88 research outputs found

    Octyl-decorated Fréchet-type dendrons : a general motif for visualisation of static and dynamic behaviour using scanning tunnelling microscopy

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    Firstly, a short overview on supramolecular chemistry including definitions, basic principles and examples taken from the literature of 2D and 3D self-assembly processes is given in Chapter 1. The introduction is completed by some general ideas of dendrimer chemistry. In the second Chapter the techniques used in this thesis are introduced with a special focus on scanning tunnelling microscopy (STM). Besides the mode of operation and the data processing, the historical background is briefly described. The following four Chapters present STM studies of monolayers formed by different types of compounds, all functionalised with Fréchet-type dendrons. Not only static features of monolayers such as conformational analysis of single molecules have been investigated, but also dynamic processes such as delayed conversion of a whole domain and conformational changes by protonation have been examined. The 2D properties of monolayers on a graphite surface have been compared with the X-ray data of 3D single crystals. For two compounds, the same molecular arrangement has been detected in monolayers on graphite and in single crystals. Together with organic molecules, the self-assembly of metal complexes possessing tpy ligands and organometallic species with platinum(II) bis(alkynyl) units has been examined. Not all of these metal complexes were stable under the scanning conditions used in STM. A synthetic programme leading to dendrimer-functionalised organic and organometallic compounds has been developed. Discussions of synthetic routes are given at the beginning of each Chapter. Chaptercompares X-ray diffraction methods with STM, the two main analysis tools used for investigation of self-organised assemblies in the solid state in this thesis. In the second part of Chapter 7, the results presented in the previous Chapters are discussed with some general reflections on the self-assembling properties of Fréchet-type dendrimers with pendant octyl groups. Additional to the studies of self-assembled monolayers, the formation of metallomacrocycles has been investigated using two novel homoditopic tpy ligands. This work is presented in Chapter 8. It was demonstrated that the ring-size depends on the metal used for the cyclisation. Furthermore, some of the macrocycles formed self-assembled monolayers on graphite, which have been examined using STM. One homoditopic ligand formed a molecular square by complexation with an iron(II) salt which was analysed using single crystal X-ray diffraction. This thesis has brought together the realms of chemical design with studies of the physical behaviour of the envisioned molecules on the surface. It has been demonstrated that Fréchet-type dendrimers with octyl end-groups are a general motif for visualisation of static and dynamic behaviour using STM

    Predicting the influence of a p2-symmetric substrate on molecular self-organization with an interaction-site model

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    An interaction-site model can a priori predict molecular selforganisation on a new substrate in Monte Carlo simulations. This is experimentally confirmed with scanning tunnelling microscopy on Fre´chet dendrons of a pentacontane template. Local and global ordering motifs, inclusion molecules and a rotated unit cell are correctly predicted

    Impact of obesity on the response to tumor necrosis factor inhibitors in axial spondyloarthritis.

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    Few studies have investigated the impact of obesity on the response to tumor necrosis factor inhibitors (TNFi) in patients with axial spondyloarthritis (axSpA). The aim of our study was to investigate the impact of different body mass index (BMI) categories on TNFi response in a large cohort of patients with axSpA. Patients with axSpA within the Swiss Clinical Quality Management (SCQM) program were included in the current study if they fulfilled the Assessment in Spondyloarthritis International Society (ASAS) criteria for axSpA, started a first TNFi after recruitment, and had available BMI data as well as a baseline and follow-up visit at 1 year (±6 months). Patients were categorized according to BMI: normal (BMI 18.5 to <25), overweight (BMI 25-30), and obese (BMI >30). We evaluated the proportion of patients achieving the 40% improvement in ASAS criteria (ASAS40), as well as Ankylosing Spondylitis Disease Activity Score (ASDAS) improvement and status scores at 1 year. Patients having discontinued the TNFi were considered nonresponders. We controlled for age, sex, HLA-B27, axSpA type, BASDAI, BASMI, elevated C-reactive protein (CRP), current smoking, enthesitis, physical exercise, and co-medication with disease-modifying antirheumatic drugs, as well as with nonsteroidal anti-inflammatory drugs in multiple adjusted logistic regression analyses. A total of 624 axSpA patients starting a first TNFi were considered in the current study (332 patients of normal weight, 204 patients with overweight, and 88 obese patients). Obese individuals were older, had higher BASDAI levels, and had a more important impairment of physical function in comparison to patients of normal weight, while ASDAS and CRP levels were comparable between the three BMI groups. An ASAS40 response was reached by 44%, 34%, and 29% of patients of normal weight, overweight, and obesity, respectively (overall p = 0.02). Significantly lower odds ratios (ORs) for achieving ASAS40 response were found in adjusted analyses in obese patients versus patients with normal BMI (OR 0.27, 95% confidence interval (CI) 0.09-0.70). The respective adjusted ASAS40 OR in overweight versus normal weight patients was 0.62 (95% CI 0.24-1.14). Comparable results were found for the other outcomes assessed. Obesity is associated with significantly lower response rates to TNFi in patients with axSpA

