Reactive magnesia (MgO)-activated ground granulated blast furnace slag (GGBS) is a newly developed binder for soil stabilization/solidification. It can be used as an alternative of conventional ...hydraulic binders for the stabilization/solidification of heavy metal-contaminated soils. Acid rain exposure has been found to weaken the heavy metal immobilization in solidified/stabilized soils in the long term. However, very limited studies have been conducted to investigate the effect of acid rain on the physical and strength properties of GGBS–MgO-stabilized heavy metal-contaminated soils. In this study, GGBS–MgO-stabilized lead (Pb)-contaminated soils are subjected to the semi-dynamic leaching test using the simulated acid rain (SAR) as leachant, which has pH values of 2.0, 3.0, 4.0, and 5.0. Deionized water (pH 7.0) is also used for comparison. Dry density, soil pH, needle penetration depth, and unconfined compressive strength (
q
u
) of the solidified/stabilized soils are measured after the leaching test. The results show that exposure to SAR yields reduction in
q
u
and soil pH, whereas the needle penetration depth increases and dry density changes only marginally. The
q
u
of the solidified/stabilized soils increases noticeably with increased GGBS–MgO content. It is also found that the stabilized Pb-contaminated soil exhibits lower
q
u
than its clean soil counterpart. Furthermore, a quantitative relationship is proposed to correlate the normalized needle penetration resistance with the normalized
q
u
. Finally, a multiple linear regression is performed to statistically reveal the dependence of soil strength on three independent variables, which are SAR pH, Pb concentration and binder content.
•Three different data driven models were used for forecasting river flow.•We compared the performance of three models in the semiarid mountain region.•SVM model performed better than ANN and ANFIS in ...the river flow forecasting.
Data driven models are very useful for river flow forecasting when the underlying physical relationships are not fully understand, but it is not clear whether these data driven models still have a good performance in the small river basin of semiarid mountain regions where have complicated topography. In this study, the potential of three different data driven methods, artificial neural network (ANN), adaptive neuro fuzzy inference system (ANFIS) and support vector machine (SVM) were used for forecasting river flow in the semiarid mountain region, northwestern China. The models analyzed different combinations of antecedent river flow values and the appropriate input vector has been selected based on the analysis of residuals. The performance of the ANN, ANFIS and SVM models in training and validation sets are compared with the observed data. The model which consists of three antecedent values of flow has been selected as the best fit model for river flow forecasting. To get more accurate evaluation of the results of ANN, ANFIS and SVM models, the four quantitative standard statistical performance evaluation measures, the coefficient of correlation (R), root mean squared error (RMSE), Nash–Sutcliffe efficiency coefficient (NS) and mean absolute relative error (MARE), were employed to evaluate the performances of various models developed. The results indicate that the performance obtained by ANN, ANFIS and SVM in terms of different evaluation criteria during the training and validation period does not vary substantially; the performance of the ANN, ANFIS and SVM models in river flow forecasting was satisfactory. A detailed comparison of the overall performance indicated that the SVM model performed better than ANN and ANFIS in river flow forecasting for the validation data sets. The results also suggest that ANN, ANFIS and SVM method can be successfully applied to establish river flow with complicated topography forecasting models in the semiarid mountain regions.
Listeria monocytogenes is an important food‐borne pathogenic bacterium that causes human disease, resulting in economic losses worldwide. The current detection methods for L. monocytogenes are not ...well suited for direct field testing because they involve complicated, time‐consuming operations. A simple, efficient method is vital for L. monocytogenes detection. In this study, we combined isothermal recombinase polymerase amplification (RPA) with a lateral flow (LF) strip to rapidly and reliably detect L. monocytogenes. In the presence of biotin‐ and digoxin‐modified primers, RPA produced numerous digoxin‐ and biotin‐attached duplex DNA products. These products were detected on an LF strip via dual immunoreactions (digoxin on the duplex DNA reacted with the anti‐digoxin antibody on the gold nanoparticle (Au‐NP) and the biotin on the duplex DNA captured by the streptavidin on the LF test zone). The accumulation of Au‐NPs produced characteristic bands, enabling the visual detection of L. monocytogenes without instrumentation. This assay could be used to detect L. monocytogenes within 15 min, including DNA amplification with RPA for 10 min at 39 °C and visualization of the amplicons by LF strips for 5 min. Experiments confirmed a detection limit as low as 300 fg of DNA and 1.5 × 101 CFU in pure cultures. Furthermore, RPA‐LF exhibited no cross‐reactions with pathogens. Evaluation of the method with food samples indicated that the detection limit was substantially improved to 1.5 × 10° CFU for the original bacterial content in 25 g/mL samples after enrichment for 6 hr. RPA‐LF can be used as a sensitive and rapid detection technique for L. monocytogenes.
