bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulatory T Cells Modulate Staphylococcal Enterotoxin B-Induced Effector T-Cell Activation and Acceleration of Colitis
Authors: Heriazon Armando , Zhou Pengfei , Borojevic Rajka , Foerster Katharina , Streutker Catherine J. , Ng Terry , Croitoru Kenneth
Published: December 2008

Oral administration of bacterial superantigenStaphylococcus aureusenterotoxin B (SEB) activates mucosal T cells but does not cause mucosal inflammation. We examined the effect of oral SEB on the development of mucosal inflammation in mice in the absence of regulatory T (Treg) cells. SCID mice were fed SEB 3 and 7 days after reconstitution with CD4+CD45RBhighor CD4+CD45RBhighplus CD4+CD45RBlowT cells. Mice were sacrificed at different time points to examine changes in tissue damage and in T-cell phenotypes. Feeding SEB failed to produce any clinical effect on SCID mice reconstituted with CD4+CD45RBhighand CD4+CD45RBlowT cells, but feeding SEB accelerated the development of colitis in SCID mice reconstituted with CD4+CD45RBhighT cells alone. The latter was associated with an increase in the number of CD4+Vβ8+T cells expressing CD69 and a significantly lower number of CD4+CD25+Foxp3+T cells. These changes were not observed in SCID mice reconstituted with both CD45RBhighand CD45RBlowT cells. In addition, SEB impaired the development of Treg cells in the SCID mice reconstituted with CD4+CD45RBhighT cells alone but had no direct effect on Treg cells. In the absence of Treg cells, feeding SEB induced activation of mucosal T cells and accelerated the development of colitis. This suggests that Treg cells prevent SEB-induced mucosal inflammation through modulation of SEB-induced T-cell activation.
Human Microbiota-Secreted Factors Inhibit Shiga Toxin Synthesis by Enterohemorrhagic
Escherichia coli
O157:H7
Authors: de Sablet Thibaut , Chassard Christophe , Bernalier-Donadille Annick , Vareille Marjolaine , Gobert Alain P. , Martin Christine
Published: December 2008

Escherichia coli
O157:H7 is a food-borne pathogen causing hemorrhagic colitis and hemolytic-uremic syndrome, especially in children. The main virulence factor responsible for the more serious disease is the Shiga toxin 2 (Stx2), which is released in the gut after oral ingestion of the organism. Although it is accepted that the amount of Stx2 produced by
E. coli
O157:H7 in the gut is critical for the development of disease, the eukaryotic or prokaryotic gut factors that modulate Stx2 synthesis are largely unknown. In this study, we examined the influence of prokaryotic molecules released by a complex human microbiota on Stx2 synthesis by
E. coli
O157:H7. Stx2 synthesis was assessed after growth of
E. coli
O157:H7 in cecal contents of gnotobiotic rats colonized with human microbiota or in conditioned medium having supported the growth of complex human microbiota. Extracellular prokaryotic molecules produced by the commensal microbiota repress
stx
2
mRNA expression and Stx2 production by inhibiting the spontaneous and induced lytic cycle mediated by RecA. These molecules, with a molecular mass of below 3 kDa, are produced in part by
Bacteroides thetaiotaomicron
, a predominant species of the normal human intestinal microbiota. The microbiota-induced
stx
2
repression is independent of the known quorum-sensing pathways described in
E. coli
O157:H7 involving SdiA, QseA, QseC, or autoinducer 3. Our findings demonstrate for the first time the regulatory activity of a soluble factor produced by the complex human digestive microbiota on a bacterial virulence factor in a physiologically relevant context.
Extrapulmonary Dissemination of
Mycobacterium bovis
but Not
Mycobacterium tuberculosis
in a Bronchoscopic Rabbit Model of Cavitary Tuberculosis
Authors: Nedeltchev Gueno G. , Raghunand Tirumalai R. , Jassal Mandeep S. , Lun Shichun , Cheng Qi-Jian , Bishai William R.
Published: December 2008

The rabbit model of tuberculosis is attractive because of its pathophysiologic resemblance to the disease in humans. Rabbits are naturally resistant to infection but may manifest cavitary lung lesions. We describe here a novel approach that utilizes presensitization and bronchoscopic inoculation to reliably produce cavities in the rabbit model. With a fixed inoculum of bacilli, we were able to reproducibly generate cavities by using
Mycobacterium bovis
Ravenel,
M. bovis
AF2122,
M. bovis
BCG,
M. tuberculosis
H37Rv,
M. tuberculosis
CDC1551, and the
M. tuberculosis
CDC1551 Δ
sig
C mutant.
M. bovis
infections generated cavitary CFU counts of 10
6
to 10
9
bacilli, while non-
M. bovis
species and BCG yielded CFU counts that ranged from 10
4
to 10
8
bacilli. Extrapulmonary dissemination was almost exclusively noted among rabbits infected with
M. bovis
Ravenel and AF2122. Though all of the species yielded secondary lesions at intrapulmonary sites,
M. bovis
infections led to the most apparent gross pathology. Using the
M. tuberculosis icl
and
dosR
gene expression patterns as molecular sentinels, we demonstrated that both the cavity wall and cavity lumen are microenvironments associated with hypoxia, upregulation of the bacterial dormancy program, and the use of host lipids for bacterial catabolism. This unique cavitary model provides a reliable animal model to study cavity pathogenesis and extrapulmonary dissemination.
Cytogeography of Solidago subsect. Glomeruliflorae (Asteraceae: Astereae)
Authors: Cook Rachel E. , Semple John C.
Published: December 2008

