bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Intra-Arterial Thrombolysis Safe After Full-Dose Intravenous Recombinant Tissue Plasminogen Activator for Acute Ischemic Stroke?
Authors: Shaltoni Hashem M. , Albright Karen C. , Gonzales Nicole R. , Weir Raymond U. , Khaja Aslam M. , Sugg Rebecca M. , Campbell Morgan S. , Cacayorin Edwin D. , Grotta James C. , Noser Elizabeth A.
Published: November 2006

Background and Purpose—

The optimal approach for acute ischemic stroke patients who do not respond to intravenous recombinant tissue plasminogen activator (IV rt-PA) is uncertain. This study evaluated the safety and response to intra-arterial thrombolytics (IATs) in patients unresponsive to full-dose IV rt-PA.

Methods—

A case series from a prospectively collected database on consecutive acute ischemic stroke patients treated with IATs after 0.9 mg/kg IV rt-PA during a 7-year interval was collected. Primary outcome measures included symptomatic intracranial hemorrhage and mortality. As indicators of response, secondary outcome measures were recanalization and discharge disposition.

Results—

Sixty-nine patients (mean±SD age, 60±13 years; range, 26 to 85 years; 55% male) with a median pretreatment National Institutes of Health Stroke Scale score of 18 (range, 6 to 39) were included. IV rt-PA was started at 124±32 minutes (median, 120 minutes) and IAT, at 288±57 minutes (median, 285 minutes). IATs consisted of reteplase (n=56), alteplase (n=7), and urokinase (n=6), with an average total dosage of 2.8 U, 8.6 mg, and 700 000 U, respectively. Symptomatic intracranial hemorrhage occurred in 4 of 69 (5.8%) patients; 3 cases were fatal. Recanalization was achieved in 50 (72.5%) and a favorable outcome (home or inpatient rehabilitation) in 38 (55%).

Conclusions—

IAT therapy after full-dose IV rt-PA in patients with persisting occlusion and/or lack of clinical improvement appears safe compared with IV rt-PA alone or low-dose IV rt-PA followed by IAT. A high rate of recanalization and favorable outcome can be achieved.
Chronic Treatment With Minocycline Preserves Adult New Neurons and Reduces Functional Impairment After Focal Cerebral Ischemia
Authors: Liu Zhengyan , Fan Yang , Won Seok Joon , Neumann Melanie , Hu Dezhi , Zhou Liangfu , Weinstein Philip R. , Liu Jiaing
Published: November 2006

Background and Purpose—

Evidence suggests that activated microglia are detrimental to the survival of new hippocampal neurons, whereas blocking inflammation has been shown to restore hippocampal neurogenesis after cranial irradiation and seizure. The aim of this current study is to determine the effect of minocycline on neurogenesis and functional recovery after cerebral focal ischemia.

Methods—

Four days after temporary middle cerebral artery occlusion, minocycline was administered intraperitoneally for 4 weeks. BrdU was given on days 4 to 7 after middle cerebral artery occlusion to track cell proliferation. The number of remaining new neurons and activated microglia were quantified in the dentate gyrus. Infarct volume was measured to assess the treatment effect of minocycline. Motor and cognitive functions were evaluated 6 weeks after middle cerebral artery occlusion.

Results—

Minocycline delivered 4 days after middle cerebral artery occlusion for 4 weeks did not result in reduction in infarct size but significantly decreased the number of activated microglia in the dentate gyrus. Minocycline also significantly increased the number of newborn neurons that coexpressing BrdU and NeuN without significantly affecting progenitor cell proliferation in the dentate gyrus. Lastly, minocycline significantly improved motor coordination on the rotor rod, reduced the preferential use of the unaffected limb during exploration, reduced the frequency of footfalls in the affected limb when traversing on a horizontal ladder, and improved spatial learning and memory in the water maze test.

Conclusions—

Minocycline reduces functional impairment caused by cerebral focal ischemia. The improved function is associated with enhanced neurogenesis and reduced microglia activation in the dentate gyrus and possibly improved neural environment after chronic treatment with minocycline.
Postischemic Augmentation of Conducted Dilation in Cerebral Arterioles
Authors: Ngai Al C. , Nguyen Thien-Son , Meno Joseph R. , Britz Gavin W.
Published: November 2006

Background and Purpose—

Conducted vasomotor responses likely play an important role in cerebrovascular regulation, but it is unclear how these responses may be affected by ischemia. The purpose of this study was to evaluate the hypothesis that cerebral ischemia and reperfusion (I/R) alters vascular conduction in cerebral arterioles.

Methods—

Middle cerebral artery occlusion (MCAO) was induced by an intraluminal filament technique in 4 groups of rats: (A) 2-hour MCAO/24-hour reperfusion (n=14); (B) 2-hour MCAO/1-hour reperfusion (n=7); (C) 1-hour MCAO/24-hour reperfusion (n=6); and (D) 1-hour MCAO/1-hour reperfusion (n=5). Neurological status and infarction (2,3,5-triphenyltetrazolium chloride staining) were evaluated after I/R. Conducted vasomotor responses were assessed in intracerebral branches of the MCA, by following the longitudinal spread of vasodilation or vasoconstriction to localized microapplication of ATP or adenosine.

