943 research outputs found

    Electrochemical Raman spectroscopy of carbon nanotube energy transfer complexes

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    We present electrochemical Raman measurements on energy transfer complexes formed by combining single-walled carbon nanotubes and dye molecules. The presence of the dye molecules in the proximity of the nanotubes impacts the nanotubes’ charging behavior, leading to changes in the position of the charge neutrality point and the maximum achievable doping strength. We compare these results to spectra acquired in solution and determine the corresponding Fermi energy shifts, which are found to be similar in the energy transfer complexes and a reference sample. Our results have implications for the photoluminescence enhancement/quenching previously observed in these energy transfer complexes. Electrochemical G-mode Raman spectra at a gate voltage of −1.1 V showing much larger doping strength for the reference sample than for the energy transfer complexes, as seen in the higher-frequency and narrower peak

    Effects of Design

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    Surfactants are needed to create stable suspensions of carbon nanotubes. Increasingly, these surfactants are given additional functionalities, resulting in bigger and more complex molecules with several subunits. We investigate the effect of assembly of these subunits for a class of perylene- based functional surfactants. The subunits that all surfactants are based on are a perylene core, hydrophilic polyglycerol dendrons, and alkyl chains of different orientations and lengths. The assembly of these subunits affects both the molecules' performance as a surfactant and the efficiency of the energy-transfer complexes formed by the nanotube and surfactant through a π–π stacking mechanism. This results in a best practice guide for designing functional surfactants with π–π stacking cores, and affords more general insights that are applicable to non π–π stacking systems as well

    Excitation characteristics of different energy transfer in nanotube-perylene complexes

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    We report the properties of perylene-nanotube complexes that form efficient energy transfer systems. Most perylene-derivatives yield similar ratios between transfer and direct luminescence (0.66 ± 0.04). The photoluminescence spectra of the free compounds and the transfer complex are similar indicating that perylene and nanotubes act as separate systems. A further increase in interaction yields 40% higher transfer rates and luminescence excitation spectra that indicate a change in stacking of the perylene on the nanotube wall. All measurements are consistent with a transfer mechanism based on a dipole-dipole interaction at a distance much smaller than the Förster radius

    Validation of the Human Activity Profile Questionnaire in Patients after Allogeneic Hematopoietic Stem Cell Transplantation

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    Chronic graft-versus-host disease (cGVHD) associated morbidity and mortality remain major barriers for successful allogeneic hematopoietic stem cell transplantation (alloHSCT). Currently, no reliable measures are established to monitor cGVHD activity changes for use in clinical trials. The Human Activity Profile (HAP) patient self-report was proposed by the National Institutes of Health (NIH) cGVHD consensus project as an independent measure of patients' functional status that could also indirectly reflect improvement of cGVHD, but that has not been validated in an alloHSCT patient population. One hundred seventy-six patients (median age 44 years [range: 18-72 years] after alloHSCT were evaluated with a German translation of the HAP, the NIH criteria-based cGVHD activity assessment, the Lee cGVHD Symptom-Scale, FACT-BMT, SF36, Berlin Social Support Scale, 24-Item Adjective Measure (24-AM), Hospital Anxiety and Depression Scale, and the NCCN-Distress-Thermometer. Enrollment occurred a median of 286 (range: 85-4003) days after alloHSCT. Follow-up surveys were conducted at 1, 2, 3, 5, 8, and 12 months after the baseline survey. Although 117 patient had cGVHD at time of enrollment (mild n = 33, moderate n = 50, or severe n = 34), 59 patients were included into the study in the absence of cGVHD between days 85 and 395 after transplantation. The maximum activity score (MAS) and adjusted activity score (AAS) of the HAP correlated inversely with grading of cGVHD severity (mild, moderate, or severe) (r = −0.25 for MAS and −0.24 for AAS). Lung manifestations of cGVHD correlated with AAS (r = 0.17), but not with MAS. HAP scores correlated with subscales from other instruments measuring physical domains, especially the physical functioning scale of the SF36. Performance was improved by use of an HSCT-modified HAP scoring system that excluded activities prohibited within the first year after alloHSCT. No significant correlation of the HAP was found with personality, age, sex, symptom burden, or social functioning or social well-being. Moreover, the HAP displayed a higher sensitivity to change of cGVHD activity compared to the SF36 and the FACT-BMT. In addition, steroid myopathy correlated with both HAP scores, but not the SF36. The HAP is a simple and valid questionnaire for the evaluation of the physical activity in patients after alloHSCT, with the advantage of detecting changes in cGVHD status independently of other quality-of-life measures and with a superior sensitivity compared to the SF36

