522 research outputs found

    Nonstoichiometry in TiO

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    This paper treats a problem of nonstoichiometry in TiO2−y thin films deposited by reactive sputtering at controlled sputtering rates. Ion beam techniques, Rutherford backscattering (RBS), and nuclear reaction analysis (NRA) along with X-ray photoelectron spectroscopy have been applied to determine a deviation from stoichiometry y in the bulk and at the surface of TiO2−y layers. The critical review of these experimental methods is given. Defect structure responsible for the electrical resistivity of rutile TiO2 is discussed

    UV Spectra and Excitation Delocalization in DNA: Influence of the Spectral Width

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    The singlet excited states of the model DNA duplex (dA)10.(dT)10 are studied. Calculations are performed in the exciton theory framework. Molecular dynamics calculations provide the duplex geometry. The dipolar coupling is determined using atomic transition charges. The monomer transition energies are simulated by Gaussian functions resembling the absorption bands of nucleosides in aqueous solutions. Most of the excited states are found to be delocalized over at least two bases and result from the mixing of different monomer states. Their properties are only weakly affected by conformational changes of the double helix. On average, the highest oscillator strength is carried by the upper eigenstates. The duplex absorption spectra are shifted a few nanometers to higher energies with respect to the spectra of noninteracting monomers. The states with larger spatial extent are located close to the maximum of the absorption spectrum

    Can treatment success with 5% lidocaine medicated plaster be predicted in cancer pain with neuropathic components or trigeminal neuropathic pain?

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    An expert group of 40 pain specialists from 16 countries performed a first assessment of the value of predictors for treatment success with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain. Results were based on the retrospective analysis of 68 case reports (sent in by participants in the 4 weeks prior to the conference) and the practical experience of the experts. Lidocaine plaster treatment was mostly successful for surgery or chemotherapy-related cancer pain with neuropathic components. A dose reduction of systemic pain treatment was observed in at least 50% of all cancer pain patients using the plaster as adjunct treatment; the presence of allodynia, hyperalgesia or pain quality provided a potential but not definitively clear indication of treatment success. In trigeminal neuropathic pain, continuous pain, severe allodynia, hyperalgesia, or postherpetic neuralgia or trauma as the cause of orofacial neuropathic pain were perceived as potential predictors of treatment success with lidocaine plaster. In conclusion, these findings provide a first assessment of the likelihood of treatment benefits with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain and support conducting large, well-designed multicenter studies

    Exciton States of Dynamic DNA Double Helices: Alternating dCdG Sequences

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    The present communication deals with the excited states of the alternating DNA oligomer (dCdG)5·(dCdG)5 which correspond to the UV absorption band around 260 nm. Their properties are studied in the frame of the exciton theory, combining molecular dynamics simulations and quantum chemistry data. It is shown that the dipolar coupling undergoes important variations with the site and the helix geometry. In contrast, the energy of the monomer transitions within the double helix is not sensitive to the local environment. It is thus considered to be distributed over Gaussian curves whose maximum and width are derived from the experimental absorption spectra of nucleosides in aqueous solution. The influence of the spectral width on the excited state delocalization and the absorption spectra is much stronger than that of the oligomer plasticity. About half of the excited states are delocalized over at least two bases. Many of them result from the mixing of different monomer states and extend on both strands. The trends found in the simulated spectra, when going from non-interacting monomers to the duplex, are in agreement with experimental observations. Conformational changes enhance the diversity of the states which can be populated upon excitation at a given energy. The states with larger spatial extent are located close to the maximum of the absorption spectrum

    Parvovirus B19: Insights and implication for pathogenesis, prevention and therapy

