Steady states and dynamics of an autocatalytic chemical reaction model with decay

The dynamics and steady state solutions of an autocatalytic chemical reaction model with decay in the catalyst are considered. Nonexistence and existence of nontrivial steady state solutions are shown by using energy estimates, upper-lower solution method, and bifurcation theory. The effects of decay order, decay rate and diffusion rates to the dynamical behavior are discussed. (c) 2012 Published by Elsevier Inc

Bifurcation from a degenerate simple eigenvalue

It is proved that a symmetry-breaking bifurcation occurs at a simple eigenvalue despite the usual transversality condition fails, and this bifurcation from a degenerate simple eigenvalue result complements the classical one with the transversality condition. The new result is applied to an imperfect pitchfork bifurcation, in which a forward transcritical bifurcation changes to a backward one when the perturbation parameter changes. Several applications in ecological and genetics models are shown. (C) 2013 Elsevier Inc. All rights reserved

A Double Saddle-Node Bifurcation Theorem

In this paper, we consider an abstract equation F(lambda, u) = 0 with one parameter lambda, where F epsilon C-P(R x X, Y), p \u3e= 2, is a nonlinear differentiable mapping, and X, Y are Banach spaces. We apply Lyapunov-Schmidt procedure and Morse Lemma to obtain a double saddle-node bifurcation theorem with a two-dimensional kernel. Applications include a perturbed problem and a semilinear elliptic equation

General bubble expansion at strong coupling

The strongly-coupled system like the quark-hadron transition (if it is of first order) is becoming an active play-yard for the physics of cosmological first-order phase transitions. However, the traditional field theoretic approach to strongly-coupled first-order phase transitions is of great challenge, driving recent efforts from holographic dual theories with explicit numerical simulations. These holographic numerical simulations have revealed an intriguing linear correlation between the phase pressure difference (pressure difference away from the wall) to the non-relativistic terminal velocity of an expanding planar wall, which has been reproduced analytically alongside both cylindrical and spherical walls from perfect-fluid hydrodynamics in our previous study but only for a bag equation of state. We have also found in our previous study a universal quadratic correlation between the wall pressure difference (pressure difference near the bubble wall) to the non-relativistic terminal wall velocity regardless of wall geometries. In this paper, we will generalize these analytic relations between the phase/wall pressure difference and terminal wall velocity into a more realistic equation of state beyond the simple bag model, providing the most general predictions so far for future tests from holographic numerical simulations of strongly-coupled first-order phase transitionsComment: 22 pages, 10 figure

Impact-Oriented Contextual Scholar Profiling using Self-Citation Graphs

Quantitatively profiling a scholar's scientific impact is important to modern research society. Current practices with bibliometric indicators (e.g., h-index), lists, and networks perform well at scholar ranking, but do not provide structured context for scholar-centric, analytical tasks such as profile reasoning and understanding. This work presents GeneticFlow (GF), a suite of novel graph-based scholar profiles that fulfill three essential requirements: structured-context, scholar-centric, and evolution-rich. We propose a framework to compute GF over large-scale academic data sources with millions of scholars. The framework encompasses a new unsupervised advisor-advisee detection algorithm, a well-engineered citation type classifier using interpretable features, and a fine-tuned graph neural network (GNN) model. Evaluations are conducted on the real-world task of scientific award inference. Experiment outcomes show that the F1 score of best GF profile significantly outperforms alternative methods of impact indicators and bibliometric networks in all the 6 computer science fields considered. Moreover, the core GF profiles, with 63.6%-66.5% nodes and 12.5%-29.9% edges of the full profile, still significantly outrun existing methods in 5 out of 6 fields studied. Visualization of GF profiling result also reveals human explainable patterns for high-impact scholars

A triplex crystal digital PCR for the detection of genotypes I and II African swine fever virus

African swine fever (ASF) is a highly contagious and lethal viral disease that causes severe hemorrhagic fever in pigs. It keeps spreading around the world, posing a severe socioeconomic risk and endangering biodiversity and domestic food security. ASF first outbroke in China in 2018, and has spread to most provinces nationwide. Genotypes I and II ASF virus (ASFV) as the etiological pathogens have been found in China. In this study, three pairs of specific primers and probes targeting the ASFV B646L gene, F1055L gene, and E183L gene were designed to detect universal, genotype I, and genotype II strains, respectively. A triplex crystal digital PCR (cdPCR) was established on the basis of optimizing various reaction conditions. The assay demonstrated remarkably sensitive with low limits of detection (LODs) of 5.120, 4.218, 4.588 copies/reaction for B646L, F1055L, and E183L gene, respectively; excellent repeatability with 1.24–2.01% intra-assay coefficients of variation (CVs) and 1.32–2.53% inter-assay CVs; good specificity for only detection of genotypes I and II ASFV, without cross-reactivity with PCV2, PRV, SIV, PRRSV, PEDV, FMDV, and CSFV. The triplex cdPCR was used to test 1,275 clinical samples from Guangxi province of China, and the positivity rates were 5.05, 3.22, and 1.02% for genotype I, genotype II, and co-infection of genotypes I and II, respectively. These 1,275 clinical samples were also detected using a reported reference triplex real-time quantitative PCR (qPCR), and the agreements of detection results between these two methods were more than 98.98%. In conclusion, the developed triplex cdPCR could be used as a rapid, sensitive, and accurate method to detect and differentiate genotypes I and II strains of ASFV

Effect of quercetin on the transport of ritonavir to the central nervous system in vitro and in vivo

