105 research outputs found
Callous formation and regeneration of Sargasopsis zanardinii through culturing media
Nowadays, seaweeds have many uses in food industry, weaving, pharmacy, medicine, biotechnology and so on. Many efforts has been made to regenerate seaweeds in artificial media in order to carry out genetic engineering process since 1970. In this study we have tried to establish a proper method for sterilization and tissue culture of brown seaweed, Sargasopsis zanardinii, in 1/2PES, PES and 2PES media. After sterilization, the explants of the seaweed were cultured in liquid and solid media. Consequently turgidity in margin of explants, longitudinal cell division and formation of hairy strands, and microcallous formation were showed by explants which cultured in PES and 2PES solid media. After transporting from liquid to solid media, juglike bodies were formed on the surface of solid PES media and then some brown strands were grown from these bodies that finally were flattened. None of these results was obtained from 1/2PES media
Evaluating The Robustness of Self-Supervised Representations to Background/Foreground Removal
Despite impressive empirical advances of SSL in solving various tasks, the
problem of understanding and characterizing SSL representations learned from
input data remains relatively under-explored. We provide a comparative analysis
of how the representations produced by SSL models differ when masking parts of
the input. Specifically, we considered state-of-the-art SSL pretrained models,
such as DINOv2, MAE, and SwaV, and analyzed changes at the representation
levels across 4 Image Classification datasets. First, we generate variations of
the datasets by applying foreground and background segmentation. Then, we
conduct statistical analysis using Canonical Correlation Analysis (CCA) and
Centered Kernel Alignment (CKA) to evaluate the robustness of the
representations learned in SSL models. Empirically, we show that not all models
lead to representations that separate foreground, background, and complete
images. Furthermore, we test different masking strategies by occluding the
center regions of the images to address cases where foreground and background
are difficult. For example, the DTD dataset that focuses on texture rather
specific objects
Dynamic Sealing Using Magneto-Rheological Fluids
Micropumps are microfluidic components which are widely used in applications
such as chemical analysis, biological sensing and micro-robots. However, one
obstacle in developing micropumps is the extremely low efficiency relative to
their macro-scale counterparts. This paper presents a dynamic sealing method
for external gear pumps to reduce the volumetric losses through the clearance
between the tips of gears and the housing by using magneto-rheological (MR)
fluids. By mitigating these losses, we are able to achieve high efficiency and
high volumetric accuracy with current mechanical architectures and
manufacturing tolerances. Static and dynamic sealing using MR fluids are
investigated theoretically and experimentally. Two Mason numbers
and which are defined in terms of
pressure gradient of the flow and velocity of the moving boundary respectively
are used to characterize and evaluate the sealing performance. A range of
magnetic field intensities is explored to determine optimal sealing
effectiveness, where effectiveness is evaluated using the ratio of volumetric
loss and friction factor. Finally, we quantify the effectiveness of this
dynamic sealing method under different working conditions for gear pumps.Comment: 9 pages; 10 figures
C-Reactive Protein Identifies Low-Risk Metabolically Healthy Obese Persons: The European Prospective Investigation of Cancer-Norfolk Prospective Population Study.
BACKGROUND: Conflicting data exist about the cardiovascular risk of metabolically healthy obese persons. The prognostic value of C-reactive protein (CRP) in this intriguing group is unknown. We assessed the association between CRP levels and the risk of coronary heart disease (CHD) in metabolically healthy persons with abdominal obesity. METHODS AND RESULTS: In the European Prospective Investigation of Cancer-Norfolk prospective cohort, CRP levels and information on metabolic syndrome criteria were available for 7279 participants, of whom 825 (11%) developed CHD during a follow-up period of 10.9±1.8 years. There was a trend toward a higher multivariable-adjusted hazard ratio for CHD in metabolically healthy obese participants with CRP levels >2 mg/L compared with <2 mg/L (hazard ratio 1.59, 95% CI 0.97-2.62, P=0.066). Metabolically unhealthy obese participants had significantly higher CHD risk compared with metabolically healthy obese participants with CRP levels <2 mg/L (hazard ratio 1.88, 95% CI 1.20-2.94, P=0.006). Most important, we found that the risk of CHD among metabolically healthy obese persons with CRP levels <2 mg/L was comparable to that of metabolically healthy nonobese persons (hazard ratio 0.91, 95% CI 0.60-1.39, P=0.674). CONCLUSIONS: Among metabolically healthy obese persons, low CRP levels were associated with a CHD risk comparable to that of metabolically healthy nonobese persons. CRP appears to be an easy and widely available method for identifying a low-risk subpopulation among metabolically healthy obese persons.EPIC‐Norfolk is supported by program grants from the Medical Research Council UK and Cancer Research UK. The CRP measurements in the full cohort were supported by a grant from the Medical Research Council to the Medical Research Council Epidemiology Unit, Cambridge, United Kingdom (MRC G0701863). The funding sources had no role in the study design, the conduct of the analysis, or the decision to submit the manuscript for publication
New type of microengine using internal combustion of hydrogen and oxygen
Microsystems become part of everyday life but their application is restricted
by lack of strong and fast motors (actuators) converting energy into motion.
