775 research outputs found

    Looking for differences in wood properties as a function of the felling date: lunar phase-correlated variations in the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.)

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    A large-scale field experiment on the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.) in relation to the felling date was conducted over a period of 24weeks in order to investigate the existence of variations linked to lunar rhythms, which are mentioned as having a role in many traditional forestry practices. The measured criteria were the water loss from fresh to dry state, the shrinkage linked to this water loss, and the relative density (ratio between the dry density and the initial fresh density) for both sapwood and heartwood in Picea and heartwood in Castanea. In addition to seasonal trends, slight but significant variations with lunar periodicities (both synodic and sidereal; to a much lesser extent tropic) characterize the three investigated criteria. These lunar rhythmicities occur in both Picea and Castanea, in heartwood and sapwood. These results raise new questions and perspectives about a rhythmic character of the wood–water relation

    Looking for differences in wood properties as a function of the felling date: lunar phase-correlated variations in the drying behavior of Norway Spruce ( Picea abies Karst.) and Sweet Chestnut ( Castanea sativa Mill.)

    Get PDF
    A large-scale field experiment on the drying behavior of Norway Spruce (Picea abies Karst.) and Sweet Chestnut (Castanea sativa Mill.) in relation to the felling date was conducted over a period of 24weeks in order to investigate the existence of variations linked to lunar rhythms, which are mentioned as having a role in many traditional forestry practices. The measured criteria were the water loss from fresh to dry state, the shrinkage linked to this water loss, and the relative density (ratio between the dry density and the initial fresh density) for both sapwood and heartwood in Picea and heartwood in Castanea. In addition to seasonal trends, slight but significant variations with lunar periodicities (both synodic and sidereal; to a much lesser extent tropic) characterize the three investigated criteria. These lunar rhythmicities occur in both Picea and Castanea, in heartwood and sapwood. These results raise new questions and perspectives about a rhythmic character of the wood-water relatio

    Attosecond screening dynamics mediated by electron-localization

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    Transition metals with their densely confined and strongly coupled valence electrons are key constituents of many materials with unconventional properties, such as high-Tc superconductors, Mott insulators and transition-metal dichalcogenides. Strong electron interaction offers a fast and efficient lever to manipulate their properties with light, creating promising potential for next-generation electronics. However, the underlying dynamics is a fast and intricate interplay of polarization and screening effects, which is poorly understood. It is hidden below the femtosecond timescale of electronic thermalization, which follows the light-induced excitation. Here, we investigate the many-body electron dynamics in transition metals before thermalization sets in. We combine the sensitivity of intra-shell transitions to screening effects with attosecond time resolution to uncover the interplay of photo-absorption and screening. First-principles time-dependent calculations allow us to assign our experimental observations to ultrafast electronic localization on d-orbitals. The latter modifies the whole electronic structure as well as the collective dynamic response of the system on a timescale much faster than the light-field cycle. Our results demonstrate a possibility for steering the electronic properties of solids prior to electron thermalization, suggesting that the ultimate speed of electronic phase transitions is limited only by the duration of the controlling laser pulse. Furthermore, external control of the local electronic density serves as a fine tool for testing state-of-the art models of electron-electron interactions. We anticipate our study to facilitate further investigations of electronic phase transitions, laser-metal interactions and photo-absorption in correlated electron systems on its natural timescale

    Sudden cardiac death among general population and sport related population in forensic experience.

