bluuebunny/crossref_metadata_2025 huggingface dataset:
F 1 F O-ATPase Activity and ATP Dependence of Mitochondrial Energization in Proximal Tubules after Hypoxia/Reoxygenation
Authors: Feldkamp Thorsten , Kribben Andreas , Weinberg Joel M.
Published: April 2005

Isolated kidney proximal tubules subjected to hypoxia/reoxygenation (H/R) have incomplete recovery of mitochondrial membrane potential (ΔΨm) that can be improved, but not normalized, by ATP in permeabilized cells as measured by safranin O uptake. In these studies, the mechanisms for the decreased ΔΨm in the tubules after H/R are further investigated and impairment of the function of the mitochondrial

F

1

F

O-ATPase is assessed. Normoxic control tubules had a small ATP-dependent component to ΔΨm, but it required low micromolar levels of ATP, not the millimolar levels needed to support ΔΨm in tubules de-energized with rotenone or after H/R. Micromolar levels of ATP did not improve ΔΨm after either mild or severe H/R injury. The dependence of ΔΨm on millimolar levels of ATP after H/R decreased over time during reoxygenation. ATP hydrolysis by the oligomycin-sensitive, mitochondrial

F

1

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O-ATPase was well preserved after H/R as long as Mg2+ was available, indicating that function of both the

F

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F

O-ATPase and of the adenine nucleotide translocase, which delivers nucleotides to it, are largely intact. However, ATP hydrolysis by the ATPase did not restore ΔΨm as much as expected from the rate of ATP utilization. These findings, taken together with the observation that substrate-supported generation of ΔΨm is impaired despite intact electron transport, make it likely that uncoupling plays a major role in the mitochondrial dysfunction in proximal tubules during H/R.
Marginal Periodontium as a Potential Reservoir of Human Papillomavirus in Oral Mucosa
Authors: Hormia Marketta , Willberg Jaana , Ruokonen Hellevi , Syrjänen Stina
Published: April 2005

Background: Although human papillomaviruses (HPVs) are associated with a number of proliferative epithelial lesions including squamous cell malignancies, they can also be detected in the normal oral mucosa in 10% to 20% of the adult population. However, the point of entry and the site of replication of HPV in the oral cavity are not known. Since the gingival pocket is the only site in the oral mucosa where basal cells, known to be targets of HPV at other mucosal sites, are normally exposed to the environment, we hypothesized that this could be the site of latent HPV.

Methods: Gingival biopsies taken from 38 individuals with clinically diagnosed periodontal disease were examined. The presence of HPV DNA was studied by using nested PCR (polymerase chain reaction with MY09/MY11 and GP05+/GP06+ primers targeting the L1 region of HPV), followed by subsequent hybridization with a cocktail of 12 high‐risk HPV oligoprobes and in situ hybridization (ISH) with probes for HPV screening and the HPV subtype 16.

Results: In the present study, high‐risk HPV types were detected in 26% (8/31) of the gingival biopsies with PCR. By using in situ hybridization, the viral DNA was localized to the coronal part of the junctional epithelium in the gingival pocket.

Conclusions: The results suggest that the periodontal pocket might serve as a reservoir of HPVs in oral mucosa. While having important implications in understanding the HPV transmission, this observation does not rule out the possibility that HPV may be involved in the initiation of periodontal disease.J Periodontol 2005;76:358‐363.
Comparison of Human Mandibular Osteoblasts Grown on Two Commercially Available Titanium Implant Surfaces
Authors: Galli Carlo , Guizzardi Stefano , Passeri Giovanni , Martini Desiree' , Tinti Anna , Mauro Giovanni , Macaluso Guido Maria
Published: April 2005

Background: Surface characteristics play a major role in determining tissue response to implants and therefore their clinical outcome. The aim of the present study was to compare two commercially available titanium surfaces: plasma sprayed (TPS) and sand‐blasted, acid‐etched surface (SLA).

Methods: The surfaces were characterized by roughness testing, scanning electronic microscopy (SEM), Raman spectroscopy, and protein adsorption to determine their microtopographic and chemical properties. The effect of the surfaces on human mandibular osteoblasts was then studied in terms of cell morphology, adhesion, proliferation, and differentiation. Human osteoblasts from the mandible were cultured on these two surfaces and evaluated at 3, 6, 24, and 48 hours to determine cell attachment and morphology. Growth and differentiation kinetics were subsequently investigated by evaluating cell growth, alkaline phosphatase activity, osteocalcin and osteoprotegerin production at 7, 14, and 21 days.

Results: Although roughness was quite similar, the two surfaces presented strong differences in their topography, and cell morphology varied as a consequence. Osteoblasts on SLA appeared more elongated and spindle shaped than those on TPS, and their adhesion at 3 and 6 hours was weaker, but reached that of cells on TPS at hour 24. Cell proliferation was greater on SLA surfaces but differentiation parameters; i.e., alkaline phosphatase and osteocalcin, provided better results on TPS surfaces. Osteoprotegerin production was enhanced on TPS surfaces at days 14 and 21.

Conclusion: Although cells grown on both surfaces exhibited good adhesion capabilities, a well‐differentiated osteoblastic phenotype, and maintained a clear proliferation potential, our study suggests that plasma‐sprayed treatment offers a better performance than SLA by creating, at least in the early phases, better conditions for tissue healing. J Periodontol 2005;76:364‐372.
Implant Stability Measurements for Implants Placed at the Time of Extraction: A Cohort, Prospective Clinical Trial
Authors: Becker William , Sennerby Lars , Bedrossian Edwin , Becker Burton E. , Lucchini Jean Pierre
Published: April 2005

Background: Studies indicate that implants placed at the time of extraction have high success rates. Implants must be stable at the time of insertion. Presently there are no data indicating the degree of implant stability when implants are placed at the time of extraction. This study evaluated changes in stability of implants from implant placement to abutment connection utilizing resonance frequency analysis (RFA). The unit of measurement was the international stability quotient (ISQ).

