597 research outputs found

    Energy relaxation pathways between light-matter states revealed by coherent two-dimensional spectroscopy

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    Coupling matter excitations to electromagnetic modes inside nano-scale optical resonators leads to the formation of hybrid light-matter states, so-called polaritons, allowing the controlled manipulation of material properties. Here, we investigate the photo-induced dynamics of a prototypical strongly-coupled molecular exciton-microcavity system using broadband two-dimensional Fourier transform spectroscopy and unravel the mechanistic details of its ultrafast photo-induced dynamics. We find evidence for a direct energy relaxation pathway from the upper to the lower polariton state that initially bypasses the excitonic manifold of states, which is often assumed to act as an intermediate energy reservoir, under certain experimental conditions. This observation provides new insight into polariton photophysics and could potentially aid the development of applications that rely on controlling the energy relaxation mechanism, such as in solar energy harvesting, manipulating chemical reactivity, the creation of Bose–Einstein condensates and quantum computing

    Updating of user requirements of elderly and disabled drivers and travellers

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    The user requirements have been reassessed in the light of the results from the collaborative evaluations with other Transport Telematics Projects, as well as data and expertise gathered from the literature and other experts in the field. The user requirements identified are also the fundamental base for the development of different parts of the TELSCAN project. User requirements cover, of course, a multitude of different aspects, and to demonstrate how they have been integrated into the project’s output, they have been grouped into the following categories: • System function requirements • Interface requirements • Information requirements • Protocol requirements

    Spectroscopy of infrared-active phonons in high-temperature superconductors

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    For a large variety of superconducting materials both experimental and theoretical lattice dynamical studies have been performed to date. The assignment of the observed infrared- and Raman-active phonon modes to the particular lattice eigenmodes is generally accepted. We will concentrate here upon the analysis of the changes of the infrared-phonon parameters (frequency and linewidth) upon entering the superconducting state which, as will be shown, may provide information on the magnitude of the superconductivity-related gap and its dependence on the superconducting transition temperature Tc

