139 research outputs found
Weak Decays of Stable Open-bottom Tetraquark by SU(3) Symmetry Analysis
The exotic state which was observed by D0 Collaboration is very
likely to be a tetraquark state with four different valence quark flavors,
though the existence was not confirmed by other collaborations. The possibility
of such state still generate lots of interests in theory. In the paper, we will
study the properties of the state under the SU(3) flavor symmetry. This four
quark state with a heavy bottom quark and three light quarks(anti-quark) can
form a or representation. The weak decays can be dominant
and should be discussed carefully while such state is stable against the strong
interaction. Therefor we will study the multi-body semileptonic and nonleptonic
weak decays systematically. With the help of SU(3) flavor symmetry, we can give
the Hamiltonian in the hadronic level, then obtain the parameterized
irreducible amplitudes and the relations of different channels. At the end of
the article, we collect some Cabibbo allowed two-body and three-body weak decay
channels which can be used to reconstruct states at the branching
fraction up to be .Comment: 53 pages, 2 figure
Planar Tur\'an number of the 7-cycle
The of a
graph is the maximum number of edges in an -vertex planar graph without
as a subgraph. Let denote the cycle of length . The planar
Tur\'an number behaves differently for
and for , and it is known when .
We prove that for all , and show that equality holds for infinitely
many integers
Dense circuit graphs and the planar Tur\'an number of a cycle
The of a
graph is the maximum number of edges in an -vertex planar graph without
as a subgraph. Let denote the cycle of length . The planar Tur\'an
number is known for . We show that
dense planar graphs with a certain connectivity property (known as circuit
graphs) contain large near triangulations, and we use this result to obtain
consequences for planar Tur\'an numbers. In particular, we prove that there is
a constant so that for all . When this bound is tight up to
the constant and proves a conjecture of Cranston, Lidick\'y, Liu, and
Shantanam
The Application of Driver Models in the Safety Assessment of Autonomous Vehicles: A Survey
Driver models play a vital role in developing and verifying autonomous
vehicles (AVs). Previously, they are mainly applied in traffic flow simulation
to model realistic driver behavior. With the development of AVs, driver models
attract much attention again due to their potential contributions to AV
certification. The simulation-based testing method is considered an effective
measure to accelerate AV testing due to its safe and efficient characteristics.
Nonetheless, realistic driver models are prerequisites for valid simulation
results. Additionally, an AV is assumed to be at least as safe as a careful and
competent driver. Therefore, driver models are inevitable for AV safety
assessment. However, no comparison or discussion of driver models is available
regarding their utility to AVs in the last five years despite their necessities
in the release of AVs. This motivates us to present a comprehensive survey of
driver models in the paper and compare their applicability. Requirements for
driver models in terms of their application to AV safety assessment are
discussed. A summary of driver models for simulation-based testing and AV
certification is provided. Evaluation metrics are defined to compare their
strength and weakness. Finally, an architecture for a careful and competent
driver model is proposed. Challenges and future work are elaborated. This study
gives related researchers especially regulators an overview and helps them to
define appropriate driver models for AVs
Emerging Applications of Deep Learning in Bone Tumors: Current Advances and Challenges
Deep learning is a subfield of state-of-the-art artificial intelligence (AI) technology, and multiple deep learning-based AI models have been applied to musculoskeletal diseases. Deep learning has shown the capability to assist clinical diagnosis and prognosis prediction in a spectrum of musculoskeletal disorders, including fracture detection, cartilage and spinal lesions identification, and osteoarthritis severity assessment. Meanwhile, deep learning has also been extensively explored in diverse tumors such as prostate, breast, and lung cancers. Recently, the application of deep learning emerges in bone tumors. A growing number of deep learning models have demonstrated good performance in detection, segmentation, classification, volume calculation, grading, and assessment of tumor necrosis rate in primary and metastatic bone tumors based on both radiological (such as X-ray, CT, MRI, SPECT) and pathological images, implicating a potential for diagnosis assistance and prognosis prediction of deep learning in bone tumors. In this review, we first summarized the workflows of deep learning methods in medical images and the current applications of deep learning-based AI for diagnosis and prognosis prediction in bone tumors. Moreover, the current challenges in the implementation of the deep learning method and future perspectives in this field were extensively discussed
Functional imaging of interleukin 1 beta expression in inflammatory process using bioluminescence imaging in transgenic mice
