3,771 research outputs found
Hybrid system for ex vivo hemorheological and hemodynamic analysis: a feasibility study
Precise measurement of biophysical properties is important to understand the relation between these properties and the outbreak of cardiovascular diseases (CVDs). However, a systematic measurement for these biophysical parameters under in vivo conditions is nearly impossible because of complex vessel shape and limited practicality. In vitro measurements can provide more biophysical information, but in vitro exposure changes hemorheological properties. In this study, a hybrid system composed of an ultrasound system and microfluidic device is proposed for monitoring hemorheological and hemodynamic properties under more reasonable experimental conditions. Biophysical properties including RBC aggregation, viscosity, velocity, and pressure of blood flows are simultaneously measured under various conditions to demonstrate the feasibility and performance of this measurement system. The proposed technique is applied to a rat extracorporeal loop which connects the aorta and jugular vein directly. As a result, the proposed system is found to measure biophysical parameters reasonably without blood collection from the rat and provided more detailed information. This hybrid system, combining ultrasound imaging and microfluidic techniques to ex vivo animal models, would be useful for monitoring the variations of biophysical properties induced by chemical agents. It can be used to understand the relation between biophysical parameters and CVDs.1196Ysciescopu
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Nanoimaging of Organic Charge Retention Effects: Implications for Nonvolatile Memory, Neuromorphic Computing, and High Dielectric Breakdown Devices
While a large variety of organic and molecular materials have been found to exhibit charge memory effects, the underlying mechanism is not well-understood, which hinders rational device design. Here, we study the charge retention mechanism of a nanoscale memory system, an organic monolayer on a silicon substrate, with Au nanoparticles on top serving as the electrical contact. Combining scanning probe imaging/manipulation and density functional simulations, we observe stable charge retention effects in the system and attributed it to polaron effects at the amine functional groups. Our findings can pave the way for applications in nonvolatile memory, neuromorphic computing, and high dielectric breakdown devices
Vulvar cancer in high-income countries: Increasing burden of disease
The aim of this study was to assess trends in the age-specific incidence of vulvar cancer in 13 high-income countries satisfying a priori conditions regarding the availability of cancer registry data over a 20-year period; these were Canada, the United States, nine European countries, Australia and Japan. Five-yearly incidence and population at risk were obtained from the International Agency for Research on Cancer's Cancer Incidence in Five Continents for the years 1988-1992 (Volume 7) to 2003-2007 (Volume 10). The 5-yearly average percent change (AvPC) over the period and standardised rate ratios (SRRs) for 2003-2007 versus 1988-1992 were used to assess changes in the age-standardised incidence rates of vulvar cancer for all ages, and for <60 years and 60+ years. During the study period, the 5-yearly AvPC across the 13 countries increased by 4.6% (p = 0.005) in women of all ages, and 11.6% (p = 0.02) in those <60 years. No change was observed in women aged 60+ years (5-yearly AvPC = 0.1%, p = 0.94). The SRR for 2003-2007 versus 1988-1992 was significantly elevated in women <60 years of age (SRR = 1.38, 95% CI: 1.30-1.46), but not in women of 60+ years (SRR = 1.01, 95% CI: 0.97-1.05). The increase in incidence in women <60 years of age drove a significant increase in the overall SRR in women of all ages (SRR = 1.14, 95% CI: 1.11-1.18). Some differences in the specific findings at the individual country level were observed. The findings are consistent with changing sexual behaviours and increasing levels of exposure to human papillomavirus (HPV) in cohorts born around/after about 1950, but younger cohorts offered HPV vaccination are likely to receive some protection against developing vulvar cancer in the future
Health system interventions to integrate genetic testing in routine oncology services: A systematic review
Background
Integration of genetic testing into routine oncology care could improve access to testing. This systematic review investigated interventions and the tailored implementation strategies aimed at increasing access to genetic counselling and testing and identifying hereditary cancer in oncology.
Methods
The search strategy results were reported using the PRISMA statement and four electronic databases were searched. Eligible studies included routine genetic testing for breast and ovarian cancer or uptake after universal tumour screening for colorectal or endometrial cancer. The titles and abstracts were reviewed and the full text articles screened for eligibility. Data extraction was preformed using a designed template and study appraisal was assessed using an adapted Newcastle Ottawa Scale. Extracted data were mapped to Proctor’s et al outcomes and the Consolidated Framework for Implementation Research and qualitatively synthesised.
Results
Twenty-seven studies, published up to May 2020, met the inclusion criteria. Twenty-five studies ranged from poor (72%), fair to good (28%) quality. Most interventions identified were complex (multiple components) such as; patient or health professional education, interdisciplinary practice and a documentation or system change. Forty-eight percent of studies with complex interventions demonstrated on average a 35% increase in access to genetic counselling and a 15% increase in testing completion. Mapping of study outcomes showed that 70% and 32% of the studies aligned with either the service and client or the implementation level outcome and 96% to the process or inner setting domains of the Consolidated Framework for Implementation Research.
Conclusion
Existing evidence suggests that complex interventions have a potentially positive effect towards genetic counselling and testing completion rates in oncology services. Studies of sound methodological quality that explore a greater breadth of pre and post implementation outcomes and informed by theory are needed. Such research could inform future service delivery models for the integration of genetics into oncology services
Heteroepitaxal fabrication and structural characterizations of ultrafine GaN/ZnO coaxial nanorod heterostructures
We report on heteroepitaxial fabrication and structural characterizations of ultrafine GaN/ZnO coaxial nanorod heterostructures. The coaxial nanorod heterostructures were fabricated by epitaxial growth of a GaN layer on ultrafine ZnO nanorods. Epitaxial growth and precise control of GaN overlayer thickness were obtained by low pressure metalorganic vapor-phase epitaxy. ZnO nanorods grown on Si and sapphire substrates using catalyst-free metalorganic chemical vapor deposition exhibited diameters as small as 7 nm. Furthermore, structural properties of the coaxial nanorod heterostructures were investigated using both synchrotron-radiation x-ray diffraction and high resolution transmission electron microscopy. (C) 2004 American Institute of Physics.open115462sciescopu
Spread of Mutant Middle East Respiratory Syndrome Coronavirus with Reduced Affinity to Human CD26 during the South Korean Outbreak
The newly emerging Middle East respiratory syndrome coronavirus (MERS-CoV) causes a severe respiratory infection with a high mortality rate (similar to 35%). MERS-CoV has been a global threat due to continuous outbreaks in the Arabian peninsula and international spread by infected travelers since 2012. From May to July 2015, a large outbreak initiated by an infected traveler from the Arabian peninsula swept South Korea and resulted in 186 confirmed cases with 38 deaths (case fatality rate, 20.4%). Here, we show the rapid emergence and spread of a mutant MERS-CoV with reduced affinity to the human CD26 receptor during the South Korean outbreak. We isolated 13 new viral genomes from 14 infected patients treated at a hospital and found that 12 of these genomes possess a point mutation in the receptor-binding domain (RBD) of viral spike (S) protein. Specifically, 11 of these genomes have an I529T mutation in RBD, and 1 has a D510G mutation. Strikingly, both mutations result in reduced affinity of RBD to human CD26 compared to wild-type RBD, as measured by surface plasmon resonance analysis and cellular binding assay. Additionally, pseudotyped virus bearing an I529T mutation in S protein showed reduced entry into host cells compared to virus with wild-type S protein. These unexpected findings suggest that MERS-CoV adaptation during human-to-human spread may be driven by host immunological pressure such as neutralizing antibodies, resulting in reduced affinity to host receptor, and thereby impairs viral fitness and virulence, rather than positive selection for a better affinity to CD26. IMPORTANCE Recently, a large outbreak initiated by an MERS-CoV-infected traveler from the Middle East swept South Korea and resulted in 186 confirmed cases with 38 deaths. This is the largest outbreak outside the Middle East, and it raised strong concerns about the possible emergence of MERS-CoV mutations. Here, we isolated 13 new viral genomes and found that 12 of them possess a point mutation in the receptor-binding domain of viral spike protein, resulting in reduced affinity to the human cognate receptor, CD26, compared to the wild-type virus. These unexpected findings suggest that MERS-CoV adaptation in humans may be driven by host immunological pressure.111819Ysciescopu
Valley-Polarized Interlayer Conduction of Anisotropic Dirac Fermions in SrMnBi2
We report the valley-selective interlayer conduction of SrMnBi2 under in-plane magnetic fields. The c-axis resistivity of SrMnBi2 shows clear angular magnetoresistance oscillations indicating coherent interlayer conduction. Strong fourfold variation of the coherent peak in the c-axis resistivity reveals that the contribution of each Dirac valley is significantly modulated by the in-plane field orientation. This originates from anisotropic Dirac Fermi surfaces with strong disparity in the momentum-dependent interlayer coupling. Furthermore, we found a signature of broken valley symmetry at high magnetic fields. These findings demonstrate that a quasi-two-dimensional anisotropic Dirac system can host a valley-polarized interlayer current through magnetic valley control. &#169; 2014 American Physical Society.open1
Estimating the Cost-Effectiveness of Lung Cancer Screening with Low-Dose Computed Tomography for High-Risk Smokers in Australia
Introduction Health economic evaluations of lung cancer screening with low-dose computed tomography (LDCT) that are underpinned by clinical outcomes are relatively few. Methods We assessed the cost-effectiveness of LDCT lung screening in Australia by applying Australian cost and survival data to the outcomes observed in the U.S. National Lung Screening Trial (NLST), in which a 20% lung cancer mortality benefit was demonstrated for three rounds of annual screening among high-risk smokers age 55 to 74 years. Screening-related costs were estimated from Medicare Benefits Schedule reimbursement rates (2015), lung cancer diagnosis and treatment costs from a 2012 Australian hospital–based study, lung cancer survival rates from the New South Wales Cancer Registry (2005–2009), and other-cause mortality from Australian life tables weighted by smoking status. The health utility outcomes, screening participation rates, and lung cancer rates were those observed in the NLST. Incremental cost effectiveness ratios (ICER) were calculated for a 10-year time horizon. Results The cost-effectiveness of LDCT lung screening was estimated at AU84,700–AU233,000 (80% confidence interval: AU1,110,000)/quality-adjusted life year (QALY) gained. The ICER was more favorable when LDCT screening impact on all-cause mortality was considered, even when the costs of incidental findings were also estimated in sensitivity analyses: AU30,000 to AU$50,000/QALY. Conclusions LDCT lung screening using NLST selection and implementation criteria is unlikely to be cost-effective in Australia. Future economic evaluations should consider alternative screening eligibility criteria, intervals, nodule management, the impact and cost of new therapies, investigations of incidental findings, and incorporation of smoking cessation interventions
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