bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple short time power laws in the orientational relaxation of nematic liquid crystals
Authors: Jose Prasanth P. , Bagchi Biman
Published: November 2006

Relaxation in the nematic liquid crystalline phase is known to be sensitive to its proximity to both isotropic and smectic phases. Recent transient optical Kerr effect (OKE) studies have revealed, rather surprisingly, two temporal power laws at short to intermediate times and also an apparent absence of the expected exponential decay at longer times. In order to understand this unusual dynamics, we have carried out extensive molecular dynamics simulations of transient OKE and related orientational time correlation functions in a system of prolate ellipsoids (with aspect ratio equal to 3). The simulations find two distinct power laws, with a crossover region, in the decay of the orientational time correlation function at short to intermediate times (in the range of a few picoseconds to a few nanoseconds). In addition, the simulation results fail to recover any long time exponential decay component. The system size dependence of the exponents suggests that the first power law may originate from the local orientational density fluctuations (like in a glassy liquid). The origin of the second power law is less clear and may be related to the long range fluctuations (such as smecticlike density fluctuations)—these fluctuations are expected to involve small free energy barriers. In support of the latter, the evidence of pronounced coupling between orientational and spatial densities at intermediate wave numbers is presented. This coupling is usually small in normal isotropic liquids, but it is large in the present case. In addition to slow collective orientational relaxation, the single particle orientational relaxation is also found to exhibit slow dynamics in the nematic phase in the long time.
Improvement of unipolar power device performance using a polarization junction
Authors: Nakajima Akira , Adachi Kazuhiro , Shimizu Mitsuaki , Okumura Hajime
Published: November 2006

A concept, polarization junction (PJ), for overcoming the trade-off relationship between the area-specific on-resistance and the breakdown voltage of unipolar power devices is presented. The PJ concept is based on the charge compensation of positive and negative polarization charges at heterointerfaces. The PJ has a similar effect as superjunction without impurity doping. The performance of GaN-based conventional devices and PJ devices have been compared using numerical device simulations. Area-specific on-resistance of PJ devices became less than 1∕10 than that of conventional devices for the breakdown voltage higher than 300V.
Local and nonlocal advection of a passive scalar
Authors: Scott R. K.
Published: November 2006

Passive and active scalar mixing is examined in a simple one-parameter family of two-dimensional flows based on quasi-geostrophic dynamics, in which the active scalar, the quasi-geostrophic potential vorticity, is confined to a single horizontal surface (so-called surface quasi-geostrophic dynamics) and in which a passive scalar field is also advected by the (horizontal, two-dimensional) velocity field at a finite distance from the surface. At large distances from the surface the flow is determined by the largest horizontal scales, the flow is spectrally nonlocal, and a chaotic advection-type regime dominates. At small distances, z, scaling arguments suggest a transition wavenumber kc∼1∕2z, where the slope of the passive scalar spectrum changes from k−5∕3, determined by local dynamics, to k−1, determined by nonlocal dynamics, analogous to the transition to a k−1 slope in the Batchelor regime in three-dimensional turbulence. Direct numerical simulations reproduce the qualitative aspects of this transition. Other characteristics of the simulated scalar fields, such as the relative dominance of coherent or filamentary structures, are also shown to depend strongly on the degree of locality.
Origin of efficient luminescence from GaN:Eu3+ epitaxial films revealed by microscopic photoluminescence imaging spectroscopy
Authors: Ishizumi Atsushi , Sawahata Junji , Akimoto Katsuhiro , Kanemitsu Yoshihiko
Published: November 2006

We have studied photoluminescence (PL) properties of Eu3+-doped GaN (GaN:Eu3+) epitaxial films by microscopic PL imaging spectroscopy. The GaN:Eu3+ epitaxial films exhibit efficient red luminescence related to intra-4f transitions of Eu3+ ions. The intensity and the spectral shape of the Eu3+-related PL are sensitive to the Eu3+ concentration, the excitation wavelength, and the monitored position. Microscopic PL imaging spectroscopy revealed that efficient red luminescence of GaN:Eu3+ epitaxial films is due to Eu3+ ions around point defects and dislocations.
Subwavelength electromagnetic shielding by resonant surface
Authors: Wen He , Hou Bo , Wen Weijia
Published: November 2006

The authors studied the influence of a small resonant surface on the radiation pattern of a monopole wire antenna when the resonant surface was placed in proximity. By discussing both experiment and simulation results, the authors found that the small resonant surface can effectively block the electromagnetic wave with wavelength which is greater than its dimension. The underlying principle is attributed to the nature of resonance. Therefore, a small resonant surface may function as a subwavelength reflector and protect, to some degree, humans from exposure to electromagnetic radiation.
Integrated multiplexed biosensors based on liquid core optical ring resonators and antiresonant reflecting optical waveguides
Authors: White Ian M. , Oveys Hesam , Fan Xudong , Smith Terry L. , Zhang Junying
Published: November 2006