Results—

Local microapplication of ATP evoked a biphasic constriction (17±3%) and dilation (7±2%) response, whereas adenosine elicited only dilation (11±2%). These local responses spread longitudinally along sham-control arterioles (1 mm conduction distance) with rapid spatial decay. Ischemia followed by 24-hour reperfusion (groups A and C) led to a marked potentiation of conducted dilation responses: dilation to ATP conducted with virtually no decay in I/R arterioles. Augmentation of conductivity was not observed in the 1-hour reperfusion groups (B and D). Moreover, I/R did not alter conducted constriction.

Conclusions—

Ischemia-reperfusion led to a specific augmentation of conducted vasodilation in cerebral arterioles. Presumably, enhanced conductivity may improve cerebral perfusion after ischemia.
Vortex wakes of birds: recent developments using digital particle image velocimetry in a wind tunnel
Authors: Hedenström  , van Griethuijsen  , Rosén  , Spedding
Published: November 2006

A flying animal generates a trail of wake vortices that contain information about the time history and magnitude of aerodynamic forces developed on the wings and body. Methods for visualising and recording wake vortices have been developed, allowing quantitative measurements by digital particle image velocimetry (DPIV). Results from DPIV experiments in a wind tunnel are presented for four passerine species of differing size and morphology. The normalised vorticity and its integrated quantity, circulation (Γ) both decline gradually with increasing flight speed. The measured circulations are successfully explained by a simple aerodynamic model where a normalised circulation, Γ/Uc, represents half the time-averaged lift coefficient, which is >2 at 4 m s−1 for a thrush nightingale.
Negotiation with Terrorists
Authors: Pruitt Dean
Published: November 2006

Negotiation with non-ideological ethno-nationalist terrorists is more common and more successful than with other kinds of terrorists. Additional strategies for dealing with terrorists include combating, isolating, and mainstreaming. There are many arguments against negotiation with terrorists, but most of them do not apply to secret backchannel talks, which are usually the method of choice in first approaching these groups. The success of negotiation depends on the development of flexibility by both the terrorists and the authorities. These and other points are illustrated with case materials from the Northern Ireland peace process, and the analysis is extended, on a speculative basis, to negotiation with several Islamic terrorist groups.
Nanostructured Films Employed as Sensing Units in an "Electronic Tongue" System
Authors: da Silva B. A. , Antunes P. A. , Pasquini D. , Curvelo A. A. S. , Aroca R. F. , Riul A. , Constantino C. J. L.
Published: November 2006

Nanostructured films of lignin (macromolecule extracted from sugar cane bagasse), polypyrrole (conducting polymer) and bis butylimido perylene (organic dye) were used in the detection of trace levels of fluorine (from H2SiF6), chlorine (from NaClO), Pb+2,
Cu+2, and Cd+2 in aqueous solutions. Langmuir monolayers on ultrapure water were characterised by surface pressure-mean molecular area (Π-A) isotherms. Langmuir-Blodgett (LB) films were transferred onto gold interdigitated electrodes and used as individual sensing
units of an electronic tongue system. Impedance spectroscopy measurements were taken with the sensor immersed into aqueous solutions containing the ions described above in different molar concentrations. Fourier transform infrared absorption (FTIR) was employed to identify possible interactions
between the LB films and the analytes in solution, and no significant changes could be observed in the FTIR spectra of BuPTCD and Ppy. Therefore, the results for lignin point to an interaction involving the electronic cloud of the phenyl groups with the metallic ions.
A Template-Based Electrochemical Method for the Synthesis of High Dense Nickel Nanotube Arrays
Authors: Pi Zhenbang , Tian Tian , Tian Xike , Yang Chao , Zhang Suxin , Zheng Jianhua
Published: November 2006

High dense Ni nanotube arrays have been successfully fabricated using electrochemical method with the assistance of anodic aluminum oxide (AAO) template from NiSO4 aqueous solution without any additive. Field emission scanning electron microscope (FE-SEM) results indicate
that the pores of AAO template are high uniform and all the pores are filled with Ni nanotubes. Transmission electron microscope (TEM) results demonstrate that the diameter of Ni nanotubes is about 65 nm. The electron diffraction (ED) pattern results show that the Ni nanotubes are polycrystalline.
X-ray diffraction (XRD) pattern shows that the electrodeposited nickel is hexagonal crystal structure.
Characterization of Different Sequences of DNA on Si Substrate by Atomic Force Microscopy and Gold Nanoparticle Labeling
Authors: Jin Rong , He Xiaoxiao , Wang Kemin , Yang Liu , Li Huimin , Jin Yan , Tan Weihong
Published: November 2006

In this paper, different sequences of single-strand DNA modified on Si substrate were studied taking advantages of the high resolution of atomic force microscopy (AFM) and signal enhancement of gold nanoparticles. Two sequences of single-strand DNA, as a model, were immobilized on Si
substrate and hybridized with their sequence-complementary DNA molecules modified respectively with two sizes of gold nanoparticles. The surface of Si substrate was characterized through detecting the size and coverage of gold nanoparticles by AFM. Results demonstrated that different sizes
of gold nanoparticles represented different sequences of DNA immobilized on the substrate. Density and distribution of DNA on Si substrate can be investigated by AFM imaging using gold nanoparticles as topographic markers. Compared to other sensitive methods such as fluorescence energy transfer,
X-ray photoelectron, and radiolabeling experiments, this approach is advantageous in terms of high spatial resolution in sub-micrometer scale. This new method will be beneficial in the characterization of DNA immobilized on chip surfaces.
Systematic Studies of a Self-Assembling Peptide Nanofiber Scaffold with Other Scaffolds
Authors: Gelain Fabrizio , Lomander Andrea , Vescovi Angelo L. , Zhang Shuguang
Published: November 2006

