31 resultados para Multiphonon assisted anti Stokes process
Resumo:
It is accepted that ventilator-associated pneumonia is a frequent cause of morbidity and mortality in intensive care patients. This study describes the physicochemical properties of novel surfactant coatings of the endotracheal tube and the resistance to microbial adherence of surfactant coated endotracheal tube polyvinylchloride (PVC). Organic solutions of surfactants containing a range of ratios of cholesterol and lecithin (0:100, 25:75, 50:50, 75:25, dissolved in dichloromethane) were prepared and coated onto endotracheal tube PVC using a multiple dip-coating process. Using modulated temperature differential scanning calorimetry it was confirmed that the binary surfactant systems existed as physical mixtures. The surface properties of both surfactant-coated and uncoated PVC, following treatment with either pooled human saliva or phosphate-buffered saline (PBS), were characterised using dynamic contact angle analysis. Following treatment with saliva, the contact angles of PVC decreased; however, those of the coated biomaterials were unaffected, indicating different rates and extents of macromolecular adsorption from saliva onto the coated and uncoated PVC. The advancing and receding contact angles of the surfactant-coated PVC were unaffected by sonication, thereby providing evidence of the durability of the coatings. The cell surface hydrophobicity and zeta potentials of isolates of Staphylococcus aureus and Pseudomonas aeruginosa, following treatment with either saliva or PBS, and their adherence to uncoated and surfactant-coated PVC (that had been pre-treated with saliva) were examined. Adherence of S. aureus and Ps. aeruginosa to surfactant-coated PVC at each successive time period (0.5, 1, 2, 4, 8 h) was significantly lower than to uncoated PVC, the extent of the reduction frequently exceeding 90%. Interestingly, the microbial anti-adherent properties of the coatings were dependent on the lecithin content. Based on the impressive microbial anti-adherence properties and durability of the surfactant coating on PVC following dip coatings, it is proposed that these systems may usefully reduce the incidence of ventilator-associated pneumonia when employed as luminal coatings of the endotracheal tube.
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The present paper describes the results of an investigation into the modelling of plug assisted thermoforming. The objective of this work was to improve the finite element modelling of thermoforming through an enhanced understanding of the physical elements underlying the process. Experiments were carried out to measure the effects on output of changes in major parameters and simultaneously simple finite element models were constructed. The experimental results show that the process creates conflicting and interrelated contact friction and heat transfer effects that largely dictate the final wall thickness distribution. From the simulation work it was demonstrated that a high coefficient of friction and no heat transfer can give a good approximation of the actual wall thickness distribution. However, when conduction was added to the model the results for lower friction values were greatly improved. It was concluded that further work is necessary to provide realistic measurements and models for contact effects in thermoforming.
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The role played by firms in the prosecution of anti-dumping and countervailing duty cases in the United States is understudied. This article provides greater understanding of the challenges faced by firms during the process of prosecuting anti-dumping and countervailing duty cases in the United States. This is achieved by applying a theoretical model of corporate political activity to data collected through interviews with 24 trade attorneys in Washington, D.C., practising in the area of antidumping and countervailing duty law. Anti-dumping and countervailing duty cases are found to require significant resource commitments from firms in the participating industries, as well as requiring individual firms to make a number of strategic decisions. The value of an affirmative decision and imposition of duties to the domestic and foreign industry is found to be more nuanced than previous studies have suggested. Non-duty effects of AD and CVD cases are also confirmed. Finally a clearer understanding of the role of individual firms in anti-dumping and countervailing duty cases is shown to have the potential to improve how industry influence is taken account of in future research.
Resumo:
Until recently, the central nervous system (CNS) has been thought to be an immune privileged organ. However, it is now understood that neuroinflammation is linked with the development of several CNS diseases including late-onset Alzheimer's disease (LOAD). The development of inflammation is a complex process involving a wide array of molecular interactions which in the CNS remains to be further characterized. The development of neuroinflammation may represent an important link between the early stages of LOAD and its pathological outcome. It is proposed that risks for LOAD, which include genetic, biological and environmental factors can each contribute to impairment of normal CNS regulation and function. The links between risk factors and the development of neuroinflammation are numerous and involve many complex interactions which contribute to vascular compromise, oxidative stress and ultimately neuroinflammation. Once this cascade of events is initiated, the process of neuroinflammation can become overactivated resulting in further cellular damage and loss of neuronal function. Additionally, neuroinflammation has been associated with the formation of amyloid plaques and neurofibrillary tangles, the pathological hallmarks of LOAD. Increased levels of inflammatory markers have been correlated with an advanced cognitive impairment. Based on this knowledge, new therapies aimed at limiting onset of neuroinflammation could arrest or even reverse the development of the disease.
