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The COVID-19 (novel coronavirus disease 2019) pandemic has tremendously impacted global health and economics. Early detection of COVID-19 infections is important for patient treatment and for controlling the epidemic. However, many countries/regions suffer from a shortage of nucleic acid testing (NAT) due to either resource limitations or epidemic control measures. The exact number of infective cases is mostly unknown in counties/regions with insufficient NAT, which has been a major issue in predicting and controlling the epidemic. In this paper, we propose a mathematical model to quantitatively identify the influences of insufficient detection on the COVID-19 epidemic. We extend the classical SEIR (susceptible-exposed-infections-recovered) model to include random detections which are described by Poisson processes. We apply the model to the epidemic in Guam, Texas, the Virgin Islands, and Wyoming in the United States and determine the detection probabilities by fitting model simulations with the reported number of infected, recovered, and dead cases. We further study the effects of varying the detection probabilities and show that low level-detection probabilities significantly affect the epidemic; increasing the detection probability of asymptomatic infections can effectively reduce the the scale of the epidemic. This study suggests that early detection is important for the control of the COVID-19 epidemic.

Photocatalytic production of H2 from water based on semiconductors is a process without the consumption of fossil energy. The development of ideal photocatalyst is a challenge that limited the application of photocatalytic technology. Here, we report a stable Sr0·76Ce0·16WO4 photocatalyst for H2 evolution under visible-light irradiation, which was synthesized via a simple high-temperature solid-state method. The composition and crystal structure of this photocatalyst was identified by X-ray Diffraction, transmission electron microscope, and X-ray photoelectron spectroscopy. The scanning electron microscopy image indicates the sample compose of micrometer particles. The bandgap of the compound was estimated to be 3.18 eV, which is significantly smaller than that of pristine SrWO4 (4.87 eV) by the incorporation of Ce3+. In this experiment, the nanosized Au cocatalyst was loaded on the photocatalyst via the photodeposition method to improve the photocatalytic performances. Photocatalytic experiments revealed that photocatalytic H2 evolution rates of Sr0·76Ce0·16WO4-1.5Au sample are 45.5 μmol/h/g and 28.7 μmol/h/g in 5 vol% triethanolamine aqueous solution under simulated sunlight and visible-light irradiation, respectively, which are 1.44 times and 4.63 times higher than the cocatalysts-free one. Moreover, the apparent quantum yield of Sr0·76Ce0·16WO4-1.5Au is 0.09% at 450 nm.

Shengyu Decoction (SYD), a classical Chinese medicine formula, is good at nourishing blood, promoting blood circulation, and soothe the nerves. SYD can improve cognitive ability. This decoction is suitable for treating vascular cognitive impairment (VCI). however, its active ingredients and possible mechanism have not been investigated.This study was conducted to observe the effects of SYD on improving the cognitive abilities of rats with VCI, to explore its active ingredients and mechanism.The rats with VCI model were established by bilateral common carotid artery occlusion (BCCAO), and the effects of SYD (5, 2.5 g/kg) on the cognitive abilities of VCI rats were evaluated using the Morris water maze (MWM) and neurological assessment. The pathological changes of hippocampal CA1 were observed by HE and Nissl staining. The effect of SYD on cerebral blood flow (CBF) was evaluated by Laser Speckle Contrast Imager. The expression of CD31 in the cerebral cortex was measured by immunofluorescence (IF) to evaluate the number of cerebral micro vessels. The levels of IL-6, IL-1β, and TNF-α in the hippocampus were determined using an ELISA kit, and the active components in the plasma and brain tissues of rats after SYD administration were analyzed using UPLC-Q-TOF-MS/MS. The interaction network of the compound-target pathway was established using the SWISS Target, GO, and DAVID databases. The expression of AKT/HIF-1α/VEGF and p38 MAPK signaling pathway in the brain tissues was determined using western blotting (WB).SYD (2.5, 5 g/kg) significantly improved the cognitive abilities of VCI rats in the MWM and neurological assessment. HE and Nissl staining showed that SYD significantly ameliorated the pathological hippocampal CA1 area and increased the number of Nissl bodies. The Laser Speckle Contrast Imager showed that the cortical CBF of VCI rats in the SYD group was significantly increased, and the IF results showed that CD31 expression was significantly increased in the SYD group. The ELISA results showed that the contents of IL-6, IL-1β, and TNF-α in SYD were significantly reduced. A total of 29 compounds were found in the plasma and brain tissues of the rats treated with SYD. Network pharmacology revealed 99 targets for the treatment of VCI. Pathway enrichment analysis showed that the HIF-1 and MAPK signaling pathways might be important for SYD to ameliorate VCI. WB showed that the expressions of AKT, HIF-1α, and VEGF in the brain tissues of rats were significantly increased; in addition, NF-κB and p38 MAPK were significantly reduced in the SYD group.SYD can improve the cognitive abilities of VCI rats. The mechanism of action of its active ingredients improves cognitive impairment by affecting the AKT/HIF-1α/VEGF and p38 MAPK/NF-κB signaling pathways, promoting cerebrovascular generation, and ameliorating neuroinflammation.

