Cup Structure Research Articles

Crinoids from the Shenley Limestone (Albian) of Leighton Buzzard, Bedfordshire, UK

A diverse and exceptionally preserved crinoid fauna is described from the Early Albian (Leymeriella tardefurcata Zone) Shenley Limestone of Leighton Buzzard (Bedfordshire, England). It is unusual in the presence of a number of species which are the last records of genera common in and typical of the Jurassic (the isocrinid Balanocrinus smithi sp. nov., the millericrinids Apiocrinites gillieroni (de Loriol) and an unnamed species of Apiocrinites, and the cyclocrinid Cyclocrinus variolarius (Seeley)), in association with the first record of the typically Cretaceous Roveacrinidae (Discocrinus integer sp. nov.). Sclerocrinids (Cyrtocrinida) are represented by Torynocinus canon and Torynocrinus globosus sp. nov. The excellent preservation of the material permits new and taxonomically important observations to be made on cup structure in the sclerocrinid and roveacrinid species, and the first description of Torynocrinus brachials. Additionally, the material includes different growth stages and brachials which allow for extended diagnoses of known species. The fauna is also remarkable for the association of differently sized stalked crinoids attached either by cirri or holdfasts, and a pelagic roveacrinid.

Mechanical properties of vapor grown carbon nanofibers

Individual as-fabricated, high temperature heat-treated and graphitized/surface oxidized vapor grown carbon nanofibers (VGCNFs), with average diameter of 150 nm were tested for their elastic modulus and their tensile strength by a MEMS-based mechanical testing platform. The elastic modulus increased from 180 GPa for as-fabricated, to 245 GPa for high temperature heat-treated nanofibers. The nominal fiber strengths followed Weibull distributions with characteristic strengths between 2.74 and 3.34 GPa, which correlated well with the expected effects of heat treatment and oxidative post-processing. As-fabricated VGCNFs had small Weibull modulus indicating a broad flaw population, which was condensed upon heat treatment. For all VGCNF grades, the nanofiber fracture surface included the stacked truncated cup structure of the oblique graphene layers comprising its backbone and cleavage of the outer turbostratic or thermally graphitized layer.

Endothelial signaling in paracellular and transcellular leukocyte transmigration

As the primary physical barrier between blood and tissue compartments within the body, blood vessel endothelial cells and integrity of the cell junctions connecting them must be carefully regulated to support leukocyte transendothelial migration only when necessary. Leukocytes utilize two independent routes across the endothelium: the paracellular route involves migration in-between adjacent endothelial cells and requires the transient disassembly of endothelial cell junctions, while the transcellular route occurs directly through an individual endothelial cell, likely requiring the formation of a channel or pore. In this review, I will first summarize the signaling events that are transduced by leukocyte engagement of endothelial cell-surface receptors like ICAM-1 and VCAM-1. Some of these signals include activation of GTPases, production of reactive oxygen species, and phosphorylation of target proteins. These signaling pathways converge to cause junctional disruption, cytoskeletal remodeling, and/or the membrane fusion events that are associated with leukocyte transendothelial migration. The review will conclude with a detailed discussion of the newly characterized transmigratory cup structure, and the recent advances made towards understanding the mechanisms of transcellular transendothelial migration.

First Description of Nests and Eggs of Two Hispaniolan Endemic Species: Western Chat-tanager (Calyptophilus tertius) and Hispaniolan Highland-tanager (Xenoligea montana)

We present the first nest descriptions for two Hispaniolan endemic songbirds, the Western Chat-tanager (Calyptophilus tertius) and Hispaniolan Highland-tanager (Xenoligea montana) from a montane broadleaf forest site in the Sierra de Bahoruco of the Dominican Republic. Single Western Chat-tanager nests were found on 17 May 2002 and 9 June 2004. Both were coarsely-built, partially-domed, bulky structures 1.0–1.5 m above ground. One nest was freshly-depredated when found, whereas the second contained two eggs which hatched on 19 and 20 June. The nestlings were depredated on 25 June. A Hispaniolan Highland-tanager nest found on 27 June 2004 fledged a single chick the following day. This nest, in a vine tangle 2.5 m above ground, was an open cup structure composed of moss, small herbaceous stems, leaf fragments, lichens, and other plant fibers. We describe the eggs of both species, the nestlings of Western Chat-tanager, and the juvenal plumage of Hispaniolan Highland-tanager. We believe that depredation by introduced feral cats (Felis domesticus) and rats (Rattus spp.) is a serious problem in these montane forests.

