bluuebunny/crossref_metadata_2025 huggingface dataset:
Medical decision making in patients with knee pain, meniscal tear, and osteoarthritis
Authors: Suter Lisa G. , Fraenkel Liana , Losina Elena , Katz Jeffrey N. , Gomoll Andreas H. , Paltiel A. David
Published: October 2009

Objective

Meniscal tears and osteoarthritis (OA) frequently coexist, but to our knowledge, no data exist to identify who will benefit from arthroscopic partial meniscectomy (APM) versus nonoperative management. Our objective was to evaluate the capability of preoperative information to predict APM outcomes in OA.

Methods

Using a mathematical model and published data, we combined 2 clinical (mechanical symptoms and pain pattern) and 2 magnetic resonance imaging (tear type and bone marrow lesions) indicators into 36 possible combinations and ranked each combination according to the likelihood of having primarily tear‐ versus OA‐related pain in individuals ages 45–65 years with knee pain, OA, and meniscal tears. By considering alternative thresholds for performing APM, we identified the cutoff rank that maximized the overall population International Knee Documentation Committee (IKDC) score (0–100 scale).

Results

Rank 1 (e.g., displaced tear, locking, increased pain, no bone marrow lesions) represented the highest likelihood of APM benefit; rank 36 (e.g., oblique tear, no mechanical symptoms, static pain, severe bone marrow lesions) represented the lowest likelihood of APM benefit. Indeterminate middle ranks included individuals with mixed findings (i.e., 2 findings consistent with high and 2 with low likelihood of APM benefit). APM thresholds between ranks 17 and 23 resulted in >82% of the population receiving treatment producing the greatest possible IKDC improvement, with mean incremental gains in IKDC score of >24 points. Findings were robust across a broad range of indicator assumptions, but were sensitive to outcome assumptions.

Conclusion

Among individuals with degenerative meniscal tears and OA, easily obtainable clinical information can differentiate those who are more likely to benefit from APM.
Progressive multifocal leukoencephalopathy following rituximab treatment in a patient with rheumatoid arthritis
Authors: Fleischmann R. M.
Published: October 2009

Progressive multifocal leukoencephalopathy (PML) is a rare brain disease caused by reactivation of the JC virus. Herein, a case of PML in association with rituximab treatment in a patient with chronic rheumatoid arthritis (RA) and Sjögren's syndrome is described. The patient received 4 courses of rituximab (2 1,000‐mg infusions administered 2 weeks apart) over a period of ∼40 months, during a phase III trial and safety extension study. PML was diagnosed ∼18 months after the last rituximab course, and the patient died 1 month later. Determination of the cause of PML was confounded by the fact that the patient had developed oropharyngeal cancer, which was treated with chemoradiotherapy, 9 months prior to the development of PML. Although there was no direct evidence that linked rituximab to the development of PML, this case highlights the need to consider a diagnosis of PML in patients with RA who have been treated with rituximab and who subsequently develop new neurologic symptoms.
Impaired myofibrillar function in the soleus muscle of mice with collagen‐induced arthritis
Authors: Yamada Takashi , Place Nicolas , Kosterina Natalia , Östberg Therese , Zhang Shi‐Jin , Grundtman Cecilia , Erlandsson‐Harris Helena , Lundberg Ingrid E. , Glenmark Birgitta , Bruton Joseph D. , Westerblad Håkan
Published: October 2009

Objective

Progressive muscle weakness is a common feature in patients with rheumatoid arthritis (RA). However, little is known about whether the intrinsic contractile properties of muscle fibers are affected in RA. This study was undertaken to investigate muscle contractility and the myoplasmic free Ca2+ concentration ([Ca2+]i) in the soleus, a major postural muscle, in mice with collagen‐induced arthritis (CIA).

Methods

Muscle contractility and [Ca2+]i were assessed in whole muscle and intact single‐fiber preparations, respectively. The underlying mechanisms of contractile dysfunction were assessed by investigating redox modifications using Western blotting and antibodies against nitric oxide synthase (NOS), superoxide dismutase (SOD), 3‐nitrotyrosine (3‐NT), carbonyl, malondialdehyde (MDA), and S‐nitrosocysteine (SNO‐Cys).

Results

The tetanic force per cross‐sectional area was markedly decreased in the soleus muscle of mice with CIA, and the change was not due to a decrease in the amplitude of [Ca2+]i transients. The reduction in force production was accompanied by slowing of the twitch contraction and relaxation and a decrease in the maximum shortening velocity. Immunoblot analyses showed a marked increase in neuronal NOS expression but not in inducible or endothelial NOS expression, which, together with the observed decrease in SOD2 expression, favors peroxynitrite formation. These changes were accompanied by increased 3‐NT, carbonyl, and MDA adducts content in myofibrillar proteins from the muscles of mice with CIA. Moreover, there was a significant increase in SNO‐Cys content in myosin heavy‐chain and troponin I myofibrillar proteins from the soleus muscle of mice with CIA.

Conclusion

These findings show impaired contractile function in the soleus muscle of mice with CIA and suggest that this abnormality is due to peroxynitrite‐induced modifications in myofibrillar proteins.
Association of higher rheumatoid arthritis disease activity during pregnancy with lower birth weight: Results of a national prospective study
Authors: de Man Yaël A. , Hazes Johanna M. W. , van der Heide Hugo , Willemsen Sten P. , de Groot Christianne J. M. , Steegers Eric A. P. , Dolhain Radboud J. E. M.
Published: October 2009

Objective

To determine the outcome of pregnancy in women with rheumatoid arthritis (RA) in relation to disease activity and medication use during the pregnancy.