The authors demonstrate integrated biosensors utilizing antiresonant reflecting optical waveguides (ARROWs) to excite the whispering gallery modes of a liquid core optical ring resonator (LCORR) sensor. Because this architecture is based on integration, it is robust and well suited for dense multiplexing of sensors. They analytically and experimentally characterize the coupling between the ARROW structure and the LCORR and show good agreement between the coupling theory and experimental results. The multiplexing capability is experimentally demonstrated by exciting multiple ring resonators along a single LCORR using the ARROW array. Also, they show the label-free detection of bovine serum albumin with this LCORR-ARROW system.
Pressure-induced suppression of piezoelectric response in a Pb(Zn1∕3Nb2∕3)O3–PbTiO3 binary system single crystal near a morphotropic phase boundary
Authors: Yasuda Naohiko , Rahman Md. M. , Ohwa Hidehiro , Matsushita Mituyoshi , Yamashita Yohachi , Iwata Makoto , Terauchi Hikaru , Ishibashi Yoshihiro
Published: November 2006

Piezoelectric properties of Pb[(Zn1∕3Nb2∕3)0.91]Ti0.09O3 single crystal poled along the [001] direction in rhombohedral phase was investigated under pressures (p) up to 700MPa at 25°C. For the transverse electromechanical property, piezoelectric response on impedance and phase frequency characteristic curves abruptly disappeared above 500MPa. For the longitudinal one, sharpness of shape in their curves at resonant and antiresonant frequencies became broader above 500MPa, and piezoelectric response rapidly depressed with p. Such rapid suppression of piezoelectric response above 500MPa is considered to be due to decrease in contribution of shear mode based on volume contraction caused by hydrostatic pressure.
Growth control of tungsten oxide nanostructures on planar silicon substrates
Authors: Galléa Floriane , Li Zhengcao , Zhang Zhengjun
Published: November 2006

Tungsten oxide nanostructures were deposited on silicon substrates by a thermal oxidation approach. The major factors influencing their phase structure and growth morphology were found to be the substrate temperature and the chamber pressure. By investigating the growth process of these nanostructures, a phase growth diagram was constructed, with which one can realize the phase selection and morphology control of the tungsten oxide nanostructures by this thermal oxidation approach. The present study could be of great significance in fabricating tungsten oxide nanostructures for device applications.
Limiting ionic conductivity and solvation dynamics in formamide
Authors: Kashyap Hemant K. , Pradhan Tuhin , Biswas Ranjit
Published: November 2006

A self-consistent microscopic theory has been used to calculate the limiting ionic conductivity of unipositive rigid ions in formamide at different temperatures. The calculated results are found to be in good agreement with the experimental data. The above theory can also predict successfully the experimentally observed temperature dependence of total ionic conductivity of a given uniunivalent electrolyte in formamide. The effects of dynamic polar solvent response on ionic conductivity have been investigated by studying the time dependent progress of solvation of a polarity probe dissolved in formamide. The intermolecular vibration (libration) band that is often detected in the range of 100–200cm−1 in formamide is found to play an important role in determining both the conductivity and the ultrafast polar solvent response in formamide. The time dependent decay of polar solvation energy in formamide has been studied at three different temperatures, namely, at 283.15, 298.15, and 328.15K. While the predicted decay at 298.15K is in good agreement with the available experimental data, the calculated results at the other two temperatures should be tested against experiments.
Fabrication and characterization of single carbon nanotube emitters as point electron sources
Authors: Zhao Gongpu , Zhang Jian , Zhang Qi , Zhang Han , Zhou Otto , Qin Lu-Chang , Tang Jie
Published: November 2006

Individual carbon nanotube electron field emitters with good controllability have been fabricated in a two-step process involving (a) producing micron-size carbon fibers which contain single carbon nanotubes at their cores by a chemical vapor deposition method and (b) exposing the nanotubes by fracturing the fiber with mechanical forces and mounting the fiber to a copper wire. These fiber-nanotube electron emitters show low operating voltage, generate high field enhancement, and produce fine electron beams. The field emission characteristics and durability of this structure offer promising applications for analytical instruments where high performance point electron sources are required.
Generalized Stone-Wales transformation as the possible origin of ferromagnetism in polymeric C60: A density-functional theory study
Authors: Ribas-Ariño J. , Novoa Juan J.
Published: November 2006

Recently, there has been a proposal [Y.-H. Kim et al., Phys. Rev. B 68, 125420 (2003)] suggesting that ferromagnetic interactions in compressed and heated polymeric-C60 solids could be due to the existence of triplet open cages resulting from successive generalized Stone-Wales transformations within the C60 cage. Here, by performing B3LYP∕3-21G and B3LYP∕6-31G(d) optimizations, we carried out a systematic investigation of the thermodynamics and kinetics of the mechanism of generation of these open cages in their closed-shell singlet, open-shell singlet, and triplet states. We also computed the magnetic interactions induced by the open cages presenting a triplet ground state. Our results indicate that this mechanism is not appropriate to explain the ferromagnetism found in compressed and heated polymeric C60 for the following reasons: (a) the formation of the only open cage presenting a triplet ground state requires overpassing a highest energy point of 318kcal∕mol, well above other competitive mechanisms reported in the literature; the triplet open cages formed are not stable against their transformation into a diamagnetic intermediate; (c) the magnetic interactions between two adjacent triplet open cages are antiferromagnetic.
Investigation of the Bischler indole synthesis from 3,5-dimethoxyaniline
Authors: Black DSC , Gatehouse BMKC , Theobald F , Wong LCH
Published: November 2006