Danhe granule (DHG) is used by Chinese doctors to treat blood stasis, phlegm and dampness. Its lipid-lowering ability has been investigated in our previous research. However, the anti-liver inflammatory and fibrotic effects and mechanism of action of DHG in non-alcoholic steatohepatitis (NASH) have not been explored.To evaluate the ameliorative effects of DHG on liver inflammation and fibrosis in a methionine/choline-deficient (MCD) diet-induced NASH rat model, and its underlying mechanism.Sprague-Dawley rats were fed an MCD diet for two weeks and then treated with or without DHG by oral gavage for eight weeks. Their body weight and liver index were measured. The serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activities as well as the liver triglyceride (TG) and free fatty acid (FFA) levels were tested using reagent kits. Inflammatory cytokines, including Tnf-α, Il-β and Il-6, and fibrosis genes, including Acta2, Col1a1, Col1a2 and Tgf-β were examined by real-time quantitative PCR (RT-qPCR). Hematoxylin-eosin (HE), Oil Red O, Masson's and Sirius Red staining were used to observe liver changes. The plasma and liver ceramide levels were analyzed using HPLC-QQQ-MS/MS. The expression of serine palmitoyl-CoA transferase (Spt), ceramide synthase 6 (Cers6), dihydroceramide desaturase 1 (Des1), glucosylceramide synthase (Gcs), and ceramide kinase (Cerk) mRNA was assayed by RT-qPCR, while the protein expression of CerS6, DES1, GCS, CerK, and casein kinase 2α (CK2α) was tested by western blotting (WB). CerS6 degradation was evaluated using a cycloheximide (CHX) assay in vitro.The liver index decreased by 20% in DHG groups and the serum ALT and AST decreased by approximately 50% and 30%, respectively in the DHG-H group. The liver Oil Red O staining, TG, and FFA changes showed that DHG reduced hepatic lipid accumulation by approximately 30% in NASH rats. HE, Masson's and Sirius Red staining and the mRNA levels of Tnf-α, Il-β, Il-6, Acta2, Col1a1, Col1a2 and Tgf-β revealed that DHG alleviated liver inflammation and fibrosis in NASH rats. The ceramide (Cer 16:0), and hexosylceramide (HexCer 16:0, HexCer 18:0, HexCer 22:0, HexCer 24:0 and HexCer 24:1) levels decreased by approximately 17-56% in the plasma of the DHG-M and H rats. The Cer 16:0 content in the liver decreased by 20%, 50%, and 70% with the DHG-L, M, and H treatments; additionally, the dhCer 16:0, Cer 18:0, HexCer 18:0, HexCer 20:0 Cer 22:0-1P, Cer 24:0-1p, Cer 24:1-1p, and Cer 26:1-1p levels decreased in the DHG groups. The mRNA and protein expression levels of DES1, GCS, Cerk, CerS6, and CHX assay indicated that DHG decreased the mRNA and protein expression levels of CerK and reduced CerS6 protein expression by promoting its degradation. Additionally, DHG attenuated the protein expression of CK2α which could increase CerS6 enzymatic activity by phosphorylating its C-terminal region.DHG ameliorated the levels of liver FFA and TG and inflammation and fibrosis in MCD-induced rats, which were associated with decreasing ceramide species in the plasma and liver by reducing the expression levels of CerS6 and CerK.

