bluuebunny/crossref_metadata_2025 huggingface dataset:
Underwater Optics
Authors: Dolin Lev S. , Levin Iosif M.
Published: August 2007

Four major subjects of the underwater optics are especially important, both for fundamental study of interaction between light and water and for various technical applications. These are (1) inherent optical properties (IOP) of natural waters; (2) propagation of natural and artificial light in the water; (3) optical methods for investigation of natural waters, and (4) underwater imaging. These four items form the main content of the paper and determine the titles of its four main sections.

Section 2 presents the definitions of IOP determining light absorption and scattering in water. Methods of measuring IOP are discussed, and data on spatial and spectral distributions of IOP in natural waters are given. Physical and empirical low‐parametric models considered in the section make it possible to determine the whole set of IOP distributions, based on few measurements. Section 3 deals with the underwater light fields. Methods for solving the radiative transfer equation are considered. The section presents data on the solar irradiance and angular radiance distributions near the sea surface and at the sea depth, as well as on the light field of artificial sources. Optical methods for investigation of natural waters are discussed in Sect. 4. This section is mainly concerned with the problem of remote sensing of phytoplankton, suspended and dissolved matters by measuring the ocean color, with the account of algorithms for atmospheric correction of satellite measurements. Finally, Sect. 5 is devoted to the problem of underwater imaging. The presented theory connects the image parameters, such as modulation transfer function, contrast, signal/noise ratio with the parameters of light sources, detectors, water, and target. Comparison of the sighting range and spatial resolution in water ensured by different underwater imaging systems is given.
Ultrashort‐pulse Phenomena
Authors: Powers Peter E. , Spence David E. , Tang Chung L.
Published: August 2007

Ultrashort‐pulse phenomena are generally processes that occur on the subpicosecond to femtosecond time scale. The availability of lasers that generate ultrashort optical pulses has made possible the study of effects and processes that occur on ultrashort time scales. These measurements have led to a more fundamental understanding of processes in fields ranging from chemical kinetics to semiconductor physics. The high peak powers attainable with ultrashort‐pulse lasers has also led to new applications such as soft X‐ray generation and multiphoton microscopy. In this article, we review the generation, characterization, and a few of the applications of ultrashort optical pulses. We briefly introduce these topics with the goal of presenting an overview of the fundamental ideas. An extensive list of references is provided for each topic to give a starting point for further research.
Wave Optics
Authors: Dallas William J.
Published: August 2007

Narrowly interpreted, the term
wave optics
encompasses propagation, diffraction, interference, and thin films. Under a broader interpretation, wave optics includes those areas of optics governed by the electromagnetic wave equation. We begin with a brief review of the wave equation, which is built on the foundation of Maxwell's equations. Next is a translation of the wave equation into the propagation relations of linear systems theory. An interesting and useful aspect of propagation is the existence of helical light; light that twists as it travels. Another aspect of optical waves is its propagation from curved surfaces. We move on to interference and then diffraction. The hologram serves as an important example of interference, while the computer‐generated hologram is an example of control over diffraction. Talbot, or Fourier self‐imaging, is a stunning example of the richness of propagation from diffractive optical elements. Finally, we discuss the subject of phase retrieval from irradiance distributions on multiple surfaces.
X‐ray Optics
Authors: Michette Alan
Published: August 2007

This article describes the difficulties inherent in the optical manipulation of X‐ray beams and how they may be overcome. Related issues, such as X‐ray emission processes and sources, the ways in which X rays interact with matter, and the applications of focused X‐ray beams are also discussed.
Zeeman and Stark Effects
Authors: Silverman Mark P.
Published: August 2007

The Zeeman and Stark effects are modifications of spectral lines (displacements, splittings, and polarization changes) induced respectively by magnetic and electric fields. Application of an external static field splits the energy levels of a degenerate multiplet of states. In the Zeeman effect, levels shift up or down in energy depending on the magnitude and sign of the magnetic quantum number; in the Stark effect the shift depends only on the magnitude of the magnetic quantum number. Resulting spectral line patterns depend on the relative size of the field‐induced level splittings compared to the separation between different multiplets. This article discusses the weak‐, strong‐, and ultrastrong‐field Zeeman effects (the latter case arising when the magnetic interaction is comparable to the binding energy), and the linear and quadratic (including “ac”) Stark effects. In highly excited atoms (Rydberg atoms), where the separation between distinct manifolds is small and the electric polarizability enormous, the full range of Zeeman and Stark effects can be induced by relatively low fields. These effects have been employed to probe atomic and molecular structure, to measure inaccessible (e.g., stellar and interstellar) fields, and to gauge the influence of stray external fields in high‐precision metrology.
Wet Adsorption of a Luminescent EuIII complex on Carbon Nanotubes Sidewalls
Authors: Accorsi G. , Armaroli N. , Parisini A. , Meneghetti M. , Marega R. , Prato M. , Bonifazi D.
Published: August 2007