Methods

In a prospective study, pregnant women with RA were evaluated before conception (when possible), during each trimester of the pregnancy, and postpartum. Clinical characteristics, disease activity, medication use, and pregnancy outcome were analyzed. To examine the independent influence of prednisone use and disease activity on birth weight, regression analyses were performed, with adjustments for gestational age of the child at delivery, the sex of the newborn, and the mother's smoking status, education level, parity, and use of an assisted reproduction technique. Kaplan‐Meier curve analyses were performed to examine the association between medication use and gestational age at delivery.

Results

Data from 152 Caucasian RA patients with singleton pregnancies were available. Both the mean ± SD birth weight (3,379 ± 564 gm) and the mean ± SD birth weight standard deviation score (SDS; +0.1 ± 1.1), which is the birth weight adjusted for the gestational age and sex of the newborn, were comparable with those in the general population. On multiple linear regression analyses of birth weight and birth weight SDS, both of which were adjusted for covariates, only disease activity was associated with lower birth weight (P = 0.025). The gestational age at delivery was significantly lower in women who were taking prednisone (38.8 versus 39.9 weeks; P = 0.001), and their delivery was more often premature (<37 weeks; P = 0.004).

Conclusion

Pregnancy outcome in women with well‐controlled RA is comparable with that in the general population. The effect of prednisone on birth weight is mediated by a lower gestational age at delivery, whereas a higher level of disease activity independently influences birth weight negatively, suggesting an immune‐mediated mechanism.
A novel inhibitor of Smad‐dependent transcriptional activation suppresses tissue fibrosis in mouse models of systemic sclerosis
Authors: Hasegawa Minoru , Matsushita Yukiyo , Horikawa Mayuka , Higashi Kiyoshi , Tomigahara Yoshitaka , Kaneko Hideo , Shirasaki Fumiaki , Fujimoto Manabu , Takehara Kazuhiko , Sato Shinichi
Published: October 2009

Objective

Tissue fibrosis is a major cause of morbidity and mortality in systemic sclerosis (SSc), and an increasing number of promising molecular targets for antifibrotic therapies have been described recently. Transforming growth factor β (TGFβ) is well known to be the principal factor that leads to tissue fibrosis. The present study was undertaken to investigate the ability of HSc025, a novel small compound that antagonizes TGFβ/Smad signaling through the activation of nuclear translocation of Y‐box binding protein 1, to prevent tissue fibrosis in vitro or in mouse models of SSc.

Methods

Human dermal fibroblasts were exposed to HSc025 at various concentrations in the presence of TGFβ, and levels of collagen or fibronectin expression were determined. HSc025 (15 mg/kg/day for 14 days) was administered orally to tight skin mice and to mice with bleomycin‐induced pulmonary fibrosis. Improvement of tissue fibrosis was evaluated by histologic or biochemical examination in each model.

Results

Pretreatment with HSc025 prevented Smad‐dependent promoter activation, in a dose‐dependent manner; however, HSc025 had no effect on TGFβ‐induced phosphorylation of Smad3. The inhibitory effects of HSc025 on TGFβ‐induced collagen or fibronectin expression were also confirmed in vitro. Orally administered HSc025 significantly reduced hypodermal thickness and hydroxyproline content in tight skin mice, and markedly decreased the histologic score and hydroxyproline content in the lungs of bleomycin‐treated mice.

Conclusion

These results demonstrate that HSc025 is a novel inhibitor of TGFβ/Smad signaling, resulting in the improvement of skin and pulmonary fibrosis. Orally available HSc025 might therefore be useful in the treatment of SSc.
Dabigatran, a direct thrombin inhibitor, demonstrates antifibrotic effects on lung fibroblasts
Authors: Bogatkevich Galina S. , Ludwicka‐Bradley Anna , Silver Richard M.
Published: October 2009

Objective

Myofibroblasts are the principal mesenchymal cells responsible for tissue remodeling, collagen deposition, and the restrictive nature of lung parenchyma associated with pulmonary fibrosis. We previously reported that thrombin activates protease‐activated receptor 1 (PAR‐1) and induces a myofibroblast phenotype in normal lung fibroblasts resembling the phenotype of scleroderma lung myofibroblasts. We undertook this study to investigate whether a selective direct thrombin inhibitor, dabigatran, interferes with signal transduction in human lung fibroblasts induced by thrombin and mediated via PAR‐1.

Methods

Lung fibroblast proliferation was analyzed using the Quick Cell Proliferation Assay. Expression and organization of α‐smooth muscle actin (α‐SMA) was studied by immunofluorescence staining and immunoblotting. Contractile activity of lung fibroblasts was measured by a collagen gel contraction assay. Connective tissue growth factor (CTGF) and type I collagen expression was analyzed on Western blots.

Results

Dabigatran, at concentrations of 50–1,000 ng/ml, inhibited thrombin‐induced cell proliferation, α‐SMA expression and organization, and the production of collagen and CTGF in normal lung fibroblasts. Moreover, when treated with dabigatran (1 μg/ml), scleroderma lung myofibroblasts produced 6‐fold less α‐SMA, 3‐fold less CTGF, and 2‐fold less type I collagen compared with untreated cells.

Conclusion

Dabigatran restrains important profibrotic events in lung fibroblasts and warrants study as a potential antifibrotic drug for the treatment of fibrosing lung diseases such as scleroderma lung disease and idiopathic pulmonary fibrosis.
Distinct subtypes of myelitis in systemic lupus erythematosus
Authors: Birnbaum J. , Petri M. , Thompson R. , Izbudak I. , Kerr D.
Published: October 2009

Objective

Myelitis causes pain, weakness, and sphincteric deficits, and is 1,000‐fold more prevalent in patients with systemic lupus erythematosus (SLE) than in the general population. For the last century, descriptions of SLE myelitis have been primarily limited to case reports. In contrast, larger‐scale cohort studies have revealed that myelitis occurring in the idiopathic demyelinating diseases (i.e., multiple sclerosis versus neuromyelitis optica) represents distinct syndromes. This study was undertaken to determine whether SLE myelitis similarly encapsulates distinct syndromes.

