121 research outputs found

    Effects of sample geometry on deformation modes of bulk metallic glasses at the nano/micrometer scale

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    Author name used in this publication: Jianchao YeAuthor name used in this publication: Yong Yang2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Revelation of the effect of structural heterogeneity on microplasticity in bulk metallic-glasses

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    Author name used in this publication: Yong YangAuthor name used in this publication: Jianchao YeAuthor name used in this publication: Qing Wang2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Plasticity performance of Al0.5CoCrCuFeNi high-entropy alloys under nanoindentation

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    The statistical and dynamic behaviors of the displacement-load curves of a high-entropy alloy Al0.3CoCrCuFeNi were analyzed for the nanoindentation performed at two temperatures. Critical behavior of serrations at room temperature and chaotic flows at 200 degrees C were detected. These results are attributed to the interaction among a large number of slip hands. For the nanoindentation at room temperature recurrent partial events between slip hands introduce a hierarchy of length scales leading to a critical state. For the nanoindentation at 200 degrees C there is no spatial interference between two slip hands which is corresponding to the evolution of separated trajectory of chaotic behavior

    Stability analysis of non-autonomous reaction-diffusion systems: the effects of growing domains

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    By using asymptotic theory, we generalise the Turing diffusively-driven instability conditions for reaction-diffusion systems with slow, isotropic domain growth. There are two fundamental biological differences between the Turing conditions on fixed and growing domains, namely: (i) we need not enforce cross nor pure kinetic conditions and (ii) the restriction to activator-inhibitor kinetics to induce pattern formation on a growing biological system is no longer a requirement. Our theoretical findings are confirmed and reinforced by numerical simulations for the special cases of isotropic linear, exponential and logistic growth profiles. In particular we illustrate an example of a reaction-diffusion system which cannot exhibit a diffusively-driven instability on a fixed domain but is unstable in the presence of slow growth

    Deformation crossover : from nano- to mesoscale

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    Estimation of the incidence of genital warts and the cost of illness in Germany: A cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Human papillomavirus (HPV) is a necessary cause of cervical cancer. HPV is also responsible for benign <it>condylomata acuminata</it>, also known as genital warts. We assessed the incidence of genital warts in Germany and collected information on their management to estimate the annual cost of disease.</p> <p>Methods</p> <p>This was a multi-centre observational (cross-sectional) study of genital warts in Germany. Data were collected from gynecologists, dermatologists, and urologists seeing patients with genital warts between February and April 2005. The number of patients with new and recurrent genital warts was used to estimate the incidence in Germany. We assessed resource use for patients with genital warts seen during a two-month period as well as retrospective resource use twelve months prior to the inclusion visit through a chart review. The mean costs of treatment of patients with genital warts from third-party payer and societal perspectives were estimated, and the total annual cost of genital warts was then calculated.</p> <p>Results</p> <p>For the incidence calculation 217 specialists provided information on 848 patients and 214 specialists provided resource use data for 617 patients to assess resource consumption. The incidence of new and recurrent cases of genital warts was 113.7 and 34.7 per 100 000, respectively, for women aged 14–65 years consulting gynecologists. The highest incidence was observed in women aged 14–25 years (171.0 per 100 000) for new cases and in women aged 26–45 years (53.1 per 100 000) for recurrent cases. The sample size for males was too small to allow a meaningful estimate of the incidence. The mean direct cost per patient with new genital warts was estimated at 378 euros (95% CI: 310.8–444.9); for recurrent genital warts at 603 euros (95% CI: 436.5–814.5), and for resistant genital warts at 1,142 euros (95% CI: 639.6–1752.3). The overall cost to third-party payers was estimated at 49.0 million euros, and the total societal cost at 54.1 million euros, corresponding to an average cost per patient of 550 euros and 607 euros, respectively.</p> <p>Conclusion</p> <p>The societal burden and costs of managing and treating genital warts in Germany are considerable. A vaccination programme using the quadrivalent human papillomavirus vaccine could provide a substantial health benefit and reduce the costs associated with genital warts in Germany.</p