A designer self-assembling peptide nanofiber scaffold has been systematically studied with 10 commonly used scaffolds in a several week study using neural stem cells (NSC), a potential therapeutic source for cellular transplantations in nervous system injuries. These cells not only
provide a good in vitro model for the development and regeneration of the nervous system, but may also be helpful in testing for cytotoxicity, cellular adhesion, and differentiation properties of biological and synthetic scaffolds used in medical practices. We tested the self-assembling
peptide nanofiber scaffold with the most commonly used scaffolds for tissue engineering and regenerative medicine including PLLA, PLGA, PCLA, collagen I, collagen IV, and Matrigel. Additionally, each scaffold was coated with laminin in order to evaluate the utility of this surface treatment.
Each scaffold was evaluated by measuring cell viability, differentiation and maturation of the differentiated stem cell progeny (i.e. progenitor cells, astrocytes, oligodendrocytes, and neurons) over 4 weeks. The optimal scaffold should show high numbers of living and differentiated cells.
In addition, it was demonstrated that the laminin surface treatment is capable of improving the overall scaffold performance. The designer self-assembling peptide RADA16 nanofiber scaffold represents a new class of biologically inspired material. The well-defined molecular structure with considerable
potential for further functionalization and slow drug delivery makes the designer peptide scaffolds a very attractive class of biological material for a number of applications. The peptide nanofiber scaffold is comparable with the clinically approved synthetic scaffolds. The peptide scaffolds
are not only pure, but also have the potential to be further designed at the molecular level, thus they promise to be useful for cell adhesion and differentiation studies as well as for future biomedical and clinical studies.
Diffusion in SixGe1−x/Si Nanowire Heterostructures
Authors: Zhang Xi , Kulik Joseph , Dickey Elizabeth C.
Published: November 2006

Si0.48Ge0.52/Si tip/nanowire heterostructures were grown by pulsed laser vaporization (PLV) at a growth temperature of 1100 °C. Ge diffusion in [111]-growth Si nanowires was studied for different post-synthesis annealing temperatures from 200 °C to 800
°C. Ge composition profiles were quantified by energy-dispersive X-ray spectroscopy in a transmission electron microscope. The compositional profiles were modeled by a limited-source diffusion model to extract temperature-dependent diffusion coefficients. The Ge diffusion coefficients
followed an Arrhenius relationship with an activation energy of 0.622 ± 0.050 eV. This rather low activation energy barrier is similar to the previously reported activation energy barrier of 0.67 eV for Ge surface diffusion on Si, suggesting that surface diffusion may dominate in nanowires
at this length scale.
Social-cognitive predictors of hypothalamic-pituitary-adrenal reactivity to interpersonal conflict in emerging adult couples
Authors: Laurent Heidemarie K. , Powers Sally I.
Published: November 2006

This study tested the extent to which the social-cognitive variables of sociotropy and negative relationship attributions predict physiological stress reactivity to interpersonal conflict among emerging adult romantic partners (N = 125 couples). It was hypothesized that sociotropy and negative relationship attributions would predict increased stress reactivity, indexed by salivary cortisol levels, both independently and inter-actively. Results supported the hypotheses but pointed to more complex and gender-specific relationships; sociotropy predicted higher cortisol during the conflict for men, but this effect was mitigated by causal attributions for negative partner behaviors. For women, causal attributions also tended to lower reactivity in the sense of faster recovery after the conflict event, while responsibility attributions predicted slower recovery and more extended physiological stress.
Measuring subgoals of the sexual behavioral system: What is sex good for?
Authors: Birnbaum Gurit E. , Gillath Omri
Published: November 2006

In five studies, we created and validated a self-report measure of individual differences in sex behaviors and beliefs related to the pursuit of various subgoals of the sexual system. In a pilot study, we created an initial version, in Hebrew, of the Sexual Behavioral System Subgoals (SBSS) scale and determined its 4-factor structure. Study 1 confirmed the 4-factor structure of the SBSS: Relationship initiation; relationship maintenance; promoting frequent sexual activity; and a negative factor reflecting interference with the sexual system. Studies 2 and 3 provided additional evidence for the reliability and validity of the SBSS. In Study 4, American students completed an English translation of the SBSS. Confirmatory factor analysis provided cross-national evidence for the structure of the SBSS.
How to Transform into Goddesses and Elephants: Exploring the Potentiality of the Dialogical Self
Authors: Gieser Thorsten
Published: November 2006