Methods

We analyzed a cohort of 22 patients with SLE and myelitis. Patients were assessed for neurologic variables related to myelitis and for clinical and serologic features of SLE. Magnetic resonance images of the spine, cerebrospinal fluid profiles, and autoantibody profiles were obtained.

Results

Eleven patients presented with signs of gray matter dysfunction (i.e., flaccidity and hyporeflexia), whereas 11 patients presented with signs of white matter dysfunction (i.e., spasticity and hyperreflexia). Patients with gray matter dysfunction were more likely to have irreversible paraplegia (P< 0.01), despite presenting with a monophasic versus polyphasic course (P= 0.01), higher levels of SLE activity (mean SLE Disease Activity Index 9.8 versus 2.0;P= 0.01), and a cerebrospinal fluid profile indistinguishable from bacterial meningitis. Prior to irreversible paraplegia, these patients presented with prodromes of fever and urinary retention, but were misdiagnosed by physicians of different specialties as having urinary tract infections. Patients with white matter dysfunction were more likely to meet criteria for neuromyelitis optica (P= 0.04) and were also more likely to have antiphospholipid antibodies (lupus anticoagulant) (P= 0.01).

Conclusion

Our findings indicate that SLE myelitis encapsulates 2 distinct and previously unrecognized syndromes that can be distinguished clinically by gray matter versus white matter findings. Recognition of fever and urinary retention as prodromes of irreversible paraplegia may allow earlier diagnosis and treatment in SLE patients presenting with gray matter findings.
Role of the urate transporter SLC2A9 gene in susceptibility to gout in New Zealand Māori, Pacific Island, and Caucasian case–control sample sets
Authors: Hollis‐Moffatt Jade E. , Xu Xin , Dalbeth Nicola , Merriman Marilyn E. , Topless Ruth , Waddell Chloe , Gow Peter J. , Harrison Andrew A. , Highton John , Jones Peter B. B. , Stamp Lisa K. , Merriman Tony R.
Published: October 2009

Objective

To examine the role of genetic variation in the renal urate transporter SLC2A9 in gout in New Zealand sample sets of Māori, Pacific Island, and Caucasian ancestry and to determine if the Māori and Pacific Island samples could be useful for fine‐mapping.

Methods

Patients (n= 56 Māori, 69 Pacific Island, and 131 Caucasian) were recruited from rheumatology outpatient clinics and satisfied the American College of Rheumatology criteria for gout. The control samples comprised 125 Māori subjects, 41 Pacific Island subjects, and 568 Caucasian subjects without arthritis. SLC2A9 single‐nucleotide polymorphisms rs16890979 (V253I), rs5028843, rs11942223, and rs12510549 were genotyped (possible etiologic variants in Caucasians).

Results

Association of the major allele of rs16890979, rs11942223, and rs5028843 with gout was observed in all sample sets (P = 3.7 × 10−7, 1.6 × 10−6, and 7.6 × 10−5 for rs11942223 in the Māori, Pacific Island, and Caucasian samples, respectively). One 4‐marker haplotype (1/1/2/1; more prevalent in the Māori and Pacific Island control samples) was not observed in a single gout case.

Conclusion

Our data confirm a role of SLC2A9 in gout susceptibility in a New Zealand Caucasian sample set, with the effect on risk (odds ratio >2.0) greater than previous estimates. We also demonstrate association of SLC2A9 with gout in samples of Māori and Pacific Island ancestry and a consistent pattern of haplotype association. The presence of both alleles of rs16890979 on susceptibility and protective haplotypes in the Māori and Pacific Island sample is evidence against a role for this nonsynonymous variant as the sole etiologic agent. More extensive linkage disequilibrium in Māori and Pacific Island samples suggests that Caucasian samples may be more useful for fine‐mapping.
Increased frequency of extremely skewed X chromosome inactivation in juvenile idiopathic arthritis
Authors: Uz Elif , Mustafa Chigdem , Topaloglu Rezan , Bilginer Yelda , Dursun Ali , Kasapcopur Ozgur , Ozen Seza , Bakkaloglu Aysin , Ozcelik Tayfun
Published: October 2009

Objective

Juvenile idiopathic arthritis (JIA) is a childhood rheumatic disease of unknown etiology. Two subgroups of JIA, i.e., oligoarticular and polyarticular, are thought to have an autoimmune component, and show a higher female:male ratio. Skewed X chromosome inactivation (XCI) has previously been shown to be associated with scleroderma and autoimmune thyroiditis, 2 autoimmune disorders occurring predominantly in females. This study was undertaken to extend the analysis to the pediatric age group and to determine the XCI profiles of patients with JIA.

Methods

A polymorphic repeat in the androgen receptor gene was genotyped to determine XCI status in 81 female patients with JIA (21 with polyarticular disease and 60 with oligoarticular disease) and 211 healthy female controls. DNA obtained from venous blood samples was used for this analysis.

Results

Informative data were obtained on 62 JIA patients and 155 controls. Skewed XCI was observed in 14 patients (22.6%) and 11 controls (7.1%) (P = 0.0036), and extreme skewing was apparent in 8 patients (12.9%) and 2 controls (1.3%) (P = 0.0008).