A EuIII complex, tris‐dibenzoylmethane mono‐1,10‐phenanthroline‐europium(III) [Eu(DBM)3(Phen)], can be easily adsorbed in situ via hydrophobic interactions to single‐walled carbon nanotube (SWNT) surfaces from a methanol solution. The EuIII‐containing material has been comprehensively characterized via thermogravimetric analysis (TGA), UV‐vis‐NIR absorption and luminescence spectroscopy, Raman spectroscopy, atomic force microscopy (AFM), high‐resolution transmission electron microscopy (HR‐TEM)), Z‐contrast scanning transmission electron microscopy (STEM) imaging, and energy dispersive X‐ray spectroscopy (EDS). The photophysical investigations revealed that the presence of a SWNT framework does not affect the lanthanide‐centered luminescence stemming from the characteristic electronic transitions within the 4f shell of the EuIII ions. Such straightforward synthetic route leads to the preparation of luminescent SWNTs without significantly affecting the electronic and structural properties of the carbon framework, opening new possibilities of designing new classes of CNTs for biomedical applications.
Studies of the Temperature and Frequency Dependent Impedance of an Electroceramic Functional Oxide NTC Thermistor
Authors: Schmidt R. , Brinkman A. W.
Published: August 2007

The charge transport mechanism and the macroscopic dielectric constant in polycrystalline device materials commonly exhibit several components such as electrode‐sample interface, grain boundary and bulk contributions. In order to gain precise understanding of the functionality of polycrystalline electroceramic device materials it is essential to deconvolute these contributions. The paradigm of functional NTC thermistor ceramics based on thick film spinel manganates has been studied by temperature dependent alternating current impedance spectroscopy. Three typical relaxation phenomena were detected, which all showed a separated temperature dependence of resistivity consistent with thermally activated charge transport. The dominating grain boundary and the interface contributions exhibited distinctively different capacitance allowing clear identification. The composite nature of the dielectric properties in polycrystalline functional ceramics was emphasized, and impedance spectroscopy was shown to be a powerful tool to account for and model such behavior.
Novel Heteroleptic CuI Complexes with Tunable Emission Color for Efficient Phosphorescent Light‐Emitting Diodes
Authors: Zhang Q. , Ding J. , Cheng Y. , Wang L. , Xie Z. , Jing X. , Wang F.
Published: August 2007

A series of orange‐red to red phosphorescent heteroleptic CuI complexes (the first ligand: 2,2′‐biquinoline (bq), 4,4′‐diphenyl‐2,2′‐biquinoline (dpbq) or 3,3′‐methylen‐4,4′‐diphenyl‐2,2′‐biquinoline (mdpbq); the second ligand: triphenylphosphine or bis[2‐(diphenylphosphino)phenyl]ether (DPEphos)) have been synthesized and fully characterized. With highly rigid bulky biquinoline‐type ligands, complexes [Cu(mdpbq)(PPh3)2](BF4) and [Cu(mdpbq)(DPEphos)](BF4) emit efficiently in 20 wt % PMMA films with photoluminescence quantum yield of 0.56 and 0.43 and emission maximum of 606 nm and 617 nm, respectively. By doping these complexes in poly(vinyl carbazole) (PVK) or N‐(4‐(carbazol‐9‐yl)phenyl)‐3,6‐bis(carbazol‐9‐yl) carbazole (TCCz), phosphorescent organic light‐emitting diodes (OLEDs) were fabricated with various device structures. The complex [Cu(mdpbq)(DPEphos)](BF4) exhibits the best device performance. With the device structure of ITO/PEDOT/TCCz:[Cu(mdpbq)(DPEphos)](BF4) (15 wt %)/TPBI/LiF/Al (III), a current efficiency up to 6.4 cd A–1 with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.61, 0.39) has been realized. To our best knowledge, this is the first report of efficient mononuclear CuI complexes with red emission.
Highly Stretchable and Conductive Polymer Material Made from Poly(3,4‐ethylenedioxythiophene) and Polyurethane Elastomers
Authors: Hansen T. S. , West K. , Hassager O. , Larsen N. B.
Published: August 2007

A highly elastic and stretchable conductive polymer material resulted from blending the conductive polymer poly(3,4‐ethylenedioxythiophene):p‐tosylate and an aliphatic polyurethane elastomer. The blend inherited advantageous properties from its constituents, namely high conductivity of 120 S cm–1 from its conductive polymer component, and elastomeric mechanical properties resembling those of the polyurethane, including good adhesion to various substrates. Stretching of the blend material by up to 50 % resulted in increased conductivity, while subsequent relaxation to the unstretched state caused a decrease of conductivity compared to the pristine blend. These initial changes in conductivity were reproducible on further cycling between 50 % stretching and the unstretched state for at least 10 cycles. Stretching beyond 50 % resulted in decreasing conductivity of the blend but with substantial conductivity remaining even when stretched by 200 %. Optical, mechanical, and thermal properties of the blend, as well as high resolution electron microscopy of bulk cross‐sections, suggest that the system is a single phase and not two separate phases. Ageing experiments indicate that the material retains substantial conductivity for at least a few years at room temperature.
Electroosmosis with step changes in zeta potential in microchannels
Authors: Horiuchi Keisuke , Dutta Prashanta , Ivory Cornelius F.
Published: August 2007

This article presents an analytical solution for two‐dimensional fluid flow in a rectangular microchannel in the vicinity of a step change in the zeta (ζ) potential. The stream function is determined from the creeping flow approximation to the Navier‐Stokes equations assuming a fixed volumetric axial flow, a constant electric field, and thin symmetric double layers. The resulting biharmonic equation is solved using a double‐sided Laplace transformation, which is then inverted by Heaviside expansion. The resulting series solution provides closed‐form expressions for the velocity and pressure fields that help explain how the recirculating flows generated by an abrupt change in the surface potential may contribute both locally and globally to the hydrodynamic dispersion in straight microchannels. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Monte Carlo model of UV‐radiation interaction with TiO2‐coated spheres
Authors: Imoberdorf Gustavo E. , Alfano Orlando M. , Cassano Alberto E. , Irazoqui Horacio A.
Published: August 2007

