Electrochemical Biosensor Using DNA Embedded Phosphorothioate Modified RNA for Mercury Ion Determination

Mercury (Hg) and its compounds, originating from a variety of natural and anthropogenic sources, are ubiquitous in the natural environment, and cause severe environmental contamination and pose irreversible harm to human health. A fast and accurate sensing approach is of significant importance for mercury detection. Here, a label-free biosensor using Hg­(II)-induced cleavage of phosphorothioate (PS) modified RNA was exploited. We designed a specific single-stranded DNA embedded with four PS-modified RNA (Hg-DPR) to improve the cleavage reaction yield, and then Hg-DPR was covalently linked with single-walled carbon nanotube field effect transistor (SWNTs/FET) via a peptide bond. The Hg-DPR can be efficiently cleaved after exposure to Hg­(II), which further causes the conductivity of the SWNTs to change. Using the relative resistance change, the Hg-DPR/SWNTs/FET successfully detected Hg­(II) levels as low as 10 pM, and the calibration curves were linear in the range of 50 pM to 100 nM and 100 nM to 10 μM. Additionally, Hg-DPR/SWNTs/FET exhibited excellent sensitivity, portability, and low-cost for Hg­(II) detection

Asymmetric 3d Electronic Structure for Enhanced Oxygen Evolution Catalysis

The oxygen evolution reaction (OER) is an essential process for renewable energy, and designing a bifunctional oxygen electrocatalyst with high catalytic performance plays a significant role. In this work, FeS, Ni₃S₂, Fe₅Ni₄S₈, and N, O, S-doped meshy carbon base were successfully synthesized. The sample containing Fe₅Ni₄S₈ exhibited excellent OER performance. The density functional theory calculations indicate that the partial density of states for 3d electrons (3d-PDOS) of Fe and Ni atoms are changed from monometallic sulfide to bimetallic sulfide at the sulfur vacancy. The asymmetric 3d electronic structure optimizes the 3d-PDOS of Fe and Ni atoms, and leads to an enhanced OER activity. This work provides a new strategy to prepare a low-cost electrocatalyst for oxygen evolution with high-efficiency

Competitive Binding of Ethylene, Water, and Carbon Monoxide in Metal–Organic Framework Materials with Open Cu Sites

Metal–organic frameworks (MOFs) with open metal sites (OMS) are known to have selectivity in olefin/paraffin separations because of π–π interactions between olefin double bonds and OMS. One challenge associated with these separations is that other species that potentially bind to OMS may also be present in feed streams, causing competition for these sites. We used density functional theory (DFT) to assess the binding energy of ethylene, water, and carbon monoxide on a set of more than 60 MOFs with open Cu sites in the form of Cu dimers. One useful observation from our results is that the relative binding energies of pairs of molecules (e.g., ethylene and water) can be calculated accurately from calculations that hold the MOF structure rigid and only relax the positions of the adsorbing molecules. These kinds of calculations are far more numerically efficient than calculations that relax all degrees of freedom in the system, so this observation will be useful in future efforts to screen larger collections of materials. A second observation is that the binding energies of each molecule in the 60 MOFs are quite similar to the binding energies in CuBTC, an exemplar MOF with open Cu sites in the form of Cu dimers. Analysis of the variations that do exist in the binding energies among materials points to possible avenues for controlling either the absolute binding energies or the relative binding energies of species associated with OMS in these materials. The third observation is that two unusual MOFs can bind ethylene more strongly than water because of a dual-site binding mechanism in which an ethylene molecule can interact simultaneously with both dimers while the smaller water molecule interacts primarily with a single OMS. This observation suggests a possible avenue for developing other MOFs in which the binding energy of ethylene is higher than that of water

Additional file 1: of Prognostic value of systemic inflammatory markers in ovarian Cancer: a PRISMA-compliant meta-analysis and systematic review

Table S1. Subgroup analysis results of NLR and PLR for ovarian cancer survival (OS and PFS). (DOCX 19 kb

Seed metabolite profiling of <i>Vicia</i> species from China via GC-MS

<p>In this study, we examined <i>Vicia</i> seeds using gas chromatography-mass spectrometry (GC-MS). The metabolic differences of seeds of twelve <i>Vicia</i> species were assessed. 184 metabolites were identified. <i>Vicia</i> species were classified via multivariate data analyses into four clusters. <i>V. unijuga</i> was most enriched in fatty acids and anthraquinones contents while highest levels of amino acids, alcohols and phenolic were in <i>V. costata.</i> Clustering analysis of biochemical profiles matched with the pervious phenotypic observation with all examined species from section Cracca grouped together under one sub-cluster, except for <i>V. costata.</i></p

Additional file 1: of Morphological plasticity in Myxobolus BĂźtschli, 1882: a taxonomic dilemma case and renaming of a parasite species of the common carp

Figure S1. The intralamellar vascular site preference of M. pseudoacinosus in gills. a The plasmodia of M. pseudoacinosus developed in the lumen of lamellar capillaries. The area highlighted in blue represents the gill lamellae. b The site preference type of M. pseudoacinosus met the definition of intralamellar vascular type 3 (LV3) from the classification system of MolnĂĄr [35]. Abbreviations: P, plasmodia; LV, intralamellar vascular. (TIF 4655 kb

Heteromorphic NiCo₂S₄/Ni₃S₂/Ni Foam as a Self-Standing Electrode for Hydrogen Evolution Reaction in Alkaline Solution