    Trigeminal neuropathic pain development and maintenance in rats are suppressed by a positive modulator of alpha 6 GABA(A) receptors

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    gamma-Aminobutyric acid type A (GABA(A)) receptors containing the alpha 6 subunit are located in trigeminal ganglia, and their reduction by small interfering RNA increases inflammatory temporomandibular and myofascial pain in rats. We thus hypothesized that enhancing their activity may help in neuropathic syndromes originating from the trigeminal system. Here, we performed a detailed electrophysiological and pharmacokinetic analysis of two recently developed deuterated structurally similar pyrazoloquinolinone compounds. DK-I-56-1 at concentrations below 1 mu M enhanced gamma-aminobutyric acid (GABA) currents at recombinant rat alpha 6 beta 3 gamma 2, alpha 6 beta 3 delta and alpha 6 beta 3 receptors, whereas it was inactive at most GABA(A) receptor subtypes containing other alpha subunits. DK-I-87-1 at concentrations below 1 mu M was inactive at alpha 6-containing receptors and only weakly modulated other GABA(A) receptors investigated. Both plasma and brain tissue kinetics of DK-I-56-1 were relatively slow, with half-lives of 6 and 13 hr, respectively, enabling the persistence of estimated free brain concentrations in the range 10-300 nM throughout a 24-hr period. Results obtained in two protocols of chronic constriction injury of the infraorbital nerve in rats dosed intraperitoneally with DK-I-56-1 during 14 days after surgery or with DK-I-56-1 or DK-I-87-1 during 14 days after trigeminal neuropathy were already established, demonstrated that DK-I-56-1 but not DK-I-87-1 significantly reduced the hypersensitivity response to von Frey filaments. Significance Neuropathic pain induced by trigeminal nerve damage is poorly controlled by current treatments. DK-I-56-1 that positively modulates alpha 6 GABA(A) receptors is appropriate for repeated administration and thus may represent a novel treatment option against the development and maintenance of trigeminal neuropathic pain

    European code against cancer 4th edition: 12 ways to reduce your cancer risk

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    This overview describes the principles of the 4th edition of the European Code against Cancer and provides an introduction to the 12 recommendations to reduce cancer risk. Among the 504.6 million inhabitants of the member states of the European Union (EU28), there are annually 2.64 million new cancer cases and 1.28 million deaths from cancer. It is estimated that this cancer burden could be reduced by up to one half if scientific knowledge on causes of cancer could be translated into successful prevention. The Code is a preventive tool aimed to reduce the cancer burden by informing people how to avoid or reduce carcinogenic exposures, adopt behaviours to reduce the cancer risk, or to participate in organised intervention programmes. The Code should also form a base to guide national health policies in cancer prevention. The 12 recommendations are: not smoking or using other tobacco products; avoiding second-hand smoke; being a healthy body weight; encouraging physical activity; having a healthy diet; limiting alcohol consumption, with not drinking alcohol being better for cancer prevention; avoiding too much exposure to ultraviolet radiation; avoiding cancer-causing agents at the workplace; reducing exposure to high levels of radon; encouraging breastfeeding; limiting the use of hormone replacement therapy; participating in organised vaccination programmes against hepatitis B for newborns and human papillomavirus for girls; and participating in organised screening programmes for bowel cancer, breast cancer, and cervical cancer

    Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

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    Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

    Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

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    We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

    Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

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    Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe
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