    Peran Ayah dalam Praktik Menyusui

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    Background: In Indonesia the prevalence of exclusive breastfeeding in 2007 was 32%. Although breastfeeding is a common practice, exclusive breastfeeding remains unpracticed optimally due to some influential factors. One factor to be considered here is father\u27s role. However, until recently studies regarding father\u27s role in breastfeeding practice have not been fully explored in Indonesia. In Bukittinggi exclusive breastfeeding rate was 63,5% in 2008.Objective: To investigate the relationship between the father\u27s role and breastfeeding practices in Bukittinggi Municipality.Method: This was an observational study with cross-sectional study design. Subjects were families with babies aged 0 – 6 months using non probability sampling. The independent variable was the father\u27s role and the dependent variable was breastfeeding practices. Meanwhile, the extraneous variables included knowledge, attitude, mother\u27s occupation; father\u27s working hours in a day, and income. The data were analyzed using univariable analysis, bivariable analysis with chi-square test, and multivariable analysis with logistic regression.Results: The result of multivariable analysis showed that there was a significant relationship between the father\u27s role and breastfeeding practice, by including father\u27s knowledge, mother\u27s knowledge, father\u27s attitude and mother\u27s attitude that could predict by 12% (RP= 1.93; 95% CI= 1.36 – 2.74).Conclusion: The prevalence of exclusive breastfeeding practices in the supporting father group was greater than in the group that non-supporting father. The recommendations are that fathers should be targeted audience in the breastfeeding promotion

    Deprotection, tethering and activation of a one-legged metalloporphyrin on a chemically active metal surface: NEXAFS, synchrotron XPS and STM study of [SAc]P- Mn(III)Cl on Ag(100)

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    Abstract The structural and reactive properties of the acetyl-protected "one-legged" manganese porphyrin [SAc]P-Mn(III)Cl on Ag(100) have been studied by NEXAFS, synchrotron XPS and STM. Spontaneous surface-mediated de-protection occurs at 300 K accompanied by spreading of the resulting thio-tethered porphyrin across the metal surface. Loss of the axial chlorine ligand occurs at 498 K, without any de-metallation of the macrocycle, leaving the Mn center in a low co-ordination state. At low coverages the macrocycle is markedly tilted towards the silver surface, as is the phenyl group that forms part of the tethering "leg". In the monolayer region a striking transition occurs whereby the molecule rolls over, preserving the tilt angle of the phenyl group, strongly increasing that of the 2 macrocycle, decreasing the apparent height of the molecule and decreasing its footprint, thus enabling closer packing. These findings are in marked contrast with those previously reported for the corresponding more rigidly bound four-legged porphyrin [JACS 2009[JACS , 126, 1910 suggesting that the physico-chemical properties and potential applications of these versatile systems should be strongly dependent on the mode of tethering to the surface

    Functional outcome after perineal stapled prolapse resection for external rectal prolapse

