50 research outputs found
Causal limit on quantum communication
The capacity of a channel is known to be equivalent to the highest rate at
which it can generate entanglement. Analogous to entanglement, the notion of a
causality measure characterises the temporal aspect of quantum correlations.
Despite holding an equally fundamental role in physics, temporal quantum
correlations have yet to find their operational significance in quantum
communication. Here we uncover a connection between quantum causality and
channel capacity. We show the amount of temporal correlations between two ends
of the noisy quantum channel, as quantified by a causality measure, implies a
general upper bound on its channel capacity. The expression of this new bound
is simpler to evaluate than most previously known bounds. We demonstrate the
utility of this bound by applying it to a class of shifted depolarizing
channels, which results in improvement over previously calculated bounds for
this class of channels.Comment: 9 pages, 3 figure
Effect of Cr3C2 Content on the Microstructure and Wear Resistance of Fe3Al/Cr3C2 Composites
In this paper, an engine piston ring coating comprising composite material of Fe3Al and Cr3C2 mixed powder was prepared by laser cladding onto carbon structural steel. The microstructure and tribological properties of the cladding materials were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and wear tests. The influence mechanism of the Cr3C2 content in cladding powder was studied. During the process of wear, the soft Fe3Al/Fe2AlCr matrix is first ground off, and the hard Cr7C3 phase initially supports the abrasive surface before being worn away into hard particles, resulting in abrasive wear. With the increase in Cr3C2 content, the hardness of the cladding layer increases, the proportion of the Cr7C3 phase increases, and the morphology changes from a sparse network to a dense floccule. Of the cladding layers with different Cr3C2 content, the 15 wt.% Cr3C2 cladding layer had the lowest friction coefficient, and the 25 wt.% Cr3C2 cladding layer had the lowest wear rate. The low wear rate of the 25 wt.% Cr3C2 cladding layer can be attributed to the fact that adhesive wear does not easily occur and the fine microstructure of the strengthening phase, which facilitates better separation in the grinding surfaces
No driver, No Regulation? --Online Legal Driving Behavior Monitoring for Self-driving Vehicles
Defined traffic laws must be respected by all vehicles. However, it is
essential to know which behaviors violate the current laws, especially when a
responsibility issue is involved in an accident. This brings challenges of
digitizing human-driver-oriented traffic laws and monitoring vehicles'
behaviors continuously. To address these challenges, this paper aims to
digitize traffic law comprehensively and provide an application for online
monitoring of legal driving behavior for autonomous vehicles. This paper
introduces a layered trigger domain-based traffic law digitization architecture
with digitization-classified discussions and detailed atomic propositions for
online monitoring. The principal laws on a highway and at an intersection are
taken as examples, and the corresponding logic and atomic propositions are
introduced in detail. Finally, the digitized traffic laws are verified on the
Chinese highway and intersection datasets, and defined thresholds are further
discussed according to the driving behaviors in the considered dataset. This
study can help manufacturers and the government in defining specifications and
laws and can also be used as a useful reference in traffic laws compliance
decision-making. Source code is available on
https://github.com/SOTIF-AVLab/DOTL.Comment: 22 pages, 11 figure
Content analysis of systematic reviews on the effectiveness of Traditional Chinese Medicine
AbstractObjectiveTo evaluate evidence for the efficacy of Traditional Chinese Medicine (TCM) in systematic reviews.MethodsChinese (TCMPeriodical Literature Database, Chinese Biological Medicine database, Chinese Medical Current Contents, China Hospital Knowledge Database journal fulltext database, Virtual Machining and Inspection System, and Wanfang) and English (Cochrane Database of Systematic Reviews, PubMed and Embase) databases were searched.ResultsThree thousand, nine hundred and fifty-five articles were initially identified, 606 of which met the inclusion criteria, including 251 in English (83 from the Cochrane Database) and 355 in Chinese. The number of articles published each year increased between 1989 and 2009. Cardiocerebrovascular disease was the most studied target disease. Intervention measures includedTCM preparations (177 articles), acupuncture (133 articles) and combinations of TCM and western medicine (38 articles). Control measures included positive medical (177 articles), basic treatment (100 articles), placebo (219 articles), and blank and mutual (107 articles). All articles included at least one reference; the greatest number was 268. Six of 10 articles with high quality references demonstrated curative effectsagainst target diseasesincludingupper respiratory tract infection, dementia and depression. Interventions that were not recommendedwere tripterygium for rheumatoid arthritis andTCM syndrome differentiation for pediatric nocturia. In 10.4% of the studies, the authors concluded that the intervention had a curative effect. The assessors agreed with the authors' conclusions in 88.32% of cases, but rejected 8.94% (54 articles).Conclusion1) Training in systematic review methods, including topic selection, study design, methods and technology, should be improved. 2) Upper respiratory tract infection, dementia and depression may become the predominant diseases treatedby TCM, and the corresponding interventions could be developed into practical applications. 3) Use of non-recommended interventions should be controlled, and there should be more research on side effects
