Sensitive, Low-Background-Signal miRNA Analysis via the Self-Priming-Initiated Color Reaction Loaded on a Rolling Circle Amplification Product.

MicroRNAs (miRNAs) have been regarded as potential biomarkers in evaluating various diseases, such as pregnancy-induced hypertension and cancers. However, sensitive and reliable miRNA detection is still a challenge due to the low amplification efficiency and high background signal. Herein, we developed a colorimetric method for miRNA detection utilizing the self-priming-initiated color reaction loaded on a rolling circle amplification (RCA) product. In this method, a biotin-labeled RCA product is fixed on the surface of the streptavidin-coated wells, and the interfering components in samples are removed to avoid false reactions, thus reducing the background signals. Two signal amplification processes, including RCA and self-priming-initiated chain extension, endow the method with high sensitivity and a low limit of detection at the 10 fM level. In conclusion, our approach offers a promising perspective on sensitive and reliable miRNA detection and has the potential to be further utilized in biomedical research and early cancer detection.

Preparation and functional characteristics of protein from Ginkgo endophytic Pseudomonas R6 and Ginkgo seed.

Ginkgo seed protein (GSP) has excellent processing characteristics and antioxidant properties. In this study, Gingko endophytic protein (GEP) was synthesized by Ginkgo endophytic Pseudomonas R6. SDS-PAGE analysis indicated that the molecular weights of GSP and GEP were mainly distributed at 17 KDa and 48 KDa, respectively. FTIR showed that GEP and GSP exhibited characteristic absorption in the amide I, II, and III bands, and absorption in amide A and B indicated the presence of hydrogen bonding. HPLC analysis showed that both proteins had 17 amino acids, but their relative abundance was different, with GSP having the highest Ser content (74.713 mg/g) and GEP having the highest Val content (35.905 mg/g). Stomata were observed on the surface of both proteins by SEM, and there were lamellar and some spherical structures on GEP, while the opposite was observed on GSP. GEP had superior solubility, OHC, FC and EC, while GSP showed good WHC. Both proteins exhibited antioxidant activities, with GSP exhibiting stronger hydroxyl radical scavenging ability than GEP, with IC50 of 0.46 mg/mL and 1.54 mg/mL, respectively. This work demonstrates the antioxidant potential of GEP as an alternative to GSP in the food industry.

Photocatalytic and oxidation mechanisms of Fe-Ag@AgCl: Effect on co-existing arsenic (III) and Escherichia coli.

To address the drinking safety problems associated with high arsenic(III) (As(III)) and bacteria in underground water, core-shell Fe-Ag@AgCl nanowires were synthesized and exhibited excellent photocatalytic oxidation effects on co-existing As(III) and Escherichia coli (E. coli). With the introduction of Fe, the nanowires that were used 5 times could be easily magnetically collected, and the As(III) oxidation effect of these re-chlorinated nanowires increased from 39% to 60%. E. coli was completely inactivated within 60 min without photoreactivation after 20 min. Extracellular polymeric substances have play a protective role in the disinfection process. Quenching testing results confirmed that, except for the superoxide radical (•O2-), the subdominant active species were different for different objects: hole (hVB+) to As(III) and hydroxyl radical (•OH) to E. coli. Therefore the system with co-existing As(III) and E. coli, the inactivation effect of Fe-Ag@AgCl on E. coli decreased remarkably with an increase in As(III) concentration, while the oxidation process of As(III) was not significantly affected by E. coli until E. coli was increased to 108 cfu/mL. The photocatalytic process of co-existing As(III) and E. coli is displayed in a schematic diagram and was tested using desired results obtained from field groundwater in Xiantao City, Hubei Province. The function of Fe in band structures and density of states was analyzed using plane-wave density functional theory. These magnetic nanowires presented excellent photocatalytic ability on co-existing As(III) and E. coli, and provided new insights into drinking water safety in high-arsenic areas.

