2,600 research outputs found

    Individual variability in the perceptual learning of L2 speech sounds and its cognitive correlates

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    This study explored which cognitive processes are related to individual variability in the learning of novel phonemic contrasts in a second language. 25 English participants were trained to perceive a Korean stop voicing contrast which is novel for English speakers. They were also presented with a large battery of tests which investigated different aspects of their perceptual and cognitive abilities, as well as pre- and posttraining tests of their ability to discriminate this novel consonant contrast. The battery included: adaptive psychoacoustic tasks to determine frequency limens, a paired-association task looking at the ability to memorise the pairing of two items, a backward digit span task measuring working memory span, a sentence perception in noise task that quantifies the effect of top-down information as well as signal detection ability, a sorting task investigating the attentional filtering of the key acoustic features. The general measures that were the most often correlated with the ability to learn the novel phonetic contrast were measures of attentional switching (i.e. the ability to reallocate attention), the ability to sort stimuli according to a particular dimension, which is also somewhat linked to allocation of attention, frequency acuity and the ability to associate two unrelated events

    Observation of correlated-photon statistics using a single detector

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    We report experimental observations of correlated-photon statistics in the single-photon detection rate. The usual quantum interference in a two-photon polarization interferometer always accompanies a dip in the single detector counting rate, regardless of whether a dip or peak is seen in the coincidence rate. This effect is explained by taking into account all possible photon number states that reach the detector, rather than considering just the state post-selected by the coincidence measurement. We also report an interferometeric scheme in which the interference peak or dip in coincidence corresponds directly to a peak or dip in the single-photon detection rate.Comment: 4 pages, two-column (minor errors corrected.

    Adriamycin loading and release characteristics of albumin-heparin conjugate microspheres

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    Biodegradable ion-exchange microspheres, prepared from a prefabricated conjugate of albumin and heparin were investigated as carriers for adriamycin. The ion-exchange microspheres could be loaded with adriamycin giving payloads up to 33% w/w, depending on the heparin content of the conjugate. In vitro adriamycin release depended on the ionic strength of the release medium. In ion containing media, for instance saline, 90% of the drug was released within 45 min, whereas in non-ionic media, such as distilled water, only 30% was released. Drug release profiles could be modelled by combining ion-exchange kinetics and diffusion controlled drug release models

    Albumin-heparin microspheres as carriers for cytostatic agents

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    Much work has been done on adriamycin-loaded albumin microspheres (Alb-MS) for chemoembolization [1–4], the rationale being that site-specific drug delivery may increase the therapeutic efficacy of the drug. Alb-Ms are being investigated because of their biocompatibility and because the degradation products of these microspheres are non-toxic. However, these microspheres have some disadvantages (i.e. drug loading during the microsphere preparation, low payloads, large burst effects). These disadvantages can be overcome by the incorporation of heparin (a highly negatively charged mucopolysaccharide). Albumin-heparin microspheres were prepared (i) by crosslinking of soluble albumin and heparin first using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and subsequently glutaraldehyde (Alb-Hep-MS) and (ii) by crosslinking a preformed soluble conjugate of heparin and albumin with glutaraldehyde (Alb-Hep-Conj-MS). Albumin-heparin microspheres could be loaded with adriamycin after microsphere preparation giving payloads of 15–30%. Preliminary in vitro adriamycin release experiments showed that Alb-Hep-Conj-MS exhibit sustained release properties. Furthermore ion-exchange properties could be observed both with Alb-Hep-MS and Alb-Hep-Conj-MS. In vitro and in vivo toxicity experiments with Alb-Hep-MS showed no adverse effects

    Investigation of jetting piping system in the spudcan of wind turbine installation jack-up vessel

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    The offshore wind turbine in shallow water is installed by a self-elevated mobile unit which is usually\ud referred to as jack-up barge or jack-up vessel. The jack-up vessel consists of a buoyant platform together with\ud independent legs that can position the vessel above the water reducing external loadings for safe operation condition.\ud The retrieval process of jack-up legs could be very difficult due to the high extraction resistance caused by soft soil. In\ud soft clay, since the high suction force can be developed around the spudcan attached at the end of jack-up legs, a jetting\ud system is required to break the suction to pull out the legs. It is important to design the jetting system with optimized\ud piping arrangement to allow the easy operation. There are various factors to be considered in the design of jetting piping\ud system since the level of embedment and the type of soil and pipe size and locations, etc. can affect the performance of\ud the system. In this paper, the design of 500m^3/hr jetting system is introduced with PIPENET program analysis. Also\ud the various consideration factors in the analysis are discussed