Methods: Prior to treatment, patients were given medical history and dental evaluations. Periapical and panogram radiographs were taken. Fifty‐two patients requiring extraction of one or two teeth and implant placement immediately after extraction were enrolled in this study. Under conscious sedation and local anesthesia or local anesthesia alone, teeth were atraumatically removed and the extraction sockets were debrided. A total of 73 dental implants (57 in the maxilla, 16 in the mandible) were placed. Using a onestage approach, all implants were placed within the patient's alveolar envelope and were never placed directly into extraction sockets. All implants were placed into contained extraction sites. Bone augmentation procedures were not performed. After implant insertion, the RFA electronic transducer was attached to the head of the implant with the retaining screw. The device was attached to a computer designed to register RFA scores in ISQ units. RFA measurements were taken at implant placement and abutment connection. Bone qualities, quantity, implant length and width as well as site of placement were recorded.

Results: The average interval between implant insertion and abutment connection was 5.6 months (SD 2.05). Two implants were lost between implant insertion and 1 year. At 2 to 3 years, the cumulative survival was 97.2%. Resonance frequency measurements at implant placement showed a mean primary stability of 62.0 (SE 1.1; range 43 to 83 ISQ) and a mean secondary stability after 1 year of 64.0 (SE 1.2; range 40 to 98 ISQ) for all implants. The increase was marginally significant (generalized estimating equation z‐statistic = 1.79; P value = 0.07).

Conclusions: Implants placed at the time of extraction and inserted into native bone and not directly into extractions sockets have a high degree of initial stability as evidenced by RFA measurements. Implants with initial high ISQ levels revealed a slight drop in levels over time, while implants with levels lower than 60 had increases in levels between implant insertion and abutment connection. At 2 to 3 years the cumulative survival rate was 97.2%. J Periodontol 2005;76:391‐397.
Is Periodontitis Associated With Oral Neoplasms?
Authors: Tezal Mine , Grossi Sara G. , Genco Robert J.
Published: April 2005

Background: Infections have been suggested in the etiology of oral cancer. This study was carried out to evaluate the effect of periodontal disease on oral soft tissue lesions.

Methods: A total of 13,798 subjects aged 20 years and older with at least six natural teeth and who participated in the Third National Health and Nutrition Examination Survey (NHANES III) constituted the study population. Severity of periodontal disease was represented by clinical attachment loss (CAL) and was dichotomized as ≤1.5 mm versus >1.5 mm according to its distributions in the NHANES III population. Three separate dependent variables were employed: 1) tumor (non‐specific); 2) precancerous lesions; and 3) any oral soft tissue lesion. The independent effect of CAL on those three dependent variables was assessed by weighted multiple logistic regression analyses adjusting for the effects of number of filled teeth, number of decayed teeth, presence of prosthesis, age, gender, race/ethnicity, education, tobacco, alcohol, occupational hazard, and interaction term “tobacco*occupational hazard.” Odds ratios (OR) and their 95% confidence intervals (CI) were calculated.

Results: CAL was not related to the presence of any soft tissue lesion (OR = 1.09, 95% CI: 0.91 to 1.31), but was specifically related to the presence of tumor (OR = 4.57, 95% CI: 2.25 to 9.30) and precancerous lesions (OR = 1.55, 95% CI: 1.06 to 2.27).

Conclusion: This study suggests associations between periodontal disease and the risk for precancerous lesions and tumors generating a hypothesis about a possible relationship between periodontal disease and oral neoplasms. Prospective or well‐designed case‐control studies with histologically confirmed incident oral cancer cases are necessary to confirm this relationship. J Periodontol 2005;76:406‐410.
Prevalence of Maxillary Sinus Disease and Abnormalities in Patients Scheduled for Sinus Lift Procedures
Authors: Beaumont Christian , Zafiropoulos Gregory‐George , Rohmann Kay , Tatakis Dimitris N.
Published: April 2005

Background: The purpose of the present study was to determine the prevalence of sinus disease and abnormalities among patients scheduled to undergo direct sinus augmentation.

Methods: Forty‐five patients attending a private periodontal practice and consecutively treatment planned for sinus augmentation were referred for otorhinolaryngologic evaluation, which included a medical history and radiographic (computed tomography), clinical, and endoscopic examinations. Pathological findings were recorded and otorhinolaryngologic treatment was provided. Six months later the sinus augmentation procedure was performed and followed by postoperative evaluations for 4 to 6 months.

Results: Of the 45 subjects, 98% (44) were diagnosed with chronic periodontitis, 51% were smokers, and 27% reported a history of symptoms indicative of sinus disease. Eighteen subjects were diagnosed with sinus disease and/or abnormalities. The diagnosed conditions included chronic sinusitis, sinus cysts, nasal septum deviation, and ostium stenosis. No significant differences in age, gender, or smoking status between patients with and without sinus conditions were found (P >0.05). There was a significant association between history of symptoms and diagnosis of sinus conditions (P <0.0001). Three subjects (one treated for preoperative sinus conditions) experienced notable intra‐ or postoperative complications related to the sinus augmentation procedure.