Mechanistic Insight into Humic Acid-Enhanced Hydroxyl Radical Production from Fe(II)-Bearing Clay Mineral Oxygenation.

Hydroxyl radical (•OH) production by electron transfer from Fe(II)-bearing clay minerals to oxygen has been increasingly reported. However, the influence of ubiquitous coexisting humic acid (HA) on this process is poorly understood. Here, we investigated the effect of different HA on •OH production during the oxygenation of reduced nontronite NAu-2 (rNAu-2), montmorillonite, and sediment. Results showed that HA could enhance •OH production, and the enhancement was related to the content of reactive Fe(II) in rNAu-2 and the electron-accepting capacity of HA. Coexisting HA leads to a new electron-transfer pathway from Fe(II) in rNAu-2 to HA (instead of the HA-Fe complex) and then to O2, changing the first step of O2 reduction from one- to two-electron transfer process with H2O2 as the main intermediate. Reduced HA decomposes H2O2 to •OH at a higher yield (13.8%) than rNAu-2 (8.8%). Modeling results reveal that the HA-mediated electron-transfer pathway contributes to 12.6-70.2% of H2O2 generation and 13.2-62.1% of •OH formation from H2O2 decomposition, with larger contributions at higher HA concentrations (5-100 mg C/L). Our findings implicate that HA-mediated electron transfer can expand the area of •OH production from the mineral surface to the aqueous phase and increase the yield of •OH production.

Visible light-activated 1-D core-shell paramagnetic Fe-Ag@AgCl as an innovative method for photocatalytic inactivation of E. coli.

Innovative paramagnetic one-dimensional (1-D) core-shell Fe-Ag@AgCl visible light-driven photocatalysts are synthesized through a template-assisted electrodeposition method trailed by FeCl3 in-situ oxidation. The metallic nature of Fe-Ag@AgCl is confirmed through scanning electron microscopy (SEM) and crystal nature through X-ray diffraction (XRD). The controllable diameter of Fe-Ag is obtained through the selection of hollow size of the polycarbonate (PC) template. Electron impedance spectroscopy (EIS) confirms through the introduction of Fe to the Ag core that has prolonged the recombination of electron and hole. Escherichia coli (E. coli) are employed as the target bacteria to evaluate the photocatalytic disinfection performances. A total of 1.30 mg of Fe-Ag@AgCl is proved to be able to completely inactivate 107 CFU (colony forming units)/mL after 120 min of visible light irradiation. The transition electron microscopy (TEM) confirms the stability of the material after the photo reaction. As Fe-Ag@AgCl possesses magnetic properties, the material is recovered through the application of an external magnetic field. SEM images and results of 3D emission extraction matrix (EEM) depict that the bacteria cell death is caused by membrane permeability changes caused by the reduction of membrane associated proteins.

A novel compound wind speed forecasting model based on the back propagation neural network optimized by bat algorithm.

Wind power, a clean and renewable resource, is regarded as one of the most promising and economical resources during the transformation from fossil fuels to new energy resources. Thus, the accuracy of wind speed forecasting work is very important to integrate the wind resource into electrical power system on a large scale. To improve the short-term wind speed forecasting accuracy, a novel compound model is introduced in this paper. For the proposed model, the fast ensemble empirical mode decomposition method was employed to do the data preprocessing. After the data preprocessing, phase space reconstruction was used for choosing each sub-series' input and output vectors for the forecasting model dynamically. Then, the bat algorithm was applied to optimize the connection weights and thresholds of the traditional back propagation neural network. The forecasting results can be obtained through the aggregation of sequential prediction. The performance evaluation of this proposed model indicates that it can capture the nonlinear characteristics of the wind speed signal efficiently. The proposed model shows better performance when being compared with the parallel models.

Relationship between the physicochemical properties of sludge-based carbons and the adsorption capacity of dissolved organic matter in advanced wastewater treatment: Effects of chemical conditioning.

