bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of moxifloxacin compared to teicoplanin in the treatment of implant‐related chronic osteomyelitis in rats
Authors: Ozturan Kutay Engin , Yucel Istemi , Kocoglu Esra , Cakici Husamettin , Guven Melih
Published: April 2010

Treatment of implant‐related chronic osteomyelitis is often difficult and usually consists of implant removal, extensive surgical debridement, and prolonged antibiotic use. This study was performed to assess the efficacy of moxifloxacin compared to a glycopeptide, teicoplanin in chronic implant‐related methicillin‐sensitive Staphylococcus aureus (MSSA) osteomyelitis. The left femoral medullar cavities of 60 Wistar male rats were contaminated with 100 µl of 108 cfu/ml methicillin‐sensitive S. aureus (ATCC 29213) and Kirschner wires were placed into the medulla of the femur. After 6 weeks, rats were randomly divided into five groups. In two groups, the Kirschner wires were removed. Experimental groups were as follows: group 1: contaminated, Kirschner wire inside, received teicoplanin; group 2: contaminated, Kirschner wire removed, received teicoplanin; group 3: contaminated, Kirschner wire inside, received moxifloxacin; group 4: contaminated, Kirschner wire removed, received moxifloxacin; group 5: contaminated, Kirschner wire inside, no antibiotics (control group). Groups 1 and 2 received teicoplanin (20 mg/kg once daily), whereas groups 3 and 4 received moxifloxacin (10 mg/kg twice daily) intraperitoneally for 28 days. At the end of the treatment, animals were sacrificed by inhalation anesthesia with ether and femora were retrieved and bacterial counts (cfu/g) were determined. Bacterial counts in all study groups were significantly reduced relative to the control. The decrease of bacterial counts was more prominent in group 4 compared to group 1 (p = 0.001) and group 2 (p = 0.003). Moxifloxacin therapy is an effective alternative to teicoplanin for chronic implant‐related MSSA osteomyelitis. Published by Wiley Periodicals, Inc. J Orthop Res 28:1368–1372, 2010
Raman and IR spectra of K4Nb6O17and K4Nb6O17·3H2O single crystals
Authors: Ma̧czka M. , Ptak M. , Majchrowski A. , Hanuza J.
Published: April 2010

Polarised Raman and IR spectra of K4Nb6O17 and K4Nb6O17· 3H2O single crystals were measured. The obtained spectra are discussed using the factor group approach for the orthorhombic P21nb space group and assignment of bands to the respective motions of atoms is proposed. In particular, we have shown that the bands above 770 cm−1 can be attributed to the stretching modes of short niobium–oxygen bonds, which are present in this material due to the pronounced layered structure, whereas the potassium atoms contribute to the bands observed below 180 cm−1. Our studies have revealed that intercalation of water molecules leads to shifts, broadening and changes in intensity of some bands. These changes have been attributed to slight changes in the bond lengths and angles, interactions of the water molecules with K atoms and structural disorder introduced by the intercalated water molecules. However, the main structural framework was preserved. Copyright © 2010 John Wiley & Sons, Ltd.
Perceived benefits and barriers to joint protection among people with rheumatoid arthritis and occupational therapists. A mixed methods study
Authors: Niedermann K. , Hammond A. , Forster A. , de Bie R.
Published: April 2010

Background: Deciding whether or not to perform a health behaviour is an active decision‐making process which has an impact on current and future behaviour and can be influenced by the beliefs both of patients and their healthcare professionals. The aim of this study was to explore rheumatoid arthritis (RA) patients' and occupational therapists' (OTs) perceptions of the benefits of and barriers to performing joint protection (JP).

Methods: A mixed methods design was used. Questionnaires applied a theoretical framework of key themes to assess the relevance of JP benefits and barriers both to people with RA and OTs. Focused interviews with people with RA then enabled data triangulation. Investigator triangulation was used to check the validity of data interpretation.

Findings: Ten people with RA and nine OTs participated. From the questionnaires, both groups agreed that highly relevant key themes for JP benefits were physical well‐being, potential benefit and personal control. By contrast, the three key themes for JP barriers – negative attitude of others, negative impact on others and taking time from other things – were relevant for the majority of the OTs but not patients. The interviews enabled an understanding of the meaning behind RA patients' ratings, particularly their differences from OTs. People with RA explained JP benefits, and disease acceptance had altered some initial barriers into perceived benefits over time.

Conclusions: Emphasizing benefits and identifying individually relevant barriers could be an important communication strategy for OTs in understanding patients' rationale for whether or not to adopt JP methods. Copyright © 2010 John Wiley & Sons, Ltd.
Der Lotus‐Effekt: Selbstreinigung mikrostrukturierter Oberflächen
Authors: Fürstner Reiner , Neinhuis Christoph , Barthlott Wilhelm
Published: April 2010

Die Lotusblume gilt in den asiatischen Religionen als Symbol der Reinheit: Makellos sauber entfalten sich ihre Blätter aus schlammigen Gewässern. Untersuchungen dieses Phänomens zeigten, wie sich Pflanzen gegen Schmutz und Keime schützen. Anhand dieser Kenntnisse können nun künstliche, biomimetische Oberflächen mit ähnlichen Eigenschaften entwickelt werden.
Der Natur auf der Spur
Authors: Michael Katja
Published: April 2010