Practical Application
Recombinase polymerase amplification (RPA) can amplify target DNA at 37 to 42 °C without a thermal cycler. Lateral flow (LF) strips are portable, cheap and easy to operate. RPA combined with LF strips to detect Listeria monocytogenes can be widely used in remote areas.
Background
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been spreading rapidly around the world, while “multisystem inflammatory syndrome in children” (MIS-C) is a new ...type of syndrome that has now been reported in many countries. Similar and different characteristics between KD and MIS-C have been reported in a variety of literature. We aimed to focus on reviewing clinical presentations, diagnosis, and treatment of KD and MIS-C.
Methods
We searched articles in the electronic databases, including the Cochrane Library database, EMBASE, and MEDLINE with the keywords “multiple inflammatory syndrome” and/or “COVID-19” and/or “Kawasaki disease” and “children”.
Results
Main presentations of MIS-C and KD include fever, rashes, mucous membrane involvement, conjunctivitis, hands and feet erythema/edema, and cervical lymphadenopathy. However, compared with the highest incidence of KD among some Asian countries, MIS-C is common among Black and Hispanic children. MIS-C is common in older children and teenagers, whereas classic KD is common in children under five years of age. Gastrointestinal symptoms, shock, and coagulopathy are common in MIS-C patients but are not common in classic KD. Cardiac manifestations are more common than KD, including myocarditis with cardiac dysfunction and coronary artery dilation or aneurysms. Severe cases in MIS-C present with vasodilated or cardiogenic shock that requires fluid resuscitation, muscular support, and even mechanical ventilation and extracorporeal membrane oxygenation (ECMO), whereas KD rarely presents with these manifestations and requires these treatments. Increased serum ferritin, leukopenia, lymphopenia and thrombocytopenia are common in MIS-C. However, thrombocytosis is a characteristic feature of KD. Intravenous immunoglobulin (IVIG) and moderate-high dose aspirin are still a standard recommended treatment for KD. In addition to the above-mentioned medications, steroids and biological drugs are frequently used in patients with MIS-C. Most of the children with KD have a good prognosis; however, the long-term clinical outcomes of MIS-C are not clear.
Conclusions
The overall presentation and treatment of MIS-C appear to overlap with KD. However, there are still great differences between the syndromes, and it is controversial to say whether MIS-C is a new entity or is a “severe type” of KD.
Intercropping is one of the most vital practice to improve land utilization rate in China that has limited arable land resource. However, the traditional intercropping systems have many disadvantages ...including illogical field lay-out of crops, low economic value, and labor deficiency, which cannot balance the crop production and agricultural sustainability. In view of this, we developed a novel soybean strip intercropping model using maize as the partner, the regular maize-soybean strip intercropping mainly popularized in northern China and maize-soybean relay-strip intercropping principally extended in southwestern China. Compared to the traditional maize-soybean intercropping systems, the main innovation of field lay-out style in our present intercropping systems is that the distance of two adjacent maize rows are shrunk as a narrow strip, and a strip called wide strip between two adjacent narrow strips is expanded reserving for the growth of two or three rows of soybean plants. The distance between outer rows of maize and soybean strips are expanded enough for light use efficiency improvement and tractors working in the soybean strips. Importantly, optimal cultivar screening and increase of plant density achieved a high yield of both the two crops in the intercropping systems and increased land equivalent ratio as high as 2.2. Annually alternative rotation of the adjacent maize- and soybean-strips increased the grain yield of next seasonal maize, improved the absorption of nitrogen, phosphorus, and potasium of maize, while prevented the continuous cropping obstacles. Extra soybean production was obtained without affecting maize yield in our strip intercropping systems, which balanced the high crop production and agricultural sustainability.