Pyrolysis carbonisation is a promising technology to convert organic waste into valuable carbon-based materials. However, sludge is generally highly compressible and difficult to dewater because of its high concentrations of biopolymers; the bound water of sludge is trapped in a network composed of biopolymers. Therefore, chemical conditioning is an indispensable step for improving sludge dewaterability performance. In the present work, the effects of different chemical conditioning agents (polymeric aluminium chloride (PACl), iron(III) chloride (FeCl3), KMnO4-Fe(II) and Fenton's reagent) on the physicochemical properties of sludge-based carbons (SBCs) were systematically studied and the SBCs were further used in advanced wastewater treatment. The adsorption mechanisms of dissolved organic matters (DOMs) by different SBCs were also investigated. The results showed that conditioning with KMnO4-Fe(II) and Fenton's reagent improved the specific surface area of the SBCs, whereas inorganic salt flocculation conditioning reduced the porosity of the SBCs. In addition, we found that the Fenton-SBC and Mn/Fe-SBC performed better than the other investigated SBCs in the removal of organic compounds from secondary effluent and that the pseudo-second-order kinetic model could better describe the process of DOMs adsorption by all of the investigated SBCs. Moreover, three-dimensional fluorescence excitation-emission matrix spectroscopy in combination with an analysis of the physical and chemical fractionation of DOMs showed that all of the SBCs performed well in the adsorption of aromatic substances, hydrophobic acids and hydrophobic neutrals, whereas the Mn/Fe-SBC and Fenton-SBC performed better than the other SBCs in the removal of weakly hydrophobic acids.

A Review of PCSK9 Inhibitors and their Effects on Cardiovascular Diseases.

BACKGROUND: Cardiovascular diseases remain the leading cause of morbidity and mortality in the world, with elevated Low-Density Lipoprotein-Cholesterol (LDL-C) levels as the major risk factor. Lower levels of LDL-C can effectively reduce the risk of cardiovascular diseases. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in regulating the degradation of hepatic LDL receptors that remove LDL-C from the circulation. PCSK9 inhibitors are a new class of agents that are becoming increasingly important in the treatment to reduce LDL-C levels. Two PCSK9 inhibitors, alirocumab and evolocumab, have been approved to treat hypercholesterolemia and are available in the United States and the European Union. Through the inhibition of PCSK9 and increased recycling of LDL receptors, serum LDL-C levels can be significantly reduced. OBJECTIVE: This review will describe the chemistry, pharmacokinetics, and pharmacodynamics of PCSK9 inhibitors and their clinical effects.

Establishment and evaluation of a model for predicting 3-month mortality in Chinese patients with hepatic encephalopathy.

Hepatic encephalopathy (HE) is a serious complication of liver disease. To establish a model for predicting 3-month mortality in patients with HE in China. This retrospective study included 609 patients with HE admitted to the Peoples' Hospital, Liaocheng City, China (August 2006 to January 2016). Patients were allocated to a modeling (n = 409) or validation (n = 200) group. Demographic/clinical characteristics, laboratory test results, Model for End Stage Liver Disease (MELD) score and Child-Turcotte-Pugh (CTP) score were extracted from medical records. A model for predicting death within 3 months after admission was established using logistic regression analysis (modeling group). Model validity (validation group) was assessed using receiver operating characteristic (ROC) curve analysis. 270/409(66.0%) patients died in the modeling group and 142/203(70.0%) died in the validation group. Compared with survivors, patients who died had more severe HE, and higher MELD score, CTP score, incidence of complications including hepatorenal syndrome (HRS) and upper gastrointestinal bleeding, and values for laboratory parameters including red blood cell count(RBC) and total bilirubin(TBIL)(P < 0.05). Regression analysis revealed RBC, TBIL, HE stage, HRS and upper gastrointestinal bleeding as independent factors associated with death (P < 0.05). The area under the ROC curve (AUC) for the model was 0.931.The model had a higher Youden index than MELD or CTP scores and predicted death in the validation group with a sensitivity of 83.1% and specificity of 93.4%. The established model has superior performance to MELD and CTP scores for predicting mortality in patients with HE.

