd, PdO or Pd2F6 and AsF5 in aHF. All attempts to prepare PdFAsF6 were unsuccessful. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Ligating Ability of Functionalised Diaminodimethylsilanes towards Zirconium(IV)
Authors: Passarelli Vincenzo , Benetollo Franco , Zanella Pierino 
Published: March 2004

AbstractThe functionalised diaminodimethylsilanes SiMe2[NH(CH2)nX]2 (X = NMe2, n = 2, H2L1; n = 3, H2L2; X = OMe, n = 2, H2L3; n = 3, H2L4) have been synthesised by aminolysis of SiMe2Cl2 with NH2(CH2)nX, and their ligating ability towards zirconium(IV) has been investigated. The syntheses of [ZrY2(L)] (Y = Cl, NMe2, Me; L = L1, L2, L3, L4) are reported and the solid‐state structures of some selected compounds determined by X‐ray crystallography. In addition, the solution molecular structures of all the metal derivatives have been elucidated by variable‐temperature multinuclear 1D/2D NMR spectroscopy, and the dynamics have been investigated in some selected cases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Syntheses, Structures and Redox Properties of New Macrocyclic Triazatriolefinic Pd0 Complexes and Their Polypyrrole Modified Electrodes − Application to Heterogeneous Catalytic Suzuki Cross‐Coupling Reactions
Authors: Llobet Antoni , Masllorens Ester , Rodríguez Montserrat , Roglans Anna , Benet‐Buchholz Jordi 
Published: March 2004

AbstractNew triolefinic macrocyclic ligands of the type (E,E,E)‐1,6,11‐tris(arenesulfonyl)‐1,6,11‐triazacyclopentadeca‐3,8,13‐triene (aryl: a = ferrocenyl, b = 4‐pyrrol‐1‐ylphenyl, c = 4‐methylphenyl) and their Pd0 complexes (1aab, 1abb and 1bcc) have been prepared and characterized. Further structural characterization in the solid state has also been performed by means of X‐ray diffraction analysis for the complex 1bcc. The redox properties of both the ligands and their Pd complexes have been studied using cyclic voltammetric and coulombimetric techniques. In particular, complexes and ligands containing the pyrrole group do polymerize upon exposure to sufficiently positive potentials, on glassy carbon electrodes, generating highly stable modified electrodes. The new modified electrodes are efficient and selective heterogeneous catalysts for Suzuki cross‐couplings, benefiting from simple removal of the catalyst from the reaction vessel. As an example, more than 2·105 metal cycles are achieved at 65 °C in the coupling of phenylboronic acid and cinnamyl bromide. Iodoarenes and phenylboronic acid are also converted into biphenyls with relatively good conversions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electronic Structures and Reactivities of Corrole−Copper Complexes
Authors: Luobeznova Inna , Simkhovich Liliya , Goldberg Israel , Gross Zeev 
Published: March 2004

AbstractThe spectroscopic and electrochemical examination of the mononuclear copper complexes of 5,10,15‐tris(pentafluorophenyl)corrole and 5,10,15‐tris(2,6‐dichlorophenyl)corrole (1a and 2a, respectively) and of the corresponding dinuclear corrole dimers 1b and 2b reveal the existence of two almost degenerate electronic states. The lower state consists of copper(III) ions coordinated by closed‐shell corrolato trianions and the higher state is composed of copper(II) ions chelated by open‐shell corrolato dianions. The contributions from both states are evident in the molecular structure of monomeric and mononuclear 2a, which displays a distorted square‐planar coordination geometry around the metal ion and short Cu−N bond lengths typical of copper(III), together with some non‐equivalence of the Cα−Cmeso bond lengths that might reflect the open‐shell character of the macrocycle. The latter state is most likely to be responsible for the dimerization process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Structural and Theoretical Studies of New Ruthenium‐Amidato Complexes with Phenanthroline Ligands Containing H‐Bonding Groups
Authors: Rais Daniela , Gould Ian R. , Vilar Ramón , White Andrew J. P. , Williams David J. 
Published: March 2004

AbstractThe syntheses, characterization and coordination chemistry of two new 1,10‐phenanthroline‐based ligands are presented here. Crystallographic studies have shown that both molecules display hydrogen‐bonding and π−π stacking interactions, generating interesting supramolecular assemblies in the solid state. The reactions of these ligands with [RuCl2(PPh3)3] have been performed and two new ruthenium‐amidato complexes have been prepared. In both cases, the presence of a pyridyl group in the ligand backbone favours the deprotonation of one of the carboxyamido moieties leading to a tridentate coordination mode of the ligands. The structural characterization of one of the ruthenium complexes is also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The First Amine‐Templated Layered Metal Selenates
Authors: Udayakumar D. , Dan Meenakshi , Rao C. N. R. 
Published: March 2004

