This paper performs qualitative analysis on an SIS epidemic reaction–diffusion system with a linear source in spatially heterogeneous environment. The main feature of our model lies in that its total ...population number varies, compared to its counterpart proposed by Allen et al. 2. The uniform bounds of solutions are derived, based on which, the threshold dynamics in terms of the basic reproduction number is established and the global stability of the unique endemic equilibrium is discussed when spatial environment is homogeneous. In particular, the asymptotic profile of endemic equilibria is determined if the diffusion rate of the susceptible or infected population is small or large. The theoretical results show that a varying total population can enhance persistence of infectious disease, and therefore the disease becomes more threatening and harder to control.
Tea is widely consumed all over the world. Generally, tea is divided into six categories: White, green, yellow, oolong, black, and dark teas, based on the fermentation degree. Tea contains abundant ...phytochemicals, such as polyphenols, pigments, polysaccharides, alkaloids, free amino acids, and saponins. However, the bioavailability of tea phytochemicals is relatively low. Thus, some novel technologies like nanotechnology have been developed to improve the bioavailability of tea bioactive components and consequently enhance the bioactivity. So far, many studies have demonstrated that tea shows various health functions, such as antioxidant, anti-inflammatory, immuno-regulatory, anticancer, cardiovascular-protective, anti-diabetic, anti-obesity, and hepato-protective effects. Moreover, it is also considered that drinking tea is safe to humans, since reports about the severe adverse effects of tea consumption are rare. In order to provide a better understanding of tea and its health potential, this review summarizes and discusses recent literature on the bioactive components, bioavailability, health functions, and safety issues of tea, with special attention paid to the related molecular mechanisms of tea health functions.
Background and Aim
This study aims to systematically analyze the effect of long‐term therapy with proton pump inhibitors (PPIs) on the risk of gastric cancer.
Methods
PubMed, EMBASE, Cochrane ...Library, China National Knowledge Infrastructure (CNKI), and China biomedical literature database (CBM) were searched for studies before February 2019. We evaluated the quality of the included articles through the Newcastle‐Ottawa Scale and gathered relevant data to calculate the pooled odds ratio (OR) through Stata14.0.
Results
Seven relevant articles conformed to the inclusion criteria; 943 070 patients were included. The pooled OR was 2.50; 95% CI (1.74, 3.85); the subgroup analysis results showed that patients who had used PPIs for more than 36 months were most likely to develop gastric cancer, and an increased risk was observed among patients after Helicobacter pylori eradication. Noncardia gastric cancer was more likely to develop.
Conclusions
Long‐term use of PPIs can possibly increase the risk of gastric cancer even among patients after H. pylori eradication; in particular, for noncardia gastric cancer, the risk increases with longer durations of PPI use. Due to the limited number of studies, more high‐quality studies are required to be designed.
Background and Aim
Lean non‐alcoholic fatty liver disease (NAFLD) is a potentially metabolically unhealthy state that refers to NAFLD occurring in non‐overweight/nonobese subjects. Yet its global ...epidemiology and metabolic characteristics are not extensively elucidated.
Methods
PubMed, EMBASE, Web of Science and Cochrane databases were searched for eligible studies until January 2020. Random‐effects/fixed‐effects models were used to estimate the global prevalence of lean NAFLD and to compare clinical characteristics among lean non‐NAFLD, lean NAFLD, and overweight/obese NAFLD subjects. “Lean” NAFLD was defined by ethnic‐specific body mass index measurements in the normal range. Meta‐regression and subgroup analyses were performed to determine potential sources of heterogeneity.
Results
A total of 33 observational studies were included with 205 307 individuals from 14 countries. The global prevalence of lean NAFLD was 4.1% (95% confidence interval CI: 3.4–4.8%). In lean subjects, the prevalence of NAFLD was 9.7% (95% CI: 7.7–11.8%). The prevalence of lean NAFLD with diabetes, hypertension, metabolic syndrome, dyslipidemia, or central obesity was 0.6% (95% CI: 0.4–0.9%), 1.8% (95% CI: 1.2–2.5%), 1.4% (95% CI: 1.0–1.9%), 2.8% (95% CI: 1.9–3.7%), and 2.0% (95% CI: 1.6–2.4%), respectively. The prevalence of lean NAFLD showed an upward trend between 1988 and 2017. Asian individuals had the highest prevalence of lean NAFLD (4.8%, 95% CI: 4.0–5.6%). Middle‐aged people (45–59 years old) had the highest prevalence of lean NAFLD (4.4%, 95% CI: 3.2–5.5%). The prevalence of metabolic complications in lean non‐NAFLD, lean NAFLD, and overweight/obese NAFLD groups increased sequentially.
Conclusions
Lean NAFLD occurs with metabolic complications and is not an uncommon condition. The highest prevalence of lean NAFLD occurs in middle‐aged individuals of Asian countries.
In this work, we develop a new modeling framework to study the impact of bacterial hyperinfectivity on cholera epidemics in a spatially heterogeneous environment. Our model is built on a ...reaction-advection-diffusion system to represent spatiotemporal dynamics of cholera transmission, and incorporates bacterial hyperinfectivity and spatial heterogeneity. Firstly, we define the basic reproduction number R0 and establish the global threshold dynamics based on R0. Secondly, the global attractivity of the unique endemics equilibrium is discussed when the spatial environment is homogeneous and waning cholera immunity, advection and intrinsic growth of bacteria are ignored. Thirdly, the dependence of R0 on model parameters are numerically investigated. The theoretical results are obtained for some specific cases. Our result highlights the importance of hyperinfectivity and its interplay with spatial heterogeneity. Particularly, our findings indicate ignoring hyperinfectivity may underestimate the risk of infection.
