Target-induced differences in the electrostatic interactions between methylene blue (MB) and indium tin oxide (ITO) electrode surface was firstly employed to develop a homogeneous electrochemical ...biosensor for flap endonuclease 1 (FEN1) detection. In the absence of FEN1, the positively charged methylene blue (MB) is free in the solution and can diffuse onto the negatively charged ITO electrode surface easily, resulting in an obvious electrochemical signal. Conversely, with the presence of FEN1, a 5′-flap is cleaved from the well-designed flapped dumbbell DNA probe (FDP). The remained DNA fragment forms a closed dumbbell DNA probe to trigger hyperbranched rolling circle amplification (HRCA) reaction, generating plentiful dsDNA sequences. A large amount of MB could be inserted into the produced dsDNA sequences to form MB-dsDNA complexes, which contain a large number of negative charges. Due to the strong electrostatic repulsion between MB-dsDNA complexes and the ITO electrode surface, a significant signal drop occurs. The signal change (ΔCurrent) shows a linear relationship with the logarithm of FEN1 concentration from 0.04 to 80.0 U/L with a low detection limit of 0.003 U/L (S/N = 3). This study provides a label-free and homogeneous electrochemical platform for evaluating FEN1 activity.
Two new metal–organic frameworks (MOFs) based on TMBDI linker (TMBDI = 2,3,5,6-tetramethyl-1,4-diisophthalate) and M2(COO)4 paddlewheel, {Zn2(TMBDI)(H2O)2•2.5DMF•2(1,4-dioxane)•6H2O} n (UPC-6) and ...{Co2(TMBDI) (DMA)2•2DMA•5EtOH} n (UPC-8), have been obtained under solvothermal conditions. Due to the low stability of Zn/Co paddlewheels upon the removal of axial solvates, UPC-6 and UPC-8 possesses a very low surface area and adsorption capacity. Through metal-ion metathesis in a single-crystal-to-single-crystal fashion, two new Cu(II) MOFs (termed Cu-UPC-6 and Cu-UPC-8) with identical robust frameworks were produced, which could not be prepared by routine solvothermal methods. Meanwhile, the influence of the reaction solvents on the metathesis process were also investigated, and the results show that the form of solvented ions can induce obviously kinetic issues. Through gas adsorption measurements, the stability and porosity of frameworks have been shown improved significantly.
Glass metal–organic framework (MOF) films can be fabricated from their crystalline counterparts through a melt‐quenching process and are prospective candidates for gas separation because of the ...elimination of the grain boundaries in crystalline MOF films. However, current techniques are limited to producing glass MOF films with a thickness of tens of micrometers, which leads to ultralow gas permeances. Here, we report a novel cathodic deposition‐assisted synthesis of glass ZIF‐62 films with a thickness as low as ~1 μm. Electrochemical analyses and deposition experiments suggest that the cathodic deposition can lead to pure crystalline ZIF‐62 films with a controllable thickness of ~2 μm to ~15 μm. Accordingly, glass ZIF‐62 films with a thickness of ~1 μm to ~10 μm can be obtained after a thermal treatment. The fabricated defect‐free glass ZIF‐62 film measuring 2 μm in thickness shows a remarkable CO2/N2 and CO2/CH4 selectivity of 31.4 and 33.4, respectively, with a CO2 permeance which is over 30 times higher than the best‐performing glass ZIF‐62 films in literature.
Unlike traditional methods that lead to glass MOF films with a thickness of tens of micrometers, the proposed cathodic deposition‐assisted approach can produce glass MOF films with a thickness of 2 μm. The fabricated thin glass ZIF‐62 film shows a record‐high CO2 permeance without compromising the selectivity in CO2/N2 and CO2/CH4 separations.
Stature and weight are important growth and development traits for animals, which also significantly affect the productivity of livestock. Polymorphic adenoma gene 1 (PLAG1) is located in the ...growth-related quantitative trait nucleotides (QTN), and its variation has been determined to significantly affect the body stature of bovines. This study found that novel 15-bp InDel could significantly influence important growth traits in goats. The frequencies of genotypes of the 15-bp mutation and relationship with core growth traits such as body weight, body height, height at hip cross, chest circumference, hip width and body index were explored in 1581 individuals among 4 Chinese native goat breeds. The most frequent genotypes of Shaanbei white Cashmere goat (SWCG), Inner Mongolia White Cashmere goat (IMCG) and Guanzhong Dairy goat (GZDG) were II genotypes (insertion/insertion), and the frequency of ID genotype (insertion/deletion) was found to be slightly higher than that of II genotype in Hainan Black goat (HNBG), showing that the frequency of the I allele was higher than that of the D allele. In adult goats, there were significant differences between 15-bp variation and body weight, chest circumference and body height traits in SWCG (p < 0.05). Furthermore, the locus was also found to be significantly correlated with the body index of HNBG (p = 0.044) and hip width in GZDG (p = 0.002). In regard to lambs, there were significant differences in height at the hip cross of SWCG (p = 0.036) and hip width in IMWC (p = 0.005). The corresponding results suggest that the 15-bp InDel mutation of PLAG1 is associated with the regulation of important growth characteristics of both adult and lamb of goats, which may serve as efficient molecular markers for goat breeding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Liquid–Liquid Triboelectric Nanogenerator
In article number 2208393, Ho Cheung Shum and co‐workers investigate mechanisms of contact electrification in various liquid‐liquid systems and thus ...demonstrate a liquid‐liquid triboelectric nanogenerator to harvest energy from rainwater. It can generate a high charge density (3.63 μC/L) with high output stability (crest factor ≈1.1), highlighting the promise of all‐liquid systems in distributed green energy and passive sensors.