Synthesis of AG@AgCl Core-Shell Structure Nanowires and Its Photocatalytic Oxidation of Arsenic (III) Under Visible Light.

Ag@AgCl core-shell nanowires were synthesized by oxidation of Ag nanowires with moderate FeCl3, which exhibited excellent photocatalytic activity for As(III) oxidation under visible light. It was proved that the photocatalytic oxidation efficiency was significantly dependent on the mole ratio of Ag:AgCl. The oxidation rate of As(III) over Ag@AgCl core-shell nanowires first increased with the decrease of Ag0 percentage, up until the optimized synthesis mole ratio of Ag nanowires:FeCl3 was 2.32:2.20, with 0.023 mg L-1 min-1 As(III) oxidation rate; subsequently, the oxidation rate dropped with the further decrease of Ag0 percentage. Effects of the pH, ionic strength, and concentration of humic acid on Ag@AgCl photocatalytic ability were also studied. Trapping experiments using radical scavengers confirmed that h+ and ·O2- acted as the main active species during the visible-light-driven photocatalytic process for As(III) oxidation. The recycling experiments validated that Ag@AgCl core-shell nanowires were a kind of efficient and stable photocatalyst for As(III) oxidation under visible-light irradiation.

Efficiently Visible-Light Driven Photoelectrocatalytic Oxidation of As(III) at Low Positive Biasing Using Pt/TiO2 Nanotube Electrode.

A constant current deposition method was selected to load highly dispersed Pt nanoparticles on TiO2 nanotubes in this paper, to extend the excited spectrum range of TiO2-based photocatalysts to visible light. The morphology, elemental composition, and light absorption capability of as-obtained Pt/TiO2 nanotubes electrodes were characterized by FE-SEM, energy dispersive spectrometer (EDS), X-ray photoelectron spectrometer (XPS), and UV-vis spectrometer. The photocatalytic and photoelectrocatalytic oxidation of As(III) using a Pt/TiO2 nanotube arrays electrode under visible light (λ > 420 nm) irradiation were investigated in a divided anode/cathode electrolytic tank. Compared with pure TiO2 which had no As(III) oxidation capacity under visible light, Pt/TiO2 nanotubes exhibited excellent visible-light photocatalytic performance toward As(III), even at dark condition. In anodic cell, As(III) could be oxidized with high efficiency by photoelectrochemical process with only 1.2 V positive biasing. Experimental results showed that photoelectrocatalytic oxidation process of As(III) could be well described by pseudo-first-order kinetic model. Rate constants depended on initial concentration of As(III), applied bias potential and solution pH. At the same time, it was interesting to find that in cathode cell, As(III) was also continuously oxidized to As(V). Furthermore, high-arsenic groundwater sample (25 m underground) with 0.32 mg/L As(III) and 0.35 mg/L As(V), which was collected from Daying Village, Datong basin, Northern China, could totally transform to As(V) after 200 min under visible light in this system.

Age at onset of recurrent major depression in Han Chinese women - a replication study.

BACKGROUND: The relationship between age at onset (AAO) and major depression (MD) has been studied in US, European and Chinese populations. However, larger sample studies are needed to replicate and extend earlier findings. METHODS: We re-examined the relationship between AAO and the clinical features of recurrent MD in Han Chinese women by analyzing the phase I (N=1848), phase II (N=4169) and total combined data (N=6017) from the CONVERGE project. Linear, logistic, multiple linear and multinomial logistic regression models were used to determine the association of AAO with continuous, binary and categorical variables. RESULTS: The effect size of the association between AAO and clinical features of MD was quite similar in the phase I and phase II samples. These results confirmed that MD patients with earlier AAO tended to suffer more severe, recurrent and chronic illness and cases of MD with earlier AAO showed increased neuroticism, greater family history and psychiatric comorbidity. In addition, we showed that earlier AAO of MD in Han Chinese women was associated with premenstrual symptoms, postnatal depression, a highly authoritarian or cold childhood parental rearing style and a reduced probability for having melancholia. LIMITATIONS: Data were collected retrospectively through interview and recall bias may have affected the results. CONCLUSIONS: MD with earlier AAO in Han Chinese women shows a distinct set of clinical features which are similar to those reported in Western populations.