Conclusions: The results indicate that, in a population of patients with chronic periodontitis, presence of sinus conditions is strongly associated with a history of indicative symptoms and is independent of age, gender, and smoking status. The results reinforce the importance of careful detailed history taking and thorough clinical and radiographic evaluation prior to performing sinus augmentation. J Periodontol 2005;76:461‐467.
Nanomanipulation by Atomic Force Microscopy
Authors: Rubio‐Sierra F. J. , Heckl W. M. , Stark R. W.
Published: April 2005

The linking of our macroscopic world to the nanoscopic world of single molecules, nanoparticles and functional nanostructures is a technological challenge. Researchers in nanobiotechnology face the questions “How extract and analyze a single nano‐object?”, “How to pick and place nano‐objects?” and “How to prototype a functional nanostructure?”. Here, nanomanipulation by an atomic force microscope (AFM) in combination with optical manipulation by a microbeam laser offers a practicable solution. In such a system, the AFM can be operated as a nanorobot for manipulation purposes allowing for nanometer precision. A contact free manipulation is achieved by the laser microbeam.
SiC/Si3N4 Nano‐Composites: Crystallization Kinetics of Precursor‐derived Amorphous Ceramic Solids of Type Si‐C‐N
Authors: Schmidt H. , Borchardt G.
Published: April 2005

The crystallization kinetics of precursor‐derived amorphous Si‐C‐N ceramics is investigated by X‐ray diffractometry. Annealing leads to crystallization where composites of nano‐crystalline SiC and micro‐crystalline Si3N4 are formed. Both crystalline phases are developed during a simultaneous diffusion controlled nucleation and growth process. The rate constants of crystallization obey an Arrhenius behaviour with a very high activation enthalpy, which is the reason for a relatively uniform temperature stability of the amorphous state.
Supramolecular Microcontact Printing and Dip‐Pen Nanolithography on Molecular Printboards
Authors: Bruinink Christiaan M. , Nijhuis Christian A. , Péter Mária , Dordi Barbara , Crespo‐Biel Olga , Auletta Tommaso , Mulder Alart , Schönherr Holger , Vancso G. Julius , Huskens Jurriaan , Reinhoudt David N.
Published: April 2005

The transfer of functional molecules onto self‐assembled monolayers (SAMs) by means of soft and scanning‐probe lithographic techniques—microcontact printing (μCP) and dip‐pen nanolithography (DPN), respectively—and the stability of the molecular patterns during competitive rinsing conditions were examined. A series of guests with different valencies were transferred onto β‐cyclodextrin‐ (β‐CD‐) terminated SAMs and onto reference hydroxy‐terminated SAMs. Although physical contact was sufficient to generate patterns on both types of SAMs, only molecular patterns of multivalent guests transferred onto the β‐CD SAMs were stable under the rinsing conditions that caused the removal of the same guests from the reference SAMs. The formation of kinetically stable molecular patterns by supramolecular DPN with a lateral resolution of 60 nm exemplifies the use of β‐CD‐terminated SAMs as molecular printboards for the selective immobilization of printboard‐compatible guests on the nanometer scale through the use of specific, multivalent supramolecular interactions. Electroless deposition of copper on the printboard was shown to occur selectively on the areas patterned with dendrimer‐stabilized gold nanoparticles.
Synthesis and Modification of Terrylenediimides as High‐Performance Fluorescent Dyes
Authors: Nolde Fabian , Qu Jianqiang , Kohl Christopher , Pschirer Neil G. , Reuther Erik , Müllen Klaus
Published: April 2005

Two new synthetic approaches to terrylenediimides, highly photostable fluorescent dyes, are described. For the first time terrylenediimide has been synthesised in a straightforward procedure that makes large quantities available. The second route includes an efficient cross‐coupling reaction followed by a cyclodehydrogenation. Monofunctionalisation of the imide structure allows terrylenediimides now to be coupled with a variety of compounds, for example, by Suzuki cross‐coupling, which can lead to an array of terrylenediimides with new functional groups such as hydroxy, amino, or carboxy groups needed to link up with other molecules. The functionalisation in the bay region is used to tune the properties of terrylenediimides and extend the range of applications, for example, by introducing water solubility. These tetrasubstituted terrylenediimides offer, depending on the substituents used, exciting features such as good solubility in common organic solvents, water solubility, or NIR absorption.
An Electrophilic Cleavage Procedure for the Asymmetric Dihydroxylation: Direct Enantioselective Synthesis of Cyclic Boronic Esters from Olefins
Authors: Hövelmann Claas H. , Muñiz Kilian
Published: April 2005

A variation within the osmium‐catalysed asymmetric dihydroxylation (AD) of olefins is described that yields cyclic boronic esters from olefins in a straight‐forward manner. This process represents the first real product alteration in asymmetric dihydroxylation, since all previous protocols lead to free diols exclusively. A protocol based on the Sharpless AD conditions (for enantioselective oxidation of prochiral olefins) was developed that gives cyclic boronic esters with excellent enantiomeric excesses (ee's). Some of the ee's are higher than those reported for conventional AD. The unprecedented role of phenyl boronic acid on the course of the AD reaction was investigated in detail. PhB(OH)2 does not interfere with the chiral ligand, leaving the enantioselective step of olefin oxidation intact. The main role of the boronic acids—apart from protecting the diol products against potential overoxidation—relies on removing the diol entity in an electrophilic cleavage, which is in contrast to the conventional hydrolytic cleavage of the AD protocols. Thus, a mechanistically new cleavage for enantioselective dihydroxylation reactions is introduced within the present work.
The organization of projections from the amygdala to visual cortical areas TE and V1 in the macaque monkey
Authors: Freese Jennifer L. , Amaral David G.
Published: April 2005