Cyclization of the amino ketones
(3a,b) derived from 3,5- dimethoxyaniline, and phenacyl bromide and
4-bromophenacyl bromide respectively, afforded 2-arylindoles (8a,b) in
preference to 3-aryl- indoles(7). The 3-(4'-bromophenyl)indole (7b) was also
isolated in the presence of polyphosphoric acid, but not when amine
hydrochloride catalysis was employed. The structure of 2-(4'-bromophenyl)-4,6-
dimethoxyindole (8b) was confirmed by X-ray diffraction studies.
The chemical constituents of Australian Zanthoxylum species. VII. Some transformation products of suberosin
Authors: Mock JR , Senior RG , Taylor WC
Published: November 2006

Photosensitized oxidation
of suberosin yielded suberenol (2), isosuberenol (6) and, under certain conditions,
6,6'-ethylenebis(7- methoxy-2H-1-benzopyran-2-one). The epoxy alcohol (7a), its
methyl ether and the aldehyde (3) were also obtained, but these are believed to
be artefacts formed under the conditions of workup. Autoxidation of suberosin does
not appear to occur readily. Other oxygenated derivatives of suberosin were
prepared by chemical methods. ���
Dehydration of suberenol and isosuberenol
yielded the diene (5) which on treatment with acid gave in low yield a
bis-coumarin, isomeric with cyclobisuberodiene, for
which structure (24) is suggested.
Crystal structures of hexa(N-methylurea)cobalt(II) sulfate and thiosulfate
Authors: Figgis BN , Skelton BW , White AH
Published: November 2006

The crystal structures of
the title compounds, [Co(C2H6N2O)6](SO4)(1)
and[Co(C2H6N2O)6](S2O3)
(2), have been determined at 295 K by X-ray diffraction using diffractometer
data and refined by least squares to residuals of 0.042 (1), 0.043 (2) [875 and
926 reflections with I > (3σ(I)]. Crystals are trigonal,
R 3c, a 1.4890(1) nm, α 43.34(1)° (1); a 1.4760(3) nm, α 44.53(1)°
(2), Z 2. The compounds are isostructural; the complex
cation has 3 symmetry, Co-O, 209.6(2) (1), 209.9(2) pm (2); the geometry of the
ligand is well defined and precise, but the anions,
located at sites of symmetry 32, are disordered. ��� The cobalt environment is distorted from Oh
symmetry, being compressed along the threefold axis.
Crystal structure of the ferromagnetic polymer potassium Bis(carbonato)cuprate(II)
Authors: Farrand A , Gregson AK , Skelton BW , White AH
Published: November 2006

The crystal structure of
the title compound, K2Cu(CO3)2, has been
determined by single-crystal X-ray diffraction at 295(1) K, and refined by
least squares to a residual of 0.027 for 1441 'observed' reflections. Crystals
are orthorhombic, space group Fdd2, a 11.425(3), b 17.658(4), c 6.154(2) A, Z
8. The structure comprises potassium cations embedded in an infinite
three-dimensional polymeric anionic array of square-planar coordinated copper
atoms with bridging carbonate groups [Cu-O 1.934(2), 1.936(2) Ǻ]. Within
the latter, the non- coordinating oxygen-carbon bond is shorter [1.259(3)
Ǻ] than the other two [1.303(3), 1.307(2) Ǻ] and the O-C-O angle
opposite it is correspondingly reduced to 117.1(2)°. The CO3 plane
lies at 83.9° to the CuO4 'plane'.
Structural and biochemical studies of the C-terminal domain of mouse peptide-N-glycanase identify it as a mannose-binding module
Authors: Zhou Xiaoke , Zhao Gang , Truglio James J. , Wang Liqun , Li Guangtao , Lennarz William J. , Schindelin Hermann
Published: November 2006

The inability of certain N-linked glycoproteins to adopt their native conformation in the endoplasmic reticulum (ER) leads to their retrotranslocation into the cytosol and subsequent degradation by the proteasome. In this pathway the cytosolic peptide-N-glycanase (PNGase) cleaves the N-linked glycan chains off denatured glycoproteins. PNGase is highly conserved in eukaryotes and plays an important role in ER-associated protein degradation. In higher eukaryotes, PNGase has an N-terminal and a C-terminal extension in addition to its central catalytic domain, which is structurally and functionally related to transglutaminases. Although the N-terminal domain of PNGase is involved in protein–protein interactions, the function of the C-terminal domain has not previously been characterized. Here, we describe biophysical, biochemical, and crystallographic studies of the mouse PNGase C-terminal domain, including visualization of a complex between this domain and mannopentaose. These studies demonstrate that the C-terminal domain binds to the mannose moieties of N-linked oligosaccharide chains, and we further show that it enhances the activity of the mouse PNGase core domain, presumably by increasing the affinity of mouse PNGase for the glycan chains of misfolded glycoproteins.
Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition
Authors: Fagot Joël , Cook Robert G.
Published: November 2006