Chromosome numbers were determined for 347 individuals of Solidago subsect. Glomeruliflorae (Torr. & A. Gray) Nesom, including 151 new reports. Previously unpublished documented reports are for the following taxa: Solidago caesia  L. var. caesia R.E. Cook & Semple, S. caesia var. zedia R.E. Cook & Semple, Solidago curtisii Torr. & A. Gray var. curtisii (Small) R.E. Cook & Semple, S. curtisii var. flaccidifolia (Small) R.E. Cook & Semple, Solidago flexicaulis  L., Solidago glomerata  Michx., and Solidago lancifolia  (Torr. & A. Gray) Chapm. All counts for S. caesia, Solidago macrophylla  Pursh., and Solidago ouachitensis  Taylor & Taylor were diploid (2n = 18). Two published counts for Solidago albopilosa E.L. Braun were tetraploid. Counts of 2n = 18 and 36 were made for S. flexicaulis. Counts of 2n = 18, 36, and 54 were made for S. curtisii. Counts of 2n = 108 and 126 were made for S. glomerata, and 2n = 90 for S. lancifolia. Cytogeographic maps of S. albopilosa , S. caesia var. caesia, S. curtisii var. curtisii, S. curtisii var. flaccidifolia, S. flexicaulis, S. glomerata, S. lancifolia, S. macrophylla, and S. ouachitensis were prepared including all counts. The following are first documented reports for the taxon: S. caesia var. zedia , 2n = 18, one population; S. lancifolia, 2n = 90, four populations.
The rotated-lamina syndrome. VIII. Lamina rotation and anisophylly in two species ofElatostema(Urticacae), and early development of seedlings ofE. sessile
Authors: Charlton W. A.
Published: December 2008

Elatostema rugosum A. Cunn. and Elatostema sessile J.R. Forst. & G. Forst. have dorsiventral shoots in which the leaves are arranged in anisophyllous pairs forming four ranks: two on the dorsal and two on the ventral side of the shoot. The ventral leaves have expanded asymmetrical leaf blades with lamina rotation, i.e., the lamina develops in the bud facing towards the upper side of the shoot rather than towards the shoot apex. Each ventral leaf has an asymmetrical intrapetiolar stipule. Lamina rotation occurs by asymmetrical development at the base of the leaf blade above the attachment of the stipule. The dorsal leaves are small, scale-like, approximately symmetrical exstipulate structures. The development of the ventral leaf is generally similar to that found in previous studies of related anisophyllous cases, but the dorsal leaf is reduced to a scale and is simpler than in related cases. Seedlings of E. sessile have been examined to investigate the way in which the combination of unusual features of shoot structure is produced, and also to cast light on the homology of the dorsal leaf. Anisophylly and asymmetry appear in the first pair of leaves formed above the cotyledons in seedlings and become accentuated in subsequent pairs. Events in seedlings suggest the dorsal leaf is derived by reduction from an initial state with blade, stipule, and basal region to the basal region alone. The rapid establishment of lamina rotation and asymmetry in the seedling shoot differs from most other cases described and adds to previous arguments that lamina rotation has arisen independently in a number of taxonomic groups.
Crustal structure and early Tertiary extensional tectonics of the Omineca belt at 51°N latitude, southern Canadian Cordillera
Authors: Johnson Bradford J. , Brown Richard L.
Published: December 2008

A crustal cross section through the Omineca belt at the latitude of the Trans-Canada Highway has been drawn to satisfy available surface geological information and Lithoprobe seismic data from this part of the Cordilleran hinterland. Palinspastic restoration of Tertiary normal-sense shear zones leads to the conclusion that the Omineca belt at latitude 51°N was extended in the Eocene by approximately 45 km, 20–25% of the width of the belt. It is shown that the Okanagan–Eagle River fault, which defines the western margin of the Shuswap metamorphic core complex, is likely to have accommodated approximately 30 km of displacement. Restoration of this fault and of 15 km displacement on the Columbia River fault (eastern margin of the Shuswap complex) juxtaposes upper-crustal rocks with similar stratigraphic, structural, and metamorphic characteristics and indicates that the crust was over 50 km thick prior to Eocene extension. Comparison of the crustal geometry in the present and restored sections suggests that extensional strain was partitioned such that the upper crust was most highly attenuated above the central Shuswap complex, whereas the lower crust was most greatly stretched beneath the Intermontane and western Omineca belts.
Marine reservoir corrections for bowhead whale radiocarbon age determinations
Authors: Dyke Arthur S. , McNeely Roger N. , Hooper James
Published: December 2008

Twenty-two pairs of radiocarbon dates on driftwood and bowhead whale (Balaena mysticetus) bones from raised beaches, dates on whale bone and terrestrial plant detritus from a stratigraphie section, and 25 additional dates on whale bones from the lowest (≤1 ka BP) raised beaches in the eastern Canadian Arctic suggest that a marine reservoir correction of about −200 years is appropriate for normalized age determinations on bone collagen from the bowhead whale in this region. This is less than the correction (−400 years) normally applied to carbonate shells of marine molluscs from this region. The carbon in bowhead collagen appears to be derived from the whales' zooplankton food rather than from marine bicarbonate.
Parataxonomic classification of ornithoid eggshell fragments from the Oldman Formation (Judith River Group; Upper Cretaceous), southern Alberta
Authors: Zelenitsky Darla K. , Hills L. V. , Currie Philip J.
Published: December 2008