We examined the organization of amygdaloid projections to visual cortical areas TE and V1 by injecting anterograde tracers into the amygdaloid complex ofMacaca fascicularismonkeys. The magnocellular and intermediate divisions of the basal nucleus of the amygdala gave rise to heavy projections to both superficial layers (border of I/II) and deep layers (V/VI) throughout the rostrocaudal extent of area TE. Although most of the injections led to heavier fiber and terminal labeling in the superficial layers of area TE, the most dorsal injections in the basal nucleus produced denser labeled fibers and terminals in the deep layers of area TE. Area V1 received projections primarily from the magnocellular division of the basal nucleus, and these terminated exclusively in the superficial layers. As in area TE, projections from the amygdala to area V1 were distributed throughout its rostrocaudal and transverse extents. Labeled axons demonstrated 11.67 varicosities/100 μm on average in the superficial layers of area TE and 8.74 varicosities/100 μm in the deep layers. In area V1 we observed 8.24 varicosities/100 μm. Using confocal microscopy, we determined that at least 55% of the tracer‐labeled varicosities in areas TE and V1 colocalized synaptophysin, a marker of synaptic vesicles, indicating that they are probably synaptic boutons. Electron microscopic examination of a sample of these varicosities confirmed that labeled boutons formed synapses in areas TE and V1. These feedback‐like projections from the amygdala have the potential of modulating key areas of the visual processing system. J. Comp. Neurol. 486:295–317, 2005. © 2005 Wiley‐Liss, Inc.
Double bouquet cell in the human cerebral cortex and a comparison with other mammals
Authors: Yáñez Inmaculada Ballesteros , Muñoz Alberto , Contreras Julio , Gonzalez Juncal , Rodriguez‐Veiga Elisia , DeFelipe Javier
Published: April 2005

Double bouquet cells (DBCs) are neocortical γ‐aminobutyric acid (GABA)ergic interneurons characterized by the vertical bundling of its axon, which are generally termed “bundles” or “horse‐tails.” Using immunocytochemistry for the calcium binding protein calbindin, we have analyzed the morphology, density, and distribution of DBC horse‐tails in different cortical areas of the human cortex (Brodmann's areas 10, 4, 3b, 22, 18, and 17). Although DBC horse‐tails were very numerous and regularly distributed in all cortical areas, variations were observed both in terms of morphology and density. We distinguished two major classes of DBC horse‐tails: the thicker complex type (type I) that had more axon collaterals; and the simple type (type II). The density of DBC horse‐tails was significantly higher in areas 17, 18, 22, and 4 than in areas 3b and 10. Moreover, the proportion of type I and type II DBC horse‐tails varied in the cortical areas studied. We also examined the distribution of DBC horse‐tails in frontal, parietal, and occipital areas of different mammalian species. We found DBCs to be present in carnivores but not in rodents, lagomorphs, or artiodactyls. In carnivores, relatively few DBC horse‐tails can be identified and they were generally found in the occipital cortex. Therefore, there is significant variability in the morphology and distribution of DBC horse‐tails in different species and cortical areas. We conclude that, although these interneurons may be an important element in the organization of cortical microcolumns in primates, this is not the case in other mammalian species. J. Comp. Neurol. 486:344–360, 2005. © 2005 Wiley‐Liss, Inc.
Nerve growth factor‐mediated collateral sprouting of central sensory axons into deafferentated regions of the dorsal horn is enhanced in the absence of the p75 neurotrophin receptor
Authors: Hannila Sari S. , Kawaja Michael D.
Published: April 2005

This study examined the growth capacity of nerve growth factor (NGF)‐responsive dorsal root ganglion (DRG) central processes using mice of the following genotypes: wildtype, p75 neurotrophin receptor (p75NTR) exon III null mutant, NGF transgenic, and NGF transgenic with p75NTR exon III null mutation (NGF/p75‐/‐). In wildtype and p75NTR exon III null mutant mice calcitonin gene‐related peptide (CGRP) immunoreactivity in the dorsal horn is dramatically reduced at both 3 and 28 days after rhizotomy. NGF transgenic and NGF/p75‐/‐ mice also display reduced CGRP immunoreactivity 3 days after rhizotomy, but by postsurgical day 28 significant increases in the density of CGRP‐positive axons are observed in the injured dorsal horns of these mice. Interestingly, NGF/p75‐/‐ mice displayed significantly more new axonal growth when compared to NGF transgenic mice expressing full‐length p75NTR. Immunohistochemical and ultrastructural analyses revealed that this axonal growth is not the result of regeneration but rather injury‐induced sprouting by intact DRG central processes into the lesion site. This collateral growth is restricted to deafferentated areas of the dorsal horn, and we therefore propose that this is an example of compensatory sprouting by NGF‐sensitive axons in the spinal cord, a response that is enhanced in the absence of NGF binding to p75NTR. J. Comp. Neurol. 486:331–343, 2005. © 2005 Wiley‐Liss, Inc.
Crystal Structure and Magnetism of the Double Perovskite Sr3Fe2MoO9:A Neutron Diffraction Study
Authors: Viola María C. , Alonso José A. , Pedregosa José C. , Carbonio Raul E.
Published: April 2005