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    Parvovirus B19 (B19V) is a small ssDNA non-enveloped virus, member of Parvoviridae family. The infection is widely diffused and is responsible for a broad range of clinical manifestations including fifth disease in children, transient aplastic crisis in patients with haematological disorders, non-immune hydrops fetalis in pregnant women, persistent anaemia in immunocompromised patients, arthropathy and inflammation of various other tissues. B19V infects and replicates in erythroid progenitor cells (EPCs) in the bone marrow. The depletion of infected EPCs represents the pathogenetic mechanisms of some haematological B19V-associate diseases. Following a primary infection, the virus can establish lifelong persistence in several tissues. Currently, the pathological potential of persistent virus on the cellular signalling pathways remains unclear. In non-erythroid tissues, the infection is usually, abortive, and the virus seems to exert its pathological role through indirect mechanisms, such as induction of inflammatory and autoimmune processes, or through virus-induced apoptosis mediated by viral proteins. In addition to the diseases for which the etiological role of B19V has been fully demonstrated, there are several clinical conditions, including autoimmune diseases, that are presumably, but not certainly, associated with B19V infection. In this review, we describe recent findings that may give us new insight into the pathogenic role of B19V in systemic sclerosis, an autoimmune disease of unknown multifactorial aetiology. Furthermore, we describe the latest findings on the intrauterine B19V infections. Moreover, since there are some ongoing interesting studies focused on vaccine development and antiviral drug discovery for the prevention and treatment of parvovirus B19 infection we described some advances in this field of research

    Conformational analysis of nucleic acids revisited: Curves+

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    We describe Curves+, a new nucleic acid conformational analysis program which is applicable to a wide range of nucleic acid structures, including those with up to four strands and with either canonical or modified bases and backbones. The program is algorithmically simpler and computationally much faster than the earlier Curves approach, although it still provides both helical and backbone parameters, including a curvilinear axis and parameters relating the position of the bases to this axis. It additionally provides a full analysis of groove widths and depths. Curves+ can also be used to analyse molecular dynamics trajectories. With the help of the accompanying program Canal, it is possible to produce a variety of graphical output including parameter variations along a given structure and time series or histograms of parameter variations during dynamic

    The journeys of patients with trigeminal neuralgia on a background of multiple sclerosis

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    Aim: Multiple sclerosis (MS) is well recognized as a secondary cause for trigeminal neuralgia (TN). In this case series, we detail the management of all the patients with TN and MS (pwTNMS) presenting to a specialist unit. Materials & methods: A prospective patient database was used to extract key clinical data on pharmacological, psychometric and surgical management of 20 pwTNMS. Results: 65% of pwTNMS underwent surgical interventions for management of their pain.12/20 achieved remission periods, through surgery and/or medication. Significant improvement was noted on the global impression of change illustrated by a p < 0.001. Conclusion: pwTNMS require a multifaceted approach combining polypharmacy, surgical interventions and psychological support. Developing self-management skills is crucial if patients are to live well with pain

    Burden of illness of trigeminal neuralgia among patients managed in a specialist center in England

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    BACKGROUND: Trigeminal neuralgia (TN) causes severe episodic, unilateral facial pain and is initially treated with antiepileptic medications. For patients not responding or intolerant to medications, surgery is an option. METHODS: In order to expand understanding of the pain-related burden of illness associated with TN, a cross-sectional survey was conducted of patients at a specialist center that utilizes a multidisciplinary care pathway. Participants provided information regarding their pain experience and treatment history, and completed several patient-reported outcome (PRO) measures. RESULTS: Of 129 respondents, 69/128 (54%; 1 missing) reported no pain in the past 4 weeks. However, 84 (65%) respondents were on medications, including 49 (38%) on monotherapy and 35 (27%) on polytherapy. A proportion of patients had discontinued at least one medication in the past, mostly due to lack of efficacy (n = 62, 48%) and side effects (n = 51, 40%). A total of 52 (40%) patients had undergone surgery, of whom 30 had microvascular decompression (MVD). Although surgery, especially MVD, provided satisfactory pain control in many patients, 29% of post-surgical patients reported complications, 19% had pain worsen or stay the same, 48% were still taking pain medications for TN, and 33% reported new and different facial pain. CONCLUSIONS: In most PRO measures, respondents with current pain interference had poorer scores than those without pain interference. In the Patient Global Impression of Change, 79% expressed improvement since beginning of treatment at this clinic. These results indicate that while the multidisciplinary approach can substantially alleviate the impact of TN, there remains an unmet medical need for additional treatment options
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