Examination of a large number of eggshell fragments collected from the Oldman Formation of southern Alberta reveals a greater ootaxonomic diversity than is known from complete eggs or clutches. Three new oogenera and oospecies of the ornithoid-ratite morphotype and one of the ornithoid-prismatic morphotype are established, based on the eggshell fragments. Porituberoolithus warnerensis oogen. et oosp. nov. and Continuoolithus canadensis oogen. et oosp. nov. have a microstructure similar to that of elongatoolithid eggs of theropod dinosaurs. Tristraguloolithus cracioides oogen. et oosp. nov. and Dispersituberoolithus exilis oogen. et oosp. nov. possess an external zone and thus have a microstructure like modern avian eggshell. Tristraguloolithus has a shell thickness, microstructure, and surface sculpture similar to those of recent bird eggshell of the family Cracidae (order Galliformes). Dispersituberoolithus exhibits the primitive or normal eggshell condition of some recent neognathous avian taxa. The ootaxa described indicate a diversity of both avian and theropod dinosaur egg layers within Devil's Coulee and Knight's Ranch, southern Alberta, during the Late Cretaceous.
Propagation dissymétrique et seuil de Cerenkov dans les milieux diélectriques mobiles
Authors: Kallas N C , Hobeika R
Published: December 2008

We emphasize, as a result of the asymmetric Maxwell–Mindowski energy momentum tensor, two specific effects of some anisotropy appearing in a dielectric isotropic homogeneous moving medium that show in one hand a non-conservation law of the macroscopic parameters ε and μ that does not agree with previous ones, and on the other hand, and never treated so far, a case of the non-colinearity between the momentum and the velocity of a photon propagating in such a medium. A never foreseen possibility for this anisotropy to vanish is attained for a velocity βc corresponding to Cerenkov’s threshold.
State space approach to solids and fluids
Authors: Ezzat M A
Published: December 2008

In this survey, developments in the theory of both thermoelasticity and fluid mechanics have been reviewed, and appropriate references are supplied throughout. Review of the method of the matrix exponential, which constitutes the basis of the state-space approach, is given.PACS Nos.: 46.35+z, 47.65+a
Long-time behaviour of an initially localized quantum state
Authors: Shegelski M R.A. , Hnybida J
Published: December 2008

The long-time behaviour of an initially localized quantum state is shown to decay as t –3/2 for any potential well and any potential barrier. An example using a delta barrier is also calculated fully. The result is general yet the proof uses a simple method that is clear and accessible to a wide audience. The effect of bound states on the long-time behaviour is also considered. When there are bound states the long-time behaviour is different.PACS Nos.: 03.65.–w, 03.65.Xp
Elastic properties of lead-phosphate glasses doped with erbium trioxide
Authors: Eraiah B , Geetha D , Anavekar R V
Published: December 2008

The elastic properties of xEr2O3·(50 – x) PbO·50P2O5 (x = 0.1 to 0.5 mol%) glasses are investigated using ultrasonic pulse-echo measurements and their elastic properties are characterized at room temperature. Results from the studies show that both longitudinal and transverse velocities increase with increase of Er2O3 concentration. The elastic constants C11, C12, C44, and Young’s modulus show increasing trend while Bulk modulus and Poisson’s ratio show an increasing trend up to 0.4 mol% and 0.3 mol% of Er2O3, respectively, then there is sudden decreasing trend observed. But in the case of Debye temperatures the reverse trend has been observed. Another notable observation is that the glass with 0.4 mol% and 0.5 mol% of Er2O3 concentration exhibits high velocities and high elastic moduli. This behavior of the elastic properties is related to the change in the structure of glasses as well as the interatomic bonding.PACS No.: 62.20.DC
An improved synthesis of sitophilure
Authors: Lu Cuifen , Nie Junqi , Yang Guichun , Chen Zuxing
Published: December 2008

The asymmetric synthesis of sitophilure was carried out in 8 steps, with 42% overall yield and 97% enantiomeric excess from propionaldehyde. The synthesis relied on an approach employing an asymmetric acyl-thiazolidinethione propionate aldol reaction to establish two stereogenic centers.Key words: sitophilure, thiazolidinethione, chiral auxiliary, synthesis.
Oxalate bridged heteronuclear compounds containing MM quadruple bonds (M = Mo and W) and their radical cations
Authors: Chisholm Malcolm H , Patmore Nathan J
Published: December 2008

The heteronuclear MM quadruply bonded oxalate bridged compound [(t-BuCO2)3MoW]2(µ-C2O4) (I) has been prepared from the reaction between MoW(O2Ct-Bu)4and oxalic acid and characterized by elemental analysis,1H NMR and UV-vis spectroscopy, and electrochemical studies. Single electron oxidation of I by reaction with Ag+PF6–leads to the formation of the kinetically labile radical cation I+, which has been characterized by UV-vis, NIR, and EPR spectroscopy. The latter results are compared with the properties of their related homonuclear Mo4- and W4-oxalate bridged compounds and their respective radical cations. The spectroscopic features of the related radical cations [(t-BuCO2)6MoxWy(µ-C2O4)]+, where x = 1, 2, 3 and y = 4 – x, are also described with the conclusion that the [(t-BuCO2)3Mo2(µ-C2O4)W2(O2Ct-Bu)3]+and [(t-BuCO2)3Mo2(µ-C2O4)MoW (O2Ct-Bu)3]+cations are valence trapped on the Robin and Day scheme for the classification of mixed valence compounds.Key words: molybdenum, tungsten, mixed valence.
Study of aerobic oxidation of phenyl PtII complexes (dpms)PtIIPh(L) (dpms = di(2-pyridyl)methanesulfonate; L = water, methanol, or aniline)
Authors: Khusnutdinova Julia R , Zavalij Peter Y , Vedernikov Andrei N
Published: December 2008