Bulk synthesis of carbon nanostructures: Hollow stacked-cone-helices by chemical vapor deposition

Bulk synthesis of hollow carbon stacked-cone-helices of diameter from 10 nm to 0.5 μm is reported. The fibres’ walls are made up of parallel stacked-cone-like structures with an inter-cone distance from 3.38 to 3.5 Å. Apex angles observed are in the range from 30° to 110°, suggesting that the carbon nanofibres are constructed by a single graphene sheet which forms a helical structure instead of a stacked cone or open stacked cup structure. A new 3-D construction of the stacked-cone-helix is presented. Our results show that metal Pd catalyst plays a key role in obtaining carbon products with cone-helix structure and high yield (200%). These novel fibres could be used as nano-wire templates, micro-spray, and field emitters.

Inplenary and explenary radial facets in cladid crinoids

Three types of radial facets have been recognized in the cladid crinoids. These are: • Angustary—the facet occupies less than 70% of the width of the distal end of the radial. • Peneplenary—the facet occupies between 70% and 99% of the width of the distal end of the radial. • Plenary—the facet occupies the full width of the radial facet. Both the angustary and peneplenary radial facets have interradial notches between adjacent radial facets along the sutures on the distal ends of the radials. The radial facets are here referred to as inplenary if an interradial notch (here referred to as exinterradial notch) is between the distal ends of the transverse ridges and the aboral parts of the muscle fields are abutting at the suture. If the interradial notch is between the muscle fields and the distal ends of the transverse ridges are abutting, then the radial facet is referred to as explenary and the notch as ininterradial. The origin of these conditions is uncertain. However, they may be an evolutionary transition between the peneplenary and plenary conditions or they may be a secondary response to evolutionary changes in the cup structure. The explenary radial facets may have resulted in minimal contact of the primibrachials when opening, closing, or manipulating the arms. It is here proposed that the interradial notch be restricted to the condition wherein the nonarticular surface extends along the suture entirely across the distal end of the radial completely separating adjacent radial facets. Recognition of the inplenary and explenary radial facets should be useful in consistency of description, evolutionary studies, paleoecologic implications, and classification of the cladid crinoids.

A New Notation System of Object Manipulation in the Nesting-Cup Task for Chimpanzees and Humans

The nesting-cup task has been used to assess cognitive capability in humans as well as non-human primates. Previous studies have attempted to highlight interesting aspects of behavior by constructing and assessing various categories of manipulation. The present study introduces a new notation system for describing manipulation in nesting-cup tasks in the form of sequential codes. Following this notation, the entire process of manipulating cups can be divided into a sequence of behavioral segments. Each segment corresponds to a single manipulation of a cup, recorded as two numerical and one letter codes indicating object, location, and action, respectively. These codes describe the full extent of the subjects' manipulation, which can thus be traced retrospectively in its entirety by decoding the behavioral segments from the sequence. The subjects were three infant chimpanzees, three adult chimpanzees, and two human children. Segment-based analysis revealed developmental changes in the use of three strategies (pairing, pot, and subassembly), which previous studies have used as reliable indicators of cognitive development. Subassembly, regarded as the most advanced strategy for combining cups in human development, is defined as the placing of a previously constructed structure consisting of two or more cups into or onto another cup or cup structure. The three infant chimpanzees and two adult chimpanzees rarely showed subassembly, in contrast with frequent use by experienced adult chimpanzees and humans. Analysis of transition in cup state revealed a dynamic process in terms of progression and regression within a trial. The tendency to show progressive patterns of transition was related to the use of the subassembly strategy in both humans and chimpanzees. In addition, a case study of nine-cup manipulation by a chimpanzee is reported through sequential codes. Taken together, these data clearly demonstrate the potential of the proposed notation system in describing subjects' performance in nesting-cup tasks.