High blood pressure (BP) continues to be a major, poorly controlled but modifiable risk factor for cardiovascular death. Among key Western lifestyle factors, a diet poor in fiber is associated with ...prevalence of high BP. The impact of lack of prebiotic fiber and the associated mechanisms that lead to higher BP are unknown. Here we show that lack of prebiotic dietary fiber leads to the development of a hypertensinogenic gut microbiota, hypertension and its complications, and demonstrate a role for G-protein coupled-receptors (GPCRs) that sense gut metabolites.
One hundred seventy-nine mice including C57BL/6J, gnotobiotic C57BL/6J, and knockout strains for GPR41, GPR43, GPR109A, and GPR43/109A were included. C57BL/6J mice were implanted with minipumps containing saline or a slow-pressor dose of angiotensin II (0.25 mg·kg
·d
). Mice were fed diets lacking prebiotic fiber with or without addition of gut metabolites called short-chain fatty acids (SCFA) produced during fermentation of prebiotic fiber in the large intestine), or high prebiotic fiber diets. Cardiac histology and function, BP, sodium and potassium excretion, gut microbiome, flow cytometry, catecholamines and methylation-wide changes were determined.
Lack of prebiotic fiber predisposed mice to hypertension in the presence of a mild hypertensive stimulus, with resultant pathological cardiac remodeling. Transfer of a hypertensinogenic microbiota to gnotobiotic mice recapitulated the prebiotic-deprived hypertensive phenotype, including cardiac manifestations. Reintroduction of SCFAs to fiber-depleted mice had protective effects on the development of hypertension, cardiac hypertrophy, and fibrosis. The cardioprotective effect of SCFAs were mediated via the cognate SCFA receptors GPR43/GPR109A, and modulated L-3,4-dihydroxyphenylalanine levels and the abundance of T regulatory cells regulated by DNA methylation.
The detrimental effects of low fiber Westernized diets may underlie hypertension, through deficient SCFA production and GPR43/109A signaling. Maintaining a healthy, SCFA-producing microbiota is important for cardiovascular health.
•A novel neural network based approach to handwritten mathematical expression recognition.•An end-to-end encoder-decoder framework to alleviate the problem caused by an explicit symbol segmentation ...and the computational demands of employing a mathematical expression grammar.•The deep fully convolutional neural network as the encoder.•The coverage-based attention model to incorporate the attention history.•Attention visualization to show the link between the input image and output symbol sequence in latex format.•To the best of our knowledge, achieving the best published expression recognition accuracy on CROHME 2014 competition set by only using the official training data.
Machine recognition of a handwritten mathematical expression (HME) is challenging due to the ambiguities of handwritten symbols and the two-dimensional structure of mathematical expressions. Inspired by recent work in deep learning, we present Watch, Attend and Parse (WAP), a novel end-to-end approach based on neural network that learns to recognize HMEs in a two-dimensional layout and outputs them as one-dimensional character sequences in LaTeX format. Inherently unlike traditional methods, our proposed model avoids problems that stem from symbol segmentation, and it does not require a predefined expression grammar. Meanwhile, the problems of symbol recognition and structural analysis are handled, respectively, using a watcher and a parser. We employ a convolutional neural network encoder that takes HME images as input as the watcher and employ a recurrent neural network decoder equipped with an attention mechanism as the parser to generate LaTeX sequences. Moreover, the correspondence between the input expressions and the output LaTeX sequences is learned automatically by the attention mechanism. We validate the proposed approach on a benchmark published by the CROHME international competition. Using the official training dataset, WAP significantly outperformed the state-of-the-art method with an expression recognition accuracy of 46.55% on CROHME 2014 and 44.55% on CROHME 2016.
•SPC significantly improves strength and reduces leachability of the soils.•SPC effectively reduces volume and size of inter-aggregate and air pores.•SPC stabilization significantly reduces acid ...soluble fractions of heavy metals.•Hydroxyapatite and heavy metal-bearing hydroxyapatite form in stabilized soils.