    Tuning plasticity of in-situ dendrite metallic glass composites via the dendrite-volume-fraction-dependent shear banding

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    This work performs a systematic investigation of identifying how the volume fraction of the in-situ dendrites affects the plasticity of metallic glass composites. The quasi-static uniaxial compressions show that the global plastic strain does not follows a linear rule-of-mixture with the dendrite volume faction, instead, a slow-fast slow enhancement behaviour is observed with increasing dendrite volume fraction. It is demonstrated that the nucleation and propagation of shear bands in these composites are dependent on the dendrite volume fraction. When the dendrite volume fraction exceeds a critical value, multiple shear bands emerge in a spherical plastic zone around a dendrite. It is further proposed that the percolation of these spherical plastic zones contributes to the fast increase in the plastic strain of the glass composites. Our findings offer important implications for the microstructural optimization of the metallic glass composites with desirable mechanical properties

    Development of a Bead-Based Multiplex Genotyping Method for Diagnostic Characterization of HPV Infection

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    The accurate genotyping of human papillomavirus (HPV) is clinically important because the oncogenic potential of HPV is dependent on specific genotypes. Here, we described the development of a bead-based multiplex HPV genotyping (MPG) method which is able to detect 20 types of HPV (15 high-risk HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68 and 5 low-risk HPV types 6, 11, 40, 55, 70) and evaluated its accuracy with sequencing. A total of 890 clinical samples were studied. Among these samples, 484 were HPV positive and 406 were HPV negative by consensus primer (PGMY09/11) directed PCR. The genotyping of 484 HPV positive samples was carried out by the bead-based MPG method. The accuracy was 93.5% (95% CI, 91.0–96.0), 80.1% (95% CI, 72.3–87.9) for single and multiple infections, respectively, while a complete type mismatch was observed only in one sample. The MPG method indiscriminately detected dysplasia of several cytological grades including 71.8% (95% CI, 61.5–82.3) of ASCUS (atypical squamous cells of undetermined significance) and more specific for high grade lesions. For women with HSIL (high grade squamous intraepithelial lesion) and SCC diagnosis, 32 women showed a PPV (positive predictive value) of 77.3% (95% CI, 64.8–89.8). Among women >40 years of age, 22 women with histological cervical cancer lesions showed a PPV of 88% (95% CI, 75.3–100). Of the highest risk HPV types including HPV-16, 18 and 31 positive women of the same age groups, 34 women with histological cervical cancer lesions showed a PPV of 77.3% (95% CI, 65.0–89.6). Taken together, the bead-based MPG method could successfully detect high-grade lesions and high-risk HPV types with a high degree of accuracy in clinical samples

    Factors that influence nurses' assessment of patient acuity and response to acute deterioration.

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    BACKGROUND: nurses play a crucial role in the early recognition and management of the deteriorating patient. They are responsible for the care they provide to their patients, part of which is the monitoring of vital signs (blood pressure, pulse, respiratory rate and temperature), which are fundamental in the surveillance of deterioration. The aim of this study was to discover what factors influence how nurses assess patient acuity and their response to acute deterioration. METHODS: a generic qualitative approach was used. Some 10 nurses working in an acute NHS trust were interviewed using a semi- structured approach, with equal representation from medical and surgical inpatient wards. RESULTS: the main themes identified were collegial relationships, intuition, and interpretation of the MEWS system (Modified Early Warning Score). Collegial relationships with the medical staff had some influence on the nurses' assessment, as they tended to accept the medical peers' assessment as absolute, rather than their own assessment. It was also highlighted that nurses relied on the numerical escalation of the MEWS system to identify the deteriorating patient, instead of their own clinical judgement of the situation. Interestingly, the nurses found no difficulty in escalating the patient's care to medical staff when the patient presented with a high MEWS score. The difficulty arose when the MEWS score was low-the participants found it challenging to authenticate their findings. CONCLUSION: this study has identified several confounding factors that influence the ways in which nurses assess patient acuity and their response to acute deterioration. The information provides a crucial step forward in identifying strategies to develop further training
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