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    <p>Abstract</p> <p>Background</p> <p>A new surgical technique, the Perineal Stapled Prolapse resection (PSP) for external rectal prolapse was introduced in a feasibility study in 2008. This study now presents the first results of a larger patient group with functional outcome in a mid-term follow-up.</p> <p>Methods</p> <p>From December 2007 to April 2009 PSP was performed by the same surgeon team on patients with external rectal prolapse. The prolapse was completely pulled out and then axially cut open with a linear stapler at three and nine o'clock in lithotomy position. Finally, the prolapse was resected stepwise with the curved Contour<sup>® </sup>Transtar™ stapler at the prolapse's uptake. Perioperative morbidity and functional outcome were prospectively measured by appropriate scores.</p> <p>Results</p> <p>32 patients participated in the study; median age was 80 years (range 26-93). No intraoperative complications and 6.3% minor postoperative complications occurred. Median operation time was 30 minutes (15-65), hospital stay 5 days (2-19). Functional outcome data were available in 31 of the patients after a median follow-up of 6 months (4-22). Preoperative severe faecal incontinence disappeared postoperatively in 90% of patients with a reduction of the median Wexner score from 16 (4-20) to 1 (0-14) (<it>P </it>< 0.0001). No new incidence of constipation was reported.</p> <p>Conclusions</p> <p>The PSP is an elegant, fast and safe procedure, with good functional results.</p> <p>Trial registration</p> <p>ISRCTN68491191</p

    Concerns about anti-angiogenic treatment in patients with glioblastoma multiforme

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    BACKGROUND: The relevance of angiogenesis inhibition in the treatment of glioblastoma multiforme (GBM) should be considered in the unique context of malignant brain tumours. Although patients benefit greatly from reduced cerebral oedema and intracranial pressure, this important clinical improvement on its own may not be considered as an anti-tumour effect. DISCUSSION: GBM can be roughly separated into an angiogenic component, and an invasive or migratory component. Although this latter component seems inert to anti-angiogenic therapy, it is of major importance for disease progression and survival. We reviewed all relevant literature. Published data support that clinical symptoms are tempered by anti-angiogenic treatment, but that tumour invasion continues. Unfortunately, current imaging modalities are affected by anti-angiogenic treatment too, making it even harder to define tumour margins. To illustrate this we present MRI, biopsy and autopsy specimens from bevacizumab-treated patients. Moreover, while treatment of other tumour types may be improved by combining chemotherapy with anti-angiogenic drugs, inhibiting angiogenesis in GBM may antagonise the efficacy of chemotherapeutic drugs by normalising the blood-brain barrier function. SUMMARY: Although angiogenesis inhibition is of considerable value for symptom reduction in GBM patients, lack of proof of a true anti-tumour effect raises concerns about the place of this type of therapy in the treatment of GBM

    In-vivo X-ray Dark-Field Chest Radiography of a Pig

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    X-ray chest radiography is an inexpensive and broadly available tool for initial assessment of the lung in clinical routine, but typically lacks diagnostic sensitivity for detection of pulmonary diseases in their early stages. Recent X-ray dark-field (XDF) imaging studies on mice have shown significant improvements in imaging-based lung diagnostics. Especially in the case of early diagnosis of chronic obstructive pulmonary disease (COPD), XDF imaging clearly outperforms conventional radiography. However, a translation of this technique towards the investigation of larger mammals and finally humans has not yet been achieved. In this letter, we present the first in-vivo XDF full-field chest radiographs (32 x 35 cm(2)) of a living pig, acquired with clinically compatible parameters (40 s scan time, approx. 80 mu Sv dose). For imaging, we developed a novel high-energy XDF system that overcomes the limitations of currently established setups. Our XDF radiographs yield sufficiently high image quality to enable radiographic evaluation of the lungs. We consider this a milestone in the bench-to-bedside translation of XDF imaging and expect XDF imaging to become an invaluable tool in clinical practice, both as a general chest X-ray modality and as a dedicated tool for high-risk patients affected by smoking, industrial work and indoor cooking

    Human cytomegalovirus immediate-early 1 protein rewires upstream STAT3 to downstream STAT1 signaling switching an IL6-type to an IFNγ-like response