Es ist das enorme Potential für den Fortschritt in nahezu allen naturwissenschaftlichen Disziplinen, das Bioorganiker dazu inspiriert, Biopolymere, ihre monomeren Bausteine und Naturstoffe auf molekularer Ebene zu erforschen und sich zunutze zu machen Wie vielfältig die Forschung ist, zeigt alljährlich das Nachwuchswissenschaftlersymposium „Bioorganische Chemie”︁.
Gibt es ehrliche Preise für die Umweltbelastung?
Authors: Schoenberg Dieter
Published: April 2010

Es kann, so sagt Andreas Troge, der Präsident des Umweltbundesamtes, durch die politisch‐ökonomischen Entscheidungssysteme nicht gelingen, Umweltschäden real in Mark und Pfennig zu bewerten. Es fehlen die wissenschaftlichen Grundlagen, um ökologisch richtige Preise zu ermitteln.
E‐Commerce in der Chemie ‐Fußnote oder Strukturbruch?
Authors: Jung Udo , Willers Yves P.
Published: April 2010

Alle Unternehmen ‐ auch in der chemischen Industrie ‐stehen vor der Aufgabe, die durch das Internet hervorgerufene Informationsrevolution aktiv zu nutzen und für die eigene Geschäftsstrategie und die damit verbundenen Geschäftsprozesse zu konkretisieren. Auch in der Chemie ist ein radikaler Strukturbruch absehbar.
Raising awareness about fecal incontinence
Authors: Bliss Donna Z. , Norton Christine , Vodusek David B.
Published: April 2010

There is a lack of awareness about fecal incontinence despite its prevalence and adverse impact on quality of life. Inadequate knowledge about fecal incontinence deters help‐seeking, therapeutic consultation, and clinical research about effective prevention and management strategies. A systematic, evidenced‐based approach to raise awareness of fecal incontinence is essential to forward progress and overcome multiple barriers. In this manuscript, strategies of this approach are prioritized and focus on increasing continence literacy and communication, emphasizing prevention and screening, disseminating evidenced‐based management interventions, and promoting larger scale impact through effective partnerships. Neurourol. Urodynam. 29:612–615, 2010. Copyright © 2010 Wiley‐Liss, Inc.
Genetics and the lower urinary tract
Authors: Norton Peggy , Milsom Ian
Published: April 2010

Many complex disorders have been found to have a heritable component, including lower urinary tract dysfunction. Twin studies have indicated that genetic contributions to urinary incontinence (UI) may be as important as environmental influences. Linkage to chromosome 9 has been demonstrated in families with pelvic organ prolapse and stress UI. An increasing number of incontinence specialists are studying subjects with lower urinary tract dysfunction using single nucleotide polymorphisms, linkage analyses of siblings, and large association studies. These findings have exciting implications for future prevention and treatment of UI. Neurourol. Urodynam. 29:609–611, 2010. © 2010 Wiley‐Liss, Inc.
Crystallization and morphology of polymerized cyclic butylene terephthalate
Authors: Wu Chang‐Mou , Jiang Chi‐Wea
Published: April 2010

The crystallization behavior and morphology of polymerized cyclic butylene terephthalate (pCBT) were investigated by thermal differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The spherulite growth rate was analyzed based on the Hoffman and Lauritzen theory to better understand the crystallization behavior. We found four typical morphologic features of pCBT corresponding to the crystallization temperature spectrum: usual negative spherulite, unusual spherulite, mixed birefringence spherulite coexisting with boundary crystals, and highly disordered spherulitic crystallites. The Avrami crystallization kinetics confirmed the occurrence of combined heterogeneous nucleation accompanied by a change in the spherulitic shape of pCBT, which also agreed with the PLM results. The equilibrium melting temperature and glass transition temperature of pCBT were 257.8 °C and 41.1 °C, respectively. A regime II–III transition occurred at 200.9 °C, which was 10 °C lower than that reported for poly(butylene terephthalate) (PBT). Coinciding with and attributed to the regime transition, the boundary crystal disappeared at temperatures above 200 °C and the morphology changed from the mixed type to highly disordered spherulitic crystallites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1127–1134, 2010
Nanostructured polybenzoxazine thermosets via reaction‐induced microphase separation
Authors: Li Yan , Zheng Sixun
Published: April 2010

A multiblock copolymer consisting of main‐chain polybenzoxazine and poly(propylene oxide) blocks was synthesized via Mannich polycondensation among 4,4′‐dihydroxyldiphenylisopropane, 4,4′‐diaminodiphenylmethane, amino‐terminated poly(propylene oxide), and paraformaldehyde, which was evidenced by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gel permeation chromatography. The multiblock copolymer was incorporated into polybenzoxazine to access the nanostructured polybenzoxazine thermosets. The morphology of the thermosets was investigated by means of atomic force microscopy and small angle X‐ray scattering. It was judged that the formation of the nanostructures in the thermosetting composites follows the mechanism of reaction‐induced microphase separation. Owing to the big difference in thermal stability between polybenzoxazine thermosets and poly(propylene oxide), the nanostructured thermosets were subjected to the pyrolysis at moderate elevated temperatures to remove poly(propylene oxide) microdomains, to access the nanoporous polybenzoxazine thermosets. The nanoporosity of the resulting polybenzoxazine thermosets was investigated by means of Fourier transform infrared spectroscopy and field‐emission scanning electronic microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1148–1159, 2010
Morphological evolution and orientation development of stretched iPP films: Influence of draw ratio
Authors: Zhou Ying‐Guo , Turng Lih‐Sheng , Shen Chang‐Yu
Published: April 2010