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The exchange of histones with protamines in sperm DNA results in sperm chromatin compaction and protection. Variations in sperm protamine expression are associated with male infertility. The aim of this study was to investigate relationships between DNA fragmentation, sperm protamines and assisted reproduction treatment. Semen and spermatozoa prepared by density-gradient centrifugation (DGC) from 73 men undergoing IVF and 24 men undergoing intracytoplasmic sperm injection (ICSI) were included in the study. Nuclear DNA fragmentation was assessed using the alkaline Comet assay and protamines were separated by acid-urea polyacrylamide gels. Sperm DNA fragmentation and protamine content (P1-DNA, P2-DNA, P1 + P2-DNA) decreased in spermatozoa after DGC. Abnormally high and low P1/P2 ratios were associated with increased sperm DNA fragmentation. Couples with idiopathic infertility had abnormally high P1/P2 ratios. Fertilization rates and embryo quality decreased as sperm DNA fragmentation or protamines increased. Sperm DNA fragmentation was lower in couples achieving pregnancies after IVF, but not after ICSI. There was no correlation between protamine content (P1-DNA, P2-DNA, P1 + P2-DNA) or P1/P2 ratios and IVF or ICSI pregnancies. Increased sperm DNA fragmentation was associated with abnormal protamination and resulted in lower fertilization rates, poorer embryo quality and reduced pregnancy rates. During late spermatogenesis, around 85% of the histones in the sperm nucleus are replaced with protamines. This process results in sperm chromatin compaction and also transcription silencing. In the human, protamines are comprised of two types: protamine-1 (P1) and protamine-2 (P2). Variations in sperm protamine expression are associated with male infertility. Similarly, sperm DNA integrity is important for male fertility. The aim of this study was to investigate relationships between DNA fragmentation, sperm protamines and assisted reproduction treatment. Semen and spermatozoa prepared by density-gradient centrifugation (DGC) from 73 men undergoing IVF and 24 men undergoing intracytoplasmic sperm injection (ICSI) were included in the study. Nuclear DNA fragmentation was assessed using the alkaline Comet assay and protamines were separated by acid-urea polyacrylamide gels. Sperm DNA fragmentation and protamine content decreased in spermatozoa after DGC. Abnormally high and low P1/P2 ratios were associated with increased sperm DNA fragmentation. Couples with idiopathic infertility had abnormally high P1/P2 ratios. Fertilization rates and embryo quality decreased as sperm DNA fragmentation or protamines increased. Sperm DNA fragmentation was lower in couples achieving pregnancies after IVF, but not after ICSI. There was no correlation between protamine content or P1/P2 ratios and IVF or ICSI pregnancies. Increased sperm DNA fragmentation was associated with abnormal protamination and resulted in lower fertilization rates, poorer embryo quality and reduced pregnancy rates.
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The imaging properties of a phase conjugating lens operating in the far field zone of the imaged source and augmented with scatterers positioned in the source near field region are theoretically studied in this paper. The phase conjugating lens consists of a double sided 2D assembly of straight wire elements, individually interconnected through phase conjugation operators. The scattering elements are straight wire segments which are loaded with lumped impedance loads at their centers. We analytically and numerically analyze all stages of the imaging process; i) evanescent-to-propagating spectrum conversion; ii) focusing properties of infinite or finite sized phase conjugating lens; iii) source reconstruction upon propagating-to-evanescent spectrum conversion. We show that the resolution that can be achieved depends critically on the separation distance between the imaged source and scattering arrangement, as well as on the topology of the scatterers used. Imaged focal widths of up to one-seventh wavelength are demonstrated. The results obtained indicate the possibility of such an arrangement as a potential practical means for realising using conventional materials devices for fine feature extraction by electromagnetic lensing at distances remotely located from the source objects under investigation