Previous research has shown that birds and primates have a rich repertoire of behavioral and cognitive skills, but the mechanisms underlying these abilities are not well understood. A common hypothesis is that these adaptations are mediated by an efficient long-term memory, allowing animals to remember specific external events and associate appropriate behaviors to these events. Because earlier studies have not sufficiently challenged memory capacity in animals, our comparative research examined with equivalent procedures the size and mechanisms of long-term memory in baboons and pigeons. Findings revealed very large, but different, capacities in both species to learn and remember picture–response associations. Pigeons could maximally memorize between 800 and 1,200 picture–response associations before reaching the limit of their performance. In contrast, baboons minimally memorized 3,500–5,000 items and had not reached their limit after more than 3 years of testing. No differences were detected in how these associations were retained or otherwise processed by these species. These results demonstrate that pigeons and monkeys have sufficient memory resources to develop memory-based exemplar or feature learning strategies in many test situations. They further suggest that the evolution of cognition and behavior importantly may have involved the gradual enlargement of the long-term memory capacities of the brain.
An escort mechanism for cycling of export chaperones during flagellum assembly
Authors: Evans Lewis D. B. , Stafford Graham P. , Ahmed Sangita , Fraser Gillian M. , Hughes Colin
Published: November 2006

Assembly of the bacterial flagellar filament requires a type III export pathway for ordered delivery of structural subunits from the cytosol to the cell surface. This is facilitated by transient interaction with chaperones that protect subunits and pilot them to dock at the membrane export ATPase complex. We reveal that the essential export protein FliJ has a novel chaperone escort function in the pathway, specifically recruiting unladen chaperones for the minor filament-class subunits of the filament cap and hook-filament junction substructures. FliJ did not recognize unchaperoned subunits or chaperone-subunit complexes, and it associated with the membrane ATPase complex, suggesting a function postdocking. Empty chaperones that were recruited by FliJ
in vitro
were efficiently captured from FliJ-chaperone complexes by cognate subunits. FliJ and subunit bound to the same region on the target chaperone, but the cognate subunit had a ≈700-fold greater affinity for chaperone than did FliJ. The data show that FliJ recruits chaperones and transfers them to subunits, and indicate that this is driven by competition for a common binding site. This escort mechanism provides a means by which free export chaperones can be cycled after subunit release, establishing a new facet of the secretion process. As FliJ does not escort the chaperone for the major filament subunit, cycling may offer a mechanism for export selectivity and thus promote assembly of the junction and cap substructures required for initiation of flagellin polymerization.
A subunit of the mediator complex regulates vertebrate neuronal development
Authors: Wang Xiaoqun , Yang Nan , Uno Etsuko , Roeder Robert G. , Guo Su
Published: November 2006

The unique profiles of gene expression dictate distinct cellular identity. How these profiles are established during development is not clear. Here we report that the mutant
motionless
(
mot
), identified in a genetic screen for mutations that affect neuronal development in zebrafish, displays deficits of monoaminergic neurons and cranial sensory ganglia, whereas expression of the pan-neuronal marker Hu is largely unperturbed; GABAergic and subsets of cranial motor neurons do not appear to be deficient. Positional cloning reveals that
mot
encodes Med12, a component of the evolutionarily conserved Mediator complex, whose
in vivo
function is not well understood in vertebrates.
mot
/
med12
transcripts are enriched in the embryonic brain and appear distinct from two other Mediator components Med17 and Med21. Delivery of human
med12
RNA into zebrafish restores normality to the
mot
mutant and, strikingly, leads to premature neuronal differentiation and an increased production of monoaminergic neuronal subtypes in WT. Further investigation reveals that
mot
/
med12
is necessary to regulate, and when overexpressed is capable of increasing, the expression of distinct neuronal determination genes, including
zash1a
and
lim1
, and serves as an
in vivo
cofactor for Sox9 in this process. Together, our analyses reveal a regulatory role of Mot/Med12 in vertebrate neuronal development.
Ablation of hippocampal neurogenesis impairs contextual fear conditioning and synaptic plasticity in the dentate gyrus
Authors: Saxe Michael D. , Battaglia Fortunato , Wang Jing-Wen , Malleret Gael , David Denis J. , Monckton James E. , Garcia A. Denise R. , Sofroniew Michael V. , Kandel Eric R. , Santarelli Luca , Hen René , Drew Michael R.
Published: November 2006

Although hippocampal neurogenesis has been described in many adult mammals, the functional impact of this process on physiology and behavior remains unclear. In the present study, we used two independent methods to ablate hippocampal neurogenesis and found that each procedure caused a limited behavioral deficit and a loss of synaptic plasticity within the dentate gyrus. Specifically, focal X irradiation of the hippocampus or genetic ablation of glial fibrillary acidic protein-positive neural progenitor cells impaired contextual fear conditioning but not cued conditioning. Hippocampal-dependent spatial learning tasks such as the Morris water maze and Y maze were unaffected. These findings show that adult-born neurons make a distinct contribution to some but not all hippocampal functions. In a parallel set of experiments, we show that long-term potentiation elicited in the dentate gyrus in the absence of GABA blockers requires the presence of new neurons, as it is eliminated by each of our ablation procedures. These data show that new hippocampal neurons can be preferentially recruited over mature granule cells
in vitro
and may provide a framework for how this small cell population can influence behavior.
Two-photon vibrational spectroscopy for biosciences based on surface-enhanced hyper-Raman scattering
Authors: Kneipp Janina , Kneipp Harald , Kneipp Katrin
Published: November 2006