Oxidation of phenyl PtII complexes K[(dpms)PtIIPh2], 1, (dpms)PtIIPh(MeOH), 2, (dpms)PtIIPh(OH2), 3, and methyl PtII complex (dpms)PtIIMe(NH2Ph), 6, with O2 in aqueous or methanol solutions under ambient conditions leads to corresponding (dpms)PtIVR(X)OH complexes (R = X = Ph, 7; R = Ph, X = OH, 8; R = Ph, X = OMe, 9; R = Me, X = NHPh; 11; dpms = di(2-pyridyl)methanesulfonate). Complexes 7–9 could be isolated in high yield. Complex 11 as well as its phenyl analogue (dpms)PtIVPh(NHPh)OH, 10 can be prepared in high yield by oxidation of corresponding (dpms)PtIIR(NH2Ph) with H2O2 in methanol. Phenyl PtII complexes (dpms)PtIIPh(HX) derived from HX = aniline and DMSO, 4 and 5, respectively, are inert toward O2. The rate of oxidation of 1–5 with O2 decreases in the order 1 > 3 ~ 2 » 4, and 5 is unreactive. Methyl analogues are significantly more reactive compared with their phenyl counterparts. Proposed mechanism of oxidation with O2 includes formation of anionic species (dpms)PtIIR(X)– responsible for reaction with dioxygen. Attempts at C–O and C–N reductive elimination from phenyl PtIV complexes 7–10 do not lead to phenyl derivatives PhX at 80–100 °C, consistent with the results of the DFT estimates of corresponding activation barriers, ΔG0 exceeding 28 kcal/mol.Key words: platinum phenyl complexes, oxidation, dioxygen, aqueous solution, mechanism.
B-N as a C-C substitute in aromatic systems
Authors: Bosdet Michael J.D , Piers Warren E
Published: December 2008

The substitution of isoelectronic B–N units for C–C units in aromatic hydrocarbons produces novel heterocycles with structural similarities to the all-carbon frameworks, but with fundamentally altered electronic properties and chemistry. Since the pioneering work of Dewar some 50 years ago, the relationship between B–N and C–C and the wealth of parent all-carbon aromatics has captured the imagination of organic, inorganic, materials, and computational chemists alike, particularly in recent years. New applications in biological chemistry, new materials, and novel ligands for transition-metal complexes have emerged from these studies. This review is aimed at surveying activity in the area in the past couple of decades. Its organization is based on ring size and type of the all-carbon or heterocyclic subunit that the B–N analog is derived from. Structural aspects pertaining to the retention of aromaticity are emphasized, along with delineation of significant differences in physical properties of the B–N compound as compared to the C–C parent.Key words: boron-nitrogen heterocycles, aromaticity, organic materials, main-group chemistry.
Phenylsilane dehydrocoupling and addition to styrene catalyzed by (R-indenyl)Ni(phosphine)(methyl) complexes
Authors: Chen Yaofeng , Zargarian Davit
Published: December 2008

This report describes the synthesis and characterization of the Ni–Me complexes (R-indenyl)Ni(PR′3)Me (R = 1-i-Pr, 1-SiMe3, and 1,3-(SiMe3)2; R′= Me, Ph) and outlines their catalytic reactivities in the dehydrogenative oligomerization of PhSiH3 and its addition to styrene in the absence of initiators/activators. Observation of higher hydrosilylation activities for PPh3-based compounds featuring bulky substituents on the indenyl ligand confirms earlier suggestions that phosphine dissociation is an important component of the catalytic cycle for this reaction. In contrast, oligomerization of PhSiH3 is more facile with PMe3-based precursors and independent of the steric bulk of the indenyl ligand, implying that this reaction does not involve phosphine dissociation. These conclusions are consistent with the variable-temperature 1H NMR spectra of {1,3,-(SiMe3)2-indenyl}Ni(PR′3)Me and various structural parameters observed in the solid-state structures of {1,3,-(SiMe3)2-indenyl}Ni(PPh3)Me, {1,3,-(SiMe3)2-indenyl}Ni(PMe3)Cl, and {1-SiMe3-indenyl}Ni(PMe3)Me.Key words: nickel-indenyl complexes, hydrosilylation, hydrosilane oligomerization.
Approaches to alkane functionalization with Tp′Pt and (nacnac)Pt reagents
Authors: West Nathan M , Templeton Joseph L
Published: December 2008

In this perspective article we give an overview of our studies of C–H activation with platinum over the past decade. The scorpionate ligand Tp′ (Tp′ = hydrotris(3,5-dimethylpyrazolyl)borate) has exhibited the ability to stabilize both Pt(IV) and Pt(II) complexes due to flexibility between κ3 and κ2 binding modes. Control of the Tp′ coordination mode and Pt oxidation state is tightly coupled with acid/base chemistry. This ability allowed us to model a spectrum of intermediates in C–H activation reactions, including Pt(IV) alkyl hydrides, five-coordinate Pt(IV) silyl hydrides, and Pt(II) benzene complexes. We have been able to observe sturdy Pt(II) benzene complexes and probe their equilibria with the respective C–H activated Pt(IV) species in the presence of an added ligand. We have also taken steps toward functionalizing hydrocarbons with Tp′Pt by dehydrogenation of alkanes and by arylation of olefins. We have recently turned to bidentate nacnac (nacnac = N-phenyl-β-enamineimine) ligands in the hopes of catalytically functionalizing hydrocarbons.Key words: C–H activation, reductive elimination, Tp′Pt, five-coordinate, β-diiminate.
Kaolinite–poly(methacrylamide) intercalated nanocomposite via in situ polymerization
Authors: Elbokl Tamer A , Detellier Christian
Published: December 2008