Conclusion

Our findings in the present study indicate that skewed XCI may be a risk factor for the occurrence of autoimmune disorders, including JIA.
Differential mechanism of NF‐κB inhibition by two glucocorticoid receptor modulators in rheumatoid arthritis synovial fibroblasts
Authors: Gossye Valerie , Elewaut Dirk , Bougarne Nadia , Bracke Debby , Van Calenbergh Serge , Haegeman Guy , De Bosscher Karolien
Published: October 2009

Objective

To investigate and compare the molecular mechanisms by which 2 glucocorticoid receptor (GR)–activating compounds, dexamethasone (DEX) and Compound A (CpdA), interfere with the NF‐κB activation pathway in rheumatoid arthritis (RA) synovial cells.

Methods

Quantitative polymerase chain reaction was performed to detect the tumor necrosis factor α (TNFα)–induced cytokine gene expression of interleukin‐1β (IL‐1β) and to investigate the effects of DEX and CpdA in RA fibroblast‐like synoviocytes (FLS) transfected with small interfering RNA (siRNA) against GR (siGR) compared with nontransfected cells. Immunofluorescence analysis was used to detect the subcellular distribution of NF‐κB (p65) under the various treatment conditions, and active DNA‐bound p65 was measured using a TransAM assay and by chromatin immunoprecipitation analysis of IL‐1β. Signaling pathways were studied via Western blotting of siGR‐transfected cells, compared with nontransfected and nontargeting siRNA–transfected control cells, to detect the regulation of phospho‐IKK, IκBα, phospho‐p38, phospho‐ERK, and phospho‐JNK.

Results

Both DEX and CpdA efficiently inhibited IL‐1β gene expression in a GR‐dependent manner. In addition, CpdA attenuated the TNFα‐induced nuclear translocation and DNA binding of p65 in RA FLS, via the attenuation of IKK phosphorylation and subsequent IκBα degradation. CpdA also displayed profound effects on TNFα‐induced MAPK activation. The effects of CpdA on TNFα‐induced kinase activities occurred independently of the presence of GR. In sharp contrast, DEX did not affect TNFα‐induced IKK phosphorylation, IκBα degradation, p65 nuclear translocation, or MAPK activation in RA FLS.

Conclusion

DEX and CpdA display a dissimilar molecular mechanism of interaction with the NF‐κB activation pathway ex vivo. A dual pathway, partially dependent and partially independent of GR (nongenomic), may explain the gene‐inhibitory effects of CpdA in RA FLS.
Identification of RGS1 as a candidate biomarker for undifferentiated spondylarthritis by genome‐wide expression profiling and real‐time polymerase chain reaction
Authors: Gu Jieruo , Wei Yu‐Ling , Wei James C. C. , Huang Feng , Jan Ming‐Shiou , Centola Michael , Frank Mark B. , Yu David
Published: October 2009

Objective

To compare gene expression profiles between ankylosing spondylitis (AS) and undifferentiated spondylarthritis (uSpA) patients with inflammatory low back pain.

Methods

Peripheral blood mononuclear cells (PBMCs) from patients with AS, patients with uSpA, and healthy subjects were screened using genome‐wide microarrays, followed by validation by real‐time polymerase chain reaction (PCR).

Results

Microarray profiling and real‐time PCR assays showed only minor differences between AS patients and healthy subjects. In contrast, 20 genes were strikingly more highly expressed in uSpA patients. Regulator of G protein signaling 1 (RGS1) was identified as the most useful biomarker for distinguishing uSpA patients, and to a lesser extent AS patients, from control subjects (P = 2.3 × 10−7 and 6.7 × 10−3, respectively). These findings were verified in an independent cohort that also included patients with rheumatoid arthritis and patients with mechanical low back pain. The receiver operating characteristic area under the curve values in the first and second cohorts of uSpA patients were 0.99 and 0.93, respectively (P = 1 × 10−4). To evaluate the possible derivation of RGS1, we cultured a monocyte‐derived cell line with a panel of cytokines and chemokines. RGS1 was significantly induced either by tumor necrosis factor α (TNFα) or by interleukin‐17 (IL‐17).

Conclusion

Our findings indicate that uSpA PBMCs carry strikingly more highly expressed genes compared with PBMCs from AS patients or healthy subjects, and that TNFα‐ and IL‐17–inducible RGS1 is a potential biomarker for uSpA, and to a lesser extent for AS, with inflammatory low back pain.
Minimizing operating points for way point tracking of an unstable nonlinear plant
Authors: Liu Guangyu , Yang Ran
Published: October 2009

Stability analysis of way point tracking of an open loop unstable nonlinear system is overwhelmingly ignored in the literature. Taking a spherical inverted pendulum as an example, the stability issue of way point tracking for an unstable nonlinear system is properly addressed and solved by incorporating nonlinear stabilizing controllers that could minimize the number of operating points. The underlying principle in stability analysis of way point tracking easily extends to other unstable nonlinear systems. Effectiveness of the proposed idea is evaluated in computer simulation. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Globally decentralized adaptive backstepping neural network tracking control for unknown nonlinear interconnected systems
Authors: Chen Weisheng , Li Junmin
Published: October 2009

A globally stable decentralized adaptive backstepping neural network tracking control scheme is designed for a class of large‐scale systems with mismatched interconnections. Under the assumption that the subsystems share the reference signals from the other subsystems, neural networks are used to approximate the unknown interconnections dependent on all reference signals such that the NN approximation domain can be determined a priori based on the bounds of reference signals. The proposed control approach can guarantee that all closed‐loop signals are globally uniformly ultimately bounded and that the tracking errors converge to a small residual set around the origin. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Prototype formation in autism: Can individuals with autism abstract facial prototypes?
Authors: Gastgeb Holly Zajac , Rump Keiran M. , Best Catherine A. , Minshew Nancy J. , Strauss Mark S.
Published: October 2009