Two-photon excitation is gaining rapidly in interest and significance in spectroscopy and microscopy. Here we introduce a new approach that suggests versatile optical labels suitable for both one- and two-photon excitation and also two-photon-excited ultrasensitive, nondestructive chemical probing. The underlying spectroscopic effect is the incoherent inelastic scattering of two photons on the vibrational quantum states called hyper-Raman scattering (HRS). The rather weak effect can be strengthened greatly if HRS takes place in the local optical fields of gold and silver nanostructures. This so-called surface-enhanced HRS (SEHRS) is the two-photon analogue to surface-enhanced Raman scattering (SERS). SEHRS provides structurally sensitive vibrational information complementary to those obtained by SERS. SEHRS combines the advantages of two-photon spectroscopy with the structural information of vibrational spectroscopy and the high-sensitivity and nanometer-scale local confinement of plasmonics-based spectroscopy. We infer effective two-photon cross-sections for SEHRS on the order of 10
−46
to 10
−45
cm
4
·s, similar to or higher than the best “action” cross-sections (product of the two-photon absorption cross-section and fluorescence quantum yield) for two-photon fluorescence, and we demonstrate HRS on biological structures such as single cells after incubation with gold nanoparticles.
Wilms' tumor 1-associating protein regulates G
2
/M transition through stabilization of cyclin A2 mRNA
Authors: Horiuchi Keiko , Umetani Michihisa , Minami Takashi , Okayama Hiroto , Takada Shinji , Yamamoto Masayuki , Aburatani Hiroyuki , Reid Patrick C. , Housman David E. , Hamakubo Takao , Kodama Tatsuhiko
Published: November 2006

Wilms' tumor 1-associating protein (WTAP) has been reported to be a ubiquitously expressed nuclear protein. Although a relation to splicing factors has been postulated, its actual physiological function still remains to be elucidated. To investigate the role of WTAP, we generated WTAP-knockout mice and performed small interfering RNA (siRNA)-mediated knockdown analyses in primary cultured cells. In DNA microarrays using human umbilical vein endothelial cells, WTAP-targeted siRNA treatment resulted in markedly reduced expression of cell-cycle-related genes. siRNA-mediated WTAP knockdown down-regulated the stability of cyclin A2 mRNA through a nine-nucleotide essential sequence in cyclin A2 mRNA 3′ UTR. WTAP knockdown induced G
2
accumulation, which is partially rescued by adenoviral overexpression of cyclin A2. Moreover, WTAP-null mice exhibited proliferative failure with death resulting at approximately embryonic day 6.5, an etiology almost identical to cyclin A2-null mice. Collectively, these findings establish WTAP as an essential factor for the stabilization of cyclin A2 mRNA, thereby regulating G
2
/M cell-cycle transition.
The potential rate of bed-load transport
Authors: Gomez Basil
Published: November 2006

Averages of measurements made in three rivers characterized by a high availability of sediment in relation to runoff, and comparable data that represent the high end of the range of transport rates observed during three sets of laboratory experiments, confirm there is an upper, particle-size-dependent limit to bed-load transport efficiency. Incorporating the regression relation derived from these six diverse and unrelated data sets into R. A. Bagnold's classic formulation yields
i

b

= ω [0.0115·
D
50
−0.51
]/0.63. This straightforward scale correlation can be used to estimate the potential rate of bed-load transport (for average conditions) in gravel-bed rivers when sediment transport is constrained neither by the supply of sediment to nor by the amount of sediment available in the channel. The independent application of this empirical limit formula to two rivers with applicable bed-load transport regimes reveals a good (±10%) correspondence between average observed and predicted transport rates.
Reversal of airway hyperresponsiveness by induction of airway mucosal CD4+CD25+ regulatory T cells
Authors: Strickland Deborah H. , Stumbles Philip A. , Zosky Graeme R. , Subrata Lily S. , Thomas Jenny A. , Turner Debra J. , Sly Peter D. , Holt Patrick G.
Published: November 2006

An important feature of atopic asthma is the T cell–driven late phase reaction involving transient bronchoconstriction followed by development of airways hyperresponsiveness (AHR). Using a unique rat asthma model we recently showed that the onset and duration of the aeroallergen-induced airway mucosal T cell activation response in sensitized rats is determined by the kinetics of functional maturation of resident airway mucosal dendritic cells (AMDCs) mediated by cognate interactions with CD4+ T helper memory cells. The study below extends these investigations to chronic aeroallergen exposure. We demonstrate that prevention of ensuing cycles of T cell activation and resultant AHR during chronic exposure of sensitized rats to allergen aerosols is mediated by CD4+CD25+Foxp3+LAG3+ CTLA+CD45RC+ T cells which appear in the airway mucosa and regional lymph nodes within 24 h of initiation of exposure, and inhibit subsequent Th-mediated upregulation of AMDC functions. These cells exhibit potent regulatory T (T reg) cell activity in both in vivo and ex vivo assay systems. The maintenance of protective T reg activity is absolutely dependent on continuing allergen stimulation, as interruption of exposure leads to waning of T reg activity and reemergence of sensitivity to aeroallergen exposure manifesting as AMDC/T cell upregulation and resurgence of T helper 2 cytokine expression, airways eosinophilia, and AHR.
Pivotal roles of CD8+ T cells restricted by MHC class I–like molecules in autoimmune diseases
Authors: Das Gobardhan , Das Jyoti , Eynott Paul , Zhang Yingyu , Bothwell Alfred L.M. , Kaer Luc Van , Shi Yufang
Published: November 2006