This article uses examples of shape-shifting, that is, the process whereby people believe themselves to transform into another being, to demonstrate that cultural contexts do not modify only the content of the dialogical self and how it is methodologically approached. It will be shown that shape-shifting in its respective cultural context modifies the mechanisms of the dialogical self. Drawing on ethnographies of modern witches in the UK and shape-shifters of the Kuranko people from Sierra Leone, I will argue that shape-shifting is a process whereby an external position temporarily transforms into a dominating internal position which expropriates all other internal positions. Ultimately, the position becomes external again and stabilizes itself—along with its associated positions—within the Personal Position Repertoire by continuous practice. Finally, it will be argued that new knowledge in the form of ‘poetic wisdom’ may be gained through shape-shifting.
Animated Corpses: Communicating with Post Mortals in an Anatomical Exhibition
Authors: Hirschauer Stefan
Published: November 2006

‘Plastinates’ (i.e. corpses conserved through plastics) are lab created artifacts which since the nineties have been the subject of a cultural field experiment via an anatomical exhibition. Similarly to brain-dead or digitalized bodies, they constitute an ambiguous form of post-mortem existence. The article inquires after the ways in which the ontological status of these entities is constituted through the practices of body donors, anatomists and visitors. Plastinates owe their ambiguity to an oscillation between two different frames of perception. Their meaning is determined by the extent to which an anatomy exhibition can impose a ‘medical gaze’ over a non-professional way of perception, which would stubbornly associate bodies with persons. This association depends on two qualities of plastinates, which refer back to the donor: on the one hand, they draw the observer into a communicational relationship, since the body is the archetypal medium of the self-representation of persons. On the other hand, the plastinated body, considered as ‘bequest’, acquires a biographical dimension: though the exhibition tries to appropriate the individual body anatomically, as an exemplar of a timeless, abstract idea of the human, the visitor’s mundane perspective reintegrates the exhibit into history. Plastinates are the embodied expression of the last will of those people whom the public meets in the exhibition.
Email from Nancy Nutsucker
Authors: Paasonen Susanna
Published: November 2006

This article addresses the representational conventions and gendered forms of address in online pornography through analysis of 366 unsolicited email (spam) messages advertising porn websites. Combining content description with close reading, it considers the terminology, imagery, narrative elements and points of view employed in advertising commercial heterosexual pornography. The spam advertisements create excessive displays of gender difference. It seems that limited female agency is central, especially in messages advertising reality sites structured by gendered relations of control. Arguing that such displays of control should not be automatically translated as displays of power, this article investigates the representational logic of mainstream pornography as one based on binary differences, juxtapositions and easily recognizable types.
DIY selves?
Authors: Lewis Tania
Published: November 2006

In Ulrich Beck’s writings on the ‘risk society’ he depicts contemporary western social identity as reflexive and ad hoc-shaped through calculative strategies of self-management rather than traditional social categories such as class. Beck’s model of ‘reflexive individualization’ can be seen to be particularly pertinent to the realm of health today, which is increasingly marked by discourses of the ‘DIY’ subject. This article uses the findings of a study of young people’s use of online health information as a means of examining the utility of Beck’s theories. Comparing the experiences of young people from different social backgrounds, the article complicates the assertion that social identity has broken free of its class affiliations. Adopting the term ‘health habitus’, the article suggests that one way of countering the problematic tendency in Beck’s work to displace questions of social location is to ground the notion of reflexive individualization in Bourdieu’s concept of habitus.
Illite-smectite diagenesis and palaeotemperatures in Northern North Sea Quaternary to Mesozoic shale sequences
Authors: Pearson M. J. , Small J. S.
Published: November 2006

Clay mineral abundances and illite-smectite (I/S) compositions have been determined by X-ray diffraction (XRD) in shales of Permo-Triassic to Quaternary age from seven wells in the Viking Graben and Moray Firth. Chemical analyses of size fractions provide evidence that diagenetic illitization of smectite has occurred during burial by uptake of Al and K, and release of Si. K-feldspar was probably the main source of K for illitization. The depth at which random I/S disappears occurs at similar temperatures (mean 93°C) in each well for which reliable measurements are available. Vitrinite reflectance measurements at this depth are also similar (mean 0·64% R0) and correspond to early oil generation. I/S diagenetic levels may have been imprinted by a Tertiary heating event.
The influence of crystallinity on magnetic ordering in natural ferrihydrites
Authors: Murad E. , Bowen L. H. , Long G. J. , Quin T. G.
Published: November 2006

Mössbauer spectra of three natural ferrihydrites of different crystallinities were collected between 295 and 4·2 K. Optimal fits of the room-temperature spectra were obtained using distributions of quadrupole-split doublets; half-widths of the distributions (0·71–0·86 mm/s) increased, and maxima (at 0·62–0·78 mm/s) shifted to higher quadrupole splittings with decreasing crystallinity. Rather poorly-defined magnetically-ordered spectral components appeared and gradually replaced the superparamagnetic doublets as temperatures were reduced. Blocking temperatures between 115 and 28 K, derived from the relative areas under the doublets and magnetic sextets, indicated average particle sizes between ∼ 5 and 3 nm. The sextets were relatively broad and could be fitted with distributions of hyperfine fields. These distributions narrowed and their maxima shifted to higher fields as temperatures decreased; the influence of superparamagnetism was no longer apparent at 4·2 K.
Improving soil clay minerals studies by high-gradient magnetic separation
Authors: Righi D. , Jadault P.
Published: November 2006