Varying the processing conditions of semicrystalline polymers can produce different morphologies of crystallization, which leads to different properties. There have been extensive studies of flow‐induced crystallization on isotactic polypropylene (iPP) using predominantly shear flow. A stretching method, deduced from extrusion, was introduced to study the morphological evolution of elongation‐induced shish‐kebab crystallization. Different morphologies of the resultant samples with different draw ratios (DRs) were carefully investigated and characterized via differential scanning calorimetry, polarizing light microscopy, scanning electron microscopy, atomic force microscopy, and 2D small‐angle X‐ray scattering. In addition, the degree of orientation of the samples with different DRs was also investigated using the 2D wide‐angle X‐ray scattering technique. The results indicate that the elongation‐induced morphology is strongly dependent on the effective stretching flow expressed in terms of the DR, which is defined as the ratio of rates between take‐up and the extrusion. The spherulite is dominant at low DRs, but it starts to deform along the stretching direction with increasing DR. The shish‐kebab structure in the stretched film, composed of stretched chains (shish) and layered crystalline lamellae (kebabs), increases gradually with an increase in the DR, whereas the spherulites gradually decreased. Furthermore, the overall orientation of α‐phase crystals, expressed by the Hermans orientation parameter, is also found to increase dramatically with the DR, and the rate of increase strongly depends on the DR. The different crystal morphologies are attributed to crystallization induced by different elongations of the stretched iPP films. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1223–1234, 2010
A new route of manipulation of poly(L‐lactic acid) crystallization by self‐assembly of p‐tert‐butylcalix[8]arene and toluene
Authors: Wen Liang , Xin Zhong , Hu Dongkang
Published: April 2010

A novel nucleating agent (TBC8‐t), self‐assembled with p‐tert‐butylcalix[8]arene (TBC8) and toluene, was used to manipulate the crystallization behavior of poly(L‐lactic acid) (PLLA). Toluene molecules were used to adjust the crystallization structure of TBC8. Differential scanning calorimetry results show that the crystallization peak temperature (Tc) and crystallization rate (ΔHc/time) of PLLA nucleated with TBC8‐t are 132.3 °C and 0.24 J/gs, respectively, which are much higher than that with conventional nucleating agent‐talc (Tc = 119.3 °C, ΔHc/time = 0.13 J/gs). The results of polarized optical microscopy demonstrate that TBC8‐t could greatly enhance the crystallization rate of PLLA by increasing the nucleation rate rather than crystal growth rate. Along with an improvement of the crystallization rate, the crystalline morphology of PLLA is also affected by TBC8‐t. The addition of TBC8‐t transforms most of the original spherulite crystals into sheaf‐like crystals. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1235–1243, 2010
Another view on the analysis of cardiovascular morbidity/mortality trials
Authors: Rosenkranz Gerd K.
Published: April 2010

In many morbidity/mortality studies, composite endpoints are considered. Although the primary interest is to demonstrate that an invention delays death, the expected death rate is often that low that studies focussing on survival exclusively are not feasible. Components of the composite endpoint are chosen such that their occurrence is predictive for time to death. Therefore, if the time to non‐fatal events is censored by death, censoring is no longer independent. As a consequence, the analysis of the components of a composite endpoint cannot be reasonably performed using classical methods for the analysis of survival times like Kaplan–Meier estimates or log‐rank tests. In this paper we visualize the impact of disregarding dependent censoring during the analysis and discuss practicable alternatives for the analysis of morbidity/mortality studies. In the context of simulations we provide evidence that copula‐based methods have the potential to deliver practically unbiased estimates of hazards of components of a composite endpoint. At the same time, they require minimal assumptions, which is important since not all assumptions are generally verifiable because of censoring. Therefore, there are alternative ways to analyze morbidity/mortality studies more appropriately by accounting for the dependencies among the components of composite endpoints. Despite the limitations mentioned, these alternatives can at minimum serve as sensitivity analyses to check the robustness of the currently used methods. Copyright © 2010 John Wiley & Sons, Ltd.
Small‐load nanoindentation experiments on metals
Authors: Campbellová Anna , Klapetek Petr , Buršíková Vilma , Valtr Miroslav , Buršík Jiří
Published: April 2010

The loading curve dependency and presence of ‘pop‐in’ effects were studied for different materials and indentation methods specifically on metals with face‐centered cubic (Ni) and tetragonal (Sn) crystalline structures. The nanoindentation experiments were performed on a CSM UNHT (ultra nano hardness tester) instrument using a diamond Berkovich tip and on an atomic force microscope using a steel indentation cantilever. The dependence of the pop‐in creation on the grain orientation (determined using electron backscatter diffraction (EBSD)) was compared with those in the literature and molecular dynamics simulations, using a combination of the embedded atom method and density functional theory (DFT). Due to its computational demands, DFT was used only for validation of the performance of the classical molecular dynamics code. Copyright © 2010 John Wiley & Sons, Ltd.
Near‐field optical microscopy simulations using graphics processing units
Authors: Klapetek Petr , Valtr Miroslav
Published: April 2010