Photocatalysis is one of the advanced oxidation techniques that are being studied for the treatment of polluted air and water from different sources. From a kinetic point of view, photocatalytic reaction rates are strongly dependent not only on the reactant and product concentrations, but also on the rate of photon absorption. Unfortunately, the local rate of photon absorption is usually difficult to evaluate because of (i) the inherent complexity of the system and (ii) the lack of data concerning the photocatalyst optical properties. The final objective of this project is focused on the development of a complete model of the radiation field; the bed structure, and the flow pattern to describe the operation of a fixed bed photocatalytic reactor. In this article, the interaction between radiative energy and TiO2‐coated fused‐silica sphere beds was studied. The proposed model was built applying the Monte Carlo method, taking into account the complex reflection/refraction/absorption interactions between radiation and the packed bed. To obtain experimental measurements, an ad hoc device was designed and built. This device allows us to validate the proposed radiation model, and to obtain the optical parameters of the composite photocatalyst, i.e., the refractive index and the surface rough index of the fused‐silica spheres, as well as the refractive index and the optical thickness of the TiO2 films. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Mechanical strength of solid catalysts: Recent developments and future prospects
Authors: Wu Dongfang , Zhou Jiancheng , Li Yongdan
Published: August 2007

Mechanical strength of solid catalysts is one of the most important factors for the reliable and efficient performance of a reactor. Some recent developments on the basic mechanics of solid catalysts are reviewed in this article. The main concepts discussed are the brittle fracture which leads to the mechanical failure of the catalyst pellets, the measurement and statistical properties of the catalyst strength data, the mechanical reliability of the catalyst pellets, the mechanical properties of the catalyst packed beds, etc. For the purpose of an integrated research on catalyst mechanical properties, a multi‐scale framework for the mechanics of the fixed bed catalysts is also proposed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and advancement. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Weight for age charts for children with achondroplasia
Authors: Hoover‐Fong J.E. , McGready J. , Schulze K.J. , Barnes H. , Scott C.I.
Published: August 2007

To develop accurate weight for age charts for individuals with achondroplasia. These novel weight for age, gender‐specific growth curves for achondroplasia patients from birth through 16 years were constructed from a longitudinal, retrospective, single observer cohort study of 334 individuals with achondroplasia. Weight for age data from 301 subjects in this achondroplasia cohort, constituting 1,964 total weight measurements, are presented in these weight for age curves. Percentiles (5, 25, 50, 75, 95th) were estimated across the age continuum by gender, using a 1 month window (±0.5 months) around each time point of interest. Percentiles were smoothed using a quadratic, penalized smoother by a semi‐parametric model approach. Raw weight data from the achondroplasia cohort are compared to that of average stature children presented in the current CDC growth curves, divided into 0–36 months and 2–16 years. There was overlap of birth weight between achondroplasia and average stature infants. This statistical modeling method can be applied to other anthropometric parameters collected from this achondroplasia cohort (e.g., length, BMI), other skeletal dysplasia diagnoses, and to syndromic, non‐skeletal dysplasia diagnoses which may benefit from standardization of weight for age. © 2007 Wiley‐Liss, Inc.
A novel multiple congenital anomaly–mental retardation syndrome with Pierre Robin sequence and cerebellar hypoplasia in two sisters
Authors: Stevenson David A. , Carey John C.
Published: August 2007

We report on the similar phenotypes and clinical course of two sisters. Both patients had an enlarged cisterna magna suggestive of cerebellar hypoplasia, agenesis/hypoplasia of the corpus callosum, Pierre Robin sequence requiring tracheostomy, camptodactyly, microphthalmia, colobomas, seizures, a distinctive facial appearance, global developmental delay, and mental retardation. We propose that the distinct pattern in these sisters constitutes a previously undescribed syndrome of likely autosomal recessive inheritance. © 2007 Wiley‐Liss, Inc.
Keratin as a filler for carboxylated acrylonitrile‐butadiene rubber XNBR
Authors: Prochoń M. , Przepiórkowska A. , Zaborski M.
Published: August 2007

The presented investigations concern the distribution and characterization of keratin waste, derived from the processes of cattle skins, and its use as a filler for carboxylated acrylonitrile‐butadiene rubber XNBR. The recovered keratin improves mechanical proprieties such as tensile strength, hardness, resistance to fuel and oil. The addition of keratin in a quantity of five parts per hundred rubber (XNBR) increases the crosslinking density of composites, as testified by the formed ion nodes and the existing mono and disulphide bonds. Electric conductance and water absorption increased with time for elastomers filled with protein. Therefore these composites are biodegradable after their period of use. As a result hydrophilic–hydrophobic protein–elastomeric composites will have usable properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Effect of the fiber content and plasticizer type on the rheological and mechanical properties of poly(vinyl chloride)/green coconut fiber composites
Authors: Leblanc Jean L. , Furtado Cristina R. G. , Leite Marcia C. A. M. , Visconte Leila L. Y. , de Souza Ana M. F.
Published: August 2007