The prevalence, clinical correlates and structure of phobic fears in Han Chinese women with recurrent major depression.

BACKGROUND: Phobic fears are common in the general population and among individuals with major depression (MD). We know little about the prevalence, clinical correlates, and structure of phobic fears in Chinese women with MD. METHODS: We assessed 22 phobic fears in 6017 Han Chinese women with MD. We used exploratory factor analysis to examine the structure of these phobic fears. We examined the relationship between individual phobic fears and the severity of MD, neuroticism, comorbid panic disorder, generalized anxiety disorder and dysthymia using logistic regression models. RESULTS: The frequency of phobic fears ranged from 3.0% (eating in public) to 36.0% (snakes). Phobic fears were significantly associated with more severe MD, high neuroticism, and co-morbid panic disorder, generalized anxiety disorder and dysthymia. Our factor analysis suggested four underlying subgroups of phobic fears which differed in their clinical correlates, severity and patterns of comorbidity. LIMITATIONS: Data were collected retrospectively through interview and recall bias may have affected the results. CONCLUSIONS: Phobic fears are correlated with comorbid MD and more severe MD. These phobic fears clearly subdivide into four subgroups that differ meaningfully from each other.

Clinical predictors of familial depression in Han Chinese women.

BACKGROUND: A number of clinical features potentially reflect an individual's familial vulnerability to major depression (MD), including early age at onset, recurrence, impairment, episode duration, and the number and pattern of depressive symptoms. However, these results are drawn from studies that have exclusively examined individuals from a European ethnic background. We investigated which clinical features of depressive illness index familial vulnerability in Han Chinese females with MD. METHODS: We used lifetime MD and associated clinical features assessed at personal interview in 1,970 Han Chinese women with DSM-IV MD between 30-60 years of age. Odds Ratios were calculated by logistic regression. RESULTS: Individuals with a high familial risk for MD are characterized by severe episodes of MD without known precipitants (such as stress life events) and are less likely to feel irritable/angry or anxious/nervous. CONCLUSIONS: The association between family history of MD and the lack of a precipitating stressor, traditionally a characteristic of endogenous or biological depression, may reflect the association seen in other samples between recurrent MD and a positive family history. The symptomatic associations we have seen may reflect a familial predisposition to other dimensions of psychopathology, such as externalizing disorders or anxiety states.

The impact of educational status on the clinical features of major depressive disorder among Chinese women.

BACKGROUND: Years of education are inversely related to the prevalence of major depressive disorder (MDD), but the relationship between the clinical features of MDD and educational status is poorly understood. We investigated this in 1970 Chinese women with recurrent MDD identified in a clinical setting. METHODS: Clinical and demographic features were obtained from 1970 Han Chinese women with DSM-IV major depression between 30 and 60 years of age across China. Analysis of linear, logistic and multiple logistic regression models were used to determine the association between educational level and clinical features of MDD. RESULTS: Subjects with more years of education are more likely to have MDD, with an odds ratio of 1.14 for those with more than ten years. Low educational status is not associated with an increase in the number of episodes, nor with increased rates of co-morbidity with anxiety disorders. Education impacts differentially on the symptoms of depression: lower educational attainment is associated with more biological symptoms and increased suicidal ideation and plans to commit suicide. LIMITATIONS: Findings may not generalize to males or to other patient populations. Since the threshold for treatment seeking differs as a function of education there may an ascertainment bias in the sample. CONCLUSIONS: The relationship between symptoms of MDD and educational status in Chinese women is unexpectedly complex. Our findings are inconsistent with the simple hypothesis from European and US reports that low levels of educational attainment increase the risk and severity of MDD.