The preparation and characterization of a kaolinite–methacrylamide intercalation compound was achieved by a guest-displacement method, the direct treatment of a dimethylsulfoxide (DMSO) pre-intercalate with an aqueous solution of methacrylamide under mild conditions, giving intercalation ratios up to 92% and an expansion of 0.53 nm of the interlayer space. The DMSO molecules were fully displaced from the interlayer space by methacrylamide. Only partial intercalation could be obtained with N-methylformamide (NMF) pre-intercalate. After intercalation, the monomer was thermally polymerized at 100 or 150 °C with various heating times. XRD, FTIR, 13C CP/MAS NMR, and thermogravimetric analysis confirmed that polymerization was partially achieved in the interlayer spaces, while the layered structure of kaolinite was maintained, constraining the polymer in an interlayer space of 0.57 nm in the c-direction. In good agreement with the TG data, elemental analysis gave a stoichiometry of Al2Si2O5(OH)4·(C4H7NO)0.52 for the thermally treated methacrylamide intercalate, corresponding to a ratio of one methacrylamide unit per two kaolinite structural units. The thermal stability of the methacrylamide intercalate was increased after thermal treatment and polymerization.Key words: kaolinite, intercalation, nanocomposites, aluminosilicates, layered materials, interlayer polymerization, poly(methacrylamide).
Synthesis and electrochemistry of new thienyl – Schiff base complexes
Authors: Pietrangelo A , Boden B N , MacLachlan M J , Wolf M O
Published: December 2008

The synthesis and characterization of nickel(II), copper(II), and vanadyl ([V=O]2+) complexes of two new thienyl-substituted Schiff base ligands are reported. Cyclic voltammetry of some of these complexes showed oxidation waves, but none of the complexes formed conductive polymer films upon repeated cycling. UV–vis absorption spectroscopy shows that some of the complexes exhibit enhanced conjugation, and the radical cations formed on these chromophores appear to be too stable to undergo oxidative coupling.Key words: Schiff base, salphen, conjugated polymer, electrochemistry.
Unusual coordination behaviour of the ferrocenyl-terpyridine ligand with group 11 complexes
Authors: Aguado Javier E , Gimeno M Concepción , Jones Peter G , Laguna Antonio
Published: December 2008

Complexes of the ligand Fcterpy (Fcterpy = 4′-ferrocenyl-2,2′:6′,2′-terpyridine) with group 11 metals display different coordination modes. The reaction with complexes [Cu(NO3)(PPh3)2] or [M(OTf)(PR3)] (OTf = trifluoromethyl sulphonate) gives the species [M(Fcterpy)(PR3)]X (M = Cu, X = PF6, PR3 = PPh3(1); M = Ag, X = OTf, PR3 = PPh3(2), PPh2Me (3); M = Au, X = OTf, PR3 = PPh3(4)) in which the ligand is coordinated as a tridentate chelate to the metal. Treatment with [Cu(NCMe)4]PF6or Ag(OTf) in 1:1 molar ratio gives the dinuclear complexes [M2(Fcterpy)2]X2(M = Cu (5), Ag (6)), in which the ligand is tetradentate because the central pyridine group is bonded to two metals. The reaction with the gold(I) complex [Au(C6F5)(tht)] (tht = tetrahydrothiophene) leads to the first example of a terpyridine ligand bonded to three metal atoms, [Au3(C6F5)3(Fcterpy)] (7); in the product of the corresponding reaction with the gold(III) derivative [Au(C6F5)3(OEt2)] to give [Au(C6F5)3(Fcterpy)] (8), the ligand is monodentate, which is also unusual for a terpyridine ligand.Key words: copper, silver, gold, terpyridine, ferrocene derivatives
Sensing and Responding to Excess Light
Authors: Li Zhirong , Wakao Setsuko , Fischer Beat B. , Niyogi Krishna K.
Published: December 2008

Plants and algae often absorb too much light—more than they can actually use in photosynthesis. To prevent photo-oxidative damage and to acclimate to changes in their environment, photosynthetic organisms have evolved direct and indirect mechanisms for sensing and responding to excess light. Photoreceptors such as phototropin, neochrome, and cryptochrome can sense excess light directly and relay signals for chloroplast movement and gene expression responses. Indirect sensing of excess light through biochemical and metabolic signals can be transduced into local responses within chloroplasts, into changes in nuclear gene expression via retrograde signaling pathways, or even into systemic responses, all of which are associated with photoacclimation.
Multimodal Neuroprotective Therapy With Induced Hypothermia After Ischemic Stroke
Authors: Hemmen Thomas M. , Lyden Patrick D.
Published: December 2008

Neuroprotective therapies have so far failed to provide improved neurological function and outcome after stroke. A recent focus on multimodal therapies, including the combination of neuroprotective medications with hypothermia, opens a promising new treatment strategy. Advances in hypothermia administration make it one of the most promising neuroprotective therapies available and an ideal candidate for combination with other neuroprotective approaches.
Cerebral Amyloid Angiopathy
Authors: Zipfel Gregory J. , Han Henry , Ford Andria L. , Lee Jin-Moo
Published: December 2008