The Sr3Fe2MoO9 double perovskite has been prepared in polycrystalline form by heat treatment, in air, from previously decomposed citrate precursors. This material has been studied by X‐ray (XRD), neutron powder diffraction (NPD) and magnetic measurements. At room temperature, the crystal structure is tetragonal, space group I4/m, with a = b = 5.5608(2) Å, c = 7.8471(4) Å. It is convenient to write the crystallographic formula as Sr2Fe(Fe1/3Mo2/3)O6, according to the usual nomenclature for double perovskites A2B'B''O6. The structure contains alternating FeO6 and (Fe,Mo)O6 octahedra, tilted by 3.9° in the basal ab plane. Magnetic measurements indicate a weak ferromagnetic behavior below TC = 280 K. Ideally, the Sr3Fe2MoO9 double perovskite only contains Fe3+ and Mo6+ cations, in such a way that superexchange interactions between neighboring Fe3+ spins are the only nominal mechanism accounting for the magnetism of this material. Our main finding is that this intrinsically “disordered” sample, containing a random distribution of Fe and Mo at the B'' positions, exhibits a strong magnetic scattering on the low‐angle Bragg positions, originating from naturally occurring groups of Fe3+ cations in which strong antiferromagnetic (AFM) Fe–O–Fe superexchange interactions are promoted, similar to those existing in the LaFeO3 perovskite. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cobalt(II) Complexes with Substituted Salen‐Type Ligands and Their Dioxygen Affinity in N,N‐Dimethylformamide at Various Temperatures
Authors: Huber Andreas , Müller Lutz , Elias Horst , Klement Robert , Valko Marian
Published: April 2005

Several unsymmetrically substituted salen‐type cobalt(II) Schiff‐base complexes CoL [H2L = 1,6‐bis(2‐hydroxyphenyl)‐3,3‐dimethyl‐2,5‐diaza‐1,5‐hexadiene (1); 1,6‐bis(2‐hydroxyphenyl)‐3,3‐dimethyl‐2,5‐diaza‐1,5‐heptadiene (2); 1‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐6‐(2‐hydroxyphen‐yl)‐3,3‐dimethyl‐2,5‐diaza‐1,5‐heptadiene (3); 1‐(2‐hydroxyphenyl)‐6‐methyl‐2,5‐diaza‐1,5‐nonadien‐8‐one (4); 1‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐6‐methyl‐2,5‐di‐aza‐1,5‐nonadien‐8‐one (5); 1‐(2‐hydroxyphenyl)‐3,3,6‐trimethyl‐2,5‐diaza‐1,5‐nonadien‐8‐one (6); 1‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐3,3,6‐trimethyl‐2,5‐diaza‐1,5‐nonadien‐8‐one (7)] were prepared and characterized by their UV/Vis absorption spectra, magnetic moments, and oxidation potentials. Except for complex 4 (irreversible oxidation with t½ ≈ 3 h), complexes 1–3 and 5–7 are remarkably resistant against irreversible auto‐oxidation in air‐saturated N,N‐dimethylformamide (DMF) at ambient temperature. To characterize the Lewis acidity of the cobalt center in 1–7, the equilibrium constant Kpy was determined for monoadduct formation with pyridine (CoL + pyCoL·py). An O2‐sensitive optode was used to determine the Henry constant, KH, for the system O2/DMF in the temperature range 298–228 K. The formation of 1:1 adducts of complexes 1–7 with O2 in DMF, as characterized by the equilibrium constant K, was followed spectrophotometrically in the temperature range 298–228 K. The parameters ΔHo, ΔSo, and K are reported. At 298 K, K ranges from 21.9 M–1 (5) to 155 M–1 (7). The overall spectroscopic information, including EPR spectra obtained with frozen solutions of 3 and 7 in O2‐saturated DMF, confirm that the 1:1 adducts CoL·O2 are cobalt(III) superoxo compounds. The symmetrically substituted salen complex8 [H2L = 1,6‐bis(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐3,3,4,4‐tetramethyl‐2,5‐diaza‐1,5‐hexadiene in 8] is shown to catalyze the oxidation of triphenylphosphane and 2,6‐di‐tert‐butylphenol by O2 in DMF at ambient temperature. The correlation of the data obtained for K, Kpy, and the oxidation potential E½ is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Crystallographic Studies of a Molybdenum‐Rich Diarsenotungstate and Reaction of FeIII with Its Isomerically Pureα1‐ and α2‐Monolacunary Derivatives
Authors: Mbomekalle Israel M. , Wei Lu Yu , Keita Bineta , Nadjo Louis , Neiwert Wade A. , Hardcastle Kenneth I. , Hill Craig L. , Anderson Travis M.
Published: April 2005

An isomerically pure form of the molybdenum‐richpolytungstate, [α1‐As2Mo5W12O61]10–, was prepared by adding 5 equivalents of MoVI to [α‐H2As2W12O48]12–, in thepresence of Li+. The α2‐isomer, [α2‐As2Mo5W12O61]10–, was prepared by mild alkaline (KHCO3) degradation of[α‐As2Mo6W12O62]6–. Both [α1‐As2Mo5W12O61]10– and [α2‐As2Mo5W12O61]10– react with FeIII in aqueous solution to give [α1‐As2(FeOH2)Mo5W12O61]7– (1) and [α2‐As2(FeOH2)Mo5W12O61]7– (2), respectively. The parent complex, [α‐As2Mo6W12O62]6–, was characterized by X‐ray crystallography as a mixed potassium‐sodium salt [a = 12.8412(17) Å, b = 14.8145(19) Å, c = 19.913(3) Å, α = 70.058°, β = 81.055(5)°, γ = 64,495°, triclinic, P, R1 = 4.99 % based on 9709 reflections]. All of the complexes were characterized by infrared spectroscopy, cyclic voltammetry, and elemental analyses. 183W NMR studies confirm that 1 and 2 are isomerically pure compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Amplitude modulated multipulse PPM for bandwidth‐limited optical systems
Authors: Haddad Bassel , Bross Shraga I.
Published: April 2005

