Publication date: 15 May 2018
Source:Biosensors and Bioelectronics, Volume 105
Author(s): Wei Zhang, Zhichao Dai, Xue Liu, Jimin Yang
A high-performance sensing platform based on poly-xanthurenic acid (PXA) film functionalized MoS2 nanosheets was developed for electrochemical detection of circulating tumor DNA in peripheral blood. The MoS2 nanosheets were obtained using a simple ultrasonic method from bulk MoS2. The physical adsorption between MoS2 and aromatic XA monomers effectively improved the electropolymerization efficiency, accompanied with an increased electrochemical response of PXA. The obtained PXA/MoS2 nanocomposite not only served as a substrate for DNA immobilization but also reflected the electrochemical transduction originating from DNA immobilization and hybridization without any complex labelling processes or outer indicators. The immobilization of the probe ssDNA was achieved via noncovalent assembly due to the π–π interaction between PXA and DNA bases. After the hybridization of the probe ssDNA with the target DNA, the formation of helix structure induced the resulted dsDNA to be released from the surface of the PXA/MoS2 nanocomposite. The detection limit of this constructed DNA biosensor was calculated in the linear target DNA concentrations range from 1.0 × 10–16 mol/L to 1.0 × 10-10 mol/L and it was found to be 1.8 × 10–17 mol/L.
http://ift.tt/2G2ePMT
Σάββατο 20 Ιανουαρίου 2018
High-performance electrochemical sensing of circulating tumor DNA in peripheral blood based on poly-xanthurenic acid functionalized MoS2 nanosheets
Analytical characterization of products obtained from slow pyrolysis of Calophyllum inophyllum seed cake: study on performance and emission characteristics of direct injection diesel engine fuelled with bio-oil blends
Abstract
This paper aims to analyse the characteristics and properties of the fractions obtained from slow pyrolysis of non-edible seed cake of Calophyllum inophyllum (CI). The gas, bio-oil and biochar obtained from the pyrolysis carried out at 500 °C in a fixed bed batch type reactor at a heating rate of 30 °C/min were characterized by various analytical techniques. Owing to the high volatile content of CI biomass (72.61%), it was selected as the raw material in this present investigation. GC-MS and FT-IR analysis of bio-oil showed the presence of higher amount of oxygenated compounds, phenol derivatives, esters, acid and furans. The physicochemical properties of the bio-oil were tested as per ASTM norms which imply that bio-oil is a highly viscous liquid with lower heating value as compared to that of diesel fuel. The chemical composition of evolved gas was analysed by using GC testing which revealed the presence of combustible components. The FT-IR characterization of biochar showed the presence of aliphatic and aromatic hydrocarbons whereas the elevated amount of carbon in biochar indicates its potential to be used as solid fuel. The performance and emission characteristics of CI engine were assessed with different CI bio-oil blends and compared with baseline diesel fuel. The results showed that addition of bio-oil leads to decreased brake thermal efficiency and increased brake specific energy consumption. Meanwhile, increase in blend ratio reduces harmful pollutants such as oxides of nitrogen and smoke in the exhaust. From the engine testing, it is suggested to employ 20% of CI bio-oil blends in CI engine to obtain better operation.
http://ift.tt/2G1PLVZ
Prevalence of technical errors and periapical lesions in a sample of endodontically treated teeth: a CBCT analysis
Abstract
Objectives
The aims of this study are to identify the most frequent technical errors in endodontically treated teeth and to determine which root canals were most often associated with those errors, as well as to relate endodontic technical errors and the presence of coronal restorations with periapical status by means of cone-beam computed tomography images.
Methods
Six hundred eighteen endodontically treated teeth (1146 root canals) were evaluated for the quality of their endodontic treatment and for the presence of coronal restorations and periapical lesions. Each root canal was classified according to dental groups, and the endodontic technical errors were recorded. Chi-square's test and descriptive analyses were performed.
Results
Six hundred eighty root canals (59.3%) had periapical lesions. Maxillary molars and anterior teeth showed higher prevalence of periapical lesions (p < 0.05). Endodontic treatment quality and coronal restoration were associated with periapical status (p < 0.05). Underfilling was the most frequent technical error in all root canals, except for the second mesiobuccal root canal of maxillary molars and the distobuccal root canal of mandibular molars, which were non-filled in 78.4 and 30% of the cases, respectively.
Conclusions
There is a high prevalence of apical radiolucencies, which increased in the presence of poor coronal restorations, endodontic technical errors, and when both conditions were concomitant. Underfilling was the most frequent technical error, followed by non-homogeneous and non-filled canals.