Context Rhodiola crenulata (Hook. f. et Thoms.) H. Ohba (Crassulaceae) is used to prevent and treat acute mountain sickness. However, the mechanisms underlying its effects on the central nervous system remain unclear. Objective To investigate the effect of Rhodiola crenulata on cellular metabolism in the central nervous system. Materials and methods The viability and Hif-1α levels of microglia and neurons at 5% O2 for 1, 3, 5 and 24 h were examined. We performed the binding of salidroside (Sal), rhodiosin, tyrosol and p-hydroxybenzyl alcohol to Hif-1α, Hif-1α, lactate, oxidative phosphorylation and glycolysis assays. Forty male C57BL/6J mice were divided into control and Sal (25, 50 and 100 mg/kg) groups to measure the levels of Hif-1α and lactate. Results Microglia sensed low oxygen levels earlier than neurons, accompanied by elevated expression of Hif-1α protein. Salidroside, rhodiosin, tyrosol, and p-hydroxybenzyl alcohol decreased BV-2 (IC50=1.93 ± 0.34 mM, 959.74 ± 10.24 μM, 7.47 ± 1.03 and 8.42 ± 1.63 mM) and PC-12 (IC50=6.89 ± 0.57 mM, 159.28 ± 8.89 μM, 8.65 ± 1.20 and 8.64 ± 1.42 mM) viability. They (10 μM) reduced Hif-1α degradation in BV-2 (3.7-, 2.5-, 2.9- and 2.5-fold) and PC-12 cells (2.8-, 2.8-, 2.3- and 2.0-fold) under normoxia. Salidroside increased glycolytic capacity but attenuated oxidative phosphorylation. Salidroside (50 and 100 mg/kg) treatment increased the protein expression of Hif-1α and the release of lactate in the brain tissue of mice. Conclusions These results suggest that Sal induces metabolic reprogramming by regulating the Hif-1α signalling pathway to activate compensatory responses, which may be the core mechanism underlying the effect of Rhodiola crenulata on the central nervous system.

This paper investigates the optimal impulsive management of pest growth model aiming at minimizing the amount of pests at the terminal time. By means of time-scaling and time translation transformation techniques, the gradient formulas of the cost function with respect to impulsive releasing amount and timing of natural enemies are given for three cases such as the amount control, the timing control and the mixed control. Based on the gradient formulas and the designed algorithm, we find the optimal impulsive releasing times and amounts of enemies by numerical simulations. And the mixed control strategy is illustrated to be the best strategy through comparing the three optimal control strategies with the same initial control parameters. In addition, simulations indicate that the optimization of governance policies may increase the periodic oscillation amplitude of populations, but ultimately it will reduce the amount of pests and lower the cost. Furthermore, our optimal biological interference strategies are superior to those in many literatures in which the enemy is released by the fixed amount at the fixed time.