In many green electrochemical energy devices, the conversion between oxygen and water suffers from high potential loss due to the difficulty in decreasing activation energy. Overcoming this issue ...requires full understanding of global reactions and development of strategies in efficient catalyst design. Here we report an active copper nanocomposite, inspired by natural coordination environments of catalytic sites in an enzyme, which catalyzes oxygen reduction/evolution at potentials closely approaching standard potential. Such performances are related to the imperfect coordination configuration of the copper(II) active site whose electron density is tuned by neighbouring copper(0) and nitrogen ligands incorporated in graphene. The electron transfer number of oxygen reduction is estimated by monitoring the redox of hydrogen peroxide, which is determined by the overpotential and electrolyte pH. An in situ fluorescence spectroelectrochemistry reveals that hydroxyl radical is the common intermediate for the electrochemical conversion between oxygen and water.
Benzoylaconitine (BAC), the main hydrolysate of aconitine, is a lower toxic monoester type alkaloid considered as the pharmacodynamic constituent in Aconitum species. In this study, the effects and ...mechanisms of BAC on production of inflammatory cytokines interleukin (IL)-6 and IL-8 were investigated in IL-1β-stimulated human synovial SW982 cells. The SW982 cells were incubated with BAC (0, 5 and 10 µM) before stimulating with IL-1β (10 ng/mL). The results revealed that BAC suppressed gene and protein expression of IL-6 and IL-8 induced by IL-1β. BAC decreased activation of mitogen-activated protein kinase (MAPK) and phosphorylation of Akt. BAC also inhibited degradation of inhibitor of kappaB (IκB)-α, phosphorylation and nuclear transposition of p65 protein. The results demonstrate that BAC exerts an anti-inflammatory effect dependent on MAPK, Akt and nuclear factor-κB (NF-κB) pathways in human synovial cells stimulated with IL-1β, suggesting that BAC may be exploited as a potential therapeutic agent for rheumatoid arthritis (RA) treatment.
Due to its particular structure and electronic properties originating from nitrogen doping, nitrogen doped graphene prepared by thermally annealing graphite oxide with melamine shows high ...electrocatalytic activity towards the oxidation of ascorbic acid, dopamine and uric acid. A novel NG-based electrochemical sensor has been fabricated and successfully used to simultaneously determine these biomolecules with high sensitivity and selectivity. Display omitted
► Nitrogen doped graphene (NG) prepared thermally using melamine precursor. ► NG shows highly electrocatalytic activity toward small biomolecules. ► The electrocatalytic activity depends on the doped nitrogen amount. ► NG based electrochemical biosensor detects ascorbic acid, uric acid and dopamine with high sensitivity and selectivity.
Nitrogen doped graphene (NG) was prepared by thermally annealing graphite oxide and melamine mixture. After characterization by atomic force microscopy and X-ray photoelectron spectroscopy etc., the electrochemical sensor based on NG was constructed to simultaneously determine small biomolecules such as ascorbic acid (AA), dopamine (DA) and uric acid (UA). Due to its unique structure and properties originating from nitrogen doping, NG shows highly electrocatalytic activity towards the oxidation of AA, DA and UA. The electrochemical sensor shows a wide linear response for AA, DA and UA in the concentration range of 5.0×10−6 to 1.3×10−3M, 5.0×10−7 to 1.7×10−4M and 1.0×10−7 to 2.0×10−5M with detection limit of 2.2×10−6M, 2.5×10−7M and 4.5×10−8M at S/N=3, respectively. These results demonstrate that NG is a promising candidate of advanced electrode material in electrochemical sensing and other electrocatalytic applications.
This paper presents an effective deep attention network for joint hand gesture localization and recognition using static RGB-D images. Our method trains a CNN framework based on a soft attention ...mechanism in an end-to-end manner, which is capable of automatically localizing hands and classifying gestures using a single network rather than relying on the conventional means of stage-wise hand segmentation/detection and classification. More precisely, our attention network first computes the weight for each proposal generated from the entire image, in order to judge the probability of the hand appearing in a given region. It then implements a global-sum operation for all proposals, which is influenced by their corresponding weights, in order to obtain a representation of the entire image. We demonstrate the feasibility and effectiveness of our method through extensive experiments on the NTU Hand Digits (NTU-HD) benchmark and the challenging HUST American Sign Language (HUST-ASL) dataset. Moreover, the proposed attention network is simple to train, without requiring bounding-box or segmentation mask annotations, which makes it easy to apply in hand gesture recognition systems. Based on the proposed attention network and taken RGB-D images as input, we obtain the state-of-the-art hand gesture recognition performance on the challenging HUST-ASL dataset.
Graphene can be viewed as an individual atomic plane extracted from graphite, as unrolled single-walled carbon nanotube or as an extended flat fullerene molecule. In this paper, a facile approach to ...the synthesis of high quality graphene nanosheets in large scale through electrochemical reduction of exfoliated graphite oxide precursor at cathodic potentials (completely reduced potential: −1.5 V) is reported. This method is green and fast, and will not result in contamination of the reduced material. The electrochemically reduced graphene nanosheets have been carefully characterized by spectroscopic and electrochemical techniques in comparison to the chemically reduced graphene-based product. Particularly, FTIR spectra indicate that a variety of the oxygen-containing functional groups have been thoroughly removed from the graphite oxide plane via electrochemical reduction. The chemically converted materials are not expected to exhibit graphene’s electronic properties because of residual defects. Indeed, the high quality graphene accelerates the electron transfer rate in dopamine electrochemistry (ΔE p is as small as 44 mV which is much smaller than that on a glassy carbon electrode). This approach opens up the possibility for assembling graphene biocomposites for electrocatalysis and the construction of biosensors.
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