For example, widespread internal combustion engines cannot be scaled down
because combustion reactions are quenched in a small space. Here we present an
actuator with the dimensions 100x100x5 um^3 that is using internal combustion
of hydrogen and oxygen as part of its working cycle. Water electrolysis driven
by short voltage pulses creates an extra pressure of 0.5-4 bar for a time of
100-400 us in a chamber closed by a flexible membrane. When the pulses are
switched off this pressure is released even faster allowing production of
mechanical work in short cycles. We provide arguments that this unexpectedly
fast pressure decrease is due to spontaneous combustion of the gases in the
chamber. This actuator is the first step to truly microscopic combustion
engines.Comment: Paper and Supplementary Information (to appear in Scientific Reports
Demonstration of quantum volume 64 on a superconducting quantum computing system
We improve the quality of quantum circuits on superconducting quantum
computing systems, as measured by the quantum volume, with a combination of
dynamical decoupling, compiler optimizations, shorter two-qubit gates, and
excited state promoted readout. This result shows that the path to larger
quantum volume systems requires the simultaneous increase of coherence, control
gate fidelities, measurement fidelities, and smarter software which takes into
account hardware details, thereby demonstrating the need to continue to
co-design the software and hardware stack for the foreseeable future.Comment: Fixed typo in author list. Added references [38], [49] and [52
Global mortality associated with 33 bacterial pathogens in 2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: Reducing the burden of death due to infection is an urgent global public health priority. Previous studies have estimated the number of deaths associated with drug-resistant infections and sepsis and found that infections remain a leading cause of death globally. Understanding the global burden of common bacterial pathogens (both susceptible and resistant to antimicrobials) is essential to identify the greatest threats to public health. To our knowledge, this is the first study to present global comprehensive estimates of deaths associated with 33 bacterial pathogens across 11 major infectious syndromes. Methods: We estimated deaths associated with 33 bacterial genera or species across 11 infectious syndromes in 2019 using methods from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, in addition to a subset of the input data described in the Global Burden of Antimicrobial Resistance 2019 study. This study included 343 million individual records or isolates covering 11 361 study-location-years. We used three modelling steps to estimate the number of deaths associated with each pathogen: deaths in which infection had a role, the fraction of deaths due to infection that are attributable to a given infectious syndrome, and the fraction of deaths due to an infectious syndrome that are attributable to a given pathogen. Estimates were produced for all ages and for males and females across 204 countries and territories in 2019. 95% uncertainty intervals (UIs) were calculated for final estimates of deaths and infections associated with the 33 bacterial pathogens following standard GBD methods by taking the 2·5th and 97·5th percentiles across 1000 posterior draws for each quantity of interest. Findings: From an estimated 13·7 million (95% UI 10·9–17·1) infection-related deaths in 2019, there were 7·7 million deaths (5·7–10·2) associated with the 33 bacterial pathogens (both resistant and susceptible to antimicrobials) across the 11 infectious syndromes estimated in this study. We estimated deaths associated with the 33 bacterial pathogens to comprise 13·6% (10·2–18·1) of all global deaths and 56·2% (52·1–60·1) of all sepsis-related deaths in 2019. Five leading pathogens—Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, and Pseudomonas aeruginosa—were responsible for 54·9% (52·9–56·9) of deaths among the investigated bacteria. The deadliest infectious syndromes and pathogens varied by location and age. The age-standardised mortality rate associated with these bacterial pathogens was highest in the sub-Saharan Africa super-region, with 230 deaths (185–285) per 100 000 population, and lowest in the high-income super-region, with 52·2 deaths (37·4–71·5) per 100 000 population. S aureus was the leading bacterial cause of death in 135 countries and was also associated with the most deaths in individuals older than 15 years, globally. Among children younger than 5 years, S pneumoniae was the pathogen associated with the most deaths. In 2019, more than 6 million deaths occurred as a result of three bacterial infectious syndromes, with lower respiratory infections and bloodstream infections each causing more than 2 million deaths and peritoneal and intra-abdominal infections causing more than 1 million deaths. Interpretation: The 33 bacterial pathogens that we investigated in this study are a substantial source of health loss globally, with considerable variation in their distribution across infectious syndromes and locations. Compared with GBD Level 3 underlying causes of death, deaths associated with these bacteria would rank as the second leading cause of death globally in 2019; hence, they should be considered an urgent priority for intervention within the global health community. Strategies to address the burden of bacterial infections include infection prevention, optimised use of antibiotics, improved capacity for microbiological analysis, vaccine development, and improved and more pervasive use of available vaccines. These estimates can be used to help set priorities for vaccine need, demand, and development. Funding: Bill & Melinda Gates Foundation, Wellcome Trust, and Department of Health and Social Care, using UK aid funding managed by the Fleming Fund