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The combination of milli-scale processing and microwave heating has been investigated for the Cu-catalyzed Ullmann etherification in fine-chemical synthesis, providing improved catalytic activity and selective catalyst heating. Wall-coated and fixed-bed milli-reactors were designed and applied in the Cu-catalyzed Ullmann-type CO coupling of phenol and 4-chloropyridine. In a batch reactor the results show clearly increased yields for the microwave heated process at low microwave powers, whereas high powers and catalyst loadings reduced the benefits of microwave heating. Slightly higher yields were found in the Cu/ZnO wall-coated as compared to the Cu/TiO fixed-bed flow-reactor. The benefit here is that the reaction occurs at the surface of the metal nanoparticles confined within a support film making the nano-copper equally accessible. Catalyst deactivation was mainly caused by Cu oxidation and coke formation; however, at longer process times leaching played a significant role. Catalyst activity could partially be recovered by removal of deposited by-product by means of calcination. After 6h on-stream the reactor productivities were 28.3 and 55.1kgprod/(mR3h) for the fresh Cu/ZnO wall-coated and Cu/TiO fixed-bed reactor, respectively. Comparison of single- and multimode microwaves showed a threefold yield increase for single-mode microwaves. Control of nanoparticles size and loading allows to avoid high temperatures in a single-mode microwave field and provides a novel solution to a major problem for combining metal catalysis and microwave heating. Catalyst stability appeared to be more important and provided twofold yield increase for the CuZn/TiO catalyst as compared to the Cu/TiO catalyst due to stabilized copper by preferential oxidation of the zinc. For this catalyst a threefold yield increase was observed in single-mode microwaves which, to the best of our knowledge, led to a not yet reported productivity of 172kgprod/(mR3h) for the microwave and flow Ullmann CO coupling. © 2012 Elsevier B.V.
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PURPOSE. This study evaluated the effect of transforming growth factor (TGF)-ß2 and anti-TGF-ß2 antibody in a rodent model of posterior capsule opacification (PCO). METHODS. An extracapsular lens extraction (ECLE) was performed in 72 Sprague-Dawley rats. At the end of the procedure, 10 µL TGF-ß2 (TGF-ß2-treated group), fetal calf serum (FCS)/phosphate- buffered saline (PBS; FCS/PBS-treated control group), a human monoclonal TGF-ß2 antibody (anti-TGF-ß2-treated group), or a null control IgG4 antibody (null antibody-treated control group) was injected into the capsule. Animals were killed 3 and 14 days postoperatively. Eyes were evaluated clinically prior to euthanatization, then enucleated and processed for light microscopy and immunohistochemistry afterward. PCO was evaluated clinically and histopathologically. Student's t-test and ? were used to assess differences between groups. RESULTS. There were no statistically significant clinical or histopathological differences in degree of PCO between the TGF-ß2- and FCS/PBS-treated groups at 3 and 14 days after ECLE. Nor were there differences between the anti-TGF-ß2- and the null antibody-treated groups, with the exception of the histopathology score for capsule wrinkling 3 days after ECLE (P = 0.02). a-Smooth-muscle actin staining was observed in the lens capsular bag only in areas where there was close contact with the iris. CONCLUSIONS. No sustained effect of TGF-ß2 or anti-TGF-ß2 antibody on PCO was found in rodents at the dose and timing administered in this study. Iris cells may play a role in the process of epithelial mesenchymal transition linked to PCO. Copyright © Association for Research in Vision and Ophthalmology.
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Here, we show for the first time, that the familial breast/ovarian cancer susceptibility gene BRCA1 activates the Notch pathway in breast cells by transcriptional upregulation of Notch ligands and receptors in both normal and cancer cells. We demonstrate through chromatin immunoprecipitation assays that BRCA1 is localized to a conserved intronic enhancer region within the Notch ligand Jagged-1 (JAG1) gene, an event requiring ΔNp63. We propose that this BRCA1/ΔNp63-mediated induction of JAG1 may be important the regulation of breast stem/precursor cells, as knockdown of all three proteins resulted in increased tumoursphere growth and increased activity of stem cell markers such as Aldehyde Dehydrogenase 1 (ALDH1). Knockdown of Notch1 and JAG1 phenocopied BRCA1 knockdown resulting in the loss of Estrogen Receptor-α (ER-α) expression and other luminal markers. A Notch mimetic peptide could activate an ER-α promoter reporter in a BRCA1-dependent manner, whereas Notch inhibition using a γ-secretase inhibitor reversed this process. We demonstrate that inhibition of Notch signalling resulted in decreased sensitivity to the anti-estrogen drug Tamoxifen but increased expression of markers associated with basal-like breast cancer. Together, these findings suggest that BRCA1 transcriptional upregulation of Notch signalling is a key event in the normal differentiation process in breast tissue.