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    MN and CP were supported by the Wellcome Trust (www.wellcome.ac.uk) Institutional Strategic Support Fund and CP was supported by the Deutsche Forschungsgemeinschaft (PA 815/2-1; www.dfg.de).The human cytomegalovirus (hCMV) major immediate-early 1 protein (IE1) is best known for activating transcription to facilitate viral replication. Here we present transcriptome data indicating that IE1 is as significant a repressor as it is an activator of host gene expression. Human cells induced to express IE1 exhibit global repression of IL6- and oncostatin M-responsive STAT3 target genes. This repression is followed by STAT1 phosphorylation and activation of STAT1 target genes normally induced by IFNγ. The observed repression and subsequent activation are both mediated through the same region (amino acids 410 to 445) in the C-terminal domain of IE1, and this region serves as a binding site for STAT3. Depletion of STAT3 phenocopies the STAT1-dependent IFNγ-like response to IE1. In contrast, depletion of the IL6 receptor (IL6ST) or the STAT kinase JAK1 prevents this response. Accordingly, treatment with IL6 leads to prolonged STAT1 instead of STAT3 activation in wild-type IE1 expressing cells, but not in cells expressing a mutant protein (IE1dl410-420) deficient for STAT3 binding. A very similar STAT1-directed response to IL6 is also present in cells infected with a wild-type or revertant hCMV, but not an IE1dl410-420 mutant virus, and this response results in restricted viral replication. We conclude that IE1 is sufficient and necessary to rewire upstream IL6-type to downstream IFNγ-like signaling, two pathways linked to opposing actions, resulting in repressed STAT3- and activated STAT1-responsive genes. These findings relate transcriptional repressor and activator functions of IE1 and suggest unexpected outcomes relevant to viral pathogenesis in response to cytokines or growth factors that signal through the IL6ST-JAK1-STAT3 axis in hCMV-infected cells. Our results also reveal that IE1, a protein considered to be a key activator of the hCMV productive cycle, has an unanticipated role in tempering viral replication.Publisher PDFPeer reviewe

    The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and its Implications for Structure Growth

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    We present new measurements of cosmic microwave background (CMB) lensing over 94009400 sq. deg. of the sky. These lensing measurements are derived from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB dataset, which consists of five seasons of ACT CMB temperature and polarization observations. We determine the amplitude of the CMB lensing power spectrum at 2.3%2.3\% precision (43σ43\sigma significance) using a novel pipeline that minimizes sensitivity to foregrounds and to noise properties. To ensure our results are robust, we analyze an extensive set of null tests, consistency tests, and systematic error estimates and employ a blinded analysis framework. The baseline spectrum is well fit by a lensing amplitude of Alens=1.013±0.023A_{\mathrm{lens}}=1.013\pm0.023 relative to the Planck 2018 CMB power spectra best-fit Λ\LambdaCDM model and Alens=1.005±0.023A_{\mathrm{lens}}=1.005\pm0.023 relative to the ACT DR4+WMAP\text{ACT DR4} + \text{WMAP} best-fit model. From our lensing power spectrum measurement, we derive constraints on the parameter combination S8CMBLσ8(Ωm/0.3)0.25S^{\mathrm{CMBL}}_8 \equiv \sigma_8 \left({\Omega_m}/{0.3}\right)^{0.25} of S8CMBL=0.818±0.022S^{\mathrm{CMBL}}_8= 0.818\pm0.022 from ACT DR6 CMB lensing alone and S8CMBL=0.813±0.018S^{\mathrm{CMBL}}_8= 0.813\pm0.018 when combining ACT DR6 and Planck NPIPE CMB lensing power spectra. These results are in excellent agreement with Λ\LambdaCDM model constraints from Planck or ACT DR4+WMAP\text{ACT DR4} + \text{WMAP} CMB power spectrum measurements. Our lensing measurements from redshifts z0.5z\sim0.5--55 are thus fully consistent with Λ\LambdaCDM structure growth predictions based on CMB anisotropies probing primarily z1100z\sim1100. We find no evidence for a suppression of the amplitude of cosmic structure at low redshiftsComment: 45+21 pages, 50 figures. Prepared for submission to ApJ. Also see companion papers Madhavacheril et al and MacCrann et a
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