AbstractAlthough a few open‐framework metal sulfates and selenites have been synthesized and characterized recently, it has not been possible to prepare the corresponding selenates, probably because of the instability of the +6 oxidation state of Se in alkaline media. We have been able to synthesize, for the first time, organically templated open‐framework rare earth selenates with the general formula 0.5[C2N2H10][Ln(H2O)2(SeO4)2] (I) (Ln = La, Nd or Pr) and 0.5[C4N2H14][La(SeO4)2]·0.5H2O (II), under hydrothermal conditions in an acidic medium. Crystal data: I (Ln = La): triclinic, space group = P$\bar 1$
, Mr = 491.91, a = 7.0105(8) Å, b = 7.3772(9) Å, c = 9.526(1) Å, α = 82.014(2), β = 84.514(2), γ = 84.247(2)°, V = 483.76(1) Å3, Z = 2; II: triclinic, space group = P$\bar 1$
, Mr = 478.91, a = 5.94(2), b = 7.408(3), c = 11.048(2) Å, α = 86.899(2), β = 75.971(1), γ = 79.456(2)°, V = 463.7(2) Å3, Z = 4. Being the first report of complex layered selenates, it is likely to stimulate efforts to synthesize other novel open‐framework structures making use of the selenate ion as the building unit. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Comparative in vitro and in vivo genotoxicities of 7H‐benzo[c]fluorene, manufactured gas plant residue (MGP), and MGP fractions
Authors: Cizmas Leslie , Zhou Guo‐dong , Safe Stephen H. , McDonald Thomas J. , Zhu Li , Donnelly Kirby C. 
Published: March 2004

AbstractManufactured gas plant residue (MGP) is a complex mixture of polycyclic aromatic hydrocarbons (PAHs) that is tumorigenic in the lungs of mice. This study compared the relative genotoxicity of 7H‐benzo[c]fluorene (BC), a PAH component of MGP, with MGP and MGP fractions in order to assess the contribution of BC to the genotoxicity of MGP. An MGP sample was separated into seven fractions (F1–F7) using silica gel column chromatography with petroleum ether (PE) followed by PE:acetone (99:1 v/v, then 98:2). PAHs were quantified using gas chromatography/mass spectrometry. An aliquot of F2, the fraction with the highest BC concentration and highest weighted mutagenic activity in Salmonella typhimurium strain TA98, was further separated using silica gel thin‐layer chromatography with hexane. The first F2 subfraction, sF2‐a, was enriched in BC and coeluting compounds and contained 35,000 ppm BC and 216,109 ppm carcinogenic PAHs (cPAHs, the sum of seven PAHs categorized by the U.S. EPA as class B2 carcinogens). The second F2 subfraction, sF2‐b, contained a ninefold lower concentration of BC, with 3,900 ppm BC and 45,216 ppm cPAHs. Female ICR mice received topical application of crude MGP, crude MGP spiked with analytical‐grade BC, F2, sF2‐a, sF2‐b, or analytical‐grade BC. DNA adduct levels were analyzed by nuclease P1‐enhanced 32P‐postlabeling. In lung DNA of mice receiving 0.48 or 3.0 mg/mouse, net total RAL × 109 values were F2, 30.8 and 87.2; sF2‐a, 24.8 and 106.7; and sF2‐b, 19.6 and 151.0, respectively. Mice dosed with 0.10 mg analytical‐grade BC (the mass of BC in 3.0 mg sF2‐a) exhibited a net total RAL × 109 value of 7.03 in lung DNA. This was equal to approximately 7% of the total RAL × 109 value produced by 3.0 mg sF2‐a. Thus, although BC appears to make an appreciable contribution to pulmonary adduct formation, the results suggest that MGP components other than BC play an important role in lung DNA adduct formation following topical MGP administration. Environ. Mol. Mutagen. 43:159–168, 2004. © 2004 Wiley‐Liss, Inc.
Biofilm barriers to contain and degrade dissolved trichloroethylene
Authors: Komlos John , Cunningham Alfred B. , Camper Anne K. , Sharp Robert R. 
Published: March 2004