High-gradient magnetic separation (HGMS) performed on the clay fraction (< 1 µm) of acid soils facilitates the separation and concentration of mineral fractions according to their Fe and Mg contents. As a result, smectitic layers formed by weathering of a chlorite were identified although they were not detected in the bulk sample. The concentration in the non-magnetic fraction of minerals with an intergrade vermiculite-chlorite behaviour enabled more accurate information to be obtained on these minerals.
The Hinckley index for kaolinites
Authors: Plançon A. , Giese R. F. , Snyder R.
Published: November 2006

The (02,11) X-ray diffraction band from a low-defect kaolinite from Cornwall (Hinckley index HI = 1·22) was examined to determine the defect structure. No combination of interlayer translations and admixing of dickite layers accurately modelled the observed diffraction pattern. Calculated diffraction patterns which gave a good agreement with the shape, position, and intensity of the observed peaks, uniformly had inter-peak intensities which were too weak. By treating the kaolinite as a mixture of low-defect (HI = 1·76) and moderate-defect (HI = 0·29) kaolinites, the agreement between the observed and calculated patterns was improved substantially. The existence of a mixture of two kaolinites was also found for a number of low-defect samples (HI > 0·4) from Georgia and Cornwall, and may be of even wider occurrence. The HI, which is very sensitive to the inner-peak intensities, does not estimate the types or abundances of various structural defects (the classical “crystallinity”), but is related directly, in a non-linear fashion, to the proportions of the two kinds of kaolinite which are present in the sample.
Clay mineral studies of the Tripoli Formation (Lower Messinian), Sicily
Authors: Azzaro E. , Bellanca A. , Neri R.
Published: November 2006

The characterization of clay mineral assemblages in the diatomite-dominated Tripoli Formation (Lower Messinian, central Sicily) has resulted in delineation of suites dominated by generally well-crystallized dioctahedral smectite and illite of low crystallinity, with lesser amounts of kaolinite and chlorite. These minerals are thought to have a mainly detrital origin related to the calcareous and marly formations exposed in the margins of the depositional area. Vertical fluctuations of the montmorillonite/illite ratio and changes of the crystallinity and chemical composition of these phyllosilicates support environmental interpretations from isotopic data of associated carbonates, and point to a wide variability of depositional conditions ranging from evaporating to brackish. Early diagenesis of the clay minerals was controlled by the primary composition of the sediment which, in turn, affected the porewater chemistry.
Oriented overgrowth of acicular maghemite crystals on quartz
Authors: Abreu M. M. , Figueiredo M. O. , Waerenborgh J. C. , Cabral J. M. P.
Published: November 2006

Maghemite with acicular morphology occurs as an oriented growth on fresh quartz surfaces in the magnetic sandy fraction of the B horizon of a Typic Rhodoxeralf from southern Portugal. The maghemite was characterized by Mössbauer spectroscopy, X-ray diffraction and electron microscopy (scanning and transmission), and on the basis of a structural similarity between quartz and maghemite, a mechanism has been proposed for the formation of the oriented overgrowth. Correlation with an interpretative chemical model is discussed, assuming active sites over quartz surfaces. Infrared absorption data agree with the proposed models.
Effects of dry grinding on pyrophyllite
Authors: Pérez-Rodríguez J. L. , Madrid Sánchez del Villar L. , Sánchez-Soto P.J.
Published: November 2006

Dry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ∼60 m2·g−1. Marked changes in the structure take place between 30 and 32 mins grinding. Longer grinding times increase the degree of disorder and SEM and specific surface area data suggest that aggregation occurs. XRD results indicate that some residual order persists in the degraded structure.
Mineral phases and processes within green peloids from two Recent deposits near the Congo River Mouth
Authors: Giresse P. , Wiewiora A. , Lacka B.
Published: November 2006

In the Recent sediments of the Congo River estuary, the green Fe-bearing peloids containing 7 Å phases are nearer to the river mouth than the 10 Å phyllosilicates. Measurements ofd060for 7 Å minerals in various density fractions indicated a progressive transformation of kaolinite into trioctahedral 1:1 phyllosilicates in the zone with a high sedimentation rate. Projection of the chemical composition from the approximate crystallochemical formula on to a classification field confirmed the transformation of kaolinite into a 7 Å Fe-rich phase via substitution of Fe2+and Mg for Al in the octahedral sheet, with insignificant changes in the tetrahedral sheet. The resultant transition phase has a composition closer to greenalite than berthierine. The possible advancement of the evolution process was stopped by massive formation of goethite. The 10 Å minerals formed in the grains deposited in the off-shore sediments have a homogenous composition and occur in association with goethite and quartz. These peloids show an enrichment in Al although no kaolinite is present.
Characteristics of fine pores in some halloysites
Authors: Churchman G. J. , Davy T. J. , Aylmore L. A. G. , Gilkes R. J. , Self P. G.
Published: November 2006

Isotherms were obtained for nitrogen adsorption and desorption on seven halloysite-rich samples from New Zealand and Western Australia. Calculations from these isotherms indicate that halloysites with mainly small particles (c. 0.1 μm in width) had few if any pores in the mesopore range (2–50 nm). Transmission electron microscopy (TEM) shows that cylindrical pores originate from the central holes in tubular particles. The TEM also suggests that slit-shaped pores can originate from the shrinkage of blocks of layers upon dehydration of halloysite.
Changes of mineralogical and surface properties of water dispersible clay after acid treatment of soils
Authors: Józefaciuk G. , Sokołowska Z. , Sokołowski S. , Alekseev A. , Alekseeva T.
Published: November 2006