Prototype formation is a critical skill for category learning. Research suggests that individuals with autism may have a deficit in prototype formation of some objects; however, results are mixed. This study used a natural category, faces, to further examine prototype formation in high‐functioning individuals with autism. High‐functioning children (age 8–13 years) and adults with autism (age 17–53 years) and matched controls were tested in a facial prototype formation task that has been used to test prototype formation abilities in typically developing infants and adults [Strauss, 1979]. Participants were familiarized to a series of faces depicting subtle variations in the spatial distance of facial features, and were then given a forced choice familiarity test between the mean prototype and the mode prototype. Overall, individuals in the autism group were significantly less likely to select the mean prototype face. Even though the children with autism showed this difference in prototype formation, this pattern was driven primarily by the adults, because the adults with autism were approximately four times less likely to select the mean prototype than were the control adults. These results provide further evidence that individuals with autism have difficulty abstracting subtle spatial information that is necessary not only for the formation of a mean prototype, but also for categorizing faces and objects.
Zeitvariantes Trag‐ und Schädigungsverhalten von mehrfach wiederholt beanspruchtem polymermodifizierten Beton (PCC)
Authors: Heidolf Thorsten
Published: October 2009

Im vorliegenden Beitrag werden experimentelle Untersuchungen an polymermodifiziertem Beton unter mehrfach wiederholter Druck‐ und Zugbeanspruchung vorgestellt und mit den Ergebnissen ähnlicher Versuche an Normalbeton und hochfestem Beton verglichen. Besondere Aufmerksamkeit wird dabei dem Formänderungsverhalten und der Steifigkeitsdegradation sowie dem Kriechverhalten und der Mitwirkung des Betons zwischen den Rissen gewidmet. Die signifikante Steifigkeitsdegradation sowie das nichtlineare Langzeitverhalten des Betons zeigen, dass bei der Analyse der Kriechauswirkungen des polymermodifizierten Betons auf das Tragverhalten entsprechender Konstruktionen neben den Gebrauchslasten auch die während der Lastgeschichte aufgetretenen maximalen Beanspruchungssituationen sowie die damit verbundenen Strukturveränderungen zu berücksichtigen sind.

Time‐variant Behaviour of Polymer Modified Concrete (PCC) under Repeated Stress with Consideration of Damage. Part 1: Experimental Studies

The experimental results of the investigations into polymer‐modified concrete with continuously repeated compression or tension load are introduced in the provided work and compared to similar experiments on normal‐ and high‐strength concrete. Special attention is dedicated to the stress‐strain relation and the degradation of stiffness as well as the non‐linear long‐term behaviour and tension‐stiffening. Stiffness degradation and nonlinear creep of polymer‐modified concrete show that maximum strain situations have to be taken into consideration of the behaviour analysis of concrete structures under long‐term loading.
Instandsetzung einer Betonbrücke mit Walzträgern nach dem Prinzip des Kathodischen Korrosionsschutzes
Authors: Dauberschmidt Christoph , Sodeikat Christian , Vestner Stephan
Published: October 2009

Für die Instandsetzung chloridbelasteter Stahlbetonbauwerke muss bei den so genannten konventionellen Verfahren oftmals Beton in großer Tiefe abgetragen werden. Dies verursacht hohe Kosten, stellt einen erheblichen Eingriff in das Bauwerk dar und führt nicht zuletzt zu Nutzungseinschränkungen während der Instandsetzung. Aus diesem Grund gewinnt der Kathodische Korrosionsschutz (KKS) von Stahl in Beton, eine zum Großteil zerstörungsfreie Instandsetzungsmethode, als wirtschaftliches Instandsetzungsverfahren korrosionsgefährdeter bzw.‐geschädigter Bauteile zunehmend an Bedeutung. Nachfolgend wird die Instandsetzung der Brücke über den Auer Mühlbach in München mit KKS beschrieben. Das Tragsystem der Auer Mühlbachbrücke besteht aus einbetonierten Walzträgern, die mit diskreten Einzelanoden geschützt wurden. Auf Grund der sehr hohen Überschüttung und der verkehrlichen Bedeutung dieser Brücke war der KKS besonders vorteilhaft anwendbar, da es während der gesamten Instandsetzung keinerlei Einschränkungen des Verkehrs gab.

Repair of a Concrete‐Bridge with Rolled Section Beams applying the Principle of Cathodic Protection

When repairing reinforced concrete structures containing chlorides by conventional methods, it is often necessary to remove the concrete to great depths. This causes high costs and leads to a significant intervention of the structure, combined with a limitation of use whilst repair measures. This is the reason why Cathodic Protection (CP) of reinforcement in concrete is gaining importance as predominantly non‐destructive, costeffective repair measure of structures susceptible to or damaged by corrosion. Consecutively the repair measure of the bridge over the Auer Mühlbach in Munich using CP is described. The load bearing system of the bridge of Auer Mühlbach consists of rolled section steel beams, which are protected using discrete anodes. Due to the high ground cover and the high importance to the intra‐urban traffic, the application of CP was in particular advantageously as the traffic has not been limited whilst the repair measure.
Lebensdauermanagement von Stahlbetonbauwerken
Authors: Schießl Peter , Mayer Till Felix
Published: October 2009

Dem Lebensdauermanagement von Infrastrukturbauwerken kommt vor dem Hintergrund knapper Ressourcen eine steigende Bedeutung zu. In diesem Beitrag werden die wesentlichen Bausteine eines modernen Lebensdauermanagementsystems für Stahlbetonbauwerke vorgestellt. Zentrales Element ist eine Lebensdauerbemessung, die in Abhängigkeit von den maßgebenden Schädigungsmechanismen mit unterschiedlichen Detaillierungsgraden durchgeführt werden kann. Dies ermöglicht eine Ausnutzung von Optimierungspotentialen durch Rezepturoptimierung und Bindemittelwahl. Durch geeignete Methoden während der Ausführung und nach Fertigstellung kann die tatsächliche Qualität kontrolliert werden. Die Ergebnisse der Untersuchungen während der Planungs‐ und Ausführungsphase werden in einem Geburtszertifikat zusammengefasst, das die Grundlage für den Wartungsplan bildet. Die Ergebnisse der Inspektionen werden herangezogen, um die Prognose der Zustandsentwicklung während der Nutzung kontinuierlich zuzuschärfen.