Unlike T cells restricted by major histocompatibility complex (MHC) class Ia or class II molecules, T cells restricted by MHC class I–like molecules demonstrate properties of both innate and adaptive immunity and are therefore considered innate-like lymphocytes (ILLs). ILLs are believed to have immunoregulatory functions, but their roles in autoimmunity and defense against infections remain elusive. To study the properties of ILLs, we generated mice expressing only MHC class I–like molecules by crossing CIITA−/− with Kb−/−Db−/− mice. Surprisingly, these mice developed a lymphoproliferative syndrome and autoimmunity, most notably inflammatory bowel disease (IBD) and insulitis. The CD8+ ILLs in these mice exhibit a constitutively activated phenotype, and depletion of these cells abolished the autoimmune disorders. In addition, adoptive transfer of CD8+ ILLs from Kb−/−Db−/−CIITA−/− mice to Rag-1−/−pfn−/− mice also resulted in IBD and insulitis. These findings provide direct evidence that CD8+ ILLs are sufficient to initiate and mediate autoimmune diseases.
Th17 functions as an osteoclastogenic helper T cell subset that links T cell activation and bone destruction
Authors: Sato Kojiro , Suematsu Ayako , Okamoto Kazuo , Yamaguchi Akira , Morishita Yasuyuki , Kadono Yuho , Tanaka Sakae , Kodama Tatsuhiko , Akira Shizuo , Iwakura Yoichiro , Cua Daniel J. , Takayanagi Hiroshi
Published: November 2006

In autoimmune arthritis, traditionally classified as a T helper (Th) type 1 disease, the activation of T cells results in bone destruction mediated by osteoclasts, but how T cells enhance osteoclastogenesis despite the anti-osteoclastogenic effect of interferon (IFN)-γ remains to be elucidated. Here, we examine the effect of various Th cell subsets on osteoclastogenesis and identify Th17, a specialized inflammatory subset, as an osteoclastogenic Th cell subset that links T cell activation and bone resorption. The interleukin (IL)-23–IL-17 axis, rather than the IL-12–IFN-γ axis, is critical not only for the onset phase, but also for the bone destruction phase of autoimmune arthritis. Thus, Th17 is a powerful therapeutic target for the bone destruction associated with T cell activation.
Randomized Controlled Trials of Pediatric Massage: A Review
Authors: Beider Shay , Moyer Christopher A.
Published: November 2006

The existing reviews of massage therapy (MT) research are either limited to infants, adults, or were conducted prior to the publication of the most recent studies using pediatric samples. Randomized controlled trials (RCTs) of pediatric MT are reviewed. A literature search yielded 24 RCTs of pediatric MT, defined as the manual manipulation of soft tissue intended to promote health and well‐being in recipients between 2 and 19 years of age. Because RCTs of pediatric MT varied considerably in the amount and types of data reported, quantitative and narrative review methods were both used. Single‐dose and multiple‐dose effects were examined separately. Among single‐dose effects, significant reductions of state anxiety were observed at the first session (g = 0.59, P < 0.05) and the last session (g = 1.10, P < 0.01) of a course of treatment. Effects for salivary cortisol (g = 0.28), negative mood (g = 0.52) and behavior (g = 0.37) were non‐significant. Three of eleven multiple‐dose effects were statistically significant. These were trait anxiety (g = 0.94, P < 0.05), muscle tone (g = 0.90, P < 0.01) and arthritis pain (g = 1.33, P < 0.01). Results of studies not permitting effect size calculation were judged to be generally consistent with quantitative results. MT benefits pediatric recipients, though not as universally as sometimes reported. Numerous weaknesses endemic to MT research (e.g. low statistical power, frequent failure to report basic descriptive statistics) are identified, and recommendations for future pediatric MT research are discussed.
ArabidopsisFAMA Controls the Final Proliferation/Differentiation Switch during Stomatal Development
Authors: Ohashi-Ito Kyoko , Bergmann Dominique C.
Published: November 2006

Coordination between cell proliferation and differentiation is essential to create organized and functional tissues. Arabidopsis thaliana stomata are created through a stereotyped series of symmetric and asymmetric cell divisions whose frequency and orientation are informed by cell–cell interactions. Receptor-like proteins and a mitogen-activated protein kinase kinase kinase were previously identified as negative regulators of stomatal development; here, we present the characterization of a bona fide positive regulator. FAMA is a putative basic helix-loop-helix transcription factor whose activity is required to promote differentiation of stomatal guard cells and to halt proliferative divisions in their immediate precursors. Ectopic FAMA expression is also sufficient to confer stomatal character. Physical and genetic interaction studies combined with functional characterization of FAMA domains suggest that stomatal development relies on regulatory complexes distinct from those used to specify other plant epidermal cells. FAMA behavior provides insights into the control of differentiation in cells produced through the activity of self-renewing populations.
Binding of mitochondrial leader sequences to Tom20 assessed using a bacterial two‐hybrid system shows that hydrophobic interactions are essential and that some mutated leaders that do not bind Tom20 can still be imported
Authors: Mukhopadhyay Abhijit , Yang Chun‐song , Weiner Henry
Published: November 2006

