219 research outputs found

    Functional approach to quantum friction: effective action and dissipative force

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    We study the Casimir friction due to the relative, uniform, lateral motion of two parallel semitransparent mirrors coupled to a vacuum real scalar field, ϕ\phi. We follow a functional approach, whereby nonlocal terms in the action for ϕ\phi, concentrated on the mirrors' locii, appear after functional integration of the microscopic degrees of freedom. This action for ϕ\phi, which incorporates the relevant properties of the mirrors, is then used as the starting point for two complementary evaluations: Firstly, we calculate the { in-out} effective action for the system, which develops an imaginary part, hence a non-vanishing probability for the decay (because of friction) of the initial vacuum state. Secondly, we evaluate another observable: the vacuum expectation value of the frictional force, using the { in-in} or Closed Time Path formalism. Explicit results are presented for zero-width mirrors and half-spaces, in a model where the microscopic degrees of freedom at the mirrors are a set of identical quantum harmonic oscillators, linearly coupled to $\phi

    Imported malaria in an area in southern Madrid, 2005-2008

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    <p>Abstract</p> <p>Background</p> <p>In Spain, malaria cases are mostly due to migrants and travellers returning from endemic areas. The objective of this work was to describe the malaria cases diagnosed at the Severo Ochoa University Hospital (HUSO) in Leganés in the south of the Madrid Region from 2005 to 2008.</p> <p>Methods</p> <p>Descriptive retrospective study performed at HUSO. Data sources are registries from the Microbiology Department and malaria cases notified to the Preventive Medicine Department. Analysed parameters were: administrative, demographical, related to the stay at the endemic country, clinical, microbiological diagnosis method, pregnancy, treatment and prophylaxis, co-infections, and days of hospital stay.</p> <p>Results</p> <p>Fifty-seven patients diagnosed with malaria were studied. Case distribution per year was 13 in 2005, 15 in 2006, 15 in 2007 and 14 in 2008. Thirty-three patients were female (57.9%) and 24 male (42.1%). Mean age was 27.8 years. Most of the malaria cases were acquired in Nigeria (49.1%) and Equatorial Guinea (32.7%). 29.1% of the patients were immigrants who had arrived recently, and 61.8% acquired malaria when travelling to their countries of origin to visit friends and relatives (VFR). Majority of cases were diagnosed between June and September. Microscopy was positive in 39 cases (68.4%) immunochromatography in 42 (73.7%) and PCR in the 55 cases where performed. <it>Plasmodium falciparum </it>was responsible for 94.7% of the cases. The more frequent symptoms were fever (77.2%), followed by headache and gastrointestinal symptoms (33.3%). Nine cases needed hospital admittance, a pregnant woman, three children, four VFR and an African tourist, but all evolved favourably. Chemoprophylaxis data was known from 55 patients. It was taken correctly in one case (1.8%), in five (9.1%) the prophylaxis was improper while the others 49 (89.1%) cases had not followed any anti-malarial prophylaxis.</p> <p>Conclusions</p> <p>Children, pregnant women and the VFR have the highest risk to present severe malaria and to need hospital admittance. Another important risk factor for acquiring malaria is incorrect prophylaxis. The first place for malaria acquisition was Nigeria and the main species causing malaria was <it>P. falciparum.</it></p

    The contribution of Trichoderma to balancing the costs of plant growth and defense

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    Trichoderma is a fungal genus of cosmopolitan distribution and high biotechnological value, with several species currently used as biological control agents. Additionally, the enzyme systems of the fungus are widely applied in industry. Species of Trichoderma protect plants against the attack of soil-borne plant pathogens by competing for nutrients and inhibiting or killing plant pathogenic fungi and oomycetes, through the production of antibiotics and/or hydrolytic enzymes. In addition to the role of Trichoderma spp. as biocontrol agents, they have other benefi cial effects on plants, including the stimulation of plant defenses and the promotion of plant growth. In this review, we focus on the complex plant defense signaling network that allows the recognition of fungi as non-hostile microbes, including microbial-associated molecular patterns (MAMPs), damageassociated molecular patterns (DAMPs) and secreted elicitors. We also examine how fungal interactions with plant receptors can activate induced resistance by priming and balancing plant defense and growth responses. Our observations are integrated into a model describing Trichoderma-plant hormone signaling network interactions. [Int Microbiol 2013; 16(2):69-80]Keywords: Trichoderma spp.; plant&ndash;Trichoderma symbiosis; Arabidopsis thaliana; phytohormone networking&nbsp