Life Cycle Management of Concrete Structures

On the background of scarce public resources, life cycle management of infrastructure systems has gained increasing importance. This paper presents the core components of a state‐ofthe‐art life cycle management system for reinforced concrete structures. A service life design is one of the key elements. Depending on the governing deterioration mechanisms, it can be carried out on different levels of detail and thus enables an optimisation of durability by means of optimised concrete composition and choice of binder. Quality control tools during construction and after completion allow for an assessment of the actual quality. The results of the design and construction stage are then summarised in a so‐called birth certificate which forms the basis for future inspection and maintenance planning. The results of the inspection again can be used to update the original service life design throughout the service life of the structure.
Kathodischer Korrosionsschutz im Beton
Authors: Bruns Michael , Becker Holger , Tritschler Christian , Binder Günter
Published: October 2009

Die Schleusenbrücken in Iffezheim (Rhein) weisen 30 Jahre nach ihrer Herstellung an den Wand‐ und Bodenflächen im Inneren der Hohlkästen teilweise bereits erhebliche Schäden infolge chloridinduzierter Korrosion auf. Statische Untersuchungen zeigten, dass Tragwerksreserven im Bauwerk aktivierbar und zusätzliche Ertüchtigungen durch Verstärkungsmaßnahmen relativ einfach möglich sind.

Eine herkömmliche Instandsetzung mittels Abtrag und Reprofilierung des chloridbelasteten Betons ist aufgrund der geringen Hohlkastenabmessungen praktisch nicht durchführbar. In einem der Hohlkästen wurde daher eine Kathodische‐Korrosionsschutz( KKS)‐Probeinstallation durchgeführt, mit der die Anwendbarkeit des KKS in diesem Fall anhand von zwei Anodensystemen (leitfähige Beschichtung und Titanmischoxid‐Kernanoden) überprüft werden sollte.

Die Testinstallation zeigte, dass der Schutz der Bewehrung durch den Einsatz von Kernanoden sicher erreicht werden kann. Im Fall der leitfähigen Beschichtung wurde bei der Installation offenbar ein hochohmiger Kurzschluss zwischen Anode und Bewehrung erzeugt, so dass diese Testinstallation nicht weiter ausgewertet werden konnte. Auf Grundlage der KKS‐Probeinstallation beantragte der Bauherr (WSA Freiburg) eine Zustimmung im Einzelfall für die KKS Installation mit Kernanoden bei dem zuständigen Bundesministerium für Verkehr, Bau und Stadtentwicklung (BMVBS).

Trotz der Tatsache, dass für die Gesamtmaßnahme etwa 2050 Kernanoden erforderlich werden, ist auch bei konservativen Kostenansätzen eine Sanierung im Vergleich zum Neubau überaus wirtschaftlich.
A molecular model of chromatin organisation and transcription: how a multi‐RNA polymerase II machine transcribes and remodels the β‐globin locus during development
Authors: Wong Hua , Winn Peter J , Mozziconacci Julien
Published: October 2009

We present a molecular model of eukaryotic gene transcription. For the β‐globin locus, we hypothesise that a transcription machine composed of multiple RNA polymerase II (PolII) assembles using the locus control region as a foundation. Transcription and locus remodelling can be achieved by pulling DNA through this multi‐PolII ‘reading head’. Once a transcription complex is formed, it may engage an active gene in several rounds of transcription. Observed intergenic sense and antisense transcripts may be the result of PolII pulling the DNA through the reading head whilst searching for the promoter of a gene. Support for this hypothesis is provided using various data from the literature. In the model, DNA is packed in a 30‐nm chromatin fibre, thus gene regulatory regions separated by kilobases are close in space. This, and the need to store transcription‐induced supercoiling, may explain why functionally interacting regions are often separated by many kilobases.
Copper and Zinc Binding to Amyloid‐β: Coordination, Dynamics, Aggregation, Reactivity and Metal‐Ion Transfer
Authors: Faller Peter
Published: October 2009

The metal ions copper, zinc and iron have been shown to be involved in Alzheimer's disease (AD). Cu, Zn and Fe ions are proposed to be implicated in two key steps of AD pathology: 1) aggregation of the peptide amyloid‐β (Aβ), and 2) production of reactive oxygen species (ROS) induced by Aβ. There is compelling evidence that Cu and Zn bind directly to Aβ in AD. This formation of Cu/Zn–Aβ complexes is thought to be aberrant as they have been detected only in AD, but not under healthy conditions. In this context, the understanding of how these metal ions interact with Aβ, their influence on structure and oligomerization become an important issue for AD. Moreover, the mechanism of ROS production by Cu–Aβ in relation to its aggregations state, as well as the metal‐transfer reaction from and to Aβ are crucial in order to understand why Aβ oligomers are highly toxic and why Aβ seems to bind Cu and Zn only in AD.
Interactions of KLA Amphipathic Model Peptides with Lipid Monolayers
Authors: Erbe Andreas , Kerth Andreas , Dathe Margitta , Blume Alfred
Published: October 2009