A series of poly(vinyl chloride) (PVC)/green coconut fiber (GCF) composites, with dioctyl phthalate (DOP) or thermoplastic polyurethane (TPU) as a plasticizer, were prepared by melt mixing. Their properties were studied in the molten state with an advanced nonlinear harmonic testing technique; in the solid state, the hardness and impact resistance were evaluated, and scanning electron microscopy was used for fractured surfaces. The effect of the fiber loading was investigated, as well as the role of the plasticizer. PVC–GCF composites are heterogeneous materials that, in the molten state, exhibit essentially a nonlinear viscoelastic character, in contrast to pure PVC, which has a linear viscoelastic region up to 50–60% strain. The complex modulus increases with the GCF content but in such a manner that the observed reinforcement is at best of hydrodynamic origin, without any specific chemical (i.e., permanent) interaction occurring between the polymer matrix and the fibers. As expected, PVC offers good wetting of GCFs, as reflected by the easy mixing and the rheological and mechanical properties. Fibers can be incorporated into PVC up to a 30% concentration without any problem, with the PVC/plasticizer ratio kept constant. Higher GCF levels could therefore be considered. Replacing DOP in part with TPU gives some benefit in terms of impact resistance, likely because of the viscoelastic nature of the latter and the associated energy absorption effects. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis of polystyrene microgel with a hyperbranched polyglycerol scaffold as core: Effect of shell congestion
Authors: Wan Decheng , Pu Hongting
Published: August 2007

Two hyperbranched polyglycerols (PG) (1a: Mn = 2000, 1b: Mn = 8000), both with 61% of the overall hydroxyl groups being transformed into trithiocarbonates (2a, 2b, with 16 and 65 OH groups being replaced by trithiocarbonates, respectively), can be used as a reversible addition‐fragmentation chain transfer (RAFT) agent. Polymerization of styrene mediated by 2a/2b was in a living manner, resulting in star‐like, amphiphilic, core‐shell structured polymers with 16 arms (3a) and 65 arms (3b), respectively. It was found that for system mediated by 2b, more serious side reaction (radical–radical coupling) occurred than that by 2a, most probably due to their difference in shell congestion. A shell‐crosslinked polymer could be prepared in the presence of divinylbenzene via a one‐pot route at solid content up to 20%, but analysis proved the crosslinking was incomplete. Furthermore, the 65‐arm‐star polymer (3b) more tended to undergo macroscopic rather than intramolecular crosslinking than the 16‐arm‐star polymer (3a) did. The phenomenon might again be attributed to their difference in shell congestion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Delayed memory B cell recovery in peripheral blood and lymphoid tissue in systemic lupus erythematosus after B cell depletion therapy
Authors: Anolik Jennifer H. , Barnard Jennifer , Owen Teresa , Zheng Bo , Kemshetti Sunil , Looney R. John , Sanz Iñaki
Published: August 2007

Objective

Recent data suggest that the reconstituting peripheral B cell compartment after B cell depletion therapy may be functionally immature, with a preponderance of transitional B cells and a paucity of memory B cells. This study was undertaken to determine the magnitude, duration, and cause of these defects in rituximab‐treated systemic lupus erythematosus (SLE) patients.

Methods

Fifteen patients with SLE previously treated with rituximab as part of a phase I/II dose‐escalation study were evaluated during a long‐term followup (mean followup period 41 months). B cells from peripheral blood and tonsils were assessed using multicolor flow cytometry, and their developmental pathway was classified based on the expression of defined surface markers.

Results

Reconstitution of peripheral blood CD27+ memory B cells was delayed for several years after B cell depletion therapy in a subset of patients with prolonged clinical responses and autoantibody normalization. This delay correlated with the degree of expansion of B cells of a transitional phenotype during the B cell reconstitution phase (P = 0.005) and the absence of baseline autoantibodies directed against extractable nuclear antigens (RNP, Sm, Ro antigen, La antigen). Despite the paucity of peripheral blood memory cells and the prolonged expansion of functionally immature transitional B cells, tonsil biopsy tissues revealed active germinal center (GC) reactions, but with decreased Fc receptor homolog 4–positive memory B cells.

Conclusion

These results suggest heterogeneity in the B cell depletion and reconstitution process that impacts clinical and immunologic outcomes in SLE. The presence of GC reactions, but with altered memory B cell subpopulations in tonsils, suggests that peripheral blood memory cell reconstitution lags behind a slow secondary lymphoid tissue recovery, with important implications for immunologic competence and tolerance.
Inverse relationship between matrix remodeling and lipid metabolism during osteoarthritis progression in the STR/ORT mouse
Authors: Watters James W. , Cheng Chun , Pickarski Maureen , Wesolowski Gregg A. , Zhuo Ya , Hayami Tadashi , Wang Wei , Szumiloski John , Phillips Robert L. , Duong Le T.
Published: August 2007

Objective

The biologic changes associated with osteoarthritis (OA) are incompletely understood. The aim of this study was to elucidate the molecular mechanisms underlying OA progression in an STR/Ort murine model of spontaneous disease.

Methods

Global patterns of gene expression were assessed using microarray analysis of articular cartilage/subchondral bone from the tibial plateaus of STR/Ort mice at 3, 9, and 12 months of age. The age‐dependent severity of osteophyte formation and extent of cartilage damage were determined in the corresponding femurs using microfocal computed tomography and the Mankin histologic scoring system. Pathway analysis was used to identify the functions of genes associated with OA progression, and changes in gene expression were confirmed using immunohistochemistry.