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    PURPOSE: The goal of the study was to assess the causes and analyze the cases of sudden cardiac death (SCD) victims referred to the department of forensic medicine in Lausanne, with a particular focus on sports-related fatalities including also leisure sporting activities. To date, no such published assessment has been done nor for Switzerland nor for the central Europe. METHODS: This is a retrospective study based on autopsy records of SCD victims, from 10 to 50 years of age, performed at the University Centre of Legal Medicine in Lausanne from 1995 to 2010. The study population was divided into two groups: sport-related (SR) and not sport-related (NSR) SCDs. RESULTS: During the study period, 188 cases of SCD were recorded: 166 (88%) were NSR and 22 (12%) SR. The mean age of the 188 victims was 37.3 ± 10.1 years, with the majority of the cases being male (79%). A cause of death was established in 84%, and the pathology responsible for death varied according to the age of the victims. In the NSR group, the mean age was 38.2 ± 9.2 years and there was 82% of male. Coronary artery disease (CAD) was the main diagnosis in the victims aged 30-50 years. The majority of morphologically normal hearts were observed in the 15-29 year age range. There was no case in the 10-14 year age range. In the SR group, 91% of victims died during leisure sporting activities. In this group the mean age was 30.5 ± 13.5 years, with the majority being male (82%). The main cause of death was CAD, with 6 cases (27%) and a mean age of 40.8 ± 5.5 years. The youngest victim with CAD was 33 years old. A morphologically normal heart was observed in 5 cases (23%), with a mean age of 24.4 ± 14.9 years. The most frequently implicated sporting activities were hiking (26%) and swimming (17%). CONCLUSION: In this study, CAD was the most common cause of death in both groups. Although this pathology most often affects adults over 35 years of age, there were also some victims under 35 years of age in both groups. SCDs during sport are mostly related to leisure sporting activities, for which preventive measures are not yet usually established. This study highlights also the need to inform both athletes and non athletes of the cardiovascular risks during sport activities and the role of a forensic autopsy and registries involving forensic pathologists for SR SCD

    Citalopram plus low-dose pipamperone versus citalopram plus placebo in patients with major depressive disorder: an 8-week, double-blind, randomized study on magnitude and timing of clinical response

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    Background: Selective serotonin reuptake inhibitors take several weeks to achieve their full antidepressant effects. Post-synaptic 5-HT<sub>2A</sub> receptor activation is thought to be involved in this delayed therapeutic effect. Pipamperone acts as a highly selective 5-HT<sub>2A</sub>/D<sub>4</sub> antagonist when administered in low doses. The purpose of this study was to compare citalopram 40 mg once daily plus pipamperone 5 mg twice daily (PipCit) versus citalopram plus placebo twice daily for magnitude and onset of therapeutic effect. Method: An 8-week, randomized, double-blind study in patients with major depressive disorder was carried out. Results: The study population comprised 165 patients (citalopram and placebo, n=82; PipCit, n=83) with a mean baseline Montgomery–Asberg Depression Rating Scale (MADRS) score of 32.6 (S.D.=5.5). In the first 4 weeks, more citalopram and placebo than PipCit patients discontinued treatment (18% v. 4%, respectively, p=0.003). PipCit patients had significantly greater improvement in MADRS score at week 1 [observed cases (OC), p=0.021; last observation carried forward (LOCF), p=0.007] and week 4 (LOCF, p=0.025) but not at week 8 compared with citalopram and placebo patients. Significant differences in MADRS scores favoured PipCit in reduced sleep, reduced appetite, concentration difficulties and pessimistic thoughts. Mean Clinical Global Impression–Improvement scores were significantly improved after 1 week of PipCit compared with citalopram and placebo (OC and LOCF, p=0.002). Conclusions: Although the MADRS score from baseline to 8 weeks did not differ between groups, PipCit provided superior antidepressant effects and fewer discontinuations compared with citalopram and placebo during the first 4 weeks of treatment, especially in the first week

    Attosecond timing of the dynamical Franz–Keldysh effect

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    To what extent do intra- or inter-band transitions dominate the optical response of dielectrics when pumped by a few-cycle near-infrared transient electric field? In order to find an answer to this question we investigate the dynamical Franz–Keldysh effect in polycrystalline diamond and discuss in detail the attosecond delay of the induced electron dynamics with regard to the driving transient electric field while the peak intensity is varied between 1 × 1012 and 10 × 1012 W cm−2. We found that the main oscillating feature in transient absorption at 43 eV is in phase with the electric field of the pump, to within 49 ± 78 as. However, the phase delay shows a slightly asymmetric V-shaped linear energy dispersion with a rate of about 200 as eV–1. Theoretical calculations within the dipole approximation reproduce the data and allow us to conclude that intra-band motion dominates under our experimental conditions