Examining the relationship between lifetime stressful life events and the onset of major depression in Chinese women.

BACKGROUND: In European and US studies, patients with major depressive disorder (MDD) report more stressful life events (SLEs) than controls, but this relationship has rarely been studied in Chinese populations. METHODS: Sixteen lifetime SLEs were assessed at interview in two groups of Han Chinese women: 1970 clinically ascertained with recurrent MDD and 2597 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression. RESULTS: 60% of controls and 72% of cases reported at least one lifetime SLE. Fourteen of the sixteen SLEs occurred significantly more frequently in those with MDD (median odds ratio of 1.6). The three SLEs most strongly associated with risk for MDD (OR>3.0) preceded the onset of MDD the majority of the time: rape (82%), physical abuse (100%) and serious neglect (99%). LIMITATIONS: Our results may apply to females only. SLEs were rated retrospectively and are subject to biases in recollection. We did not assess contextual information for each life event. CONCLUSIONS: More severe SLEs are more strongly associated with MDD. These results support the involvement of psychosocial adversity in the etiology of MDD in China.

Electrochemical determination of nitrite using a gold nanoparticles-modified glassy carbon electrode prepared by the seed-mediated growth technique.

Seed-mediated growth of gold nanoparticles on glassy carbon (GC) surfaces was developed. The field emission scanning electron microscopy (FE-SEM) and electrochemical characterization confirmed the effective attachment of gold nanoparticles on GC surface with such a wet-chemical method. The as-prepared gold nanoparticles attached glassy carbon electrode (Au/GCE) presented excellent catalytic ability toward the oxidation of nitrite. Compared with bare GCE and planar gold electrode, the Au/GCE obviously decreased the overpotential of nitrite oxidation and improved the peak current. The catalytic current was found to be linearly proportional to the nitrite concentration in the range of 1 x 10(-5) - 5 x 10(-3) M, with a detection limit of 2.4 x 10(-6) M. The Au/GCE was successfully applied to the electrochemical determination of nitrite in a real wastewater sample, showing excellent stability and anti-interference ability.

Treatment of nitrophenols by cathode reduction and electro-Fenton methods.

This study deals with the degradation of various nitrophenols by cathode reduction and electro-Fenton methods. Phenols (Poh), 2-nitrophenol (2-NP), 3-nitrophenol (3-NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP) are treated and different degradation sequences are obtained. The relationship between the structure and activities of nitrophenols is discussed. Using 4-NP as a model nitrophenol, the electrochemical behaviors on graphite cathode and Pt anode are analyzed by cyclic voltammetry. The contribution of different reactions to the degradation of 4-NP is investigated in divided cells. The degradation of 4-NP is much faster in the cathode cell than in the anodic cell. In the cathode cell, the degradation of 4-NP is significantly enhanced by the introduction of aeration and Fe(2+). Ultraviolet-visible (UV-vis) spectra reveal different reaction pathways for the degradation in the anodic cell and cathode cell. Treatment of high concentration of 4-NP in the undivided cell shows that more than 98% removal of 4-NP and about 13% removal of total organic carbon (TOC) are obtained for both processes, while the subsequent biodegradability test shows that electro-Fenton can eliminate the toxicity and improve the biodegradability of 4-NP. Negligible quantity of nitrate and nitrite ions detected in both processes indicates that there is no direct release of -NO(2) and -NO groups from 4-NP and its degradation intermediates. Intermediates such as hydroquinone and bezoquinone are detected by gas chromatography/mass spectrum (GC/MS). The degradation pathway of 4-NP in electro-Fenton process is proposed as the cathode reduction followed by hydroxyl oxidation.