Results

Six hundred twenty‐one genes were associated with both osteophyte formation and cartilage damage in the STR/Ort joints. Genes involved in the development/function of connective tissue and in lipid metabolism were most significantly enriched and regulated during disease progression. Genes directly interacting with peroxisome proliferator–activated receptor α (PPARα)/PPARγ were down‐regulated, whereas those genes involved with connective tissue remodeling were up‐regulated during disease progression. Associations of down‐regulation of myotubularin‐related phosphatase 1 (a phosphoinositide 3‐phosphatase involved in lipid signaling) and up‐regulation of biglycan (a member of the small leucine‐rich protein family known to modulate osteoblast differentiation and matrix mineralization) with OA progression were confirmed by immunohistochemistry.

Conclusion

Since adipogenesis and osteogenesis are inversely related in the developing skeletal tissue, these results suggest that a shift in the differentiation of mesenchymal cells from adipogenesis toward osteogenesis is a component of the OA pathophysiologic processes occurring in the tibial plateau joints of STR/Ort mice.
Pattern of interleukin‐1β secretion in response to lipopolysaccharide and ATP before and after interleukin‐1 blockade in patients with CIAS1 mutations
Authors: Gattorno Marco , Tassi Sara , Carta Sonia , Delfino Laura , Ferlito Francesca , Pelagatti Maria Antonietta , D'Osualdo Andrea , Buoncompagni Antonella , Alpigiani Maria Giannina , Alessio Maria , Martini Alberto , Rubartelli Anna
Published: August 2007

Objective

To examine the synthesis, processing, and secretion of interleukin‐1β (IL‐1β), as well as the clinical and biologic effects of IL‐1 blockade, in patients with chronic infantile neurologic, cutaneous, articular (CINCA) syndrome and Muckle‐Wells syndrome (MWS), in an effort to understand the molecular mechanisms linking mutations of the CIAS1 gene and IL‐1β hypersecretion, and the underlying response to IL‐1 receptor antagonist (IL‐1Ra).

Methods

Six patients with CINCA syndrome or MWS were treated with IL‐1Ra and followed up longitudinally. Monocytes obtained from the patients and from 24 healthy donors were activated with lipopolysaccharide (LPS) for 3 hours, and intracellular and secreted IL‐1β levels were determined by Western blotting and enzyme‐linked immunosorbent assay before and after exposure to exogenous ATP.

Results

LPS‐induced IL‐1β secretion was markedly increased in monocytes from patients with CIAS1 mutations. However, unlike in healthy subjects, secretion of IL‐1β was not induced by exogenous ATP. Treatment with IL‐1Ra resulted in a dramatic clinical improvement, which was paralleled by an early and strong down‐regulation of LPS‐induced IL‐1β secretion by the patients' cells in vitro.

Conclusion

Our results showed that the requirements of ATP stimulation for IL‐1β release observed in healthy individuals are bypassed in patients bearing CIAS1 mutations. This indicates that cryopyrin is the direct target of ATP and that the mutations release the protein from the requirement of ATP for activation. In addition, the dramatic amelioration induced by IL‐1Ra treatment is at least partly due to the strong decrease in IL‐1β secretion that follows the first injections of the antagonist. These findings may have implications for other chronic inflammatory conditions characterized by increased IL‐1β.
Enhanced efficacy of regulatory T cell transfer against increasing resistance, by elevated Foxp3 expression induced in arthritic murine hosts
Authors: Ohata Junko , Miura Tomoko , Johnson Todd A. , Hori Shohei , Ziegler Steven F. , Kohsaka Hitoshi
Published: August 2007

Objective

To investigate the efficacy of type II collagen–reactive Foxp3‐expressing T cell transfer in suppressing collagen‐induced arthritis (CIA) in relation to disease progression.

Methods

CD3‐activated CD4 T cells were retrovirally transduced with the Foxp3 gene, and their in vitro suppressive activity on T cell proliferation was assessed for correlation with Foxp3 levels. To suppress CIA, Foxp3‐transduced T cells generated with type II collagen– or ovalbumin (OVA)–pulsed dendritic cells (DCs), which were fractionated by Foxp3 levels, were adoptively transferred to mice at various time points.

Results

The in vitro suppressive activity of Foxp3‐transduced cells correlated positively with Foxp3 levels. Type II collagen–reactive, but not OVA‐reactive, Foxp3‐transduced cells significantly suppressed CIA when they were transferred before immunization, and this suppression was accompanied by decreased anti–type II collagen antibody production. Larger cell numbers were required to suppress CIA when transfer occurred 20 days after immunization, indicating that hosts became resistant to suppression. Transfer of 1 × 105 Foxp3low cells had only a marginal effect on CIA suppression in immunized hosts, while transfer of Foxp3high cells at smaller doses significantly suppressed CIA. Transfer of 1 × 105 Foxp3high cells after establishment of arthritis attenuated disease progression but did not reverse joint swelling.