Cellular elements of the neurovascular unit are essential for the physiological functioning of brain vessels. If any of these vascular elements are disturbed the consequences can be dire. Cerebral amyloid angiopathy (CAA), a disorder caused by the accumulation of amyloid in cerebral vessels, provides a case study of progressive neurovascular unit dysfunction leading to failure of vascular reactivity, smooth muscle cell loss, and eventual frank breakdown of vessel integrity resulting in recurrent and sometimes fatal intracerebral hemorrhage.
Experimental Models
Authors: Willing Alison E.
Published: December 2008

Although many potential therapeutics have improved motor and cognitive function in animal models of experimental stroke, very few have been found to have similar beneficial effects in clinical trials. In this review, we examine the advantages and disadvantages of the currently available rodent models in the development of cellular therapies for stroke and how they have been applied. The lack of translation between the animal work and clinical benefits is not because the animal models are not useful. If the recommendations of the Stroke Academic Industry Roundtable are followed, then the studies will produce more clinically relevant information about potential new cell therapies. However, it will also be necessary to design clinical trials in a manner consistent with the preclinical study results.
Genomewide Linkage in a Large Caucasian Family Maps a New Locus for Intracranial Aneurysms to Chromosome 13q
Authors: Santiago-Sim Teresa , DePalma Steven R. , Ju Kevin L. , McDonough Barbara , Seidman Christine E. , Seidman J.G. , Kim Dong H.
Published: December 2008

Background and Purpose—

Familial aggregation of intracranial aneurysms (IAs) indicates a genetic role in the pathogenesis of this disease. Despite a number of reported susceptibility loci, no disease-causing gene variants have been identified. In this study, we used a parametric genomewide linkage approach to search for new IA susceptibility loci in a large Caucasian family.

Methods—

The affection status of family members with clinical signs of IA was confirmed with medical records or through radiological or surgical examinations. All other relatives were screened using MR angiography. Genomewide linkage analysis was performed on 35 subjects using approximately 250 000 single nucleotide polymorphic markers.

Results—

Ten individuals had an IA. Linkage analysis using a dominant model showed significant linkage to a 7-cM region in 13q14.12–21.1 with a maximum logarithm of odds score of 4.56.

Conclusion—

A new IA susceptibility locus on 13q was identified, adding to the number of IA loci already reported. Given that no coding variants have been reported to date, it is possible that alternative genetic variants such as regulatory elements or copy number variation are important in IA pathogenesis. We are proceeding with attempts to identify such variants in our locus.
Translational Medicine for Stroke Drug Discovery
Authors: Feuerstein Giora Z. , Chavez Juan
Published: December 2008

Over the past 20 years, an estimated $1 billion has been spent in research and development of stroke therapeutics; however, this huge investment has failed to produce a clinically efficacious drug with the exception of the thrombolytic agent Activase (tPA). This sobering reality has been the subject of numerous reflections by renowned leaders in stroke research with special focus on the most recent failed clinical trials. The validity of the neuroprotection strategy has been questioned and efforts to substantially modify the quality of stroke research have been examined. The consistent failures of the pharmaceutical industry to develop a neuroprotective drug for ischemic stroke have had a major impact on the assessment of stroke as an attractive therapeutic area for drug discovery. Many pharmaceutical companies have scaled down their stroke programs, reflecting skepticism about the prospect of contemporary stroke drug discovery strategy based on neuroprotective agents. In this article, we present a Translational Medicine perspective on critical issues that the pharmaceutical industry and the academic community encounter but often ignore during stroke therapeutic development. This Translational Medicine framework offers a systematic analysis of the possible deficiencies that likely underwrote the colossal failure of clinical trials with neuroprotective drugs. In addition, we offer a biomarker-based system that aims at providing “proof of concept” along the discovery and development pipeline, which if implemented along early preclinical and clinical development phases, might significantly reduce risks and enable success.
Understanding White Matter Disease
Authors: Black Sandra , Gao FuQiang , Bilbao Juan
Published: December 2008

Most strokes are covert and observed incidentally on brain scans, but their presence increases risk of overt stroke and dementia. Amyloid angiopathy, associated with Alzheimer Disease (AD) causes stroke, and when even small strokes coexist with AD, they lower the threshold for dementia. Diffuse ischemic white matter disease impairs executive functioning, information processing speed, and gait. Neuroimaging techniques, such as tissue segmentation, Diffusion Tensor Imaging, MR Spectroscopy, functional MRI and amyloid PET, probe microstructural integrity, molecular biology, and activation patterns, providing new insights into brain-behavior relationships. MR-pathological studies of periventricular hyperintensity (leukoaraiosis) in aging and dementia reveal arteriolar tortuosity, reduced vessel density, and occlusive venous collagenosis which causes venous insufficiency and vasogenic edema. Activated microglia, oligodendroglial apoptosis, clasmatodendritic astrocytosis, and upregulated hypoxia-markers are seen on immunohistochemistry. Further research is needed to understand and treat this chronic subcortical vascular disease, which is epidemic in our aging population.
Recruiting Participants for Neighborhood Effects Research
Authors: Oakes J. Michael , Forsyth Ann , Hearst Mary O. , Schmitz Kathryn H.
Published: December 2008