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In 1976, Susan Brownmiller published 'Against Our Will', widely credited as the founding text of feminist anti-rape theory, in which she famously declared that rape was 'nothing more or less than a conscious process of intimidation by which all men keep all women in a state of fear'.While the scholarship and politics of Against Our Will have been subjected to numerous and compelling critiques, the work retains canonical and even foundational status within feminist anti-rape politics. In this article I attempt a critical re-examination of feminist (her)story telling practices. By situating the story told in Against Our Will beside and within Brownmiller's story of the creation of the book and her own coming-to-consciousness, a more general reexamination of the role of women's speech and (her)story-telling in feminist anti-rape politics is afforded. This re-reading draws out two central aspects of the politics of (her)story-telling which can be found in Brownmiller's work and in the Joan W. Scott quotation above. Firstly, the need to be recognised as a 'just source' of women's stories has resulted in the granting of epistemological primacy to stories of women's experience or personal statements. Secondly, the desire to compensate for the lack of a 'classical myth' to authorise women's claims, resulting in an attempt to imbue these feminist (her)stories with their own mythology.
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Objective: Despite the availability of palliative care in many countries, legalization of euthanasia and physician-assisted suicide (EAS) continues to be debated-particularly around ethical and legal issues-and the surrounding controversy shows no signs of abating. Responding to EAS requests is considered one of the most difficult healthcare responsibilities. In the present paper, we highlight some of the less frequently discussed practical implications for palliative care provision if EAS were to be legalized. Our aim was not to take an explicit anti-EAS stance or expand on findings from systematic reviews or philosophical and ethico-legal treatises, but rather to offer clinical perspectives and the potential pragmatic implications of legalized EAS for palliative care provision, patients and families, healthcare professionals, and the broader community.
Method: We provide insights from our multidisciplinary clinical experience, coupled with those from various jurisdictions where EAS is, or has been, legalized.
Results: We believe that these issues, many of which are encountered at the bedside, must be considered in detail so that the pragmatic implications of EAS can be comprehensively considered.
Significance of Results: Increased resources and effort must be directed toward training, research, community engagement, and ensuring adequate resourcing for palliative care before further consideration is given to allocating resources for legalizing euthanasia and physician-assisted suicide.
Resumo:
A microwave (MW)-assisted crosslinking process to prepare hydrogel-forming microneedle (MN) arrays was evaluated. Conventionally, such MN arrays are prepared using processes that includes a thermal crosslinking step. Polymeric MN arrays were prepared using poly(methyl vinyl ether-alt-maleic acid) crosslinked by reaction with poly(ethylene glycol) over 24 h at 80 °C. Polymeric MN arrays were prepared to compare conventional process with the novel MW-assisted crosslinking method. Infrared spectroscopy was used to evaluate the crosslinking degree, evaluating the area of the carbonyl peaks (2000–1500 cm−1). It was shown that, by using the MW-assisted process, MN with a similar crosslinking degree to those prepared conventionally can be obtained in only 45 min. The effects of the crosslinking process on the properties of these materials were also evaluated. For this purpose swelling kinetics, mechanical characterisation, and insertion studies were performed. The results suggest that MN arrays prepared using the MW assisted process had equivalent properties to those prepared conventionally but can be produced 30 times faster. Finally, an in vitro caffeine permeation across excised porcine skin was performed using conventional and MW-prepared MN arrays. The release profiles obtained can be considered equivalent, delivering in both cases 3000–3500 μg of caffeine after 24 h.
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Aims: In this paper we aim to investigate the evolution of plasmaproperties and Stokes parameters in photospheric magnetic bright pointsusing 3D magneto-hydrodynamical simulations and radiative diagnostics ofsolar granulation.
Methods: Simulated time-dependent radiationparameters and plasma properties were investigated throughout theevolution of a bright point. Synthetic Stokes profiles for the FeI630.25 nm line were calculated, which also allowed the evolution of theStokes-I line strength and Stokes-V area and amplitude asymmetries to beinvestigated.
Results: Our results are consistent withtheoretical predictions and published observations describing convectivecollapse, and confirm this as the bright point formation process.Through degradation of the simulated data to match the spatialresolution of SOT, we show that high spatial resolution is crucial forthe detection of changing spectro-polarimetric signatures throughout amagnetic bright point's lifetime. We also show that the signaturedownflow associated with the convective collapse process tends towardszero as the radiation intensity in the bright point peaks, because ofthe magnetic forces present restricting the flow of material in the fluxtube.