Conclusion

Resistance to Foxp3‐transduced T cells proceeded as CIA progressed, suggesting that late‐stage aggressive arthritis is more resistant to regulatory T cell transfer. An elevated expression level of Foxp3 in type II collagen–specific T cells improved their suppressive function in CIA. Thus, transfer of T cells expressing high levels of Foxp3 could be a strategy to overcome the induced resistance to regulatory T cell therapy.
Regulation of apoptosis in fibroblast‐like synoviocytes by the hypoxia‐induced Bcl‐2 family member Bcl‐2/adenovirus E1B 19‐kd protein–interacting protein 3
Authors: Kammouni Wafa , Wong Keng , Ma Guoping , Firestein Gary S. , Gibson Spencer B. , El‐Gabalawy Hani S.
Published: August 2007

Objective

Rheumatoid arthritis (RA) synovial hyperplasia is related in part to a resistance to apoptosis exhibited by fibroblast‐like synoviocytes (FLS). Since hypoxia is a regulator of apoptosis, and since RA synovium is hypoxic, we conducted this study to examine the effects of hypoxia on the Bcl‐2 pathway and the role this may play in regulating apoptosis in FLS.

Methods

Synovium samples from RA patients, osteoarthritis (OA) patients, and normal subjects were used for immunohistologic assessments and for generating FLS lines in vitro. FLS were stimulated under conditions of hypoxia (1% O2) and using 100 μM CoCl2 to simulate the effects of severe hypoxia. Changes in the gene expression profile of FLS were evaluated using microarrays and were confirmed by quantitative polymerase chain reaction (PCR). Changes in protein expression were detected by Western blotting. The effect of transient transfection with a BNIP3 plasmid on the apoptosis of FLS was evaluated in the presence and absence of cytokines.

Results

Gene expression profiling demonstrated that BNIP3 was unique among the BCL2 family, in that it was induced by hypoxia in FLS. Quantitative PCR indicated a 2–3‐fold induction of BNIP3 messenger RNA, and Western blotting showed a 3–5‐fold increase in the 30‐kd Bcl‐2/adenovirus E1B 19‐kd protein–interacting protein 3 (BNIP‐3) monomer. BNIP‐3 was widely expressed in RA synovium and was prominent in FLS from the lining layer. Overexpression of BNIP3 increased FLS apoptosis under hypoxic conditions, an effect that was inhibited by tumor necrosis factor α and interleukin‐1β.

Conclusion

The proapoptotic protein BNIP‐3 is induced in FLS by hypoxia and is widely expressed in RA synovium, but its proapoptotic effects may be inhibited in vivo by proinflammatory cytokines. Since overexpression of BNIP3 in FLS increases apoptosis, this may provide a novel approach for controlling synovial hyperplasia in RA.
Targeting of Gr‐1+,CCR2+ monocytes in collagen‐induced arthritis
Authors: Brühl Hilke , Cihak Josef , Plachý Jiří , Kunz‐Schughart Leoni , Niedermeier Marianne , Denzel Andrea , Rodriguez Gomez Manuel , Talke Yvonne , Luckow Bruno , Stangassinger Manfred , Mack Matthias
Published: August 2007

Objective

The chemokine receptor CCR2 is highly expressed on monocytes and considered a promising target for treatment of rheumatoid arthritis. However, blockade of CCR2 with a monoclonal antibody (mAb) during progression of collagen‐induced arthritis results in a massive aggravation of the disease. In this study we investigated why CCR2 antibodies have proinflammatory effects, how these effects can be avoided, and whether CCR2+ monocytes are useful targets in the treatment of arthritis.

Methods

Arthritis was induced in DBA/1 mice by immunization with type II collagen. Mice were treated with mAb against CCR2 (MC‐21), IgE, or isotype control antibodies at various time points. Activation of basophils and depletion of monocyte subsets were determined by fluorescence‐activated cell sorter analysis and enzyme‐linked immunosorbent assay.

Results

Crosslinkage of CCR2 activated basophils to release interleukin‐6 (IL‐6) and IL‐4. In vivo, IL‐6 release occurred only after exposure to high doses of MC‐21, whereas application of low doses of the mAb circumvented the release of IL‐6. Regardless of the dose level used, the antibody MC‐21 efficiently depleted Gr‐1+,CCR2+ monocytes from the synovial tissue, peripheral blood, and spleen of DBA/1 mice. Activation of basophils with high doses of MC‐21 or with antibodies against IgE resulted in a marked aggravation of collagen‐induced arthritis and an increased release of IL‐6. In contrast, low‐dose treatment with MC‐21 in this therapeutic setting had no effect on IL‐6 and led to marked improvement of arthritis.

Conclusion

These results show that depletion of CCR2+ monocytes may prove to be a therapeutic option in inflammatory arthritis, as long as the dose‐dependent proinflammatory effects of CCR2 mAb are taken into account.
Menopause hormonal therapy in women with systemic lupus erythematosus
Authors: Sánchez‐Guerrero Jorge , González‐Pérez Marisol , Durand‐Carbajal Marta , Lara‐Reyes Pilar , Jiménez‐Santana Luisa , Romero‐Díaz Juanita , Cravioto María‐del‐Carmen
Published: August 2007

Objective

To evaluate the effects of menopause hormonal therapy on disease activity in women with systemic lupus erythematosus (SLE).