    Design and manufacture of functional catalyst-carrier structures for the bioorthogonal activation of anticancer agents

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    Novel palladium (Pd)-loaded titanium (Ti) devices with high biocompatibility and catalytic activity were prepared using a range of fabrication methods such as powder metallurgy (i.e. sintering with and without space-holder), sputtering, pulsed laser deposition and supersonic cluster beam deposition. The surface of the Ti-[Pd] devices were physico-chemically characterised to confirm the non-alloyed state of the Pd coating onto the titanium substrate. The Pd thickness was optimised to achieve maximum surface area (i.e. maximum catalytic effect) using the minimum amount of material in each method for cost effective production. The catalytic response of the different Ti-[Pd] devices was evaluated under biocompatible conditions by employing an off-on Pd-activatable fluorescent probe. The most robust coating of Pd was produced by an optimised magnetron sputtering method. The sputtered Ti-[Pd] devices were selected to induce the bioorthogonal uncaging of the anticancer drug Vorinostat from a pharmacologically-inactive Pd-activatable precursor in cancer cell culture, demonstrating the capacity of these devices to mediate a local anti-tumour effect via in-situ release of a clinically approved drug. This approach is the first step towards surgically implantable devices that could facilitate targeting affected areas with high spatial selectivity, improving pharmacological activity and reducing systemic side effects through localised treatment directly at the cancer site

    Estimating upper-extremity function from kinematics in stroke patients following goal-oriented computer-based training

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    Introduction: After a stroke, a wide range of deficits can occur with varying onset latencies. As a result, assessing impairment and recovery are enormous challenges in neurorehabilitation. Although several clinical scales are generally accepted, they are time-consuming, show high inter-rater variability, have low ecological validity, and are vulnerable to biases introduced by compensatory movements and action modifications. Alternative methods need to be developed for efficient and objective assessment. In this study, we explore the potential of computer-based body tracking systems and classification tools to estimate the motor impairment of the more affected arm in stroke patients. Methods: We present a method for estimating clinical scores from movement parameters that are extracted from kinematic data recorded during unsupervised computer-based rehabilitation sessions. We identify a number of kinematic descriptors that characterise the patients' hemiparesis (e.g., movement smoothness, work area), we implement a double-noise model and perform a multivariate regression using clinical data from 98 stroke patients who completed a total of 191 sessions with RGS. Results: Our results reveal a new digital biomarker of arm function, the Total Goal-Directed Movement (TGDM), which relates to the patients work area during the execution of goal-oriented reaching movements. The model's performance to estimate FM-UE scores reaches an accuracy of R-2: 0.38 with an error (sigma: 12.8). Next, we evaluate its reliability (r = 0.89 for test-retest), longitudinal external validity (95% true positive rate), sensitivity, and generalisation to other tasks that involve planar reaching movements (R-2: 0.39). The model achieves comparable accuracy also for the Chedoke Arm and Hand Activity Inventory (R-2: 0.40) and Barthel Index (R-2: 0.35). Conclusions: Our results highlight the clinical value of kinematic data collected during unsupervised goal-oriented motor training with the RGS combined with data science techniques, and provide new insight into factors underlying recovery and its biomarkers

    Talking about weathering of a comercial variety of a brazilian granulite in Northern Morocco

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    The aim of this study is to explain the natural processes that led to the intense alteration observed in a commercial variety of Brazilian granulite named as «Granito Verde Eucalipto» paving a public square in Morroco. The mineralogical and microscopy study showed the occurrence of portlandite and other typical portland-like cements transformation products, such as calcite and aragonite. Subsequently, paragenesis of these carbonates with gypsum promoted quartz dissolution by alcalinolysis, a typical process of arid and semiarid weatherin