Owing to the inertness of CO2 molecules, the development of highly active photocatalysts for CO2 reduction reactions (CO2RR) remains a formidable challenge. Here, we designed an MXene-based ...single-atom Fe co-catalyst (Fe1/Ti3−xC2Ty) featuring fast Ti–Fe electron channels to achieve enhanced CO2RR performance. The synthesized Fe1/Ti3−xC2Ty exhibited a CO yield of 259.0 μmol g−1 h−1 without the addition of any organic sacrificial agents. The experimental and computational results reveal that, electrons transfer from Ti to Fe and then accumulate at the active sites, which facilitates the transfer of charges and enhances the activation of CO2 molecules. This work provides a new direction of MXene-based non-noble-metal monoatomic catalysts for efficient photoreduction of CO2 under gas–solid photocatalytic conditions with pure water.
A Mn/Co dual nanoparticle-decorated hierarchical carbon structure was derived from a Zn/Mn/Co/chitosan composite hydrogel. This strategy critically relied on the formation of a supramolecularly ...crosslinked hydrogel that allowed the efficient and homogeneous incorporation of highly active Mn/Co species onto the surface of hierarchical carbon structures. The resultant electrocatalyst outperformed Pt/C toward the oxygen reduction reaction in 0.1 M KOH electrolytes.
A Mn/Co dual nanoparticle-decorated hierarchical carbon structure was derived from a Zn/Mn/Co/chitosan composite hydrogel as a highly efficient electro-catalyst for the oxygen reduction reaction.
This study presented a comprehensive investigation into the microstructures, strengthening mechanisms and deformation behaviours of a novel N-doped Co-28Cr-6Mo (CCMN) alloy fabricated by laser powder ...bed fusion (LPBF). In addition to the well-known cellular structures, lattice defects including dislocations and stacking faults (SFs), the near-spherical shaped Cr
2
N precipitates with two typical size distributions were detected. Tensile test results revealed that the LPBF fabricated CCMN alloy demonstrated superior yield strength of 845 ± 49 MPa and elongation to fracture of 12.7 ± 1.9%. The grain boundaries (∼277 MPa), high density of dislocations (∼176-193 MPa), Cr
2
N precipitates (∼243 MPa) and SFs (∼131 MPa) are regarded as the dominate strengthening contributors. On the other hand, HCP phase triggered by strain induced martensite transformation (SIMT) and the Lomer-Cottrell locks (L-C locks) associated with the numerous SFs significantly enhanced the alloy strain hardening rate. More importantly, the formed Cr
2
N nanoprecipitates effectively suppressed the strain localisation and the premature failure along the HCP/FCC interfaces by deflecting the continuous growth of SFs, further contributing to the high ductility of the LPBF processed CCMN alloy. The present study is expected to shed light on the future development of N-doped high-performance cobalt-based alloy for the LPBF process.
Urea concentration and pH are two crucial parameters in food and clinical analysis. Traditional analytical methods of urea and pH determination are unsuitable for field and involve complex ...instrumentation or and enzyme-based assays. In this study, we used screen printing technology to prepare an electrochemical sensor with a carbon electrode modified by a multiwalled carbon nanotube/polyaniline (MWCNT/PANi) composite for the simultaneous detection of urea and pH. Urea was detected by a simple current–potential (
I
–
V
) experiment and its concentration level on the MWCNT/PANi-modified screen-printed carbon electrode (SPCE) surface was determined by cyclic voltammetry. The MWCNT/PANi-modified SPCE had a linear response (
R
2
= 0.99902), lower detection limit, higher selectivity, and higher sensitivity than reported biosensors. Specifically, the detection limit was 10 µM and the sensitivity was 0.38 mA mM
−1
cm
−2
in the urea concentration range of 10–50 µM. Chronoamperometry was applied to investigate the changes in voltage on the MWCNT/PANi-modified SPCE with varying solution pH. The sensor exhibited excellent linearity (
R
2
= 0.99089) and an average sensitivity of 20.63 mV/pH over a wide pH range of 2–11. Thus, the MWCNT/PANi-modified SPCE has a promising field application as a simple, bifunctional non-enzymatic sensor.
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