<p>Abstract</p> <p>Background</p> <p>Interleukin 1 beta (IL-1β) plays an important role in a number of chronic and acute inflammatory diseases. To understand the role of IL-1β in disease processes and develop an <it>in vivo </it>screening system for anti-inflammatory drugs, a transgenic mouse line was generated which incorporated the transgene firefly luciferase gene driven by a 4.5-kb fragment of the human IL-1β gene promoter. Luciferase gene expression was monitored in live mice under anesthesia using bioluminescence imaging in a number of inflammatory disease models.</p> <p>Results</p> <p>In a LPS-induced sepsis model, dramatic increase in luciferase activity was observed in the mice. This transgene induction was time dependent and correlated with an increase of endogenous IL-1β mRNA and pro-IL-1β protein levels in the mice. In a zymosan-induced arthritis model and an oxazolone-induced skin hypersensitivity reaction model, luciferase expression was locally induced in the zymosan injected knee joint and in the ear with oxazolone application, respectively. Dexamethasone suppressed the expression of luciferase gene both in the acute sepsis model and in the acute arthritis model.</p> <p>Conclusion</p> <p>Our data suggest that the transgenic mice model could be used to study transcriptional regulation of the IL-1β gene expression in the inflammatory process and evaluation the effect of anti-inflammatory drug <it>in vivo</it>.</p
Relationship between Doppler ultrasound parameters of uterine artery, umbilical artery, middle cerebral artery and placental vasculopathology and pregnancy outcome in preeclampsia rat model
Objective·To measure the parameters of the uterine artery, umbilical artery and middle cerebral artery in a rat model of preeclampsia (PE) by Doppler ultrasound, and compare the pathological changes in placental blood vessels and pregnancy outcomes, in order to provide an effective method and reference for evaluating placental function in PE animal models.Methods·PE (n=8) and normal pregnancy (NP, n=8) groups in Sprague-Dawley (SD) rat models were established by intraperitoneal injections of N′-nitro-L-arginine methylesterhydrochloride (L-NAME) and 0.9% sodium chloride solution. Blood pressure and proteinuria indexes were detected to evaluate whether the model was successfully established. On gestational day 19 (GD19), Doppler ultrasound was utilized to measure the parameters of the uterine artery, umbilical artery and the fetal middle cerebral artery in both the PE and NP groups. After termination of the pregnancies, placental function was evaluated through the pathology of placental blood vessels and the quality of the fetuses and placentas.Results·In the PE group, both blood pressure (GD15: P=0.001; GD19: P=0.001) and proteinuria (GD15: P=0.001; GD19: P=0.001) were significantly higher than those in the NP group. The pulsatility index (PI) of the umbilical artery and uterine artery was notably elevated in the PE group compared to the NP group (both P=0.000). Furthermore, the resistance index (RI) of the fetal middle cerebral artery was significantly lower than that in the PE group (P=0.000). While the number of fetal rats did not differ significantly, the quality of placental and fetal rats was notably lower in the PE group (P=0.006 and P=0.000, respectively). Immunohistochemical staining of placental tissue revealed that the number of placental micro vessel densities in the PE group was less than that in the NP group (P=0.001). Correlation analysis revealed that placental micro vessel density, fetal quality and placental quality were inversely related with the RI of the umbilical artery and the PI and RI of the uterine artery, and positively correlated with the S/D, PI and RI of the fetal middle cerebral artery (all P<0.05). Conculsion·Doppler ultrasound assessment of the uterine artery, umbilical artery and middle cerebral artery indices in L-NAME-induced PE rat models effectively reflects pregnancy outcomes and placental vascular pathology. This method is valuable for evaluating placental vascular perfusion in PE rat models, offering practicality and convenience for research involving animal models
Impact of stress hyperglycemia ratio on mortality in patients with critical acute myocardial infarction: insight from American MIMIC-IV and the Chinese CIN-II study
Background: Among patients with acute coronary syndrome and percutaneous coronary intervention, stress hyperglycemia ratio (SHR) is primarily associated with short-term unfavorable outcomes. However, the relationship between SHR and long-term worsen prognosis in acute myocardial infarction (AMI) patients admitted in intensive care unit (ICU) are not fully investigated, especially in those with different ethnicity. This study aimed to clarify the association of SHR with all-cause mortality in critical AMI patients from American and Chinese cohorts.
Methods: Overall 4,337 AMI patients with their first ICU admission from the American Medical Information Mart for Intensive Care (MIMIC)-IV database (n = 2,166) and Chinese multicenter registry cohort Cardiorenal ImprovemeNt II (CIN-II, n = 2,171) were included in this study. The patients were divided into 4 groups based on quantiles of SHR in both two cohorts.
Results: The total mortality was 23.8% (maximum follow-up time: 12.1 years) in American MIMIC-IV and 29.1% (maximum follow-up time: 14.1 years) in Chinese CIN-II. In MIMIC-IV cohort, patients with SHR of quartile 4 had higher risk of 1-year (adjusted hazard radio [aHR] = 1.87; 95% CI: 1.40–2.50) and long-term (aHR = 1.63; 95% CI: 1.27–2.09) all-cause mortality than quartile 2 (as reference). Similar results were observed in CIN-II cohort (1-year mortality: aHR = 1.44; 95%CI: 1.03–2.02; long-term mortality: aHR = 1.32; 95%CI: 1.05–1.66). In both two group, restricted cubic splines indicated a J-shaped correlation between SHR and all-cause mortality. In subgroup analysis, SHR was significantly associated with higher 1-year and long-term all-cause mortality among patients without diabetes in both MIMIC-IV and CIN-II cohort.
Conclusion: Among critical AMI patients, elevated SHR is significantly associated with and 1-year and long-term all-cause mortality, especially in those without diabetes, and the results are consistently in both American and Chinese cohorts
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