Research into the effects of neighborhood environments on social and behavioral characteristics is threatened by inattention to some methodological obstacles, including the recruitment of a representative sample of resident participants. Although sampling is relatively straightforward, actual recruitment is not. The authors present the recruitment experience of the Twin Cities Walking Study addressing two questions: (a) Are randomly selected participants different from those selected by convenience? and (b) How well does the realized sample match known demographic characteristics of target neighborhoods? Of 716 total participants nested in 36 neighborhoods, 74% were randomly recruited. Socioeconomic status was positively correlated with random recruitment; nonrandom volunteers were more likely to be non-White females of lower socioeconomic status. Multivariate analyses, using propensity scores, show randomly selected and volunteer participants to be similar. The final mixed sample represented the target neighborhoods well. Supplementing a random sample with volunteers may yield a representative sample exchangeable at the group level.
Synthesis of PVP/IO-MMT Nanocomposite using Industrial Organic Montmorillonite
Authors: Dangge Gao  , Jianzhong Ma  , Hua Lu  , Yun Chu  , Zongsui Yang
Published: December 2008

Industrial organic montmorillonite (IO-MMT) was characterized by X-ray diffraction (XRD) and thermogravimetry (TG). The results indicate that IO-MMT could prepare nanocomposite directly in theory. As dispersants, different nonionic surfactants were used to disperse IO-MMT. The result shows that nonionic surfactant TO-10 was selected as optimum dispersant. Then, vinyl polymer/industrial organic montmorillonite nanocomposite (PVP/IO-MMT) was prepared by vinyl polymer (PVP) and IO-MMT which dispersed in nonionic surfactant TO-10. The structure of PVP/IO-MMT nanocomposite was characterized by XRD and TEM. The result of XRD shows that the basal spacing d value of nanocomposite is 3.53 nm. The result of TEM indicates that composite was intercalated nanocomposite. Finally, PVP/IO-MMT was applied in the leather making process to examine its properties. The pickled sheepskin was tanned with 6% PVP/IO-MMT associated with 2% chromate, the shrinkage temperature of leather can be raised to 88°C. The application results show that it is an effective way to decrease the use of chromate for nanocomposites.
Epoxy—Vermiculite Nanocomposites as Gas Permeation Barrier
Authors: Mittal V.
Published: December 2008

Epoxy nanocomposites with organically modified vermiculite were synthesized using a solution casting approach and the microstructure of the composites as well as the gas barrier properties through the cast films were analyzed. Ammonium ions of different chemical architecture were employed in order to analyze the effect on the final composite properties. The modified vermiculite mineral had much higher basal plane spacing than the montmorillonite platelets modified with the same ammonium ions owing to smaller area per cation available on the surface. The basal spacing values were enhanced after nanocomposite synthesis confirming the intergallery polymerization, though a complete exfoliation could not be achieved. Transmission Electron Microscope (TEM) analysis indicated the presence of mixed morphology with tactoids of varying thicknesses present along with a small number of single layers. The permeation properties were significantly improved, even though the pure matrix itself was resistant to oxygen and water vapor permeation. No significant effect of the chemical architecture was observed on the composite properties which were more affected by filler matrix interactions.
Design of Web Questionnaires
Authors: Toepoel Vera , Vis Corrie , Das Marcel , van Soest Arthur
Published: December 2008

In this article, an information-processing perspective is used to explore the impact of response categories on the answers respondents provide in Web surveys. Response categories have a significant effect on response formulation in questions that are difficult to process, whereas in easier questions (where responses are based on direct recall) the response scales have a smaller effect. In general, people with less cognitive sophistication are more affected by contextual cues. The Need for Cognition and the Need to Evaluate indexes for motivation account for a significant part of the variance in survey responding. Interactions of ability to process information and motivation combine in regulating responses for questions that are more difficult to process. The results hint at a substantial role of satisficing in Web surveys.
Jessie's Dream at Lucknow
Authors: Mukharji Projit Bihari
Published: December 2008

Nineteenth-century British histories of the Indian ‘Mutiny’ have usually been seen as a moment of unequivocal imperial confidence. Little account has been taken of the large number of complex, non-historical texts that memorialized the ‘Mutiny’. Victorian Britain witnessed a wide and varied interest in the representation of events of the past. The representations spanned many genres and continually multiplied in form and medium under the impetus of an expanding commodity culture. Commoditized memorial texts—unlike professional histories—are read by an extremely diverse group of people. The wide dissemination and variety made the texts semantically unstable.

By concentrating on non-historical memorial texts of the ‘Mutiny’ and by attending to both their production and consumption, we can discern a far wider set of attitudes towards the ‘Mutiny’. Not only are many of these texts revealed to be ambivalent towards the imperial project, but also indeed they reveal a multiplicity of fissures within Victorian society.
Archaeological Problems with Specialization
Authors: Menon Jaya
Published: December 2008

Archaeologists study craft production as it provides information on the ways in which artifacts were produced. Craft specialization is, however, more complicated as it involves not only techniques but also organization. In contrast to anthropology where observation can reveal the scale of production or the amount of resources or time utilized for the practise of a craft, archaeology can make only tentative interpretations. Scale of production, standardization, and levels of expertise can be understood when certain variables are known. Archaeology is a discipline that understands the past in the context of the present and thus often uses the methods of production and the function of present-day artefacts to interpret ancient artefacts. However, there is also a tendency to use present-day organizational systems to understand past production mechanisms. This may be problematic especially where past systems varied greatly from modern ones. The particular socioeconomic background of past systems must account for the forms that ancient specialization took. To explicate this, a case study of manufacture in a Harappan settlement is taken to understand the context of craft activities. The study shows that production in a large urban centre could be dispersed and episodic and yet be specialized.
Blinkered vision
Authors: Maury Laurel
Published: December 2008