Temporal Course of Cerebral Autoregulation in Patients With Narcolepsy Type 1: Two Case Reports
Cerebral autoregulation is the mechanism by which constant cerebral blood flow is maintained despite changes in arterial blood pressure. In the two presented cases, cerebral autoregulation was impaired in patients with narcolepsy type 1, and both venlafaxine and fluoxetine may have the potential to improve the impaired cerebral autoregulation. A relationship may exist between impaired cerebral autoregulation and neurological symptoms in patients with narcolepsy type 1
Effects of Nursing Quality Improvement on Thrombolytic Therapy for Acute Ischemic Stroke
Background and purpose: Intravenous thrombolytic therapy significantly improves the outcomes of acute ischemic stroke patients in a time-dependent manner. The aim of this study was to investigate whether continuous nursing quality improvement in stroke nurses has a positive effect on reducing the time to thrombolysis in acute ischemic stroke.Methods: The implementation of nursing quality improvement measures includes establishing full-time stroke nurses, pre-notification by emergency medical services (EMS), stroke team notification protocols, rapid triage, publicity and education, etc. Using a history-controlled approach, we analyzed acute ischemic stroke patients with intravenous thrombolysis during a pre-intervention period (April 1, 2015-July 31, 2016), trial period (August 1, 2016-October 31, 2016), and post-intervention period (November 1, 2016-September 30, 2017). This was done in accordance with the implementation of nursing quality improvement measures, including the general characteristics of the three groups, the time of each step in the process of thrombolysis, and the prognosis.Results: After the implementation of nursing quality improvement measures, the median door-to-needle time (DNT) was shortened from 73 min (interquartile range [IQR] 62–92 min) to 49 min (IQR 40-54 min; p < 0.001) in the post-intervention period. The median onset-to-needle time (ONT) was reduced from 193 min (IQR 155–240 min) to 167 min (IQR 125-227 min; p < 0.001). The proportion of patients with DNT ≤ 60 min increased from 23.94% (51/213) to 86.36% (190/220; p < 0.001) while the proportion of patients with DNT ≤ 40 min increased from 3.29% (7/213) to 25.00% (55/220; p < 0.001). The median time for door-to-laboratory results was decreased from 68 min to 56 min (p < 0.001). There was no significant difference in the fatality rate, 90-day modified Rankin score, length of stay or hospitalization expenses between the three groups of patients (p> 0.05).Conclusions: Implementation of nursing quality improvement measures in stroke nurses is an important factor in shortening the time of medication in patients with thrombolytic therapy, reducing the delay of intravenous thrombolysis in the hospital and helping to expedite presenting patients' arrival to the hospital post-stroke
Substrate interaction inhibits γ-secretase production of amyloid-β peptides
Combining NMR, mass spectrometry, AlphaLISA and cell assays, we discovered a compound C1 that binds C-terminal juxtamembrane lysines at the transmembrane domain of the amyloid precursor protein (APPTM) and inhibits γ-secretase production of amyloid-β with μM IC50. Our work suggests that targeting APPTM is a novel and viable strategy in AD drug discovery.This work was supported by a grant from the Warren Alpert Foundation (to C. W.), the NIH grant R21-NS109926 (to C. W.), NIH grants R01-AG008200 and RF1-NS047229 (to N. K. R.), and the NIH grant R35-GM127040 (to Y. Z.)Peer reviewe
The Impact of Variational Primary Collaterals on Cerebral Autoregulation
The influence of the anterior and posterior communicating artery (ACoA and PCoA) on dynamic cerebral autoregulation (dCA) is largely unknown. In this study, we aimed to test whether substantial differences in collateral anatomy were associated with differences in dCA in two common types of stenosis according to digital subtraction angiography (DSA): either isolated basal artery and/or bilateral vertebral arteries severe stenosis/occlusion (group 1; group 1A: with bilateral PCoAs; and group 1B: without bilateral PCoAs), or isolated unilateral internal carotid artery severe stenosis/occlusion (group 2; group 2A: without ACoA and with PCoA; group 2B: with ACoA and without PCoAs; and group 2C: without both ACoA and PCoA). The dCA was calculated by transfer function analysis (a mathematical model), and was evaluated in middle cerebral artery (MCA) and/or posterior cerebral artery (PCA). Of a total of 231 non-acute phase ischemic stroke patients who received both dCA assessment and DSA in our lab between 2014 and 2017, 51 patients met inclusion criteria based on the presence or absence of ACoA or PCoA, including 21 patients in the group 1, and 30 patients in the group 2. There were no significant differences in gender, age, and mean blood pressure between group 1A and group 1B, and among group 2A, group 2B, and group 2C. In group 1, the PCA phase difference values (autoregulatory parameter) were significantly higher in the subgroup with patent PCoAs, compared to those without. In group 2, the MCA phase difference values were higher in the subgroup with patent ACoA, compared to those without. This pilot study found that the cross-flow of the ACoA/PCoA to the affected area compensates for compromised dCA in the affected area, which suggests an important role of the ACoA/PCoA in stabilizing cerebral blood flow
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe