9,248 research outputs found
Microstructured Thin Film Nitinol for a Neurovascular Flow-Diverter
A cerebral aneurysm occurs as a result of a weakened blood vessel, which allows blood to flow into a sac or a ballooned section. Recent advancement shows that a new device, ‘flow-diverter’, can divert blood flow away from the aneurysm sac. People found that a flow-diverter based on thin film nitinol (TFN), works very effectively, however there are no studies proving the mechanical safety in irregular, curved blood vessels. Here, we study the mechanical behaviors and structural safety of a novel microstructured TFN membrane through the computational and experimental studies, which establish the fundamental aspects of stretching and bending mechanics of the structure. The result shows a hyper-elastic behavior of the TFN with a negligible strain change up to 180° in bending and over 500% in radial stretching, which is ideal in the use in neurovascular curved arteries. The simulation determines the optimal joint locations between the TFN and stent frame. In vitro experimental test qualitatively demonstrates the mechanical flexibility of the flow-diverter with multi-modal bending. In vivo micro X-ray and histopathology study demonstrate that the TFN can be conformally deployed in the curved blood vessel of a swine model without any significant complications or abnormalities
Berry chemoprevention: do berries decrease the window of opportunity for tumourigenesis
In addition to smoking and UV exposure, lifestyle factors, such as diet, nutrition, and physical activity, have been shown to play a significant role for many cancers. It is estimated that up to 50% of some cancer types are preventable; many through lifestyle and dietary changes with the presence or absence of certain dietary components strongly associated with an increased or decreased risk. Here we summarize the work that has been performed with polyphenols, with a focus on those derived from black raspberries. These have been extensively studied for the prevention and treatment of a variety of conditions and diseases. Here we focus on their use for the prevention or treatment of specific cancer types and the impact they have on biological systems. The aim is to highlight the need to improve our understanding of how the environment impacts upon the normal biological processes that affect health and disease, thereby, enabling us to implement smarter prevention and treatment measures
Unsupervised RGB-to-Thermal Domain Adaptation via Multi-Domain Attention Network
This work presents a new method for unsupervised thermal image classification
and semantic segmentation by transferring knowledge from the RGB domain using a
multi-domain attention network. Our method does not require any thermal
annotations or co-registered RGB-thermal pairs, enabling robots to perform
visual tasks at night and in adverse weather conditions without incurring
additional costs of data labeling and registration. Current unsupervised domain
adaptation methods look to align global images or features across domains.
However, when the domain shift is significantly larger for cross-modal data,
not all features can be transferred. We solve this problem by using a shared
backbone network that promotes generalization, and domain-specific attention
that reduces negative transfer by attending to domain-invariant and
easily-transferable features. Our approach outperforms the state-of-the-art
RGB-to-thermal adaptation method in classification benchmarks, and is
successfully applied to thermal river scene segmentation using only synthetic
RGB images. Our code is made publicly available at
https://github.com/ganlumomo/thermal-uda-attention
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Language and Reading Progress of Young Deaf and Hard-of-Hearing Children.
We examined the language and reading progress of 336 young DHH children in kindergarten, first and second grades. Trained assessors tested children's language, reading, and spoken and fingerspelled phonological awareness in the fall and spring of the school year. Children were divided into groups based on their auditory access and classroom communication: a spoken-only group (n = 101), a sign-only group (n = 131), and a bimodal group (n = 104). Overall, children showed delays in language and reading compared to norms established for hearing children. For language, vocabulary standard scores were higher than for English syntax. Although delayed in language, children made expected gains based on hearing norms from kindergarten to second grade. Reading scores declined from kindergarten to second grade. Spoken-only and bimodal children had similar word reading and reading comprehension abilities and higher scores than sign-only children. Spoken-only children had better spoken phonological awareness and nonword reading skills than the other two groups. The sign-only and bimodal groups made similar and significant gains in ASL syntax and fingerspelling phonological awareness
Outcomes of outpatient parenteral antimicrobial therapy with ceftriaxone for methicillin-susceptible Staphylococcus aureus bloodstream infections—a single-center observational study
Background:
Methods: Adult patients with methicillin-susceptible
Results: Of 243 patients included, 148 (61%) were discharged on ceftriaxone and 95 (39%) were discharged on either oxacillin or cefazolin. The ceftriaxone group had lower rates of intensive care unit care, endocarditis, and shorter duration of bacteremia, but higher rates of cancer diagnoses. There was no significant difference in the composite adverse outcome in the oxacillin or cefazolin group vs the ceftriaxone group (18 [19%] vs 31 [21%];
Conclusions: For patients with MSSA BSI discharged on OPAT, within the limitations of the small numbers and retrospective design we did not find a significant difference in outcomes for ceftriaxone therapy when compared with oxacillin or cefazolin therapy
Breast Milk from Tanzanian Women has Divergent Effects on Cell-Free and Cell-Associated HIV-1 Infection in Vitro.
Transmission of HIV-1 during breastfeeding is a significant source of new pediatric infections in sub-Saharan Africa. Breast milk from HIV-positive mothers contains both cell-free and cell-associated virus; however, the impact of breast milk on HIV-1 infectivity remains poorly understood. In the present study, breast milk was collected from HIV-positive and HIV-negative Tanzanian women attending antenatal clinics in Dar es Salaam. Milk was analyzed for activity in vitro against both cell-free and cell-associated HIV-1. Potent inhibition of cell-free R5 and X4 HIV-1 occurred in the presence of milk from all donors regardless of HIV-1 serostatus. Inhibition of cell-free HIV-1 infection positively correlated with milk levels of sialyl-Lewis(X) from HIV-positive donors. In contrast, milk from 8 of 16 subjects enhanced infection with cell-associated HIV-1 regardless of donor serostatus. Milk from two of these subjects contained high levels of multiple pro-inflammatory cytokines including TNFα, IL-1β, IL-6, IL-8, MIP-1α, MIP-1β, MCP-1 and IP-10, and enhanced cell-associated HIV-1 infection at dilutions as high as 1∶500. These findings indicate that breast milk contains innate factors with divergent activity against cell-free and cell-associated HIV-1 in vitro. Enhancement of cell-associated HIV-1 infection by breast milk may be associated with inflammatory conditions in the mother and may contribute to infant infection during breastfeeding
The electronic transport properties and microstructure of carbon nanofiber/epoxy composites
Carbon nanofibres (CNF) were dispersed into an epoxy resin using a
combination of ultrasonication and mechanical mixing. The electronic transport
properties of the resulting composites were investigated by means of impedance
spectroscopy. It was found that a very low critical weight fraction (pc = 0.064
wt %) which may be taken to correspond to the formation of a tunneling
conductive network inside the matrix. The insulator-to-conductor transition
region spanned about one order of magnitude from 0.1 to 1 wt %. Far from the
transition, the conductivity increased by two orders of magnitude. This
increase and the low value of the conductivity were explained in terms of the
presence of an epoxy film at the contact between CNF. A simple model based on
the CNF-CNF contact network inside the matrix was proposed in order to evaluate
the thickness of that film.Comment: 7 page
Five years of observations of ozone profiles over Lauder, New Zealand
Altitude profiles of ozone (O3) over Lauder (45°S, 170°E) performed using a lidar, ozonesondes, and the satellite-borne Stratospheric Aerosol and Gas Experiment (SAGE II) instrument are presented. These data form one of the few long-term sets of O3 profiles at a Southern Hemisphere location. In the 5 years of data presented, the dominant variation is the annual cycle, the phase and amplitude of which differ below and above 27.5 km. Superposed are irregular episodic variations, caused by various processes. The first process studied is stratosphere-troposphere exchange, characterized by dry and O3-rich air residing in the troposphere, which was found in 21% of the measurements. The second relates to the positioning of the higher polar vortex over Lauder, often in combination with the exchange of air between midlatitude and subtropical stratospheric regions. We present examples of this which were observed over Lauder during the 1997 winter. This winter was selected for further study because of the record-low O3 amounts measured. The third process is mixing of O3-depleted vortex air with midlatitude air after the vortex breakup. We present one example, which shows that a filament originating from the depleted Antarctic vortex significantly lowers O3 amounts over Lauder around 27 November 1997. There is thus a connection between Antarctic O3 depletion and later decrease of O3 amounts at a Southern Hemisphere midlatitude location, namely Lauder
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