Scanning near‐field optical microscopy (NSOM) is a perspective method for local analysis of optical parameters of nanostructures used in electro‐optics, photonics and many other field of research. Due to complicated nature of topography‐related effects in the optical signal, which can influence or completely alter the NSOM data, the practical use of this method for quantitative analysis is still limited. One of the approaches to determine the effects of topography on optical data is to simulate NSOM images using an electromagnetic field modeling method, e.g. finite difference in time domain method. However, this approach is extremely slow, as full electromagnetic field propagation calculation must be run for each pixel of the resulting simulated image. In this paper, we present a fast method for computing simulated NSOM images based on the use of a graphics processing unit (GPU or computer graphics card) in order to speed up the computations. We will show that the large speedup using this approach (more than 40 times) allows us to simulate images in a time comparable to their real measurement, which increases the possibilities of quantitative analysis using NSOM. Data simulated by a GPU will be compared with those of real measurements as well. Copyright © 2010 John Wiley & Sons, Ltd.
An XPS study of the interatomic charge distribution in stainless steels
Authors: Diplas S. , Moslemzadeh N. , Watts J. F. , Beamson G. , Tsakiropoulos P.
Published: April 2010

The secondary spectral feature of the Al Kα‐excited Ni 2p spectrum, positioned at a kinetic energy of approximately 6 eV lower than the main Ni 2p peak, is known as either the 2p satellite (in the case of inorganic materials) or a plasmon loss peak (in the case of metals). This feature was used to probe changes in the local electronic structure of Ni in stainless steels. The results were compared with a previous study on Auger parameter and core–core–valence (CCV) Auger lines acquired using Cu Kα radiation. The position of the secondary peak shifts to higher binding energy as the number of Fe atoms around Ni increases and this is consistent with the idea of charge transfer from Fe to Ni 3d irrespective of whether the peak is treated as a plasmon or satellite. Previous studies on Ni alloys showed that as the concentration of the more electropositive partners in the Ni alloy (such as Fe in a NiFe alloy) increased compared to Ni, the intensity of the Ni energy loss decreased. However, contrary to previous studies, in steels that we studied, the intensity of the secondary peak increases as the concentration of Fe (or even Cr) increases. Copyright © 2010 John Wiley & Sons, Ltd.
Nanopowders with superparamagnetic Fe3C particles and their annealing behaviour
Authors: David B. , Schneeweiss O. , Pizúrová N. , Dumitrache F. , Fleaca C. , Alexandrescu R.
Published: April 2010

Two samples of nanopowders containing superparamagnetic Fe3C and Fe3O4/γ–Fe2O3 particles and carbon black were synthesized by the method of laser‐induced homogeneous pyrolysis of gaseous precursors. Both were characterized by XRD, HR‐TEM, Mössbauer spectrometry and standard magnetic measurements. The mean crystallite size of Fe3C was 3 nm for the first sample and 10 nm for the second sample. Fe3C phase in both samples exhibited reduced Curie temperature and smeared ferromagnetic–paramagnetic transition. After annealing of the samples at 800 °C for 30 min the Curie temperature of the recrystallized Fe3C phase in both samples was ∼214 °C (standard bulk value). Copyright © 2010 John Wiley & Sons, Ltd.
Leptin Functions Peripherally to Regulate Differentiation of Mesenchymal Progenitor Cells
Authors: Scheller Erica L. , Song Junhui , Dishowitz Michael I. , Soki Fabiana Naomi , Hankenson Kurt D. , Krebsbach Paul H.
Published: April 2010

Leptin functions through a well-documented central neuroendocrine pathway to regulate bone mass. However, the ability of leptin to modulate bone mass through a peripheral mechanism has been debated due to conflicting in vitro results and lack of sufficient in vivo models. We utilized mice with LoxP sites introduced into the long-form leptin receptor (ObRb) gene to determine how leptin regulates mesenchymal progenitor cell (MPC) differentiation and osteoblast function in vitro and in vivo. Rapid phosphorylation of Stat3 after leptin treatment of bone marrow stromal cells (BMSCs) from mice with conditional deletion of ObRb in macrophages (LysMCre+F/F) confirmed expression of functional leptin receptors by BMSCs. Adenovirus-Cre mediated disruption of ObRb in primary stromal cells decreased mineralization and increased adipogenesis. In contrast, BMSCs harvested from leptin-signaling deficient Ob/Ob or Db/Db mice showed increased mineralization. To determine the physiologic relevance of these differences, mice with cell-specific deletion of ObRb in mesenchymal precursors (3.6Cre+F/F) or osteoblasts (2.3Cre+F/F) were generated. Although the 2.3Cre+F/F mice were grossly normal, the 3.6Cre+F/F mice displayed mild obesity that was not attributed to food intake. Femurs of 3.6Cre+F/F animals showed a 58%–61.9% increase in trabecular bone volume and a 65.5%–74% increase in bone mineral density. Cortical volume and mineral content were also increased 18%–22%. Primary 3.6Cre+F/F BMSCs recapitulated the high mineralization phenotype of Ob/Ob and Db/Db BMSCs. We conclude that leptin may have multiple peripheral roles depending on the differentiation state of MPC. Leptin (a) helps maintain MPCs in an undifferentiated state and (b) promotes mineralization of more differentiated osteoblasts.
RFID reader collision problem: performance analysis and medium access
Authors: Yoon Wonyong , Vaidya Nitin H.
Published: April 2010