Mineralogical and water adsorption properties of water dispersible clays extracted from five soils of different typology after treatment with acid to different pH levels, were studied. The mineral composition, total and divalent iron content, surface areas and average adsorption energies of water dispersible clays were complicated functions of pH, reflecting the simultaneous effects of mineral destruction and aggregate disruption processes under influence of protons on soils. The magnetic susceptibilities of water dispersible clays were the lowest at pH 2 and roughly constant at higher pH values indicating the dissolution of crystalline forms of Fe below pH 3. The broadening of the peaks of adsorption energy distribution functions with decrease in pH is related to increasing formation of amorphous material from mineral phases.
Sorptive capacity of montmorillonite for hydroxy-Cr polymers and the mode of Cr complexation
Authors: Dubbin W. E. , Goh Tee Boon
Published: November 2006

Separate montmorillonite suspensions were treated with CrCl3 to give seven Cr(III) concentrations. Each suspension was then titrated with 0.1 N NaOH to give a NaOH/Cr3+ molar ratio of 2.5. Montmorillonite was an effective sorbent for hydroxy-Cr species up to 1200 cmol(+)/kg; above that concentration, sorption continued, though less efficiently. However, N2-BET specific surfaces and cation exchange capacity measurements indicated that the montmorillonite could sorb significantly more than 1200 cmol(+)/kg. There was virtually no exchangeable Cr in any of the clays, suggesting that this element was covalently bonded to the siloxane surface. Infrared spectroscopy revealed a vibration at 1015–1020 cm–1 in the Cr clays which was not present in the control. This new absorption band was attributed to an attenuation of the Si–O a11 vibration caused by inner-sphere complexation of the interlayer Cr with the siloxane oxygen. Because Cr was strongly held and efficiently sorbed, montmorillonite was shown to be an effective sorbent for hydroxy-Cr polymers.
Physicochemical properties of protein-smectite and protein-Al(OH)x-smectite complexes
Authors: Violante A. , de Cristofaro A. , Rao M.A. , Gianfreda L.
Published: November 2006

Proteins (catalase, albumin, pepsin and lysozyme with different molecular weights and isoelectric points) were differently adsorbed at pH 7.0 on the clay fraction of three raw Na-saturated smectites (Crook and Uri montmorillonites and one hectorite). The adsorption isotherms of proteins on clay minerals showed typical Langmuir characteristics. Lysozyme was adsorbed under the effect of electrostatic interactions between the opposite charges of clay surfaces and protein molecules, whereas catalase and albumin were adsorbed under the effect of non-electrostatic forces. Pepsin was held in relatively high amounts only on the surfaces of hectorite. Proteins were intercalated in the interlayers spaces of smectites, usually undergoing extensive unfolding. Protein-smectite complexes showed different behaviour to heating treatment. Some complexes remained practically unchanged after heating at 200°C. Presence of ‘wrecks’ of interlayered materials was found after heating at 500°C for two hours. The amounts of proteins adsorbed on the external and interlamellar surfaces of clay minerals, partially coated with OH-Al species, were much lower than those fixed on the clean clays. Only lysozyme was intercalated in chlorite-like complexes.
Diversity of smectite origins in Late Cretaceous sediments: example of chalks from northern france
Authors: Deconinck J. F. , Chamley H.
Published: November 2006

According to XRD, DTA, geochemistry and electron microscopy data of a few selected samples, three categories of smectitic clay minerals occur in the Cenomanian and Turonian chalks sampled in several sections of northern France. The first one corresponds to detrital illitesmectite mixed-layers reworked from pedogenic blankets. The second category, characterized by crystalline overgrowths around detrital particles, is especially well-developed in slowly deposited sediments. The third category, located in thin marly horizons, corresponds to Cheto-montmorillonite derived from the submarine alteration of volcanic glass. Smectitic minerals having distinct origins may therefore occur at different levels of a given formation. From these examples, the smectite-rich clay sedimentation of the Late Cretaceous is tentatively explained by the combination of favourable factors induced mainly by highstand of the sea-level. The climatic conditions, the reduction of continental areas, the development of carbonate platforms and the decrease in sedimentation rates constitute the most relevant of these factors.
Conversion of pre-RISC to holo-RISC by Ago2 during assembly of RNAi complexes
Authors: Kim Kevin , Lee Young Sik , Carthew Richard W.
Published: November 2006

In the Drosophila RNA interference (RNAi) pathway, small interfering RNAs (siRNAs) direct Argonaute2 (Ago2), an endonuclease, within the RNA-induced silencing complex (RISC) to cleave complementary mRNA targets. In vitro studies have shown that, for each siRNA duplex, RISC retains only one strand, the guide, and releases the other, the passenger, to form a holo-RISC complex. Here, we have isolated a new Ago2 mutant allele and provide, for the first time, in vivo evidence that endogenous Ago2 slicer activity is important to mount an RNAi response in Drosophila. We demonstrate in vivo that efficient removal of the passenger strand from RISC requires the cleavage activity of Ago2. We have also identified a new intermediate complex in the RISC assembly pathway, pre-RISC, in which Ago2 is stably bound to double-stranded siRNA.
Human First-Trimester Fetal MSC Express Pluripotency Markers and Grow Faster and Have Longer Telomeres Than Adult MSC
Authors: Guillot Pascale V. , Gotherstrom Cecilia , Chan Jerry , Kurata Hiroshi , Fisk Nicholas M.
Published: November 2006