Optical direct‐detection systems have been considered before for high‐speed intersatellite links. In this paper, we consider a three‐level amplitude modulated multipulse pulse‐position modulation (PPM) for use in bandwidth limited direct detection optical systems. Specifically, we investigate the capacity, cutoff rate and error probability of this modulation scheme. This facilitates the evaluation of the bandwidth efficiency of the proposed modulation as compared to regular multipulse PPM, which delivers the same throughput and detection quality under the same average‐power constraint. Copyright © 2005 AEIT.
Differences in nuclear positioning of 1q12 pericentric heterochromatin in normal and tumor B lymphocytes with 1q rearrangements
Authors: Barki‐Celli Leila , Lefebvre Christine , Le Baccon Patricia , Nadeau Gwenael , Bonnefoix Thierry , Usson Yves , Vourc'h Claire , Khochbin Saadi , Leroux Dominique , Callanan Mary
Published: April 2005

The frequent rearrangement of chromosome band 1q12 constitutive heterochromatin in hematologic malignancies suggests that this rearrangement plays an important pathogenetic role in these diseases. The oncogenic mechanisms linked to 1q12 heterochromatin are unknown. Constitutive heterochromatin can epigenetically regulate gene function through the formation of transcriptional‐silencing compartments. Thus, as a first step toward understanding whether 1q12 rearrangements might compromise such activity in tumor cells, we investigated the 3‐D organization of the 1q12 heterochromatin domain (1q12HcD) in normal and tumor B lymphocytes. Strikingly, in normal B cells, we showed that the 1q12HcD dynamically organizes to the nuclear periphery in response to B‐cell receptor engagement. Specifically, we observed an almost twofold increase in 1q12Hc domains at the extreme nuclear periphery in activated versus resting B lymphocytes. Remarkably, 1q12Hc organization was noticeably altered in tumor cells that showed structural alterations of 1q12; the 1q12Hc domains were significantly displaced from the extreme nuclear periphery compared to normal activated B lymphocytes (P > 0.0001), although overall peripheral localization was maintained. In a case in which there was a translocation of IGL enhancer to 1q, the altered nuclear positioning of the 1q12HcD was even more pronounced (5% of the 1q12Hc domains at the nuclear periphery compared to 20% in other lymphoma lines), and we were able to mimic this effect in two additional B‐cell tumor lines by treatment with trichostatin A, a histone deacetylase (HDAC) inhibitor. Taken together, these results point to the 1q12HcD having a specific, nonrandom, and regulated peripheral organization in B lymphocytes. This organization is significantly disrupted in lymphoma cells harboring 1q rearrangements. © 2005 Wiley‐Liss, Inc.
Multiple roles for MMPs and TIMPs in cerebral ischemia
Authors: Cunningham Lee Anna , Wetzel Monica , Rosenberg Gary A.
Published: April 2005

Matrix metalloproteinases (MMPs) are matrix‐degrading enzymes involved in diverse homeostatic and pathological processes. Several MMPs are expressed within the CNS and serve important normal and pathological functions during development and adulthood. An early and major pathological effect of MMP activity after cerebral ischemia is opening of the blood‐brain barrier (BBB). More recent work demonstrates emerging roles for MMPs and their natural inhibitors, tissue inhibitors of metalloproteinases (TIMPs), in the regulation of neuronal cell death. In addition, MMPs and TIMPs are likely to play important roles during the repair phases of cerebral ischemia, particularly during angiogenesis and reestablishment of cerebral blood flow. This review attempts to elucidate how MMPs and TIMPs may provide detrimental or beneficial actions during the injury and repair processes after cerebral ischemia. These processes will have important implications for therapies using MMP inhibitors in stroke. © 2005 Wiley‐Liss, Inc.
Astrocyte activation and reactive gliosis
Authors: Pekny Milos , Nilsson Michael
Published: April 2005

Astrocytes become activated (reactive) in response to many CNS pathologies, such as stroke, trauma, growth of a tumor, or neurodegenerative disease. The process of astrocyte activation remains rather enigmatic and results in so‐called “reactive gliosis,” a reaction with specific structural and functional characteristics. In stroke or in CNS trauma, the lesion itself, the ischemic environment, disrupted blood‐brain barrier, the inflammatory response, as well as in metabolic, excitotoxic, and in some cases oxidative crises—all affect the extent and quality of reactive gliosis. The fact that astrocytes function as a syncytium of interconnected cells both in health and in disease, rather than as individual cells, adds yet another dimension to this picture. This review focuses on several aspects of astrocyte activation and reactive gliosis and discusses its possible roles in the CNS trauma and ischemia. Particular emphasis is placed on the lessons learnt from mouse genetic models in which the absence of intermediate filament proteins in astrocytes leads to attenuation of reactive gliosis with distinct pathophysiological and clinical consequences. © 2005 Wiley‐Liss, Inc.
Microglia as potential contributors to motor neuron injury in amyotrophic lateral sclerosis
Authors: Sargsyan Siranush A. , Monk Peter N. , Shaw Pamela J.
Published: April 2005