New York-based reviewer Maury warns editors to ignore the American Midwest and South at their peril: America’s heavyweight media doesn’t pay attention to what goes on in the South, particularly the non-coastal South and the Midwest, and apparently don’t cover the area with freelancers. With the internet, one would think that bloggers would raise the alert, or that the national media would notice stories in local newspapers, but no… The international press needs to start watching the American South and Midwest on their own… Don’t take only The New York Times' word on what’s going on in the United States. What big media misses, in terms of landmass, would hold most of Europe.
Not finally…
Authors: White Michael
Published: December 2008

Guardian assistant editor White looks back on this year's political party conferences and reflects: At all three conferences, "the leader", and what he or his spin-doctors think and say, is all-consuming. This is both politically unhealthy and journalistically soul-destroying. But we do our best to sustain interest and to be busy on the many platforms which a modern newspaper or TV channel feels must be stood upon: print, audio, internet TV, blogs, line-by-line as it happens reporting, plus the traditional newspaper model: reports, commentary, diaries, cartoons, leaders, colour pieces, features, the political sketch… We fan out like the hunter-gatherers we all once were, following such ancient half-remembered instinct to attend fringe meetings in the hope that someone our audience has heard of will attack the leadership, or abuse the European Union or immigrants. In these disciplined times it rarely happens, but we try.
Sarah Palin's a journalist, too
Authors: Bird Kenton
Published: December 2008

Sarah Palin’s selection as the Republican vice presidential nominee raised questions not only about her qualifications to hold the nation’s second highest office, but also the suitability of someone with a journalism background to succeed in politics at the national level, writes the current director of the School of Journalism and Mass Media at the University of Idaho, where Sarah Palin studied. Gov. Palin is not the first candidate on a national ticket in the United States to have been a journalist, observes Bird. Warren Harding, President from 1921 until 1923, was editor of the Marion, Ohio, Daily Star before venturing into politics and Al Gore, defeated for the presidency by George W Bush in 2000, worked as an investigative reporter from 1971 to 1976 at The Tennessean in Nashville. Bird investigates ways the attributes of a good journalist might help a politician.
Mining for gold in the blogosphere
Authors: Dale Iain
Published: December 2008

Top bloggers have become more influential than many print journalism specialists. But how many make the web pay?

In the United States political bloggers have taken on an importance that would be unthinkable in the UK, writes top UK political blogger Dale. In Britain it’s very different. The development of the UK political blogosphere, while much heralded in almost weekly newspaper features, is way behind that of the United States. Few bloggers have any sort of media profile and even fewer make any money at all out of their online activities… Blogs here haven’t got the moneymaking ability of those in the US, or their influence, or their profile. But in three or four years, they just might.
Labour's love lost?
Authors: Seddon Mark
Published: December 2008

Once again the left-wing Tribune's future is uncertain. Why is it, asks a former editor, that publications of the Left often fail to thrive?

A former editor of Tribune observes that the left-wing publication’s future is once again under threat and asks to what extent is the permanently cash-strapped years of Tribune’s existence and its possible closure a measure of a decline amongst the political weeklies. “There is an uncomfortable truth for the Left, and this at a time when the future for the niche market weeklies looks a good deal more promising than it does for many daily newspapers. It is that for the last 30 years, magazines of the Right, such as The Spectator, have tended to prosper, while New Statesman and Tribune, and on the Communist left, the daily Morning Star, have slowly declined.”
How SEO is changing journalism
Authors: Richmond Shane
Published: December 2008

Search engine optimisation can ensure content attracts maximum web hits. And it doesn't mean conning readers, says an online editor

The communities editor of Telegraph.co.uk advocates the writing of articles and headlines with search criteria as a guide. But search engines will not end up dictating our news agenda as well as the way we format our stories, he argues: “Giving readers what they want is a sensible strategy, even though the overall mix of stories within a publication has to be balanced. Different editors will make different choices, but they are editorial choices, not SEO choices. SEO is value neutral. It doesn’t require you to dumb down, to fill your stories with the names of celebrities or to write 500 articles about Viagra every month. Even if you write about badgers, thermal dynamics or parachuting you will want your article to be seen by people who care about those topics. SEO techniques will give your article a better chance of being found.”
Holding ourselves accountable
Authors: Pritchard Stephen
Published: December 2008

U.S. papers dispensing with their ombudsmen are misguided, it is argued. Transparency is vital to rebuild public trust

The ombudsman of The Observer newspaper notes that editors of American newspapers are shedding staff at an alarming rate as the financial crisis translates into a sharp downturn in advertising and readerships melt away and that among the casualties are 12 news ombudsmen: men and women who work within newsrooms, dealing with complaints, publishing corrections and writing columns and internal memos on their papers’ journalism. He believes that this short-term thinking is wrong and those in the UK who have yet to appoint an ombudsman need to ask themselves if they can afford to be without one: “It’s all about transparency. From transparency flows trust. Show your readers that you care about accuracy, about fairness, about getting the story right and you gain their trust. If they trust you they will buy you.”
Different horses, different courses
Authors: Delano Anthony
Published: December 2008

Media degrees have been under attack, even in this journal. An educator defends the values of higher journalistic education

Journalists turned academic Delano writes that few occupations display such a gulf between ideals and reality as journalism and journalism education is no different. Journalism graduates will learn whatever their particular university is best able to offer. Universities are far from equal. Some turn out better history or science graduates than others. Some have demanding entrance requirements; others are so desperate for funding that they will admit virtually all comers. Some will not have the equipment to teach journalism to modern requirements; administration or staff may not be up to the job… So what is the value of a journalism degree? Even though it is now being taught and studied as never before, journalism continues to elude definition.