The RFID reader collision problem, in which an RFID reader's interrogation is interfered by other concurrent readers' transmission, is considered an important issue to reliable operation and thus to the wide‐spread deployment of RFID networks. In this paper, we present modeling and analysis of the RFID reader collision problem. We observe asymmetry between an RFID reader's and a tag's communication capabilities and develop an RFID radio model based on the asymmetry. By the model, we characterize the spatial reuse of RFID reader networks, and deriveconcurrent interrogation distancebeyond which readers can transmit simultaneously without causing collision and the carrier sense threshold corresponding to the distance. We also examine the dual‐channel mode where available bandwidth is divided into two channels by which reader‐to‐tag communication and tag‐to‐reader communication are separated. We analyze and evaluate the performance of the dual‐channel mode in terms of spatial reuse and interrogation completion time. Copyright © 2010 John Wiley & Sons, Ltd.
The development of emotion
Authors: Marshall Peter J.
Published: April 2010

Given that they are responsible for much of the meaning that we attribute to our existence, emotions could be said to have a central role in the psychological life of humans. But given this fundamental level of significance, the construct of emotion remains poorly understood, with the field of emotion research being full of conflicting definitions and opposing theoretical perspectives. In this review, one particular aspect of research into emotion is considered: the development of emotion in infancy and early childhood. The development of the emotional life of the child has been the focus of a vast amount of research and theorizing, so in a brief review it is only possible to scratch the surface of this topic. Rather than any attempt at a comprehensive account, three perennial questions in theorizing and research on early emotional development will be considered. First, what develops in emotional development? Second, what is the relation of cognitive development to emotional development? Third, how has the study of early individual differences in emotion expression typically been approached? In relation to the first question, four theoretical approaches to emotional development are described. For the second question, the focus is on the relation of self‐awareness to the development of emotion. Finally, for the third question, the use of temperament theory as a framework for understanding individual differences in emotion expression is examined. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Psychology > Development and Aging

Psychology > Emotion and Motivation
Aging and cognition
Authors: Mather Mara
Published: April 2010

As we grow older, we gain knowledge and experience greater emotional balance, but we also experience memory loss and difficulties in learning new associations. Which cognitive abilities decline, remain stable or improve with age depends on the health of the brain and body as well as on what skills are practiced or challenged in everyday life. Recent research provides a growing understanding of the relationship between physical and cognitive changes across the life span and reveals ways to increase mental sharpness and avoid cognitive decline. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Psychology > Development and Aging
Electrophysiological models of neural processing
Authors: Nelson Mark E.
Published: April 2010

The brain is an amazing information processing system that allows organisms to adaptively monitor and control complex dynamic interactions with their environment across multiple spatial and temporal scales. Mathematical modeling and computer simulation techniques have become essential tools in understanding diverse aspects of neural processing ranging from sub‐millisecond temporal coding in the sound localization circuity of barn owls to long‐term memory storage and retrieval in humans that can span decades. The processing capabilities of individual neurons lie at the core of these models, with the emphasis shifting upward and downward across different levels of biological organization depending on the nature of the questions being addressed. This review provides an introduction to the techniques for constructing biophysically based models of individual neurons and local networks. Topics include Hodgkin‐Huxley‐type models of macroscopic membrane currents, Markov models of individual ion‐channel currents, compartmental models of neuronal morphology, and network models involving synaptic interactions among multiple neurons. WIREs Syst Biol Med 2011 3 74–92 DOI: 10.1002/wsbm.95

This article is categorized under:

Models of Systems Properties and Processes > Mechanistic Models
MOFs by Transformation of 1D‐Coordination Polymers II: The Homoleptic Divalent Rare Earth 3D Benzotriazolate $\rm ^3_\infty[Eu(Btz)_2]$ Initiating from $\rm ^1_\infty[Eu(Btz)_2(BtzH)_2]$
Authors: Rybak Jens‐Christoph , Schellenberg Inga , Pöttgen Rainer , Müller‐Buschbaum Klaus
Published: April 2010

The solvent free reaction route produces coordination polymers that have a dimensionality of the linkage, which is increasing with the thermal energy. The synthesis of the 3D metal organic framework (MOF) structure $\rm ^3_\infty[Eu(Btz)_2]$ marks the final thermal reaction step within the system europium/1H‐1,2,3‐benzotriazole. It can be obtained by a reaction of the metal with a melt of benzotriazole above 230 °C or from thermal treatment of the 1D coordination polymer$\rm ^1_\infty[Eu(Btz)_2(BtzH)_2]$ (Btz– = 1,2,3‐benzotriazolate anion, C6H4N3–; BtzH = 1H‐1,2,3‐benzotriazole, C6H5N3), which is formed first at about 100 °C from the same reagents. In addition to the trivalent rare earth ions it can thus be shown that also divalent EuII together with benzotriazole exhibits transformation of a 1D coordination polymer into a 3D MOF. The homoleptic framework $\rm ^3_\infty[Eu(Btz)_2]$ exhibits a high thermal stability (525 °C) for an exothermically decomposing coordination compound. As $\rm ^3_\infty[Eu(Btz)_2]$ is always obtained as a microcrystalline product, structure solution and refinement were achieved by X‐ray powder techniques. For further characterization 151Eu‐Mössbauer, IR, and Raman spectroscopy as well as micro and thermal analysis were carried out.
Mixed Valence Tungsten (IV,V) Compounds with Layered Structures (Part III) [2]: Synthesis and Crystal Structure of Ag1–x[W2O2Cl6] and Investigations on the Ag+ Ion Mobility
Authors: Beck Johannes , Hoffbauer Wilfried , Kusterer Christian , Schieweling Marcel
Published: April 2010