    Measurement And Modeling Of Short Copper Cables For Ultra-wideband Communication

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    High-speed communication using the copper network, originally installed for telephony, is one of the dominant Internet access techniques. Several variants of a technology referred to as digital subscriber line (DSL) have been developed, standardized and installed during the last two decades. Essentially, DSL achieves high rates by exploiting wide bands of the copper cable channel. The shorter the cable, the wider the band that can be used efficiently for communication. Current DSL standards foresee the use of bands up to 30MHz. Cable properties have been studied by means of measurements, characterization and modeling up to frequencies of 30MHz. Recent investigations have shown that it is feasible both from technical and from economical point of view to exploit very short cables (up to 200m) even further and use bands above 30MHz. A prerequisite for further evaluation and the design of such ultra-wideband copper (UWBC) systems is the extension of existing cable models to higher frequencies. This paper presents wideband measurement results of insertion loss and crosstalk coupling in a 10-pair cable of various length values for frequencies up to 200MHz. We compare the results with extrapolations of cable models that are established in the 30MHz-range.6390Chen, W.Y., (1998) DSL: Simulation Techniques and Standards Development for Digital Subscriber Line Systems, , Macmillan Technical Publishing, ISBN 1-57870-017-5G.selt: Updated issues list for G.selt (2004) ITU-T Temporary Document SS U09, , ITU-TAsymmetric digital subscriber line (ADSL) transceivers (1999) ITU Recommendation G.992.1, , ITU-T, JuneAsymmetric digital subscriber line (ADSL) transceivers (1999) ITU Recommendation G.992.2, , ITU-T, JuneAsymmetric digital subscriber line (ADSL) extended bandwidth (ADSL2+) (2005) ITU Recommendation G.992.5, , ITU-TStarr, T., Cioffi, J.M., Silverman, P., (1998) Understanding Digital Subscriber Line Technology, , Prentice Hall, Englewood CliffsDedieu, H., The copper channel - Loop charactersitics and models (2005) Fundamentals of DSL Technology, , ch. ISBN 0849319137, AUERBACHVan Der Brink, R.F.M., (1998) Cable Reference Models for Simulating Metallic Access Networks, , Permanent Document TM6(97), ETSI STC TM6, Luleå, Sweden, JunePaul, C.R., (1994) Analysis of Multiconductor Transmission Lines, , Wiley, ISBN 0-471-02080-XCook, J.W., (1996) Parametric Modelling of Twisted Pair Cables for VDSL, , Temporary Document TD22, ETSI STC TM6, Vienna, Austria, MarVan Der Brink, R.F.M., (1997) Measurements and Models on Dutch Cables, , Temporary Document TD15, ETSI STC TM6, Tel Aviv, Israel, MarPollakowski, M., (1996) DTAG Cables Transmission Characteristics, , Temporary Document TD40, ETSI STC TM6, Vienna, Austria, MarPythoud, F., (1998) Model of Swiss Access Network Cables, , Temporary Document TD48, ETSI STC TM6, Madrid, Spain, JanHeylen, L., Musson, J., (1999) Cable Models Predict Physically Impossible Behavior in Time Domain, , Temporary Document TD08, ETSI STC TM6, Amsterdam, Netherlands, NovMusson, J., (1998) Maximum Likelihood Estimation of the Primary Parameters of Twisted Pair Cables, , Temporary Document TD06, ETSI STC TM6, Madrid, Spain, SeptBoets, P., Zekri, M., Van Biesen, L., Bostoen, T., Pollet, T., On the identification of cables for metallic access networks (2001) 18th IEEE Instrumentation and Measurement Technology Conference IMTC2001, 2, pp. 1348-1353. , Budapest, Hungary, MayBostoen, T., Boets, P., Zekri, M., Van Biesen, L., Pollet, T., Rabijns, D., Estimation of the transfer function of the access network by means of one-port scattering parameter measurements at the central office (2002) IEEE Journal on Selected Areas in Communication, 20, pp. 936-948. , JuneVery-high-bit-rate Digital Subscriber Line (VDSL) metallic interface part 1: Functional requirement and common specification (2001) T1E1.4/2000-009R3, , ANSI T1E1.4, FebVan Der Brink, R.F.M., (2001) Laboratory Performance Tests for XDSL Systems, , Permanent Document TM6(98)10, ETSI STC TM6, Sophia Antipolis, France, FebValenti, C., NEXT and FEXT models for twisted-pair North American loop plant (2002) IEEE Journal on Selected Areas in Communication, 20, pp. 893-900. , JuneNedev, N.H., McLaughlin, S., Cook, J.W., Wideband UTP cable measurements and modelling for MIMO systems (2004) Proc. European Signal Processing Conf. EUSIPCO 2004, , (Vienna, Austria), SeptMagesacher, T., Henkel, W., Tauböck, G., Nordström, T., Cable measurements supporting xDSL technologies (2002) Journal E&i Elektrotechnik und Informationstechnik, 199, pp. 37-43. , FebMagesacher, T., Ödling, P., Börjesson, P.O., Henkel, W., Nordström, T., Zukunft, R., Haar, S., On the capacity of the copper cable channel using the common mode (2002) Proc. IEEE Global Telecommun. Conf. GLOBECOM 2002, , (Taipei, Taiwan), NovTomita, N., Ohmura, M., Low-frequency crosstalk loss characteristics of balanced cables (1989) Electron. Commun. Japan, Part 1, 72 (3), pp. 95-105Goedbloed, J.J., Aspects of EMC at the equipment level (1997) Proc. 12th Intl. Symp. Electromagn. Compat., pp. 23-38. , (Zurich, Switzerland), FebWerner, J.J., The HDSL environment (1991) IEEE Journal on Selected Areas in Communication, 9, pp. 785-800. , AugConte, R.A., A crosstalk model for balanced digital transmission in multipair cables (1986) AT&T Tech. J., 65, pp. 41-59. , May-JunSchutt-Aine, J.E., High-frequency characterization of twisted-pair cables (2001) IEEE Trans. on Commun., 49, pp. 598-601. , AprGresh, P.A., Physical and transmission characteristics of customer loop plant (1969) The Bell System Technical Journal, 48, pp. 3337-3385. , DecManhire, L.M., Physical and transmission characteristics of customer loop plant (1978) The Bell System Technical Journal, 57, pp. 35-39. , JanPierce, S.B., Crosstalk in twisted pair circuits (1986) Proc. Intl. Wire and Cable Symp., pp. 349-354Fung, A., Lee, L.S., Falconer, D.D., A facility for near end crosstalk measurements on ISDN subscriber loops (1989) Proc. IEEE Global Telecommun. Conf, , paper 54.

    Calcium supplementation and risk of dementia in women with cerebrovascular disease

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    OBJECTIVE: To determine whether calcium supplementation is associated with the development of dementia in women after a 5-year follow-up. METHODS: This was a longitudinal population-based study. The sample was derived from the Prospective Population Study of Women and H70 Birth Cohort Study in Gothenburg, Sweden, and included 700 dementia-free women aged 70–92 years. At baseline in 2000–2001, and at follow-up in 2005–2006, the women underwent comprehensive neuropsychiatric and somatic examinations. A CT scan was performed in 447 participants at baseline. Information on the use and dosage of calcium supplements was collected. Dementia was diagnosed according to DSM-III-R criteria. RESULTS: Women treated with calcium supplements (n = 98) were at a higher risk of developing dementia (odds ratio [OR] 2.10, 95% confidence interval [CI] 1.01–4.37, p = 0.046) and the subtype stroke-related dementia (vascular dementia and mixed dementia) (OR 4.40, 95% CI 1.54–12.61, p = 0.006) than women not given supplementation (n = 602). In stratified analyses, calcium supplementation was associated with the development of dementia in groups with a history of stroke (OR 6.77, 95% CI 1.36–33.75, p = 0.020) or presence of white matter lesions (OR 2.99, 95% CI 1.28–6.96, p = 0.011), but not in groups without these conditions. CONCLUSIONS: Calcium supplementation may increase the risk of developing dementia in elderly women with cerebrovascular disease. Because our sample was relatively small and the study was observational, these findings need to be confirmed