    Mechanistic studies on human minor histocompatibility antigens in graft-versus-host disease

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    In this thesis, we have explored the mechanism of minor H antigen-related GVHD. Hereto, we developed and validated new methods to detect and to phenotype minor H antigen-specific T cells on cryo-preserved human tissues. Using these methods, we investigated the influence of the ubiquitously expressed minor H antigen HY in skin GVHD. This first report on the in situ detection of skin-infiltrating HY-specific T cells in GVHD affected tissue of pediatric patient__s points to an active role of these T cells in the pathophysiology of acute GVHD after gender mismatched HSCT. Using our skin explant methodologies, we also aimed at gathering insights into the postulated involvement of hematopoietic-system restricted HA-1 in GVHD. This study was challenged by the contradictory results of clinical studies on the influence of HA-1 with GVHD. We showed that recognition of skin samples reconstituted with mature DCs, facilitated infiltration and local activation of HA-1-specific T cells. Although the infiltrated and activated HA-1-specific T cells did not cause skin tissue destruction in our model, our results provide a first step in understanding the reported association of HA-1 mismatching with clinical GVHD. Finally, we performed a large multi-center population-based study comprising 849 HSCT pairs, investigating the effect of broadly expressed and hematopoietic restricted minor H antigen-mismatching on GVHD and on relapse incidence after HLA-matched and HLA-identical HSCT. We showed that mismatching for broadly expressed autosomally encoded minor H antigens is associated with increased GVHD in HLA-identical, but not in HLA-matched unrelated HSCT. Disparities between donor and recipient for hematopoietic system-specific autosomally encoded minor H antigens do neither influence the development of GVHD nor had an effect on relapse incidence. Importantly however were the significantly lower relapse rates and disease free survival observed in those patients who suffered from GVHD.UBL - phd migration 201

    Preparation and characterization of albumin-heparin microspheres

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    Albumin-heparin microspheres were prepared by a two-step process which involved the preparation of a soluble albumin-heparin conjugate, followed by formation of microspheres from this conjugate or by a double cross-linking technique involving both coupling of soluble albumin and heparin and microsphere stabilization in one step. The first technique was superior since it allowed better control over the composition and the homogeneity of the microspheres. Microspheres could be prepared with a diameter of 5Âż35Âżm. The size could be controlled by adjusting the emulsification conditions. The degree of swelling of the microspheres was sensitive to external stimuli, and increased with increasing pH and decreasing ionic strength of the medium

    Quantum interference with beamlike type-II spontaneous parametric down-conversion

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    We implement experimentally a method to generate photon-number−-path and polarization entangled photon pairs using ``beamlike'' type-II spontaneous parametric down-conversion (SPDC), in which the signal-idler photon pairs are emitted as two separate circular beams with small emission angles rather than as two diverging cones.Comment: 4 pages, two-colum

    Capacity to consent to research: The evolution and current concepts

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    The ethical problem of the need to conduct research on the very conditions that impair the ability to consent to such research is widely acknowledged. People with cognitive impairment and mental illness have an equitable right to research being conducted in areas relevant to their treatment and care, and should be given an equitable opportunity to participate in such research, even if they lack capacity. They also have a right to adequate safeguards to protect their interests and respect their wishes in regards to research participation. Provisions for involvement in research of those who are unable to give consent have only developed over the last 50 years. Over this period we have witnessed a proliferation of policies, regulations and laws that govern research involving subjects unable to give consent. There has been a parallel increase in our understanding of the concepts of consent and capacity, specifically as it relates to the research context, with development of standards for research consent and instruments to guide capacity evaluation. We review the evolution of research governance and the underlying ethical principles that underpin such regulations, approaches to capacity evaluation and the use of proxies and advance research directives to facilitate research participation in adults who lack capacity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94739/1/appy210.pd

    Experimental Entanglement Concentration and Universal Bell-state Synthesizer

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    We report a novel Bell-state synthesizer in which an interferometric entanglement concentration scheme is used. An initially mixed polarization state from type-II spontaneous parametric down-conversion becomes entangled after the interferometric entanglement concentrator. This Bell-state synthesizer is universal in the sense that the output polarization state is not affected by spectral filtering, crystal thickness, and, most importantly, the choice of pump source. It is also robust against environmental disturbance and a more general state, partially mixed−-partially entangled state, can be readily generated as well.Comment: Minor update (Newer data
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