Previous studies pointed to the importance of leucine residues in the binding of mitochondrial leader sequences to Tom20, an outer membrane protein translocator that initially binds the leader during import. A bacteria two‐hybrid assay was here employed to determine if this could be an alternative way to investigate the binding of leader to the receptor. Leucine to alanine and arginine to glutamine mutations were made in the leader sequence from rat liver aldehyde dehydrogenase (pALDH). The leucine residues in the C‐terminal of pALDH leader were found to be essential for TOM20 binding. The hydrophobic residues of another mitochondrial leader F1β‐ATPase that were important for Tom20 binding were found at the C‐terminus of the leader. In contrast, it was the leucines in the N‐terminus of the leader of ornithine transcarbamylase that were essential for binding. Modeling the peptides to the structure of Tom20 showed that the hydrophobic residues from the three proteins could all fit into the hydrophobic binding pocket. The mutants of pALDH that did not bind to Tom20 were still imported in vivo in transformed HeLa cells or in vitro into isolated mitochondria. In contrast, the mutant from pOTC was imported less well (∼50%) while the mutant from F1β‐ATPase was not imported to any measurable extent. Binding to Tom20 might not be a prerequisite for import; however, it also is possible that import can occur even if binding to a receptor component is poor, so long as the leader binds tightly to another component of the translocator.
Value of eosinophil cationic protein and tryptase levels in bronchoalveolar lavage fluid for predicting lung function impairment in anaesthetised, asthmatic children*
Authors: Von Ungern‐Sternberg B. S. , Sly P. D. , Loh R. K. S. , Isidoro A. , Habre W.
Published: November 2006

Bronchial hyperactivity, a key feature of active asthma in children, is a risk factor for respiratory adverse events in the peri‐operative period. The presence of activated eosinophils in the lungs and mast cell degranulation can contribute to bronchial hyperreactivity. Eosinophil cationic protein is released by activated eosinophils and tryptase reflects mast cell degranulation. This study focused on the relationship of respiratory mechanics, eosinophil cationic protein and tryptase levels in bronchoalveolar lavage fluid in asthmatic and healthy children under general anaesthesia. We measured eosinophil cationic protein and tryptase levels in bronchoalveolar lavage fluid from 21 asthmatic and 21 healthy children following induction of general anaesthesia. Respiratory system resistance and dynamic compliance were measured during mechanical ventilation. Eosinophil cationic protein was more common in bronchoalveolar lavage fluid from asthmatics (12/21) than from controls (4/21, p = 0.01) and was present at higher levels (p = 0.002). Tryptase was also more common in the asthmatics (8/21vs1/21, p = 0.01). Respiratory resistance was significantly higher in asthmatic children with detectable eosinophil cationic protein levels than in those with undetectable eosinophil cationic protein levels (p = 0.019). Furthermore, 50% of the asthmatics with detectable eosinophil cationic protein exhibited bronchospasm after sampling their bronchoalveolar lavage fluid. These findings suggested that high levels of eosinophil cationic protein in the bronchoalveolar lavage fluid are associated with irritable airways, presumably secondary to airway inflammation, and this might be a useful marker for respiratory adverse events in the peri‐operative period.
PGK deficiency
Authors: Beutler Ernest
Published: November 2006

Phosphoglycerate kinase (PGK) deficiency is one of the relatively uncommon causes of hereditary non‐spherocytic haemolytic anaemia (HNSHA). The gene encoding the erythrocyte enzyme PGK1, is X‐linked. Mutations of this gene may cause chronic haemolysis with or without mental retardation and they may cause myopathies, often with episodes of myoglobinuria, or a combination of these clinical manifestations. Twenty‐six families have been described and in 20 of these the mutations are known. The reason for different clinical manifestations of mutations of the same gene remains unknown.
Capture and generation of adenovirus specific T cells for adoptive immunotherapy
Authors: Chatziandreou Ilenia , Gilmour Kimberly C. , McNicol Anne‐Marie , Costabile Maurizio , Sinclair Joanna , Cubitt David , Campbell John D. M. , Kinnon Christine , Qasim Waseem , Bobby Gaspar H.
Published: November 2006

Adenoviral infections represent a major cause of morbidity and mortality following haematopoietic stem cell transplantation. Current anti‐viral agents are virostatic and it is evident that elimination of adenovirus (ADV) infection is only achieved by recovery of cellular immunity. Using an interferon‐gamma (IFN‐γ) secretion and capture assay to isolate ADV‐specific T cells, followed by a 2 week expansion and restimulation protocol, we generated ADV T cells that may be used for cellular immunotherapy. In contrast to virus‐specific T cells for cytomegalovirus or Epstein‐Barr virus, the ADV response was dominated by CD4+ T cells and the majority of captured cells exhibited an effector/memory immunophenotype. Highly specific antigen responses were demonstrated by intracellular IFN‐γ expression and cytotoxicity assays when the expanded cells underwent restimulation with ADV‐pulsed target cells. Although T cells were initially generated in response to ADV species C, the expanded populations also showed strong activity against ADV species B, suggesting cross‐reactivity across ADV species; a finding that has important clinical consequences in the paediatric setting, where the majority of infections are caused by ADV type B and C. The protocols can be readily translated to generate ADV‐specific T cells suitable for clinical use and offer an effective immunotherapeutic strategy to control ADV infection.
Treatment of hereditary angioneurotic oedema (HANE) with tibolone
Authors: Ott H. W. , Mattle V. , Hadziomerovic D. , Licht P. , Döinghaus K. , Rubbert A. , Manger K. , Manger B. , Kalden J. , Wildt L.
Published: November 2006

Objective  Eight women, aged 25–58 years, with hereditary angioneurotic oedema (HANE) were treated with tibolone, a synthetic steroid exhibiting oestrogenic, androgenic and progestational activity.