AbstractBiologically produced subsurface barriers (i.e., biofilm barriers) are a viable technology for controlling contaminant migration from hazardous waste sites. Biofilm barriers are created through the injection of bacteria and selective growth medium into a series of wells downstream of a contaminant plume. Adequate substrate addition enables the bacteria to grow and form thick biofilms capable of uniform plugging of the subsurface. This technology has been successful in significantly reducing porous media permeability in bench‐scale and field‐scale applications. The research presented herein expands on current biofilm barrier technology by examining the feasibility of using a biofilm barrier to not only control contaminant migration through permeability reduction, but also facilitate contaminant biodegradation. The experimental scenario involved the creation of a dual‐species biofilm matrix: one organism to reduce porous media permeability through thick biofilm formation and another organism to degrade a contaminant, in this case trichloroethylene (TCE). Porous medium column experiments demonstrated that a dual‐species biofilm barrier can be created and that growth medium concentration was a very important variable in controlling simultaneous TCE degradation and permeability reduction. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 69–77, 2004
Soil lead bioavailability and in situ remediation of lead‐contaminated soils: A review
Authors: Hettiarachchi Ganga M. , Pierzynski Gary M. 
Published: March 2004

AbstractThe environmental risk from soil lead (Pb) is related to its bioavailability. Soil Pb bioavailability depends on the solubility of Pb solid phases and other site‐specific soil chemistry, suggesting that in situ stabilization of soil Pb can be accomplished by changing soil Pb chemistry. This paper presents a review of soil Pb bioavailability and an evaluation of in situ stabilization methods that can be used to reduce Pb bioavailability. A promising in situ approach involves the amendment of Pb‐contaminated soil with phosphorus (P) in various forms or P with other amendments. Two general categories of P are insoluble forms, such as phosphate rock or synthetic apatites, and soluble forms typically present in commercially available fertilizer products or phosphoric acid. Numerous indirect assessment techniques show marked reductions in soil Pb biovailability upon addition of P and other amendments to Pb‐contaminated soils. The techniques include physiologically based extraction tests, plant uptake of Pb, and other soil Pb extraction methods. More directly, animal feeding studies also show reductions in soil Pb biovailability. In situ stabilization of soil Pb using P and other soil amendments is an emerging technology integrating soil chemistry, agricultural practices, and engineering that is gaining public and regulatory acceptance. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 78–93, 2004
Effect of duct velocity profile and buoyancy‐induced flow on efficiency of transient hydrodynamic removal of a contaminant from a cavity
Authors: Fang Lih‐chuan 
Published: March 2004

AbstractThis paper describes a preliminary numerical analysis of the effect of duct velocity profile and buoyancy‐induced flow generated by the heat source on hydrodynamic removal of contaminants contained in cavities. The process of fluid renewal in a cavity is modelled via a numerical solution of the Navier–Stokes equations coupled with the energy equation for transient flows. The foulant has the same density as the fluid in the duct and the duct velocity profile is considered to be Poiseuille flow and Couette flow, respectively. The results show that the change in Grashof number and duct flow velocity profile causes a dramatic difference in the observed flow patterns and cleaning efficiency. From a cleaning perspective, the results suggest that Couette flow at higher value of Grashof number becomes more effective in further purging of contaminated fluid from a cavity. Copyright © 2004 John Wiley & Sons, Ltd.
Improving the accuracy of the spatial discretization in finite‐difference electrochemical kinetic simulations, by means of the extended Numerov method
Authors: Bieniasz Lesław K. 
Published: March 2004

AbstractThe fourth‐order accurate, three‐point finite‐difference Numerov spatial discretization provides accurate and efficient solutions to the time‐dependent governing differential equations of electrochemical kinetics in one‐dimensional space geometry, when the equations contain first time derivatives of the solution, second spatial derivatives, and homogeneous reaction terms only. However, the original Numerov discretization is not applicable when the governing equations involve first spatial derivative terms. To overcome this limitation, an appropriately extended Numerov discretization is required. We examine the utility of one of such extensions, first described by Chawla. Relevant discrete formulae are outlined for systems of linear governing equations involving first derivative terms, and applied to five representative example models of electrochemical transient experiments. The extended Numerov discretization proves to have an accuracy and efficiency comparable to the original Numerov scheme, and its accuracy is typically up to four orders of magnitude higher, compared to the conventional, second‐order accurate spatial discretization, commonly used in electrochemistry. This results in a considerable improvement of efficiency. Therefore, the application of the extended Numerov discretization to the electrochemical kinetic simulations can be fully recommended. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1075–1083, 2004