    Inadequate Clearance of Translocated Bacterial Products in HIV-Infected Humanized Mice

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    Bacterial translocation from the gut and subsequent immune activation are hallmarks of HIV infection and are thought to determine disease progression. Intestinal barrier integrity is impaired early in acute retroviral infection, but levels of plasma lipopolysaccharide (LPS), a marker of bacterial translocation, increase only later. We examined humanized mice infected with HIV to determine if disruption of the intestinal barrier alone is responsible for elevated levels of LPS and if bacterial translocation increases immune activation. Treating uninfected mice with dextran sodium sulfate (DSS) induced bacterial translocation, but did not result in elevated plasma LPS levels. DSS-induced translocation provoked LPS elevation only when phagocytic cells were depleted with clodronate liposomes (clodrolip). Macrophages of DSS-treated, HIV-negative mice phagocytosed more LPS ex vivo than those of control mice. In HIV-infected mice, however, LPS phagocytosis was insufficient to clear the translocated LPS. These conditions allowed higher levels of plasma LPS and CD8+ cell activation, which were associated with lower CD4+/CD8+ cell ratios and higher viral loads. LPS levels reflect both intestinal barrier and LPS clearance. Macrophages are essential in controlling systemic bacterial translocation, and this function might be hindered in chronic HIV infection

    Enhancement of antibody-dependent cellular cytotoxicity is associated with treatment response to extracorporeal photopheresis in SĂ©zary syndrome.

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    SĂ©zary syndrome (SS) is a rare, leukemic type of cutaneous T-cell lymphoma (CTCL), for which extracorporeal photopheresis (ECP) is a first-line therapy. Reliable biomarkers to objectively monitor the response to ECP in patients with SS are missing. We examined the quantitative and qualitative impact of ECP on natural killer (NK) cell activity in SS patients, and especially their functional ability for antibody-dependent cell-mediated cytotoxicity (ADCC). Further, we addressed the question whether the magnitude of the effect on ADCC can be associated with the anti-cancer efficacy of ECP in SS patients. We assessed numbers of NK cells, ADCC activity, and treatment response based on blood tumor staging in a cohort of 13 SS patients (8 women, 5 men) treated with ECP as a first-line therapy. Blood samples were collected before treatment start and after an average of 9 months of uninterrupted ECP treatment. NK cell numbers were reduced in SS patients compared to healthy individuals and showed a tendency of recovery after long-term ECP treatment, independent of the clinical response to treatment. Patients with marginal increase (≀1.5 AU-fold) or lack of increase in ADCC activity failed to respond clinically to treatment, while patients with an increased ADCC activity showed a reduction in blood tumor burden. NK-mediated ADCC is selectively enhanced and might be a mechanism underlying the effect of ECP while in addition it can possibly serve as a reliable biomarker to objectively monitor response to ECP in patients with SS

    HIV-Specific Cellular Immune Response Is Inversely Correlated with Disease Progression as Defined by Decline of CD4+ T Cells in Relation to HIV RNA Load

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    The average time between infection with human immunodeficiency virus (HIV) and development of acquired immune deficiency syndrome is ∌8 years. However, progression rates vary widely, depending on several determinants, including HIV-specific immunity, host genetic factors, and virulence of the infecting strain. In untreated HIV-infected patients with different progression rates, we examined HIV-specific T cell responses in combination with host genetic markers, such as chemokine/chemokine-receptor (CCR) polymorphisms and human leukocyte antigen (HLA) genotypes. HIV-specific CD4+ T cell responses and, to a lesser extent, HIVspecific CD8+ T cell responses were inversely correlated with progression rate. Slower progression was not related to polymorphisms in CCR genes, HLA genotype, or GB virus C coinfection. These data suggest that HIV-specific T cell responses are involved in protecting the host from disease progressio
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