Background and aim: Understanding the molecular biological mechanisms underlying laryngeal squamous cell carcinoma (LSCC) invasion and metastasis is crucial for diagnosis, treatment, and prognosis. We aimed to examine the expression of the tumor suppressor microRNA-204-5p (miR-204-5p) and its target gene, forkhead box C1 (FOXC1), in human LSCC and explore their roles in the malignant behaviors of LSCC Hep-2 and TU-177 cells. Methods: The regulatory effects of miR-204-5p on the 3′ untranslated region of FOXC1 predicted by bioinformatics were tested by dual-luciferase reporter assay. Quantitative RT-PCR was used to detect mRNA expression in 43 fresh samples of LSCC and corresponding adjacent normal mucosa (ANM). FOXC1 protein expression was examined by immunohistochemistry. miR-204-5p mimics and FOXC1 siRNA were transfected into LSCC cell lines Hep-2 and TU-177 to observe malignant behavior. miR-204-5p mimics were injected into Hep-2 or TU-177 xenograft tumors in nude mice to examine tumor growth. Results: The miR-204-5p mRNA level was lower in all 43 LSCC samples than in the ANM samples, but the FOXC1 level was higher in the LSCC samples than in the ANM samples. The miR-204-5p level was lower for stage III and IV cancer and lymph node N+ status samples than for stage I and II cancer and N0 status samples. FOXC1 mRNA and protein levels were higher for N+ than for N0 LSCC. The miR-204-5p mRNA levels were lower in Hep-2 and TU-177 cells than in ANM tissues, but FOXC1 mRNA levels were higher in Hep-2 and TU-177 cells than in ANM tissues. Dual-luciferase reporter assays demonstrated the targeted regulatory effects of miR-204-5p on the FOXC1 3′ UTR. Cell proliferation and colony formation was facilitated with miR-204-5p mimics and FOXC1 siRNA, with weaker cell migration and invasion than the controls. Moreover, miR-204-5p overexpression or FOXC1 knockdown inhibited the EMT process in LSCC cells. In vivo experiments demonstrated that injection of miR-204-5p into Hep-2 and TU-177 xenograft tumors in nude mice significantly inhibited tumor growth. Conclusions: miR-204-5p is involved in the invasion and metastasis of LSCC. It has a targeted regulatory effect on FOXC1 expression; malignant LSCC behaviors, including cell proliferation, invasion, and metastasis, are suppressed, and tumor growth in vivo is inhibited. This suggests that miR-204-5p may be a target for molecular therapy of LSCC in the future.

To date, various methods have been used to synthesize ZnGa2O4 material to promote photodegradation performance. However, cocatalysts, which usually play a crucial role in the photocatalyst system, have not been studied extensively in photocatalytic degradation reactions. In this paper, ZnGa2O4 semiconducting material was synthesized by a traditional high-temperature solid-state reaction. The as-prepared powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet&ndash, visible diffused reflectance spectroscopy. The results indicate that the as-prepared sample is a highly crystallized granular sample with a bandgap of 4.44 eV and a uniform particle size distribution. Density functional theory (DFT) was utilized to calculate the electronic structure of ZnGa2O4. The valence bands and conduction bands were chiefly composed of O 2p atomic orbitals and the hybridization orbitals of Ga 4s4p and Zn4s4p, respectively. The photocatalytic performance was tested via the decomposition of rhodamine B (RhB) under the irradiation of ultraviolet light. Cu, Ag, Au, Ni, Pt, and Pd cocatalysts were loaded on the ZnGa2O4 photocatalyst by a photodeposition method. The relatively optimal cocatalyst of ZnGa2O4 in the photocatalytic degradation reaction is Au. Thereafter, the effect of loading different usage amounts of the Au cocatalyst for the photodegradation of the ZnGa2O4 photocatalyst was studied in detail. The experimental results displayed that the optimum photodegradation activity was confirmed with the 3 wt% Au/ZnGa2O4 sample, which was 14.1 times more than the unloaded photocatalyst. The maximum photocatalytic degradation ratio of RhB was 96.7%, with 180 min under ultraviolet light.