The reaction of metallic silver with tungsten tetrachlorideoxide WOCl4 or the reaction of AgCl with WOCl3, both at 690 K, lead to Ag1–x[W2O2Cl6] as black lustrous crystal needles. The compound shows a substantial phase field width in the silver content depending on reaction temperature and reaction time and crystals with x = 0, 0.38 and 0.82 were isolated. The crystal structure determinations (monoclinic, C2/m) show the structure to be isotypic to those of Tl[W2O2Cl6] and K0.84[W2O2Cl6] with the presence of 1D polymeric [W2O2Cl6]n strands and Ag+ ions with a variety in the occupation of the respective crystallographic site. Ag1–x[W2O2Cl6] represents a mixed valence compound with a variable ratio of W(IV) and W(V) in the W2 dumbbells with a short W–W separation of 2.85 Å. In Fourier maps the electron density of the Ag ion appears smeared over a large area. By structure determinations of stoichiometric Ag1.0[W2O2Cl6] at temperatures of 123, 193, and 293 K a double minimum potential was found with the silver ion dynamically disordered over two flat basins with a thermal activation barrier of 13 meV. No long range ion mobility is present since the Ag+ ions are trapped within a coordinating cage consisting of ten chlorine atoms of the surrounding [W2O2Cl6] strands forming a distorted bicapped cube. By MAS‐NMR spectroscopic measurements on the 109Ag nuclei at different temperatures, the spin lattice relaxation times were determined giving a thermally activated barrier of 15 meV. The electronic conductivity of pressed powder samples of Ag[W2O2Cl6] by a four‐probe measurement applying direct current is 1 Ω–1·cm–1 at room temperature and 10–3 Ω–1·cm–1 at 25 K. For the conduction mechanism at low temperatures a variable range hopping mechanism is suggested, whereas at higher temperatures a standard semi‐conductivity with a bandgap of 60 meV is present.
Freizeitgroßprojekte: Mehr Chancen oder Risiken für die Stadtentwicklung?
Authors: Schemel Hans-Joachim
Published: April 2010

On the basis of a comparison of current conditions in Murich and Oberhausen with regard to both the local economy and the state of urban development, the authors attempt to establish just what are the critical factors which determine whether the decision to locate a major leisure project (an “FGP”) in a particular city harbours more advantages or disadvantages for the city concerned. The authors look critically at the arguments frequently advanced in favour of FGPs, namely the “added leisure value” and “locational benefits”, as well as the gains anticipated for the city's economic strength, for city and regional development, for the city's image and for its competitive position vis-à-vis other cities. Proceeding from an appraisal of the current leisure value of the two cities, they go on to examine and to assess the impact of such a new FGP on the existing range of decentralised retail and leisure amenities. Where the initial assessment of a city's leisure value is high, an FGP is unlikely to be capable of generating additional demand. Thus, the very significant displacement of demand which can be expected to take place following the opening of a new FGP will be accompanied by losses in terms of both leisure value and urbanity. The authors also indicate what factors need to be considered in selecting the right location for an FGP, assuming that such a development is deemed desirable from an urban development perspective.
Prevalence, Risk Factors, and Management of Seroma Formation After Breast Approach Endoscopic Thyroidectomy
Authors: Shan Cheng‐Xiang , Zhang Wei , Jiang Dao‐Zhen , Zheng Xiang‐Min , Liu Sheng , Qiu Ming
Published: April 2010

Background

Breast approach endoscopic thyroidectomy (BAET) allows surgeons to remove a thyroid tumor from a remote site while providing a scarless cosmetic appearance in the neck. However, seroma formation after subcutaneous dissection could lead to flap detachment, incision dehiscence, and wound infection. Chronic formation of seromas could substantially compromise the esthetic outcome of BAET. We evaluated the prevalence, risk factors, and treatments of seroma after BAET.

Methods

A total of 344 patients who underwent BAET between 2001 and 2008 at our institution were recruited; data were collected prospectively. The characteristics and outcomes of patients who developed seromas were compared with those of patients who did not. Regression analysis was used to identify the independent risk factors for seroma formation. The frequency and volume of aspirations were noted until the seroma went into remission.

Results

The overall postoperative prevalence of seroma formation was 2.9%. There was a significant difference in seroma formation based on age, hypertension, body mass index (BMI), and area of subcutaneous dissection space (ASDS). Percutaneous aspiration alone or combined with external compression was extremely effective. The frequency and total volume of aspirations were 1–7 and 6–120 ml, respectively. As a result of prolonged seroma formation, one patient developed an expanding pseudo‐bursa that created a tumor‐like effect in the anterior chest wall.