The biological properties of stem cells are key to the success of cell therapy, for which MSC are promising candidates. Although most therapeutic applications to date have used adult bone marrow MSC, increasing evidence suggests that MSC from neonatal and mid-gestational fetal tissues are more plastic and grow faster. Fetal stem cells have been isolated earlier in development, from first-trimester blood and hemopoietic organs, raising the question of whether they are biologically closer to embryonic stem cells and thus have advantages over adult bone marrow MSC. In this study, we show that human first-trimester fetal blood, liver, and bone marrow MSC but not adult MSC express the pluripotency stem cell markers Oct-4, Nanog, Rex-1, SSEA-3, SSEA-4, Tra-1-60, and Tra-1-81. In addition, fetal MSC, irrespective of source, had longer telomeres (p < .001), had greater telomerase activity (p < .01), and expressed more human telomerase reverse transcriptase (p < .01). Fetal MSC were also more readily expandable and senesced later in culture than their adult counterparts (p < .01). Compared with adult MSC, first-trimester fetal tissues constitute a source of MSC with characteristics that appear advantageous for cell therapy.
Modeling cyclic behavior of geosynthetics using mathematical functions combined with Masing rule and bounding surface plasticity
Authors: Liu H. , Ling H. I.
Published: November 2006

In the numerical analysis of geosynthetic-reinforced soil structures subjected to earthquake loadings, the constitutive model for the geosynthetic reinforcement is important, because it affects the accuracy of numerical simulations. Two different approaches for modeling the monotonic and cyclic behavior of geosynthetic reinforcements are discussed in this paper: a nonlinear mathematical function combined with the modified Masing rule, and bounding surface plasticity. The Masing rule was modified so that it can simulate the hysteretic behavior of geosynthetics under cyclic loading, including the decrease in the residual strain rate with the number of loading cycles (cyclic strain-hardening). For the bounding surface model, different bounding lines were defined for primary loading, unloading, and reloading. An exponential function was used as the bounding line for primary loading in order to capture the stiffening behavior of some geosynthetics. Constitutive models were proposed based on the two approaches for different types of geosynthetic. Experimental results for six geogrids were used to verify the proposed models, and it was shown that they were able to capture the nonlinear and hysteretic behavior of the corresponding geosynthetics. It was shown that the approach utilizing a mathematical function combined with the modified Masing rule is simple and straightforward. Bounding surface plasticity provides an approach that is more rational for simulating the cyclic behavior of geosynthetics, especially for the case of irregular earthquake loading.
Modal Logics of Topological Relations
Authors: Lutz Carsten , Wolter Frank
Published: November 2006

Logical formalisms for reasoning about relations between spatial regions play a fundamental role in geographical information systems, spatial and constraint databases, and spatial reasoning in AI. In analogy with Halpern and Shoham's modal logic of time intervals based on the Allen relations, we introduce a family of modal logics equipped with eight modal operators that are interpreted by the Egenhofer-Franzosa (or RCC8) relations between regions in topological spaces such as the real plane. We investigate the expressive power and computational complexity of logics obtained in this way. It turns out that our modal logics have the same expressive power as the two-variable fragment of first-order logic, but are exponentially less succinct. The complexity ranges from (undecidable and) recursively enumerable to highly undecidable, where the recursively enumerable logics are obtained by considering substructures of structures induced by topological spaces. As our undecidability results also capture logics based on the real line, they improve upon undecidability results for interval temporal logics by Halpern and Shoham. We also analyze modal logics based on the five RCC5 relations, with similar results regarding the expressive power, but weaker results regarding the complexity.
Tarski's influence on computer science
Authors: Feferman Solomon
Published: November 2006

The influence of Alfred Tarski on computer science was indirect but
significant in a number of directions and was in certain respects fundamental.
Here surveyed is the work of Tarski on the decision procedure for algebra and
geometry, the method of elimination of quantifiers, the semantics of formal
languages, modeltheoretic preservation theorems, and algebraic logic; various
connections of each with computer science are taken up.
Semantics of Separation-Logic Typing and Higher-order Frame Rules for Algol-like Languages
Authors: Birkedal Lars , Torp-Smith Noah , Yang Hongseok
Published: November 2006

We show how to give a coherent semantics to programs that are well-specified
in a version of separation logic for a language with higher types: idealized
algol extended with heaps (but with immutable stack variables). In particular,
we provide simple sound rules for deriving higher-order frame rules, allowing
for local reasoning.
A DCM‐Type Red‐Fluorescent Dopant for High‐Performance Organic Electroluminescent Devices
Authors: Yao Y.‐S. , Zhou Q.‐X. , Wang X.‐S. , Wang Y. , Zhang B.‐W.
Published: November 2006