Synthetic hydroxyapatite (HA) is an efficient and environment-friendly material for the remediation of heavy metal contaminated soils. However, the application of conventional HA powder in stabilizing contaminated soils is limited, due to high cost of final products, difficulties in synthesizing purified HA crystals. A new binder named SPC, which composes of single superphosphate (SSP) and calcium oxide (CaO), is presented as an alternative in this study. HA can form in the soil matrix by an acid-base reaction between SSP and CaO, resulting in a dense structure and improved mechanical properties of treated soils. Therefore, the SPC is capable of effectively immobilizing heavy metals and elevating strength of contaminated soils, meanwhile, maintaining relatively low cost. This paper presents a systematic investigation of the performance, reaction products, and microstructural properties of a lead (Pb), zinc (Zn), and cadmium (Cd) contaminated industrial site soil stabilized with SPC binder. The effects of SPC content and curing time on the pH, leachability and strength properties of the stabilized soils are evaluated. Furthermore, modified European Communities Bureau of Reference (BCR) sequential extraction procedure (SEP), mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), and scanning electron microscope (SEM) analyses are performed to interpret the mechanisms controlling the changes in these macro-properties. The results show that the soil pH and unconfined compressive strength (UCS) increase with increasing SPC content and curing time. After 28days of curing, the UCS values of stabilized soils are approximately 2.2–5.7 times those of the untreated soil. The leachability of Pb, Zn and Cd is significantly reduced after stabilization, and the SPC content and curing time have considerable influences on the leached concentrations of heavy metals. The SEP results confirm that SPC significantly reduces the acid soluble fractions of Pb, Zn and Cd while increases their residual fractions. The MIP test results show that pore volume reduces notably and pore profile of the soil changes remarkably after SPC stabilization. The mineralogical (XRD) and microstructural (SEM) analyses reveal that the formation of heavy metal-bearing hydroxyapatites and phosphate-based precipitates are the primary mechanisms of immobilization of Pb, Zn and Cd in the SPC stabilized soil.
Epidemiological studies suggest that chronic periodontitis (CP) is closely associated with the incidence and progression of cognitive impairment. The present study investigated the causal ...relationship between CP and cognitive decline and the underlying mechanism in mice. Long-term ligature around the left second maxillary molar tooth was used to induce CP in mice. Severe alveolar bone loss and inflammatory changes were observed in gingival tissues, accompanied by progressive cognitive deficits during a 12-month period. We also observed cerebral neuronal and synaptic injury and glial activation in this mouse model of CP. Furthermore, CP mice exhibited significant dysbiosis of the oral and gut microbiota, disruption of the intestinal barrier and blood-brain barrier, increases in the serum contents of proinflammatory cytokines and lipopolysaccharide (LPS), and increases in brain LPS levels, Toll-like receptor 4 (TLR4) expression, nuclear factor-κB (NF-κB) nuclear translocation and proinflammatory cytokine mRNA levels. These results indicate that CP may directly induce progressive cognitive decline and its mechanism is probably related to microbiota-gut-brain axis disorders, LPS/TLR4/NF-κB signaling activation and neuroinflammatory responses in mice. Therefore, the microbiota-gut-brain axis may provide the potential strategy for the prevention and treatment of CP-associated cognitive impairment.
•Chronic periodontitis (CP) mice displayed progressive cognitive deficits.•Murine CP aggravated neuronal injury and neuroinflammation.•Murine CP caused the oral and gut microbiota dysbiosis.•Murine CP induced intestinal barrier damage and inflammation.•Murine CP injured blood-brain barrier and activated TLR4 pathway in the brain.
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► Effect of acid rain on leaching and hydraulic characteristics. ► Leaching of calcium and lead are significantly affected by initial pH of acid rain. ► Decreasing rate of hydraulic ...conductivity is lower in acid rain case. ► Presence of SO42− in acid rain increased the leaching mass and rate of calcium.
Remediation of contaminated lands in China urban areas is of great concern. Degradation of construction facilities caused by acid rain is a serious environmental pollution issue in China. This paper presents an investigation of the effects of acid rain on leaching and hydraulic properties of cement-based solidified/stabilized lead contaminated soil. Laboratory tests including infiltration test and soaking test are conducted. It is found that the soil hydraulic conductivity decreases with increase in the pore volume of flow of permeant liquids (acid rain and distilled water). The decreasing rate in the case of the acid rain is lower than that in the case of the distilled water. The soaking test results show that pH and the presence of sulfate ions of acid rain have considerable influence on the leached concentrations and leaching rate of calcium.
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