Clinical relevance
Evaluation of endodontic treatment quality that considers every single root canal aims on warning dental practitioners of the prevalence of technical errors that could be avoided with careful treatment planning and execution.
http://ift.tt/2Bi5ooI
Combined treatment of contaminated soil with a bacterial Stenotrophomonas strain DXZ9 and ryegrass ( Lolium perenne ) enhances DDT and DDE remediation
Abstract
Bioremediation of contaminated soils by a combinational approach using specific bacterial species together with ryegrass is a promising strategy, resulting in potentially highly efficient degradation of organic contaminants. The present study tested the combination of strain DXZ9 of Stenotrophomonas sp. with ryegrass to remove DDT and DDE contaminants from soil under natural conditions in a pot experiment. The strain DXZ9 was successfully colonized in the natural soil, resulting in removal rates of approximately 77% for DDT, 52% for DDE, and 65% for the two pollutants combined after 210 days. Treatment with ryegrass alone resulted in slightly lower removal rates (72 and 48%, respectively, 61% for both combined), while the combination of strain DXZ9 and ryegrass significantly (p < 0.05) improved the removal rates to 81% for DDT and 55% for DDE (69% for both). The half-life of the contaminants was significantly shorter in combined treatment with DXZ9 and ryegrass compared to the control. The remediation was mostly due to degradation of the contaminants, as the net uptake of DDT and DDE by the ryegrass accounted for less than 3% of the total amount in the soil. DDT is reductively dechlorinated to DDD and dehydrochlorinated to DDE in the soil; the metabolites of DDE and DDD were multiple undefined substances. The toxicity of the soil was significantly reduced as a result of the treatment. The present study demonstrates that the bioremediation of soil contaminated with DDT and DDE by means of specific bacteria combined with ryegrass is feasible.
http://ift.tt/2Bi5s87
Is trade openness good for environment in South Korea? The role of non-fossil electricity consumption
Abstract
The paper investigates the linkage of carbon dioxide (CO2) emissions, per capita real output, share of non-fossil electricity consumption, and trade openness in South Korea from 1971 to 2013. The empirical results indicate that the environmental Kuznets curve (EKC) is supported by autoregressive distributed lag (ARDL) test. Both short- and long-run estimates indicate that increasing non-fossil electricity consumption can mitigate environmental degradation, and increasing trade aggravates carbon dioxide emissions. By Granger causality, long-run causalities are found in both equations of CO2 emissions and trade openness, as well as exports and imports. In the short-run, evidence indicates feedback linkage between output and trade, unidirectional linkages from trade to emissions, from emissions to output, and from output to non-fossil electricity use. Therefore, South Korea should strengthen the sustainable economy, consume clean energy, and develop green trade.
http://ift.tt/2mV5Hld
Scholar : Chinese Journal of Stomatological Research(Electronic Version), Year 2017, Issue 06 -New Issue Alert.
Scholar : Chinese Journal of Stomatology, Year 2017, Issue 12 -New Issue Alert.
|
Effect of the carbon dioxide 10,600-nm laser and topical fluoride gel application on enamel microstructure and microhardness after acid challenge: an in vitro study
Abstract
The aim of this in-vitro study was to evaluate positive effects of the carbon dioxide laser (CO2, 10,600 nm) with acidulated phosphate fluoride (APF) gel on enamel acid resistance. Twenty extracted human third molars (40 surfaces) were randomly assigned into four groups: group C, untreated control; group L, CO2 laser alone group; group F, APF 1.23% fluoride gel; and group FL, APF 1.23% gel and laser. Samples from group L were irradiated with a CO2 laser for 30s. The parameter settings used were average power, 0.73 W; time on, 100 μs; time off, 40 ms; tip-to-tissue distance, 20 mm; tip diameter 700 μm; and energy density with movements, 5 J/cm2. Samples from group F were treated with the APF gel for 4 min, and the gel was washed off with distilled water. The enamel samples from group FL were treated with APF gel for 4 min and then irradiated with the CO2 laser for 30s without removing the gel. Each enamel sample was placed in 50 ml soft drink (pH = 2.75) for 10 min then rinsed with deionized water and stored in artificial saliva at 37 °C for 1 h. Samples were assessed for Vickers hardness number (VHN) before and after treatments and subjected to SEM analysis. Data were analyzed using a one-way analysis of variance (ANOVA) and Tukey's test (α < 0.05). After the acid challenge, the untreated C group was demineralized to a great extent and the enamel surface was with the lowest mean score of microhardness. The observed VHN in the control (C group) had a mean value of 176.13, the scores in the CO2 laser group (L group) were with mean value of 238.40, the F group with a mean value of 218.45, and the fluoride-treated and laser-irradiated FL group—with a mean of 268.28 VHN. Paired t test performed to compare groups C, L, F, and FL has shown that group FL has greater resistance to decrease in microhardness of dental enamel (P ≤ 0.05) on exposure to acidic protocol. After the acid challenge, the fluoride-treated and laser-irradiated samples (group FL) showed the least diminution in enamel surface microhardness. The sub-ablative carbon dioxide laser irradiation in combination with fluoride treatment is more effective in protecting enamel surface and resisting demineralization than CO2 laser irradiation or fluoride alone.
http://ift.tt/2DThFmr
Scholar : Chinese Journal of Otorhinolaryngology Head and Neck Surgery, Year 2017, Issue 12 -New Issue Alert.
|
Scholar : chinese Journal of Practical Stomatology, Year 2017, Issue 11 -New Issue Alert.
|
Scholar : China Journal of Oral and Maxillofacial Surgery, Year 2017, Issue 06 -New Issue Alert.
|
Scholar : Stomatology, Year 2017, Issue 12 -New Issue Alert.
|
Scholar : Chinese Journal of Otorhinolaryngology, Year 2017, Issue 12 -New Issue Alert.
|
-
Summary Insulinomas are rare neuroendocrine tumours that classically present with fasting hypoglycaemia. This case report discusses an un...
-
The online platform for Taylor & Francis Online content New for Canadian Journal of Remote Sen...