The central nervous system (CNS) is equipped with a variety of cell types, all of which are assigned particular roles during the development, maintenance, function and repair of neural tissue. One glial cell type, microglia, deserves particular attention, as its role in the healthy or injured CNS is incompletely understood. Evidence exists for both regenerative and degenerative functions of these glial cells during neuronal injury. This review integrates the current knowledge of the role of microglia in an adult‐onset neurodegenerative disease, amyotrophic lateral sclerosis (ALS), and pays particular attention to the possible mechanisms of initiation and propagation of neuronal damage during disease onset and progression. Microglial cell properties, behavior and detected inflammatory reactions during the course of the disease are described. The neuroinflammatory changes that occur in a mouse model of ALS are summarized. The understanding of microglial function in the healthy and injured CNS could offer better diagnostic as well as therapeutic approaches for prevention, retardation, or repair of neural tissue degeneration. © 2005 Wiley‐Liss, Inc.
Cross‐cultural effect on the brain revisited: Universal structures plus writing system variation
Authors: Bolger Donald J. , Perfetti Charles A. , Schneider Walter
Published: April 2005

Recognizing printed words requires the mapping of graphic forms, which vary with writing systems, to linguistic forms, which vary with languages. Using a newly developed meta‐analytic approach, aggregated Gaussian‐estimated sources (AGES; Chein et al. [2002]: Psychol Behav 77:635–639), we examined the neuroimaging results for word reading within and across writing systems and languages. To find commonalities, we compiled 25 studies in English and other Western European languages that use an alphabetic writing system, 9 studies of native Chinese reading, 5 studies of Japanese Kana (syllabic) reading, and 4 studies of Kanji (morpho‐syllabic) reading. Using the AGES approach, we created meta‐images within each writing system, isolated reliable foci of activation, and compared findings across writing systems and languages. The results suggest that these writing systems utilize a common network of regions in word processing. Writing systems engage largely the same systems in terms of gross cortical regions, but localization within those regions suggests differences across writing systems. In particular, the region known as the visual word form area (VWFA) shows strikingly consistent localization across tasks and across writing systems. This region in the left mid‐fusiform gyrus is critical to word recognition across writing systems and languages. Hum Brain Mapp 25:92–104, 2005. © 2005 Wiley‐Liss, Inc.
Involvement of the inferior frontal junction in cognitive control: Meta‐analyses of switching and Stroop studies
Authors: Derrfuss Jan , Brass Marcel , Neumann Jane , von Cramon D. Yves
Published: April 2005

There is growing evidence that a specific region in the posterior frontolateral cortex is involved intimately in cognitive control processes. This region, located in the vicinity of the junction of the inferior frontal sulcus and the inferior precentral sulcus, was termed the inferior frontal junction (IFJ). The IFJ was shown to be involved in the updating of task representations and to be activated commonly in a within‐subject investigation of a task‐switching paradigm, the Stroop task, and a verbal n‐back task. Here, we investigate the involvement of the IFJ in cognitive control by employing a meta‐analytic approach. Two quantitative meta‐analyses of functional magnetic resonance imaging (fMRI) studies were conducted. One meta‐analysis included frontal activations from task‐switching, set‐shifting, and stimulus–response (S–R) reversal studies, the other included frontal activations from color–word Stroop studies. Results showed highly significant clustering of activations in the IFJ in both analyses. These results provide strong evidence for the consistent involvement of the IFJ in both switching and Stroop paradigms. Furthermore, they support our concept of areal specialization in the frontolateral cortex, which posits that it is not only the middorsolateral part that plays an important role in cognitive control, but also the IFJ. Finally, our results demonstrate how quantitative meta‐analyses can be used to test hypotheses about the involvement of specific brain regions in cognitive control. Hum Brain Mapp 25:22–34, 2005. © 2005 Wiley‐Liss, Inc.
Meta‐analyses of object naming: Effect of baseline
Authors: Price Cathy J. , Devlin Joseph T. , Moore Caroline J. , Morton Christopher , Laird Angela R.
Published: April 2005

The neural systems sustaining object naming were examined using the activation likelihood estimation (ALE) meta‐analysis approach on the results of 16 previously published studies. The activation task in each study required subjects to name pictures of objects or animals, but the baseline tasks varied. Separate meta‐analyses were carried out on studies that used: (1) high‐level baselines to control for speech processing and visual input; and (2) low‐level baselines that did not control for speech or complex visual processing. The results of the two meta‐analyses were then compared directly, revealing a double dissociation in the activation pattern for studies using high and low baselines. To interpret the differential activations, we report two new functional imaging experiments. The aim of the first was to characterize activation differences associated with visual stimuli that are typically used in baseline conditions (complex visual features, simple structures, or fixation). The aim of the second was to classify object‐naming regions in terms of whether they were engaged preferentially by semantic or phonological processes. The results reveal a remarkably precise correspondence between the areas identified by the meta‐analyses as affected differentially by baseline and the areas that are affected differentially by non‐object structure, semantics or phonology. As expected, high‐level baselines reduced object‐naming activation in areas associated with the processing of complex visual features and speech production. In addition, high‐level baselines increased sensitivity to activation in areas associated with semantic processing, visual‐speech integration and response selection. For example, activation in the anterior temporal areas that neuropsychological studies have associated with semantic processing was more strongly activated in the context of high‐level baselines. These results therefore have implications for understanding the convergence of functional imaging and neuropsychological findings. Hum Brain Mapp 25:70–82, 2005. © 2005 Wiley‐Liss, Inc.
ALE meta‐analysis: Controlling the false discovery rate and performing statistical contrasts
Authors: Laird Angela R. , Fox P. Mickle , Price Cathy J. , Glahn David C. , Uecker Angela M. , Lancaster Jack L. , Turkeltaub Peter E. , Kochunov Peter , Fox Peter T.
Published: April 2005