    Virulence as a Side Effect of Interspecies Interaction in Vibrio Coral Pathogens

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    The increase in prevalence and severity of coral disease outbreaks produced by Vibrio pathogens, and related to global warming, has seriously impacted reef-building corals throughout the oceans. The coral Oculina patagonica has been used as a model system to study coral bleaching produced by Vibrio infection. Previous data demonstrated that when two coral pathogens (Vibrio coralliilyticus and Vibrio mediterranei) simultaneously infected the coral O. patagonica, their pathogenicity was greater than when each bacterium was infected separately. Here, to understand the mechanisms underlying this synergistic effect, transcriptomic analyses of monocultures and cocultures as well as experimental infection experiments were performed. Our results revealed that the interaction between the two vibrios under culture conditions overexpressed virulence factor genes (e.g., those encoding siderophores, the type VI secretion system, and toxins, among others). Moreover, under these conditions, vibrios were also more likely to form biofilms or become motile through induction of lateral flagella. All these changes that occur as a physiological response to the presence of a competing species could favor the colonization of the host when they are present in a mixed population. Additionally, during coral experimental infections, we showed that exposure of corals to molecules released during V. coralliilyticus and V. mediterranei coculture induced changes in the coral microbiome that favored damage to coral tissue and increased the production of lyso-platelet activating factor. Therefore, we propose that competition sensing, defined as the physiological response to detection of harm or to the presence of a competing Vibrio species, enhances the ability of Vibrio coral pathogens to invade their host and cause tissue necrosis.This research was supported in part by the EU-H2020 MetaFluidics project with grant agreement number 685474 (to J.A.) and NSF-PIRE grant number OISE1243541 (to F.R.). E.R.-P. was funded by the postdoctoral program Vali+d (GVA) (grant number APOSTD-2016-091). A.M.C.-R. and P.C.D. were supported by the National Sciences Foundation grant IOS-1656481

    Assessment of the effect of intraarticular injection of autologous adipose-derived mesenchymal stem cells in osteoarthritic dogs using a double blinded force platform analysis

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    BACKGROUND: Regenerative medicine using Mesenchymal Stem Cells (MSC) alone or combined with Plasma Rich in Growth Factors (PRGF) is a rapidly growing area of clinical research and is currently also being used to treat osteoarthritis (OA). Force platform analysis has been consistently used to verify and quantify the efficacy of different therapeutic strategies for the treatment of OA in dogs including MSC associated to PRGF, but never with AD-MSC alone. The aim of this study was to use a force platform to measure the efficacy of intraarticular ADMSC administration for limb function improvement in dogs with severe OA. RESULTS: Ten lame dogs with severe hip OA and a control group of 5 sound dogs were used for this study. Results were statistically analyzed to detect a significant increase in peak vertical force (PVF) and vertical impulse (VI) in treated dogs. Mean values of PVF and VI were significantly improved within the first three months post-treatment in the OA group, increasing 9% and 2.5% body weight, respectively, at day 30. After this, the effect seems to decrease reaching initial values. CONCLUSION: Intraarticular ADMSC therapy objectively improved limb function in dogs with hip OA. The duration of maximal effect was less than 3 months

    Hemisynthesis and Absolute Configuration of novel 6-pentyl-2H-pyran- 2-one derivatives from Trichoderma spp

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    A comparative study of the secondary metabolism of two Trichoderma spp. with that of the Thctf1 transcription factor gene null mutant of Trichoderma harzianum 34 was carried out in order to deepen our knowledge of the biosynthetic pathway and mode of action of 6-pentyl-2H-pyran-2-one (1) and its derivatives as biocontrol agents. New isolated metabolites have shed light on the detoxification mechanism of 6-pentyl-pyranone by Trichoderma spp. All new compounds were synthesized and their stereoisomer characterized. The absolute configuration of 6-[(10R,20S)-dihydroxypentyl]-2H-pyran-2-one and 6-((10S,20R)-20-propyloxiran-1-yl)-2H-pyran-2-one was determined by NMR analysis of the corresponding Mosher’s esters
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