Conclusions

Seroma formation was an uncommon minor complication after BAET. Four independent etiologic factors could predispose patients to postoperative seroma formation. Percutaneous aspiration appeared to be very effective. Prolonged seroma formation followed by development of a pseudo‐bursa could be very problematic and could substantially impair the esthetic effect of BAET.
Estimating demographic parameters for loggerhead sea turtles using mark–recapture data and a multistate model
Authors: Monk Melissa Hedges , Berkson Jim , Rivalan Philippe
Published: April 2010

The survival for adult loggerhead sea turtles from a saturation tagging study on Bald Head Island, NC, USA, was estimated using a multistate model with unobservable states to relax assumptions that are violated when survival is estimated from multistate models and produce more accurate estimates of survival, recapture, and breeding transition probabilities. The influence of time, trap dependence, and low site fidelity to the study nesting beach on survival and recapture were examined. The best model given the data included an imprecise site‐fidelity effect on survival, constrained the reproductive cycle to 4 years, and contained a time effect on recapture rates. The estimate of annual survival for adult females was of 0.85, producing the highest estimate in the literature for loggerhead sea turtles. Multistate models should be applied to other nesting beach data for sea turtles to improve survival estimates and in turn the ability to model and manage populations.
Structural insights into eukaryotic aquaporin regulation
Authors: Törnroth-Horsefield Susanna , Hedfalk Kristina , Fischer Gerhard , Lindkvist-Petersson Karin , Neutze Richard
Published: April 2010

Aquaporin‐mediated water transport across cellular membranes is an ancient, ubiquitous mechanism within cell biology. This family of integral membrane proteins includes both water selective pores (aquaporins) and transport facilitators of other small molecules such as glycerol and urea (aquaglyceroporins). Eukaryotic aquaporins are frequently regulated post‐translationally by gating, whereby the rate of flux through the channel is controlled, or by trafficking, whereby aquaporins are shuttled from intracellular storage sites to the plasma membrane. A number of high‐resolution X‐ray structures of eukaryotic aquaporins have recently been reported and the new structural insights into gating and trafficking that emerged from these studies are described. Basic structural themes reoccur, illustrating how the problem of regulation in diverse biological contexts builds upon a limited set of possible solutions.
Cellular factors implicated in prion replication
Authors: Abid Karim , Morales Rodrigo , Soto Claudio
Published: April 2010

Prions are the unconventional infectious agents responsible for prion diseases, which are composed mainly by the misfolded prion protein (PrPSc) that replicates by converting the host associated cellular prion protein (PrPC). Several lines of evidence suggest that other cellular components participate in prion conversion, however, the identity or even the chemical nature of such factors are entirely unknown. In this article we study the conversion factor activity by complementation of a PMCA procedure employing purified PrPC and PrPSc. Our results show that the conversion factor is present in all major organs of diverse mammalian species, and is predominantly located in the lipid raft fraction of the cytoplasmic membrane. On the other hand, it is not present in the lower organisms tested (yeast, bacteria and flies). Surprisingly, treatments that eliminate the major classes of chemical molecules do not affect conversion activity, suggesting that various different compounds may act as conversion factor in vitro. This conclusion is further supported by experiments showing that addition of various classes of molecules have a small, but detectable effect on enhancing prion replication in vitro. More research is needed to elucidate the identity of these factors, their detailed mechanism of action and whether or not they are essential component of the infectious particle.
Fighting disease by selective autophagy of aggregate‐prone proteins
Authors: Knævelsrud Helene , Simonsen Anne
Published: April 2010

Ubiquitinated protein aggregates are hallmarks of a range of human diseases, including neurodegenerative, liver and muscle disorders. These protein aggregates are typically positive for the autophagy receptor p62. Whereas the ubiquitin‐proteasome system (UPS) degrades shortlived and misfolded ubiquitinated proteins that are small enough to enter the narrow pore of the barrel‐shaped proteasome, the lysosomal pathway of autophagy can degrade larger structures including entire organelles or protein aggregates. This degradation requires autophagy receptors that link the cargo with the molecular machinery of autophagy and is enhanced by certain posttranslational modifications of the cargo. In this review we focus on how autophagy clears aggregate‐prone proteins and the relevance of this process to protein aggregate associated diseases.
Mining metagenomic data for novel domains: BACON, a new carbohydrate‐binding module
Authors: Mello Luciane V. , Chen Xin , Rigden Daniel J.
Published: April 2010

Third‐generation sequencing has given new impetus to protein sequence database growth, revealing new domains. Description and analysis of these is required to further improve the coverage and utility of domain databases. A novel domain, here named BACON, was discovered from analysis of metagenomic data obtained from gut bacteria. Domain architectures unambiguously link its function to carbohydrate metabolism but a further strong connection to protease domains suggests that many BACON domains bind glycoproteins. Conserved residues in the BACON domain are also characteristic of carbohydrate binding while its biased phyletic distribution and other data suggest mucin as a potential specific target.
Endoplasmic reticulum stress response is involved in Mycobacterium tuberculosis protein ESAT‐6‐mediated apoptosis
Authors: Choi Hong-Hee , Shin Dong-Min , Kang Gun , Kim Ki-Hye , Park Jin Bong , Hur Gang Min , Lee Hye-Mi , Lim Yun-Ji , Park Jeong-Kyu , Jo Eun-Kyeong , Song Chang-Hwa
Published: April 2010

Mycobacterium tuberculosis (Mtb) infection leads to the induction of the apoptotic response, which is associated with bacilli killing. The early secreted mycobacterial antigen ESAT‐6 of Mtb has been shown to induce apoptosis in human macrophages and epithelial cells. In the present study, we demonstrate that the stimulation of human epithelial A549 cells by ESAT‐6 induces the endoplasmic reticulum (ER) stress response. We observed that ESAT‐6 treatment increases intracellular Ca2+ concentration, which results in ROS accumulation, and therefore induces the onset of ER stress‐induced apoptosis. Our results uncover a novel apoptotic mechanism of ESAT‐6 through ER stress responses in pathologic conditions such as tuberculosis.
A resource dependence theory perspective of ISO 9000 in managing organizational environment
Authors: Singh Prakash J. , Power Damien , Chuong Sum Chee
Published: April 2010