Design  Pilot study.

Results  Tibolone at a dose of 2·5–7·5 mg/day significantly reduced the number and severity of attacks and the number of ampoules of C1‐esterase inhibitor (C1‐INH) needed for symptomatic therapy. The efficacy of tibolone was comparable to that of danazol, while the androgenic side‐effects were considerably reduced.

Conclusions  Tibolone may represent an alternative to danazol administration for the prophylaxis of HANE in women.
Phaeochromocytoma, new genes and screening strategies
Authors: Gimenez‐Roqueplo Anne‐Paule , Lehnert Hendrik , Mannelli Massimo , Neumann Hartmut , Opocher Giuseppe , Maher Eamonn R. , Plouin Pierre‐François ,   on behalf of the European Network for the Study of Adrenal Tumours (ENS@T) Pheochromocytoma Working Group
Published: November 2006

Following recent advances in the genetics of phaeochromocytomas and paragangliomas, the members of the European Network for the Study of Adrenal Tumours (ENS@T) Phaeochromocytoma Working Group have decided to share their genotyping data and to propose European recommendations for phaeochromocytoma/functional paraganglioma (PH/FPGL) genetic testing. Germline DNA from 642 patients was analysed by ENS@T teams. In 166 patients (25·9%) the disease was familial and caused by germline mutations in VHL (56), SDHB (34), SDHD (31), RET (31) or NF1 (14), causing von Hippel‐Lindau disease, SDHB‐ or SDHD‐PH/FPGL syndromes, multiple endocrine neoplasia type 2 (MEN 2) and type 1 neurofibromatosis (NF1), respectively. In almost 60% of inherited cases it was possible to formulate a probable genetic diagnosis based on family history and/or typical syndromic presentation. Genetic testing revealed mutations in 12·7% of cases with an apparently sporadic presentation. Several clinical characteristics, such as young age at onset, the presence of bilateral, extra‐adrenal or multiple tumours or a malignant tumour, should be seen as indications for genetic testing. The ENS@T Phaeochromocytoma Working Group recommends the genetic testing of all patients with PH and FPGL and suggests a practice algorithm for the management of their exploration.
Aspirin reduces anticardiolipin antibodies in patients with coronary artery disease
Authors: Ikonomidis I. , Lekakis J. , Vamvakou G. , Loizou S. , Revela I. , Andreotti F. , Kremastinos D. Th. , Nihoyannopoulos P.
Published: November 2006

Background  Anticardiolipin antibodies (aCL) have been found to be elevated in patients with coronary artery disease (CAD) and have been associated with an adverse outcome owing to their prothrombotic activity. The aim of this study was to investigate the effect of aspirin treatment on aCL levels in patients with chronic CAD.

Materials and methods  Forty patients with chronic CAD scheduled for elective coronary artery bypass graft surgery (CABG) and 40 healthy controls participated in the study. Patients were treated with 300 mg of aspirin once daily (o.d.) for the first 12 days and placebo for the following 12 days before CABG in a double‐blind, cross‐over trial. Immunoglobulin (Ig) G‐, IgM‐, IgA‐aCL and C‐reactive protein (CRP) levels were measured in the controls and at the end of each treatment period in the patients with CAD.

Results  The IgA‐ and IgG‐aCL levels were greater in patients with CAD than in the controls. Compared with the placebo, IgA, IgG subtypes and CRP levels were reduced after aspirin treatment (P = 0·001, P = 0·02, P = 0·04, respectively). The percentage reduction of IgA‐ and IgG‐aCL was related to the percentage reduction of CRP after aspirin (P < 0·05).

Conclusion  Aspirin treatment with 300 mg o.d. reduced the serum levels of IgA and IgG subtypes in patients with chronic CAD in parallel to a reduction in CRP. These findings offer an additional pathophysiological mechanism of the beneficial effects of aspirin in patients with chronic CAD.
Acute effects of caffeine and tobacco on arterial function and wave travel
Authors: Swampillai J. , Rakebrandt F. , Morris K. , Jones C. J. H. , Fraser A. G.
Published: November 2006

Background  Caffeine and tobacco consumption are risk factors for heart failure, but their effects remain controversial. It has been hypothesized that they cause alterations in arterial stiffness and arterial wave travel which may increase ventricular loading. In this study the authors examined the influence of these widely used stimulants on wave intensity and arterial stiffness parameters using carotid wave intensity analysis.

Materials and methods  A new Doppler‐based ultrasound method was used to measure the acute effects of caffeine and tobacco on wave intensity in the right common carotid artery. The measurements enabled changes in arterial stiffness parameters to be recorded.

Results  In 17 subjects compared with 10 controls, caffeine increased blood pressure, early systolic wave intensity and wave speed, but late‐systolic wave intensity and mid‐systolic reflections were unchanged. In 11 smokers studied before and after smoking one cigarette, blood pressure and arterial stiffness increased but wave intensity was unchanged. No changes were observed in the controls.

Conclusions  Increased wave intensity during ejection after caffeine suggested sympathomimetic effects on the left ventricular function. Increased wave speed in the common carotid artery implied augmented central loading after caffeine, but the absence of measurable changes in local arterial stiffness in the carotid artery suggested more complex and regional effects. Cigarette smoking acutely increased local arterial stiffness in the common carotid artery. These changes can be detected using wave intensity analysis.