Background: Laryngeal squamous cell carcinoma ranks second among head and neck squamous-cell carcinomas. Cancer stem cells can support cancer growth and malignant behavior. Therefore, cancer stem cells isolated from laryngeal squamous cell carcinoma tissue could be used to investigate the initiation, progression, and treatment strategies of this cancer. Methods: We isolated CD133-CD44-, CD133-CD44+, CD133+CD44- and CD133+CD44+ cell populations from laryngeal squamous-cell carcinoma cell lines Hep2 and TU-177 by magnetic-activated cell sorting. Sphere formation, cell proliferation, migration, invasion, colony formation, resistance to radio- and chemotherapy, and in vivo tumorigenicity of these populations were evaluated. Moreover, we investigated the expression of the stem-cell markers (sex determining region Y)-box 2 (SOX2) and octamer-binding transcription factor 4 (OCT4) in CD133-CD44-, CD133-CD44+, CD133+CD44-, CD133+CD44+ cell populations and parental Hep2 and TU-177 cells. Results: As compared with CD133-CD44-, CD133-CD44+, CD133+CD44- populations and parental cells, CD133+CD44+ cells showed higher cell viability, migration and invasive capability and colony formation ability as well as stronger resistance to cisplatin and irradiation. Moreover, levels of SOX2 and OCT4 and tumorigenicity in nude mice were greater in CD133+CD44+ Hep2 and TU-177 cells than other cell populations and parental cells. Conclusion: The CD133+CD44+ population of laryngeal squamous-cell carcinoma Hep2 and TU-177 cells have stem cell properties and showed more malignant features than CD133+CD44- and CD133-CD44+ cell populations. CD133+CD44+ cancer stem cells may be a promising target for developing anticancer drugs and treatment strategies for laryngeal squamous cell carcinoma.

Media coverage reduces the transmission rate from infective to susceptible individuals and is reflected by suitable nonlinear functions in mathematical modeling of the disease. We here focus on estimating the parameters in the transmission rate based on a stochastic SIR epidemic model with media coverage. In order to reduce the computational load, the Newton-Raphson algorithm and Markov Chain Monte Carlo (MCMC) technique are incorporated with maximum likelihood estimation. Simulations validate our estimation results and the necessity of a model with media coverage when modeling the contagious diseases.

Studies have shown that number line estimation is important for learning. However, it is yet unclear if number line estimation predicts different mathematical skills in different grades after controlling for age, non-verbal cognitive ability, attention, and working memory. The purpose of this study was to examine the role of number line estimation on two mathematical skills (calculation fluency and math problem-solving) in grade 2 and grade 4. One hundred and forty-eight children from Shanghai, China were assessed on measures of number line estimation, non-verbal cognitive ability (non-verbal matrices), working memory (N-back), attention (expressive attention), and mathematical skills (calculation fluency and math problem-solving). The results showed that in grade 2, number line estimation correlated significantly with calculation fluency (r = -0.27, p < 0.05) and math problem-solving (r = -0.52, p < 0.01). In grade 4, number line estimation correlated significantly with math problem-solving (r = -0.38, p < 0.01), but not with calculation fluency. Regression analyses indicated that in grade 2, number line estimation accounted for unique variance in math problem-solving (12.0%) and calculation fluency (4.0%) after controlling for the effects of age, non-verbal cognitive ability, attention, and working memory. In grade 4, number line estimation accounted for unique variance in math problem-solving (9.0%) but not in calculation fluency. These findings suggested that number line estimation had an important role in math problem-solving for both grades 2 and 4 children and in calculation fluency for grade 2 children. We concluded that number line estimation could be a useful indicator for teachers to identify and improve children’s mathematical skills.