    Observation of Umklapp processes in non-crystalline materials

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    Umklapp processes are known to exist in cristalline materials, where they control important properties such as thermal conductivity, heat capacity and electrical conductivity. In this work we report the provocative observation of Umklapp processes in a non-periodical system, namely liquid Lithium. The lack of a well defined periodicity seems then not to prevent the existence of these scattering processes mechanisms provided that the local order of the systems i.e. the maxima of the static structure factor supply the equivalent of a reciprocal lattice vector in the case of cristalline materials.Comment: 13 pages P

    Clusterin/Apolipoprotein J immunoreactivity is associated with white matter damage in cerebral small vessel diseases

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    Aim: Brain clusterin is known to be associated with the amyloid‐β deposits in Alzheimer's disease (AD). We assessed the distribution of clusterin immunoreactivity in cerebrovascular disorders, particularly focusing on white matter changes in small vessel diseases. Methods: Post‐mortem brain tissues from the frontal or temporal lobes of a total of 70 subjects with various disorders including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral amyloid angiopathy (CAA) and AD were examined using immunohistochemistry and immunofluorescence. We further used immunogold electron microscopy to study clusterin immunoreactivity in extracellular deposits in CADASIL. Results: Immunostaining with clusterin antibodies revealed strong localization in arterioles and capillaries, besides cortical neurones. We found that clusterin immunostaining was significantly increased in the frontal white matter of CADASIL and pontine autosomal dominant microangiopathy and leukoencephalopathy subjects. In addition, clusterin immunostaining correlated with white matter pathology severity scores. Immunostaining in axons ranged from fine punctate deposits in single axons to larger confluent areas with numerous swollen axon bulbs, similar to that observed with known axon damage markers such as non‐phosphorylated neurofilament H and the amyloid precursor protein. Immunofluorescence and immunogold electron microscopy experiments showed that whereas clusterin immunoreactivity was closely associated with vascular amyloid‐β in CAA, it was lacking within the granular osmiophilic material immunolabelled by NOTCH3 extracelluar domain aggregates found in CADASIL. Conclusions: Our results suggest a wider role for clusterin associated with white matter damage in addition to its ability to chaperone proteins for clearance via the perivascular drainage pathways in several disease states

    Review of "Ludica" by Riccardo Pelizzo and Mark Nowacki

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    From December 1999 until July 2001, a phase I dose escalation study was performed with (186)Re-labeled bivatuzumab, a humanized monoclonal antibody against CD44v6, on patients with inoperable recurrent or metastatic head and neck cancer. The aim of the trial was to assess the safety and tolerability of intravenously administered (186)Re-bivatuzumab and to determine the maximum tolerated dose (MTD) of (186)Re-bivatuzumab. The data were also used for dosimetric analysis of the treated patients. Dosimetry is used to estimate the absorbed doses by nontarget organs, as well as by tumors. It can also help to explain toxicity that is observed and to predict organs at risk because of the therapy given. METHODS: Whole-body scintigraphy was used to draw regions around sites or organs of interest. Residence times in these organs and sites were calculated and entered into the MIRDOSE3 program, to obtain absorbed doses in all target organs except for red marrow. The red marrow dose was calculated using a blood-derived method. Twenty-one studies on 18 patients, 5 female and 16 male, were used for dosimetry. RESULTS: The mean red marrow doses were 0.49 +/- 0.03 mGy/MBq for men and 0.64 +/- 0.03 mGy/MBq for women. The normal organ with the highest absorbed dose appeared to be the kidney (mean dose, 1.61 +/- 0.75 mGy/MBq in men and 2.15 +/- 0.95 mGy/MBq in women; maximum kidney dose in all patients, 11 Gy), but the doses absorbed are not expected to lead to renal toxicity. Other organs with doses exceeding 0.5 mGy/MBq were the lungs, the spleen, the heart, the liver, the bones, and the testes. The doses delivered to the tumor, recalculated to the MTD level of 1.85 GBq/m(2), ranged from 3.8 to 76.4 Gy, with a median of 12.4 Gy. A good correlation was found between platelet and white blood cell counts and the administered amount of activity per kilogram of body weight (r = -0.79). CONCLUSION: Dosimetric analysis of the data revealed that the range of doses to normal organs seems to be well within acceptable and safe limits. Tumor doses ranged from 4 to 76 Gy. Given the acceptable tumor doses, (186)Re-labeled bivatuzumab could be a good candidate for future adjuvant radioimmunotherapy in patients with minimal residual disease
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