Considerable works have been devoted on developing high-efficiency nonplatinum electrocatalysts for hydrogen evolution reaction (HER). Herein, 3D heteromorphic NiCo₂S₄/Ni₃S₂ nanosheets network has been constructed on Ni foam (denoted as NiCo₂S₄/Ni₃S₂/NF) serving as a self-standing electrocatalyst through directly thermal sulfurization of a single-source NiCo-layered double hydroxide precursor. The resultant NiCo₂S₄/Ni₃S₂/NF electrode exhibits outstanding electrocatalytic HER performance with an extremely low onset overpotential of 15 mV and long-term durability in alkaline solution. Such enhanced HER performance can be credited to (1) the massive exposed active sites provided by mixed transition metal chalcogenides (NiCo₂S₄ and Ni₃S₂), (2) the strong interfacial interaction at NiCo₂S₄/Ni₃S₂ heterojunction interfaces with the strengthened H binding, and (3) the porous highly conductive Ni foam substrate with accelerated electron transfer. This work opens up a new direction to fabricate effective and non-noble-metal electrodes for water splitting and hydrogen generation

Selective Cation Incorporation into Copper Sulfide Based Nanoheterostructures

Heterogeneous copper sulfide based nanostructures have attracted intense attention based on their potential to combine the plasmonic properties of copper-deficient copper sulfides with properties of other semiconductors and metals. In general, copper sulfides are versatile platforms for production of other materials by cation incorporation and exchange processes. However, the outcomes of subsequent cation exchange (CE) or incorporation processes involving nanoheterostructure (NH) templates have not been explored. In this work, we incorporate indium and tin into Cu_1.81S–ZnS NHs. We demonstrate that the outcomes of cation incorporation are strongly influenced by heterocation identity and valence and by the presence of a Cu-extracting agent. The selectivity of cation incorporation depends upon both the cation itself and the heterodomains in which CE reactions take place. The final nanocrystals (NCs) emerge in many forms including homogeneous NCs, heterodimers, core@shell NHs and NHs with three different domains. This selective cation incorporation not only facilitates the preparation of previously unavailable metal sulfide NHs but also provides insight into mechanisms of CE reactions

Field-Free Spin–Orbit Torque Switching from Geometrical Domain-Wall Pinning

Spin–orbit torques, which utilize spin currents arising from the spin–orbit coupling, offer a novel method for the electrical switching of the magnetization with perpendicular anisotropy. However, the necessity of an external magnetic field to achieve deterministic switching is an obstacle for realizing practical spin–orbit torque devices with all-electric operation. Here, we report field-free spin–orbit torque switching by exploiting the domain-wall motion in an anti-notched microwire with perpendicular anisotropy, which exhibits multidomain states stabilized by the domain-wall surface tension. The combination of spin–orbit torque, Dzyaloshinskii–Moriya interactions, and domain-wall surface-tension-induced geometrical pinning allows the deterministic control of the domain wall and offers a novel method to achieve a field-free spin–orbit torque switching. Our work demonstrates the proof of concept of a perpendicular memory cell that can be readily adopted in three-terminal magnetic memory

Table_1_Large-Scale Comparative Analysis of Eugenol-Induced/Repressed Genes Expression in Aspergillus flavus Using RNA-seq.DOCX

<p>Aflatoxin B₁ (AFB₁), which is mainly produced by Aspergillus flavus and Aspergillus parasiticus, is the most toxic and hepatocarcinogenic polyketide known. Chemical fungicides are currently utilized to reduce this fungal contaminant, but they are potentially harmful to human health and the environment. Therefore, natural anti-aflatoxigenic products are used as sustainable alternatives to control food and feed contamination. For example, eugenol, presents in many essential oils, has been identified as an aflatoxin inhibitor. However, its exact mechanism of inhibition is yet to be clarified. In this study, the anti-aflatoxigenic mechanism of eugenol in A. flavus was determined using a comparative transcriptomic approach. Twenty of twenty-nine genes in the aflatoxin biosynthetic pathway were down-regulated by eugenol. The most strongly down-regulated gene was aflMa, followed by aflI, aflJ, aflCa, aflH, aflNa, aflE, aflG, aflM, aflD, and aflP. However, the expression of the regulator gene aflR did not change significantly and the expression of aflS was slightly up-regulated. The down-regulation of the global regulator gene veA resulted in the up-regulation of srrA, and the down-regulation of ap-1 and mtfA. The early developmental regulator brlA was profoundly up-regulated in A. flavus after eugenol treatment. These results suggested a model in which eugenol improves fungal development by up-regulating the expression of brlA by the suppression of veA expression and inhibits aflatoxin production through the suppression of veA expression. Exposure to eugenol also caused dysregulated transcript levels of the G protein-coupled receptors (GPCRs) and oxylipins genes. A Gene Ontology analysis indicated that the genes that were highly responsive to eugenol were mainly enriched in RNA-binding functions, suggesting that post-transcriptional modification plays a pivotal role in aflatoxin biosynthesis. KEGG analysis showed that ribosome biogenesis was the most dysregulated pathway, suggesting that eugenol dysregulates ribosome biogenesis, which then interrupts the biosynthesis of Nor-1, Ver-1, and OmtA, and prevents aflatoxisomes performing their normal function in aflatoxin production. In conclusion, our results indicated that eugenol inhibited AFB₁ production by modulating the expression of structural genes in aflatoxin pathway, fungal antioxidant status, post-transcriptional modifications and biosynthesis of backbone enzymes in A. flavus.</p