Maternal systemic immune response is regulated by conceptus-derived signals through peripheral blood mononuclear cells (PBMCs) via blood circulation during early pregnancy in cattle. In this study, the PBMCs from day 18 in non-pregnant cows and days 14, 18 and 30 in pregnant cows were used to explore the expression of interferon-gamma (IFN-γ), interleukin 4 (IL-4) and IL-10, and the plasma progesterone (P4) concentration was also determined. The results showed that the expression levels of mRNA and the protein of IFN-γ were lower and that IL-4 and IL-10 were higher in the PBMCs from the pregnant cows than in those of non-pregnant cows. From this study, early pregnancy induced a lower Th1 immunity (IFN-γ) and a higher Th2 immunity (IL-4 and IL-10) in the PBMCs, which may be related to interferon-tau and P4, thereby contributing to successful pregnancy in cattle.

Aiming at the weight of trust someone given to participate in the interaction in Hegselmann–Krause’s type consensus model is the same and virtual social networks among individuals with different level of education, personal influence, etc. For differences between agents, a novelty bounded confidence model was proposed with leader’s opinion considered priority. Interaction neighbors can be divided into two kinds. The first kind is made up of “opinion leaders” group, another kind is made up of ordinary people. For different groups to give different weights of trust. We also analyzed the related characteristics of the new model under the symmetrical bounded confidence parameters and combined with the classical HK model were analyzed. Simulation experiment results show that no matter the network size and initial view is subject to uniform distribution or discrete distribution. We can control the “opinion-leader” good change the number of views and values, and even improve the convergence speed. Experiment als...

Background: Laryngeal squamous cell carcinoma ranks second among head and neck squamous-cell carcinomas. Cancer stem cells can support cancer growth and malignant behavior. Therefore, cancer stem cells isolated from laryngeal squamous cell carcinoma tissue could be used to investigate the initiation, progression, and treatment strategies of this cancer. Methods: We isolated CD133-CD44-, CD133-CD44+, CD133+CD44- and CD133+CD44+ cell populations from laryngeal squamous-cell carcinoma cell lines Hep2 and TU-177 by magnetic-activated cell sorting. Sphere formation, cell proliferation, migration, invasion, colony formation, resistance to radio- and chemotherapy, and in vivo tumorigenicity of these populations were evaluated. Moreover, we investigated the expression of the stem-cell markers (sex determining region Y)-box 2 (SOX2) and octamer-binding transcription factor 4 (OCT4) in CD133-CD44-, CD133-CD44+, CD133+CD44-, CD133+CD44+ cell populations and parental Hep2 and TU-177 cells. Results: As compared with CD133-CD44-, CD133-CD44+, CD133+CD44- populations and parental cells, CD133+CD44+ cells showed higher cell viability, migration and invasive capability and colony formation ability as well as stronger resistance to cisplatin and irradiation. Moreover, levels of SOX2 and OCT4 and tumorigenicity in nude mice were greater in CD133+CD44+ Hep2 and TU-177 cells than other cell populations and parental cells. Conclusion: The CD133+CD44+ population of laryngeal squamous-cell carcinoma Hep2 and TU-177 cells have stem cell properties and showed more malignant features than CD133+CD44- and CD133-CD44+ cell populations. CD133+CD44+ cancer stem cells may be a promising target for developing anticancer drugs and treatment strategies for laryngeal squamous cell carcinoma.

The alkaloid-induced electrocarboxylation of 4-methylpropiophenone is examined in mild conditions. Comparative studies with several inductors indicate that the efficient enantiodiscrimination of the electrocarboxylation depends on the nucleophilic quinuclidine nitrogen atom and the OH group of the inductors.

In pest control, taking the lag of parasitic eggs, the lag effect of pesticide poisoning and the age of releasing natural enemies as control variables, combined with the crop fertility cycle, researches on the optimization problem of pest control models at seedling stage, the bud stage, and filling stage of crops fill in a gap. For these purposes, a generalized hybrid optimization problem involving state delay with characteristic times and parameter control is presented. Then an algorithm based on a gradient computation is given. Finally, two examples in an agroecological system are given to exhibit the effectiveness of the proposed optimization algorithm.