Interactions of the cationic amphipathic peptide KLALKLALKALKAALKLA‐NH2 (KLAL) and its double D‐amino acid replacement analogues l11k12‐KLAL and k9a10‐KLAL with lipid monolayers of anionic POPG, zwitterionic POPC and mixtures thereof at the air/water interface were investigated by infrared reflection– absorption spectroscopy (IRRAS). At high surface pressure (>30 mN m−1) all peptides incorporated into lipid monolayers containing at least 25 % anionic POPG, and adopted an α‐helical conformation. Creation of free surface by expansion of the monolayers resulted in an additional adsorption of peptides from the subphase, but now in a β‐sheet conformation; this led to the coexistence of peptides in two distinctly different conformations within the lipid monolayer. The β‐sheets bound to the free surface could be squeezed out of the film by compressing the film to low surface areas, whereas the α‐helices remained bound to the lipids until the film collapsed. When bound to the lipid monolayer, the helical axis of the peptides is oriented almost parallel to the surface of the monolayer.
Bailout stenting for critical coarctation in premature/critical/complex/early recoarcted neonates
Authors: Gorenflo Matthias , Boshoff Derize E. , Heying Ruth , Eyskens Benedicte , Rega Filip , Meyns Bart , Gewillig Marc
Published: October 2009

Background: Surgical repair of critical coarctation can be problematic in premature, critical, complex, or early postoperative neonates. Objectives: We aimed to review our experience with stent implantation to defer urgent surgery to an elective time. Methods: Fifteen neonates with severe aortic coarctation: five premature‐hypotrophic (1,400–2,000 g), six critical and complex cardiac malformation, four early (1 day [0–2 days]; median [range]) after surgical coarctectomy or complex arch reconstruction. Bare coronary stents (diameter 4.0 [3.5–5.0] mm; length 10 [8–16] mm) were used. Stents were removed surgically depending on clinical needs. Results: Adequate aortic flow was obtained in 15 patients. The femoral artery was preserved in 13/15 patients. Two deaths occurred before stent removal and were nonprocedure related. In patients with simple stented coarctation, the stent was removed after 2.8 [0.2–5.0] months. In complex cardiac malformation, stents were finally removed 3.0 [0.2–78] months after implantation. Surgical technique: simple coarctectomy end‐to‐end in eight, extensive arch patch reconstruction in four. One patient is awaiting stent removal. The final maximum systolic velocity (cw‐Doppler) across the aortic arch was 1.7 [1.2–2.5] m/sec. Conclusions: In premature/critical/complex neonates with severe coarctation, bailout stenting followed by early or late surgical coarctectomy appears a promising concept. © 2009 Wiley‐Liss, Inc.
Guidance on Safety/Health for Process Intensification including MS Design; Part I: Reaction Hazards
Authors: Klais O. , Westphal F. , Benaïssa W. , Carson D.
Published: October 2009

The implementation of process intensification by multiscale equipment will have a profound impact on the way chemicals are produced. The shift to higher space‐time yields, higher temperatures, and a confined reaction volume comprises new risks, such as runaway reactions, decomposition, and incomplete conversion of reactants. Simplified spreadsheet calculations enable an estimation of the expected temperature profiles, conversion rates, and consequences of potential malfunction based on the reaction kinetics. The analysis illustrates that the range of optimal reaction conditions is almost congruent with the danger of an uncontrolled reaction. The risk of a spontaneous reaction with hot spots can be presumed if strong exothermic reactions are carried out in micro‐designed reactors. At worst, decomposition follows the runaway reaction with the release of noncondensable gases. Calculations prove that a microreactor is not at risk in terms of overpressure as long as at least one end of the reactor is not blocked.
Shape‐Persistent Oligothienylene–Ethynylene‐Based Dendrimers: Synthesis, Spectroscopy and Electrochemical Characterization
Authors: Mishra Amaresh , Ma Chang‐Qi , Janssen René A. J. , Bäuerle Peter
Published: October 2009

A series of novel structurally well‐defined oligothienylene–ethynylene‐based dendritic macromolecules up to the 3rd generation (G3) were successfully synthesized by a combination of Pd‐catalyzed Sonogashira‐type cross‐coupling and oxidative homocoupling steps. Oxidative homocoupling of dendrons successfully afforded dendrimers up to the 2nd generation (G2). In contrast, the G3 dendrimer was effectively prepared by a four‐fold Sonogashira‐type cross‐coupling reaction. All compounds showed broad and structureless absorption and emission spectra arising from the presence of different π‐conjugated chromophores. With increasing generation, a bathochromic shift of the π–π* absorption band and an increase of the absorption coefficient were observed. The insertion of ethynylene groups into the conjugated dendrimer backbone resulted in a hypsochromic shift compared to all‐thiophene dendrimers reported earlier by our group. All dendritic compounds are fluorescent and showed moderate quantum efficiencies due to an effective intramolecular charge‐transfer (ICT) process. Cyclic voltammetry measurements also revealed the presence of multiple π‐conjugative pathways that show very broad oxidation waves for higher generations. HOMO–LUMO energy levels of these dendrons and dendrimers were estimated from optical and redox measurements and the calculated band gaps were within the range of 3.3 to 2.4 eV, typical for oligo‐ and polythiophenes. Electrochemical polymerizations of several desilylated compounds were performed and characterization of the films is reported. Preliminary bulk heterojunction solar cells that utilise these ethynylated dendrimers as the donor and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM[60]) as the acceptor showed moderate efficiencies ranging from 0.18–0.64 %.
Facile Synthesis of Gold Icosahedra in an Aqueous Solution by Reacting HAuCl4 with N‐Vinyl Pyrrolidone
Authors: Yavuz Mustafa S. , Li Weiyang , Xia Younan
Published: October 2009