The aim of this study was to identify an effective flavonoid that could improve the intracellular accumulation of ritonavir in human brain-microvascular endothelial cells (HBMECs). An in vivo experiment on Sprague-Dawley rats was then designed to further determine the flavonoid’s impact on the pharmacokinetics and tissue distribution of ritonavir. In the accumulation assay, the intracellular level of ritonavir was increased in the presence of 25 mmol L–1of flavonoids in HBMECs. Quercetin showed the strongest effect by improving the intracellular accumulation of ritonavir by 76.9 %. In the pharmacokinetic study, the presence of quercetin in the co-administration group and in the pretreatment group significantly decreased the area under the plasma concentration-time curve (AUC0-t) of ritonavir by 42.2 % (p < 0.05) and 53.5 % (p < 0.01), and decreased the peak plasma concentration (Cmax) of ritonavir by 23.1 % (p < 0.05) and 45.8 % (p < 0.01), respectively, compared to the control group (ritonavir alone). In the tissue distribution study, the ritonavir concentration in the brain was significantly increased 2-fold (p < 0.01), during the absorption phase (1 h) and was still significantly higher (p < 0.05) during the distribution phase (6 h) in the presence of quercetin

Analysis on the factors associated with COVID-19 infection among Chinese residents after the implementation of the 10 new rules to optimize COVID-19 response: a cross-sectional study

IntroductionThis study aimed to investigate the status of COVID-19 infection and the associated factors among Chinese residents after the implementation of the 10 New Rules to optimize COVID response.MethodsParticipants were recruited using convenience sampling. The study used self-filled questionnaires to examine COVID-19 infection and associated factors among Chinese residents, from December 29, 2022, to January 2, 2023. For the statistical analysis, descriptive and quantitative analyses were used. The potential risk factors for COVID-19 infection were identified by multivariable logistic regression analysis.ResultsAfter the adjustments in control strategies against COVID-19, the infection rate of COVID-19 was high among respondents, and 98.4% of individuals who tested positive showed symptoms including cough, fever, fatigue, headache, sore throat, nasal congestion, sputum production, muscle and joint pain, and runny nose. The main problems respondents reported were the shortage of drugs and medical supplies, the increased burden on families, and the unreliable information source of COVID-19 infection. Logistic regression showed that isolating patients with COVID-19 at home was associated with a lower risk of COVID-19 infection (OR = 0.58, 95%CI: 0.42–0.81).ConclusionCOVID-19 infection among residents is closely related to age, gender, and epidemic prevention measures. The government needs to strengthen education for individuals and centrally manage and properly address difficulties that may arise during COVID-19

Predictive Value of Combined Use of Ultrasonographic Indicators for Central Lymph Node Metastasis in Papillary Thyroid Carcinoma

BackgroundThe treatment scheme for papillary thyroid carcinoma (PTC) patients is related to whether lymph node metastasis is prevalent or not. The routine ultrasound indicator used alone has proven to have a low sensitivity to predict the presence of lymph node metastasis in PTC.ObjectiveTo explore the value of combined use of ultrasonographic indicators in predicting central lymph node metastasis in PTC.MethodsClinical data of PTC patients (n=446) with thyroid surgery and central neck dissection were collected retrospectively from the First Affiliated Hospital of Shihezi University School of Medicine from March 2013 to May 2020, involving sex, age, and ultrasonographic features 〔diameter of nodule, number of nodules, location of single and multiple nodules, internal composition, internal echo, boundary, margin, micro calcification, anteroposterior and transverse diameter (A/T) ratio, posterior echo attenuation, capsular invasion〕. Postoperative pathological results confirmed that 159 cases (35.65%) with central lymph node metastasis and other 287 (64.35%) without. Unconditional stepwise binary Logistic regression was used to explore the factors associated with central lymph node metastasis. Receiver operating characteristic (ROC) analysis was performed to estimate the predictive value of each indicator for central lymph node metastasis.ResultsPatients with and without central lymph node metastasis had significant differences in sex ratio, distribution of age, thyroid nodule diameter, margin conditions, and A/T ratio, as well as prevalence of micro calcification and capsular invasion (P&lt;0.05) . Binary Logistic regression analysis showed that male 〔OR=1.727, 95%CI (1.059, 2.816) 〕, &lt;45 years old 〔OR=2.690, 95%CI (1.728, 4.187) 〕, diameter of the thyroid nodule &gt;10 mm 〔OR=2.385, 95%CI (1.544, 3.684) 〕, and capsular invasion 〔OR=1.773, 95%CI (1.153, 2.724) 〕 were independently associated with increased risk of central lymph node metastasis (P&lt;0.05) . And the Logistic regression algorithm was: Logit (P) =-1.627+0.546×sex +0.989×age+0.869× (thyroid nodule diameter) +0.572× (capsular invasion) . In predicting central lymph node metastasis, the AUC of combination of four indicators in the algorithm was 0.695〔95%CI (0.650, 0.738) 〕, with 67.92% sensitivity, and 61.67% specificity, and 0.32 optimal cut-off value. The AUC of the combination of four indicators was larger than that of sex, age, thyroid nodule diameter, or capsular invasion alone (Z=4.137, 3.682, 3.070, 3.679, P&lt;0.05) .ConclusionBeing male, age &lt;45 years old, thyroid nodule diameter&gt;10 mm, and capsular invasion were independent risk factors for central lymph node metastasis in PTC, and the value of combined use of them had a higher predictive value for central lymph node metastasis