More than 900,000 organizations worldwide have registered to the ISO 9000 quality management standard. Despite its growing popularity, few studies have offered a coherent theoretical basis for the standard's appeal. A theory‐based explanation enhances understanding and appreciation for the standard, and provides clarity on how the standard benefits organizations. In this paper, we invoke the resource dependence theory (RDT) to purport that the standard is used by organizations as a tool to manage their organizational environment. It does this by specifying procedures that organizations need to manage their organization–environment boundary spanning processes. Using the RDT perspective, a model with three key constructs embodying ISO 9000 was developed: internal processes, relationships with customers and relationships with suppliers. The latter two were treated as being part of the task environment. We predicted that the external aspects of the standard affect operating performance (a measure of effectiveness), both directly and through internal processes. Empirical data from 416 ISO 9000 registered Australian manufacturing plants validated the RDT perspective, and suggest that the three constructs, individually and in isolation, are not as effective as when they are considered together. By invoking RDT, a new theoretical viewpoint to ISO 9000 has been developed that adds to other theoretical perspectives, and goes some way to explaining the growing popularity of this standard with organizations.
Article Commentary: Act to keep patients safe: Device‐related adverse event reporting
Authors: Schoem Scott R. , Shah Udayan K.
Published: April 2010

Primum non nocere— “Above all do no harm.” Since the first year of medical school, we have all heard and spoken this dictum countless times. Translating this dictum into action may present challenges in our daily practice. Every day, clinicians must distinguish between scientific evidence, clinical experience, and marketing claims by industry vendors of improved efficacy and safety regarding medical devices. Adverse event reporting and device failure notification are generally laid out well in hospital practice settings. Reporting beyond the local level takes on a new dimension for most surgeons. Perceived stigma from peers and corporations, lack of confidentiality, and cynicism regarding protective actions for patients should not limit one from “raising the alarm” when concerns arise about device safety or performance. This commentary aims to explain the process for reporting device‐related adverse events.
Cross‐hatching: A novel technique for Eustachian tuboplasty. Preliminary report
Authors: Yañez Carlos
Published: April 2010

Objective

To evaluate laser‐assisted cross‐hatching technique for treatment of patients with Eustachian tube dysfunction.

Study Design

Prospective, institutional review board‐approved surgical trial.

Setting

Tertiary care medical center.

Subjects and Methods

A total of 25 patients with Eustachian tube dysfunction underwent laser Eustachian tuboplasty with cross‐hatching technique (CHT). Surgery involved use of the argon laser to cross‐hatch the posterior cushion to modify the curvature of the cartilage of the posterior cushion and to alter the spring of the cartilage to make it wider and larger, thereby alleviating the obstructive dysfunction of the tube. None of the patients had any concurrent disease or surgical procedure.

Results

There were no surgical complications. Following CHT, subjective symptoms of an ear blockage improved in 23 of 25 (92%) patients. Posterior cushion curvature became softer and wider, and the valve appeared more open postoperatively on simple endoscopy (SE) and slow motion video endoscopic analysis (SMVEA). Mean pure‐tone average improved by 10 dB (30 dB preoperatively vs 20 dB postoperatively; P = 0.015). Abnormal tympanogram improved in 24 of 25 (96%) patients. Failure of the procedure correlated with severity of cartilage deformation and valve obstruction as measured by both SE and SMVEA. Mean follow‐up was 15 months (range 3‐37 months).

Conclusion

Cross‐hatching technique for Eustachian tuboplasty appears to be a safe and useful technique for treatment of Eustachian tube dysfunction.
Allergic rhinitis patients with recurrent acute sinusitis have increased sinonasal epithelial cell TLR9 expression
Authors: Melvin Thuy‐Anh N. , Lane Andrew P. , Nguyen Mai‐Tien , Lin Sandra Y.
Published: April 2010

Objective

Pilot study examining toll‐like receptor 9 (TLR9) expression by sinonasal epithelial cells in allergic rhinitis (AR) subjects with and without a history of recurrent acute rhinosinusitis (RARS).

Study Design

Cohort study.

Setting

Outpatient clinic.

Subjects and Methods

Adult subjects were eligible for study if skin tested positive for inhalant allergens, and positive allergens were in season at time of study. Subjects were considered to have AR+RARS if they had four symptomatic episodes with major/minor factors in 12 months and CT evidence of sinusitis. Eight AR‐only subjects and 13 AR+RARS subjects underwent endoscopic‐guided cell brushing from the middle meatus. Flow cytometry for TLR9 expression was performed on collected fresh sinonasal epithelial cells.

Results

The AR+RARS group was found to have a significant increase in TLR9 expression in the sinonasal epithelium (66% ± 30%) compared with that of AR‐only patients (32% ± 21%; P = 0.011).

Conclusion

The significant difference in expression of TLR9 in allergic sinusitis patients compared with allergy‐only patients in this study may indicate a difference in the role of innate immunity in these groups. The results suggest that expression of innate immune markers such as TLR9 may be upregulated in response to repeated microbial insults in AR+RARS. Further research is necessary to determine whether an initial impairment of innate immune gene expression may predispose some AR patients to subsequent development of RARS.