2‐(2‐tert‐Butyl‐6‐((E)‐2‐(2,6,6‐trimethyl‐2,4,5,6‐tetrahydro‐1H‐pyrrolo[3,2,1‐ij]quinolin‐8‐yl)vinyl)‐4H‐pyran‐4‐ylidene)malononitrile (DCQTB) is designed and synthesized in high yield for application as the red‐light‐emitting dopant in organic light‐emitting diodes (OLEDs). Compared with 4‐(dicyanomethylene)‐2‐tert‐butyl‐6‐(1,1,7,7,‐tetramethyljulolidyl‐9‐enyl)‐4H‐pyran (DCJTB), one of the most efficient red‐emitting dopants, DCQTB exhibits red‐shifted fluorescence but blue‐shifted absorption. The unique characteristics of DCQTB with respect to DCJTB are utilized to achieve a red OLED with improved color purity and luminous efficiency. As a result, the device that uses DCQTB as dopant, with the configuration: indium tin oxide (ITO)/N,N′‐bis(1‐naphthyl)‐N,N′‐diphenyl‐1,1′‐biphenyl‐4,4′‐diamine (NPB; 60 nm)/tris(8‐quinolinolato) aluminum (Alq3):dopant (2.3 wt %) (7 nm)/2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline (BCP; 12 nm)/Alq3(45 nm)/LiF(0.3 nm):Al (300 nm), shows a larger maximum luminance (Lmax = 6021 cd m–2 at 17 V), higher maximum efficiency (ηmax = 4.41 cd A–1 at 11.5 V (235.5 cd m–2)), and better chromaticity coordinates (Commission Internationale de l'Eclairage, CIE, (x,y) = (0.65,0.35)) than a DCJTB‐based device with the same structure (Lmax = 3453 cd m–2 at 15.5 V, ηmax = 3.01 cd A–1 at 10 V (17.69 cd m–2), and CIE (x,y) = (0.62,0.38)). The possible reasons for the red‐shifted emission but blue‐shifted absorption of DCQTB relative to DCJTB are also discussed.
Responsive Polymers at the Biology/Materials Science Interface
Authors: Alexander C. , Shakesheff K. M.
Published: November 2006

Synthetic polymers can be prepared with features that combine many of the advantageous properties of natural materials, including environmental response. This Research News article considers the different types of response that can be ‘programmed in' to polymers and the applications that are developing as a consequence of the designed responses. In particular, we focus on two key applications at the biology/materials science interface: responsive drug delivery systems and ‘smart' surfaces for cell culture and regenerative medicine.
A Cautionary Note on Design Implications when the Primary Analysis is a Stratified Analysis of a Binary Endpoint
Authors: Chuang‐Stein Christy
Published: November 2006

When the primary analysis is a stratified analysis of a binary endpoint, the commonly used CMH procedure could produce results that are quite different from those obtained by ignoring the stratification factor altogether. This means that when designing a trial with a primary endpoint that is binary, it is important that one keep in mind how the data will be analyzed. Only when design and analysis are considered in tandem will the study possess the desired properties. The discussion in this paper is illustrated by a hypothetical example, which nevertheless resembles the findings from a confirmatory trial involving the evaluation of a biologic for severe sepsis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microtiter Plate‐Based Screening for the Optimization of DNA–Protein Conjugate Synthesis by Means of Expressed Protein Ligation
Authors: Lovrinovic Marina , Niemeyer Christof M.
Published: November 2006

We report a rapid microtiter plate screening assay for the optimization of the synthesis of covalent DNA–protein conjugates by means of expressed protein ligation (EPL). The EPL method allows for the site‐specific coupling of cysteine‐modified DNA oligomers with recombinant intein‐fusion proteins, the latter containing a C‐terminal thioester that enables a mild and highly specific reaction with N‐terminal cysteine compounds. To screen for optimal reaction conditions, we developed a microtiter plate‐based assay that utilizes DNA‐directed immobilization of the products formed in the ligation reaction of cysteine‐modified DNA oligonucleotides with the model protein thioester of the maltose‐binding protein (MBP), recombinantly expressed as an intein‐fusion protein in E. coli. The screening assay allowed the rapid quantitative monitoring of various reaction parameters, such as the ratio of the reactants, reaction times, pH and ion strength of the buffer, the influence of various thiol additives and the nature of the chemical linker within the cysteine‐bearing DNA oligonucleotide. As the consequence of the assay‐based optimization, the ligation of MBP with the oligonucleotide was improved to near quantitative yields.
Shape Dependence in the Formation of Condensed Phases Exhibited by Disubstituted Sucrose Esters
Authors: Molinier Valérie , Kouwer Paul J. J. , Fitremann Juliette , Bouchu Alain , Mackenzie Grahame , Queneau Yves , Goodby John W.
Published: November 2006

We report on the self‐organizing properties of sucrose esters that are di‐(1′,6′, 1′,6, and 6,6′)‐substituted with aliphatic chains of identical or different chain lengths and levels of saturation. For the materials possessing two saturated aliphatic chains, the compounds exhibited thermotropic lamellar smectic A phases. A remarkable new phase transition was observed for the di‐octadecanoyl homologue in which one smectic A phase transformed into another with a continuous change in layer spacing, but with a discontinuous change in the correlation length. The incorporation of long cis‐unsaturated chains led to increased cross‐sectional areas of the chains relative to the sucrose head groups and, hence, columnar phases were observed.