Oxygen reduction reaction activity and surface properties of nanostructured nitrogen-containing carbon

Nitrogen-containing carbon nanostructures were prepared from the decomposition of acetonitrile at 900 °C over silica and magnesia supports impregnated with Fe, Co, or Ni. For the carbon grown from supported Fe and Co particles, compartmentalized fibers with a stacked cup structure predominantly formed, while mostly broken multi-walled nanotubes formed from Ni particles. The fibers were purified from the support by removing silica with 1 M KOH, or removing metal particles and magnesia with 1 M HCl. Surface analysis was performed with XPS and hydrophobicity comparisons. Surface properties were related to nanostructure and edge plane exposure. Activity for the ORR was highest over CN x fibers grown from supported Fe and Co particles, which may also be related to edge plane exposure, and not necessarily to the presence of metal contamination. The most active materials were generally the most selective catalysts as well. Moreover, from Tafel plot slopes a trend was observed depending on the precursor metal used to prepare the CN x . The magnitude of the Tafel slope was smallest for the samples prepared from Fe or Co precursors. Compared to a state-of-the-art platinum catalyst, the most active alternative non-noble metal catalysts had less than 100 mV potential drop difference, high selectivity for complete oxygen reduction, a similar Tafel slope, and good electrical conductivity.

B-cell activation by membrane-bound antigens is facilitated by the interaction of VLA-4 with VCAM-1

VCAM-1 is one of the main ligands of VLA-4, an integrin that is highly expressed on the surface of mature B cells. Here we find that coexpression of VCAM-1 on an antigen-bearing membrane facilitates B-cell activation. Firstly, this is achieved by mediating B-cell tethering, which in turn increases the likelihood of a B cell to be activated. Secondly, VLA-4 synergizes with the B-cell receptor (BCR), providing B cells with tight adhesion and enhanced signalling. This dual role of VCAM-1 in promoting B-cell activation is predominantly effective when the affinity of the BCR for the antigen is low. In addition, we show that the VCAM-1 ectodomain alone is sufficient to carry out this function. However, it requires the transmembrane domain to segregate properly into a docking structure characteristic of the B-cell immunological synapse (IS). These results show that the VLA-4/VCAM-1 interaction during membrane antigen recognition enhances B-cell activation and this function appears to be independent of its final peripheral localization at the IS.

Speciation and structure of copper(II) complexes with ( S)-phenylalanine- and ( S)-tryptophanhydroxamic acids in methanol/water solution: a combined potentiometric, spectrophotometric, CD and ESI-MS study

Complexation equilibria of ( S)-phenylalaninehydroxamic and ( S)-tryptophanhydroxamic acids (HL) with copper(II) were studied in methanol/water solution in order to avoid the precipitation of a polynuclear species observed in aqueous solution. Among the different techniques used (potentiometry, absorption spectrophotometry, spectropolarimetry and ESI-MS), mass spectrometry data allowed to detect a pentanuclear species [Cu 5L 4H −4] 2+ instead of the dinuclear one, [Cu 2L 2H −1] +, usually reported for the α-aminohydroxamates in aqueous solution. A cup structure of the pentanuclear cation is proposed, which is similar to that determined by X-ray analysis for the corresponding species of β-alaninehydroxamic acid.