Activation likelihood estimation (ALE) has greatly advanced voxel‐based meta‐analysis research in the field of functional neuroimaging. We present two improvements to the ALE method. First, we evaluate the feasibility of two techniques for correcting for multiple comparisons: the single threshold test and a procedure that controls the false discovery rate (FDR). To test these techniques, foci from four different topics within the literature were analyzed: overt speech in stuttering subjects, the color‐word Stroop task, picture‐naming tasks, and painful stimulation. In addition, the performance of each thresholding method was tested on randomly generated foci. We found that the FDR method more effectively controls the rate of false positives in meta‐analyses of small or large numbers of foci. Second, we propose a technique for making statistical comparisons of ALE meta‐analyses and investigate its efficacy on different groups of foci divided by task or response type and random groups of similarly obtained foci. We then give an example of how comparisons of this sort may lead to advanced designs in future meta‐analytic research. Hum Brain Mapp 25:155–164, 2005. © 2005 Wiley‐Liss, Inc.
Cerebellum and auditory function: An ALE meta‐analysis of functional neuroimaging studies
Authors: Petacchi Augusto , Laird Angela R. , Fox Peter T. , Bower James M.
Published: April 2005

Over the past two decades neuroimaging data have accumulated showing that the cerebellum, traditionally viewed only as a motor structure, is also active in a wide variety of sensory and cognitive tasks. We have proposed that instead of explicit involvement in any particular motor, sensory, or cognitive task, the cerebellum performs a much more fundamental computation involving the active acquisition of sensory data. We carried out an activation likelihood estimate (ALE) meta‐analysis to determine whether neuroimaging results obtained during a wide range of auditory tasks support this proposal. Specifically, we analyzed the coordinates of 231 activation foci obtained in 15 different auditory studies selected through an extensive search of the positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) literature. The studies selected represent a wide variety of purely auditory tasks using highly controlled synthesized acoustic stimuli. The results clearly revealed that in addition to temporal auditory areas of cerebral cortex, specific regions in the cerebellum are activated consistently across studies regardless of the particular auditory task involved. In particular, one area in left lateral crus I area showed the greatest volume and ALE peak value among the extratemporal regions. A subanalysis was carried out that ruled out the specific association of this cerebellar cluster with attentional demand. The results are consistent with the hypothesis that the cerebellum may play a role in purely sensory auditory processing, and are discussed in light of the broader idea of the cerebellum subserving a fundamental sensory function. Hum Brain Mapp 25:118–128, 2005. © 2005 Wiley‐Liss, Inc.
Counteraction by repetitive daily exposure to static magnetism against sustained blockade of N‐methyl‐D‐aspartate receptor channels in cultured rat hippocampal neurons
Authors: Hirai Takao , Taniura Hideo , Goto Yasuaki , Tamaki Keisuke , Oikawa Hirotaka , Kambe Yuki , Ogura Masato , Ohno Yu , Takarada Takeshi , Yoneda Yukio
Published: April 2005

In rat hippocampal neurons cultured with the antagonist for N‐methyl‐D‐aspartate (NMDA) receptors dizocilpine (MK‐801) for 8 days in vitro (DIV), a significant decrease was seen in the expression of microtubule‐associated protein‐2 (MAP‐2) as well as mRNA for both brain‐derived neurotrophic factor (BDNF) and growth‐associated protein‐43 (GAP‐43), in addition to decreased viability. MK‐801 not only decreased the expression of the NR1 subunit of NMDA receptors but also increased NR2A expression, without affecting NR2B expression. Repetitive daily exposure to static magnetic fields at 100 mT for 15 min led to a decrease in the expression of MAP‐2, without significantly affecting cell viability or the expression of neuronal nuclei (NeuN) and GAP‐43. However, the repetitive magnetism prevented decreases in both BDNF mRNA and MAP‐2 and additionally increased the expression of NR2A subunit, without altering NR1 expression in neurons cultured in the presence of MK‐801. Repetitive magnetism was also effective in preventing the decrease by MK‐801 in the ability of NMDA to increase intracellular free Ca2+ ions, without affecting the decrease in the maximal response. These results suggest that repetitive magnetism may at least in part counteract the neurotoxicity of MK‐801 through modulation of the expression of particular NMDA receptor subunits in cultured rat hippocampal neurons. © 2005 Wiley‐Liss, Inc.
Study of the Segmental Dynamics in Semi‐Crystalline Poly(lactic acid) using Mechanical Spectroscopies
Authors: Mano João F.
Published: April 2005

Summary: The glass transition of poly(L‐lactic acid) (PLLA) occurs not far above typical service temperatures (room or body temperatures) which has consequences on the material properties during its use, such as damping or the occurrence of structural relaxation. This work aims at characterising the glass transition dynamics of a semi‐crystalline PLLA using both dynamic mechanical analysis (DMA) and thermally stimulated recovery (TSR). The main viscoelastic parameters have been characterised at 1 Hz using DMA and the master curve obtained after isothermal experiments at different temperatures provided a full picture of the solid‐state rheological behaviour throughout a wide frequency range. The activation energies calculated from the shift factors agree with the TSR ones, exhibiting a maximum near the Tg. Above the Tg, the results can be described with the WLF model. In the glassy state, the activation energy decreases with decreasing temperatures being always higher than the prediction of the Adam and Gibbs theory, at least down to temperatures 30 °C below the Tg. This suggests the existence of non‐arrested degrees of freedom in the glassy state, being consistent with the existence of a significant degree of cooperativity in the TSR results.

Temperature dependence of the apparent activation energy across the glass transition.

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Temperature dependence of the apparent activation energy across the glass transition.