Herein we describe a protocol that generates Au icosahedra in high yields by simply mixing aqueous solutions of HAuCl4 and N‐vinyl pyrrolidone. Our mechanistic study reveals that water plays an important role in this synthesis: as a nucleophile, it attacks the gold–vinyl complex, leading to the production of an alcohol‐based AuI intermediate. This intermediate then undergoes a redox reaction in which AuI is reduced to Au0, leading to the formation of Au atoms and then Au icosahedra of about 18 nm in size at a yield of 94 %, together with a carboxylic acid in the final product. This new protocol has also been employed to prepare multiply twinned nanoparticles of Ag (15–20 nm in size), spherical aggregates (25–30 nm in size) of Pd nanoparticles, and very small nanoparticles of Pt (2 nm in size). Since no organic solvent, surfactant, or polymer stabilizer is needed for all these syntheses, this protocol may provide a simple, versatile, and environmentally benign route to noble‐metal nanoparticles having various compositions and morphologies.
Direct Comparison of the Reactivity of Model Complexes for Compounds 0, I, and II in Oxygenation, Hydrogen‐Abstraction, and Hydride‐Transfer Processes
Authors: Fertinger Christoph , Hessenauer‐Ilicheva Natalya , Franke Alicja , van Eldik Rudi
Published: October 2009

The iron(III) meso‐tetramesitylporphyrin complex is a good biomimetic to study the catalytic reactions of cytochrome P450. All of the three most discussed reactive intermediates concerning P450 catalysis (namely, Cpd 0, Cpd I, and Cpd II) can be selectively produced, identified, and stabilized for many minutes in solution at low temperature by choosing appropriate reaction conditions. In this way, their reactivity against various substrates was determined by utilizing low‐temperature rapid‐scan UV/Vis spectroscopy. Since all reactive intermediates are derived from a single model complex, the results of these kinetic measurements provide for the first time a full comparability of the determined rate constants for the three intermediates. The rate constants reveal a significant dependence of the reactivity on the type of reaction (e.g., oxygenation, hydrogen abstraction, or hydride transfer), which closely correlates with the chemical nature of Cpds 0, I, and II. The detailed knowledge of the reactivity of these intermediates provides a valuable tool to evaluate their particular role in biological systems.
Structures of Storage‐Induced Transformation Products of the Beer’s Bitter Principles, Revealed by Sophisticated NMR Spectroscopic and LC–MS Techniques
Authors: Intelmann Daniel , Kummerlöwe Grit , Haseleu Gesa , Desmer Nina , Schulze Kerstin , Fröhlich Roland , Frank Oliver , Luy Burkhard , Hofmann Thomas
Published: October 2009

Besides undesirable changes in the attractive aroma, a significant decrease in the intensity of the bitterness as well as a change of the taste into a lingering, harsh bitterness has long been known as a shelf‐life limiting factor of beer. Multiple studies have demonstrated that the aging of beer induces a decrease of the total amount of cis‐ and trans‐iso‐α‐acids, the well‐known bitter principles of beer. Although the trans‐iso‐α‐acids exclusively, not the cis‐iso‐α‐acids, were found to be degraded upon storage of beer, the key transformation products formed exclusively from the trans isomers in beer are not known. In the present study, suitable model experiments followed by LC–MS/MS and sophisticated NMR spectroscopic experiments, including the measurement of residual dipolar couplings (RDCs) in gel‐based alignment media as well as a novel broadband and B1‐field‐compensated incredible natural abundance double‐quantum transfer experiment (INADEQUATE) pulse sequence, enabled the identification of a series of previously unknown trans‐specific iso‐α‐acid transformation products, namely, tricyclocohumol, tricyclocohumene, isotricyclocohumene, tetracyclocohumol, and epitetracyclocohumol, respectively. HPLC–MS/MS analysis of these compounds, which exhibit the aforementioned harsh lingering bitter taste and have threshold concentrations ranging from 5 to 70 μmol L−1, confirmed their generation during aging of beer and, for the first time, explained the storage‐induced changes of the beer’s bitter taste on a molecular level.
Biofuel Cells Controlled by Logically Processed Biochemical Signals: Towards Physiologically Regulated Bioelectronic Devices
Authors: Katz Evgeny , Pita Marcos
Published: October 2009

Biofuel cells with a switchable power release controlled by biochemical signals, which can be logically processed by biomolecular computing systems, have been designed. The switchable properties of the biofuel cells were based on the polymer‐brush‐modified electrodes with the activity dependent on the solution pH value. The pH changes generated in situ by biocatalytic reactions allowed the reversible activation—inactivation of the bioelectrocatalytic interfaces—thus affecting the activity of the entire biofuel cells. Boolean logic operations performed by either enzyme‐ or immune‐based systems were functionally integrated with the switchable biocatalytic process allowing logic control over them. Scaling up the complexity of the biocomputing systems to complex multi‐component logic networks with a built‐in “program” resulted in the control of the bioelectronic systems by multi‐signal patterns of biochemical inputs. Future implantable biofuel cells producing electrical power on‐demand depending on physiological conditions are feasible, as the result of the present research.
ChemInform Abstract: Lewis Acidities and Hydride, Fluoride, and X‐ Affinities of the BH3‐nXn Compounds for (X: F, Cl, Br, I, NH2, OH, and SH) from Coupled Cluster Theory.
Authors: Grant Daniel J. , Dixon David A. , Camaioni Donald , Potter Robert G. , Christe Karl O.
Published: October 2009

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 of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: High‐Pressure Structural Transitions of Sc2O3 by X‐Ray Diffraction, Raman Spectra, and ab initio Calculations.
Authors: Cui Qiliang , et al. et al.
Published: October 2009

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 of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.