Stabilization of ultra-thin Pt bottom electrode for 0.15 μm cup-type BST capacitor

Structural properties and electrical properties of the ultra-thin Pt film on the cup-type structure were studied. We found that Pt film was segregated inside the cup-type structure after oxygen ambient anneal above 400 °C. For the cup-type structure, the segregation was occurred by Pt migration from bottom part of the cup structure, the thinner area, to top part of the cup structure, the thicker area. To overcome this Pt segregation issue, we developed a post-anneal sequences using hydrogen ambient. With the optimized post-anneal sequence, hydrogen anneal above 500 °C, was be able to prevent from the segregation of Pt thin film for bottom electrodes of the cup structure. It was confirmed that the Pt bottom electrode annealed in hydrogen ambient did not degrade the electrical properties of the BST film. In addition, using this novel anneal sequence, 0.15 μm cup-type BST capacitor was demonstrated the leakage current of 1 fA/cell and capacitance density of 12 fF/cell.

Inhibition of neurite outgrowth by familial Alzheimer's disease-linked presenilin-1 mutations

Two (P117L; M146L) familial Alzheimer's disease (FAD)-causing presenilin-1 (PS1) mutations have been tested for their effect in stably transfected mouse neuroblastoma (N2a) cell lines. The P117L mutation is associated with the earliest onset of AD reported so far (24 years), while the M146L is less pathogenic with the onset at about 43 years. Overexpression of wild-type ( wt) PS1 gene was associated with the marked increase in the number and the length of neuritic outgrowths accompanied by accumulation of PS1 immunoreactivity in neurites. The highly pathogenic P117L mutation completely suppressed this effect and the pattern of PS1 immunolabeling resembled a cup structure with all immunoreactivity gathered at one pole of the cell. The effect of less pathogenic M146L mutation was similar, but not as pronounced. These findings suggest that one of the normal functions of PS1 may be the control of neurite outgrowth, and the inhibitory effect of two FAD-linked mutations stresses its importance in the cellular mechanism that leads to the development of Alzheimer's disease (AD).

Enhancements to the Compact Helical System fast ion loss probe

A scintillator-based fast ion loss probe has been used to measure 40 keV neutral beam ion loss from Compact Helical System plasmas. Modifications have recently been made to the probe to expand the range of gyroradius covered and to increase the probe acceptance at low pitch angles. In addition, a lamp has been installed inside the probe to facilitate calibration of the scintillator position within the field of view of the video camera. Finally, a Faraday cup structure, integral with the scintillator, has been added to allow direct measurement of the ion current to the probe. This last feature allows much easier absolute calibration of the diagnostic.

Quantitative millimetre wave spectrometry. Part I: Design and implementation of a tracked millimetre wave confocal Fabry-Perot cavity spectrometer for gas analysis

This paper describes the design criteria and construction of a compact Fabry-Perot cavity spectrometer with frequency modulation (FM) signal recovery, for use in the 70–220 GHz region. A solid state Gunn oscillator was frequency locked to a radiofrequency synthesiser and used as the primary source. The confocal cavity comprised two brass spherical mirrors, one made part of the sample chamber and the other attached to a precision translation stage with piezoelectric displacement. The sample chamber used a PTFE cup with a central thin window 30 mm diam. supported by the rest of the cup structure which also acted as a spatial filter to suppress non-axial modes. The high quality factor cavity ( Q = 1 × 10 4) was maintained resonant with the source frequency by locking the detected FM signal in phase with the incident FM impressed upon the source, in a control loop which adjusted the cavity dimensions using the piezoelectric transducer. The first harmonic (2F) of the FM (F) was measured to recover the second derivative of the spectral line profile, as the source was scanned across it. Examples of spectra arising from 9 ppm HDO, 2.7 ppm OCS (in an excited vibrational state), HCH 18O, (2000 ppm natural abundance), HCH 17O (373 ppm natural abundance) and acrylonitrile at approximately 300 ppm, demonstrate the high sensitivity and versatility of the technique.

A novel pressure sensor structure for integrated sensors

A novel pressure sensor ‘silicon box’ structure is proposed, fabricated by one-sided processing technology. Tests and analyses show that, while the excellent performance of single crystal silicon diaphragm sensors is maintained, the new technique has advantages for both discrete and integrated pressure sensors of high yield, good uniformity, low cost and feasibility of mass production. This structure also provides some reduction of thermal stress caused by the mismatch between the chip and the substrate occurring in a silicon cup structure.