Methods

We conducted a double‐blind, randomized clinical trial involving 106 women with SLE who were in the menopausal transition or in early or late postmenopause. Patients received a continuous‐sequential estrogen‐progestogen regimen (n = 52) or placebo (n = 54). Disease activity was assessed at baseline and at 1, 2, 3, 6, 9, 12, 15, 18, 21, and 24 months, according to the SLE Disease Activity Index (SLEDAI). The primary outcome measure was global disease activity, estimated by measuring the area under the SLEDAI curve. Secondary outcome measures included maximum SLEDAI score, change in SLEDAI score, incidence of lupus flares, median time to flare, medication use, and adverse events. Results were studied using intent‐to‐treat analysis.

Results

At baseline, demographic and disease characteristics were similar in both groups. Mean ± SD SLEDAI scores were 3.5 ± 3.3 and 3.1 ± 3.4 in the menopause hormonal therapy and placebo groups, respectively (P= 0.57). Disease activity remained mild and stable in both groups throughout the trial. There were no significant differences between the groups in global or maximum disease activity, incidence or probability of flares, or medication use. Median time to flare was 3 months in both groups. Thromboses occurred in 3 patients who received menopause hormonal therapy and in 1 patient who received placebo. One patient in each group died during the trial due to sepsis.

Conclusion

Menopause hormonal therapy did not alter disease activity during 2 years of treatment. However, an apparently increased risk of thrombosis seems to be a real threat in women with SLE who receive menopausal hormone therapy.
A Parametric Comparison of Diagnostic Accuracy with Three Ordinal Diagnostic Groups
Authors: Xiong Chengjie , van Belle Gerald , Miller J. Philip , Yan Yan , Gao Feng , Yu Kai , Morris John C.
Published: August 2007

Many medical diagnostic studies involve three ordinal diagnostic groups in which the diagnostic accuracy can be summarized by the volume or partial volume under a Receiver Operating Characteristic (ROC) surface. We study in this paper the statistical comparison of diagnostic accuracy from multiple diagnostic tests when three ordinal diagnostic groups are involved. Under the assumption that the multiple diagnostic tests follow a multivariate normal distribution within each diagnostic group, we provide the asymptotic variance and covariance for the maximum likelihood estimates of the volumes under the ROC surfaces from multiple diagnostic tests and propose statistical tests to test whether the diagnostic accuracy as measured by the volume under the ROC surface is the same for multiple diagnostic tests. We also propose a confidence interval estimate to the difference of two volumes under two ROC surfaces. Our approach depends crucially on the assumptions of normal distributions on diagnostic tests, which might not be robust when such assumptions are violated. Finally, we apply our proposed methodology to a real data set of 118 subjects to compare the diagnostic accuracy of early stage Alzheimer's disease (AD) from multiple neuropsychological tests. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sense of community, civic engagement and social well‐being in Italian adolescents
Authors: Albanesi Cinzia , Cicognani Elvira , Zani Bruna
Published: August 2007

This study investigates the relationship between sense of community, civic engagement and social well‐being in a sample of Italian adolescents. Participants were 14–19 year‐old high school students (N = 566) from two demographically distinct cities. Participants completed a questionnaire assessing sense of community, social well‐being (Keyes, 1998), involvement in structured group activities (group membership) and civic engagement. Results showed that involvement in formal groups is associated with increased civic involvement and increased sense of community. Sense of community predicts social well‐being and explains some of the association between civic engagement and social well‐being. Findings suggest that, to increase social well‐being, it is important to provide adolescents with more opportunities to experience a sense of belonging to the peers' group and promote prosocial behaviours in the community context. Copyright © 2007 John Wiley & Sons, Ltd.
Non‐Colinear Polyketide Biosynthesis in the Aureothin and Neoaureothin Pathways: An Evolutionary Perspective
Authors: Traitcheva Nelly , Jenke‐Kodama Holger , He Jing , Dittmann Elke , Hertweck Christian
Published: August 2007

Aureothin and neoaureothin (spectinabilin) represent rare nitroaryl‐substituted polyketide metabolites from Streptomyces thioluteus and Streptomyces orinoci, respectively, which only differ in the lengths of the polyene backbones. Cloning and sequencing of the 39 kb neoaureothin (nor) biosynthesis gene cluster and its comparison with the aureothin (aur) pathway genes revealed that both polyketide synthase (PKS) assembly lines are remarkably similar. In both cases the module architecture breaks with the principle of colinearity, as individual PKS modules are used in an iterative fashion. Parsimony and neighbour‐joining phylogenetic studies provided insights into the evolutionary process that led to the programming of these unusual type I PKS systems and to prediction of which modules act iteratively. The iterative function of the first module in the neoaureothin pathway, NorA, was confirmed by a successful cross‐complementation.
Branched KLVFF Tetramers Strongly Potentiate Inhibition of β‐Amyloid Aggregation
Authors: Chafekar Sidhartha M. , Malda Hinke , Merkx Maarten , Meijer E. W. , Viertl David , Lashuel Hilal A. , Baas Frank , Scheper Wiep
Published: August 2007