Global burden of peripheral artery disease and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: Peripheral artery disease is a growing public health problem. We aimed to estimate the global disease burden of peripheral artery disease, its risk factors, and temporospatial trends to inform policy and public measures. Methods: Data on peripheral artery disease were modelled using the Global Burden of Disease, Injuries, and Risk Factors Study (GBD) 2019 database. Prevalence, disability-adjusted life years (DALYs), and mortality estimates of peripheral artery disease were extracted from GBD 2019. Total DALYs and age-standardised DALY rate of peripheral artery disease attributed to modifiable risk factors were also assessed. Findings: In 2019, the number of people aged 40 years and older with peripheral artery disease was 113 million (95% uncertainty interval [UI] 99·2–128·4), with a global prevalence of 1·52% (95% UI 1·33–1·72), of which 42·6% was in countries with low to middle Socio-demographic Index (SDI). The global prevalence of peripheral artery disease was higher in older people, (14·91% [12·41–17·87] in those aged 80–84 years), and was generally higher in females than in males. Globally, the total number of DALYs attributable to modifiable risk factors in 2019 accounted for 69·4% (64·2–74·3) of total peripheral artery disease DALYs. The prevalence of peripheral artery disease was highest in countries with high SDI and lowest in countries with low SDI, whereas DALY and mortality rates showed U-shaped curves, with the highest burden in the high and low SDI quintiles. Interpretation: The total number of people with peripheral artery disease has increased globally from 1990 to 2019. Despite the lower prevalence of peripheral artery disease in males and low-income countries, these groups showed similar DALY rates to females and higher-income countries, highlighting disproportionate burden in these groups. Modifiable risk factors were responsible for around 70% of the global peripheral artery disease burden. Public measures could mitigate the burden of peripheral artery disease by modifying risk factors. Funding: Bill & Melinda Gates Foundation
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Quantum-centric supercomputing for materials science: A perspective on challenges and future directions
Computational models are an essential tool for the design, characterization, and discovery of novel materials. Computationally hard tasks in materials science stretch the limits of existing high-performance supercomputing centers, consuming much of their resources for simulation, analysis, and data processing. Quantum computing, on the other hand, is an emerging technology with the potential to accelerate many of the computational tasks needed for materials science. In order to do that, the quantum technology must interact with conventional high-performance computing in several ways: approximate results validation, identification of hard problems, and synergies in quantum-centric supercomputing. In this paper, we provide a perspective on how quantum-centric supercomputing can help address critical computational problems in materials science, the challenges to face in order to solve representative use cases, and new suggested directions
Quantum-centric Supercomputing for Materials Science: A Perspective on Challenges and Future Directions
Computational models are an essential tool for the design, characterization,
and discovery of novel materials. Hard computational tasks in materials science
stretch the limits of existing high-performance supercomputing centers,
consuming much of their simulation, analysis, and data resources. Quantum
computing, on the other hand, is an emerging technology with the potential to
accelerate many of the computational tasks needed for materials science. In
order to do that, the quantum technology must interact with conventional
high-performance computing in several ways: approximate results validation,
identification of hard problems, and synergies in quantum-centric
supercomputing. In this paper, we provide a perspective on how quantum-centric
supercomputing can help address critical computational problems in materials
science, the challenges to face in order to solve representative use cases, and
new suggested directions.Comment: 60 pages, 14 figures; comments welcom
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