The key pathogenic event in the onset of Alzheimer's disease (AD) is the aggregation of β‐amyloid (Aβ) peptides into toxic aggregates. Molecules that interfere with this process might act as therapeutic agents for the treatment of AD. The amino acid residues 16–20 (KLVFF) are known to be essential for the aggregation of Aβ. In this study, we have used a first‐generation dendrimer as a scaffold for the multivalent display of the KLVFF peptide. The effect of four KLVFF peptides attached to the dendrimer (K4) on Aβ aggregation was compared to the effect of monomeric KLVFF (K1). Our data show that K4 very effectively inhibits the aggregation of low‐molecular‐weight and protofibrillar Aβ1–42 into fibrils, in a concentration‐dependent manner, and much more potently than K1. Moreover, we show that K4 can lead to the disassembly of existing aggregates. Our data lead us to propose that conjugates that bear multiple copies of KLVFF might be useful as therapeutic agents for the treatment of Alzheimer's disease.
Asymmetric Total Synthesis of (−)‐Indicol by a Carbene Cyclization–Cycloaddition Cascade Strategy
Authors: Lam Sze Kui , Chiu Pauline
Published: August 2007

The first total synthesis of a secodolastane, (−)‐indicol, has been accomplished. The key reaction is a rhodium(II)‐mediated carbene cyclization–cycloaddition cascade, by which the core bicyclo[5.4.0]undecane skeleton was assembled. In this one‐pot reaction, a domino series of transformations resulting in the construction of three σ bonds and three stereocenters was realized in good yield.
Regiodivergent Epoxide Opening: A Concept in Stereoselective Catalysis beyond Classical Kinetic Resolutions and Desymmetrizations
Authors: Gansäuer Andreas , Fan Chun‐An , Keller Florian , Karbaum Peter
Published: August 2007

An approach to highly regiodivergent epoxide openings (REOs) is presented. The very popular kinetic resolutions of epoxides and openings ofmeso‐epoxides constitute subclasses of such REOs. REOs are attractive for parallel resolutions, double asymmetric reactions of enantiomerically enriched epoxides, and for semisynthetic applications in the functionalization of natural products. They have been notoriously difficult to realize by means of SN2 mechanisms. Our titanocene‐catalyzed radical REO addresses this issue by decoupling epoxide opening and radical trapping and is firmly based on a mechanistic study of the reductive epoxide opening.
The High‐Pressure Form of Cadmium Vanadate, CdV2O6.
Authors: Belik Alexei A. , Mironov Andrei V. , Shpanchenko Roman V. , Takayama‐Muromachi Eiji
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Potassium Gallium Hydrogenphosphate Fluoride, K2Ga[H(HPO4)2]F2.
Authors: Filaretov Andrey , Schenk Kurt J. , Rusakov Dmitriy , Chapuis Gervais
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
EXAFS Investigation of U(VI), U(IV), and Th(IV) Sulfato Complexes in Aqueous Solution.
Authors: Hennig Christoph , Schmeide Katja , Brendler Vinzenz , Moll Henry , Tsushima Satoru , Scheinost Andreas C.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Solid‐State NMR Spectroscopic Study of Coordination Compounds of XeF2 with Metal Cations and the Crystal Structure of [Ba(XeF2)5][AsF6]2.
Authors: Gerken Michael , Hazendonk Paul , Iuga Adriana , Nieboer Jared , Tramsek Melita , Goreshnik Evgeny , Zemva Boris , Zheng Shaohui , Autschbach Jochen
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Low‐Temperature Crystallization of Eu‐Doped Red‐Emitting CaAlSiN3 from Alloy‐Derived Ammonometallates.
Authors: Li Jinwang , Watanabe Tomoaki , Wada Hiroshi , Setoyama Tohru , Yoshimura Masahiro
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Dinuclear Zinc‐Catalyzed Enantioselective Aza‐Henry Reaction.
Authors: Trost Barry M. , Lupton David W.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Efficient NO Equivalent for Activation of Molecular Oxygen and Its Applications in Transition‐Metal‐Free Catalytic Aerobic Alcohol Oxidation.
Authors: Xie Yi , Mo Weimin , Xu Dong , Shen Zhenlu , Sun Nan , Hu Baoxiang , Hu Xinquan
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Unprecedented Hydrogen Transfer from Water to Alkenes and Alkynes Mediated by TiIII and Late Transition Metals.
Authors: Campana Araceli G. , Estevez Rosa E. , Fuentes Noelia , Robles Rafael , Cuerva Juan M. , Bunuel Elena , Cardenas Diego , Oltra J. Enrique
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
N‐Substituted Imines by the Copper‐Catalyzed N‐Imination of Boronic Acids and Organostannanes with O‐Acyl Ketoximes.
Authors: Liu Songbai , Yu Ying , Liebeskind Lanny S.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of New NHC—Rhodium and Iridium Complexes Derived from 2,2′‐Diaminobiphenyl and Their Catalytic Activities Toward Hydrosilylation of Ketones.
Authors: Chen Tao , Liu Xu‐Guang , Shi Min
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Simple and Novel Eco‐Friendly Process for the One‐Pot Synthesis of Dithiocarbamates from Amines, Carbon Disulfide, and Epoxides.
Authors: Azizi Najmedin , Pourhasan Bahram , Aryanasab Fezzeh , Saidi Mohammad R.
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Alkyne as a Spectator Ligand for the Nickel‐Catalyzed Multicomponent Connection Reaction of Diphenylzinc, 1,3‐Butadiene, Aldehydes, and Amines.
Authors: Kimura Masanari , Tatsuyama Yasushi , Kojima Keisuke , Tamaru Yoshinao
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Cationic Rhodium(I)/Bisphosphane Complex‐Catalyzed Isomerization of Secondary Propargylic Alcohols to α,β‐Enones.
Authors: Tanaka Ken , Shoji Takeaki , Hirano Masao
Published: August 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.