Researchers identified anti–BNLF2b total antibody as a novel serologic biomarker for nasopharyngeal carcinoma. This antibody, when combined with the standard screening method, improved the positive ...predictive value to 44.6%.
This Letter reports the first example of the functionalization of single wall carbon nanotubes (SWNTs) with an enzyme via the formation of a covalent bond as shown particularly by Fourier transform ...infrared spectroscopy. Functionalization with enzymes was achieved first by acylation of the nanotubes, and was then followed by amidation. Various primary and secondary achiral and chiral amines were also tethered to the SWNTs by this method. Covalent functionalization of carbon nanotubes offers the architecture for a three-dimensional enzyme array for potential application in biosensor devices.
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•Electrospinning is a simple and valid technique to modify the electrode surface.•The electrospun core-shell MWCNTs/gelatin-Hb nanobelts was constructed on electrode.•Direct electron ...transfer between the Hb and electrode can be still achieved after the nanobelts adsorbed protein.•Catalysis of H2O2 can be still achieved after the nanobelts adsorbed protein.•The construct biosensor displayed high reproducibility, stability and selectivity after protein adsorption.
Implantable electrochemical biosensor is one powerful tool for the accurate and reliable measurements of small molecules in vivo. However, the electrode is inevitably subjected to the protein adsorption when implanted into the living animals, affecting the sensitivity and stability of biosensor. Herein, we designed the multi-walled carbon nanotubes/gelatin-hemoglobin (MWCNTs/gelatin-Hb) core-shell nanobelts constructed on glassy carbon electrode (GC) using the one-step electrospinning technique for studying the effect of protein adsorption on the electrode surface properties. The results of the water contact angle and the scanning electron microscopy (SEM) showed that the electrospun core-shell MWCNTs/gelatin-Hb nanobelts present hydrophilic and certain anti-protein adsorption properties. Direct electron transfer between the Hb molecules in the electrospun core-shell nanobelts and electrode and catalysis of hydrogen peroxide (H2O2) can be still achieved after the electrospun core-shell MWCNTs/gelatin-Hb nanobelts adsorbed protein. Moreover, compared with before protein adsorption (Kmapp =0.0155 mmol/L), the electrospun core-shell MWCNTs/gelatin-Hb nanobelts after protein adsorption still displayed high biological affinity to H2O2 (Kmapp =0.0382 mmol/L). The constructed H2O2 biosensor by using the electrospun core-shell MWCNTs/gelatin-Hb nanobelts showed high sensitivity, great reproducibility and stability after protein adsorption. This study provides a novel design and an effective platform for the development of implantable electrochemical biosensors.
•Pure Al particle layer reinforced 7075 Al composite fabricated by hot rolling.•Alp/7075Al lamellar composite shows well mechanical and damping properties.•Comprehensive damping index of the ...composite is 2.9-fold of that of the 7075 Al matrix.•Effect of Al particle layer on damping mechanism of the composite was analyzed.
The Al particle reinforced 7075 Al matrix composites with the layered structure are prepared by hot rolling to improve the damping property of the alloy. Numerous interparticle interfaces are observed in the Al particle layer (reinforcement), and the traces of no interfacial reaction or elemental diffusion are found between the matrix and reinforcement layer. The tensile strength of the composite is 29% higher than that of the matrix. The internal friction values of the Alp/7075Al lamellar composite and the 7075 Al matrix are found to increase with the increase in temperature and strain, respectively. At 570 K, the internal friction values of the composites are found to be as high as 0.105, which is 337% higher than that of the matrix, and an internal friction peak (P2) appears in the composites due to the recrystallization of Al particles at high temperature. The comprehensive damping index of the composite is found to be about 2.9-fold of the 7075 Al matrix. The damping mechanism of the composite is mainly attributed to dislocation damping, grain boundary damping, and interface damping.
Sustained cardiac pressure overload induces hypertrophy and pathological remodeling, frequently leading to heart failure. Genetically engineered hyperstimulation of guanosine 3',5'-cyclic ...monophosphate (cGMP) synthesis counters this response. Here, we show that blocking the intrinsic catabolism of cGMP with an oral phosphodiesterase-5A (PDE5A) inhibitor (sildenafil) suppresses chamber and myocyte hypertrophy, and improves in vivo heart function in mice exposed to chronic pressure overload induced by transverse aortic constriction. Sildenafil also reverses pre-established hypertrophy induced by pressure load while restoring chamber function to normal. cGMP catabolism by PDE5A increases in pressure-loaded hearts, leading to activation of cGMP-dependent protein kinase with inhibition of PDE5A. PDE5A inhibition deactivates multiple hypertrophy signaling pathways triggered by pressure load (the calcineurin/NFAT, phosphoinositide-3 kinase (PI3K)/Akt, and ERK1/2 signaling pathways). But it does not suppress hypertrophy induced by overexpression of calcineurin in vitro or Akt in vivo, suggesting upstream targeting of these pathways. PDE5A inhibition may provide a new treatment strategy for cardiac hypertrophy and remodeling.
The mechanism of graphene growth on tantalum has been studied. It has been demonstrated that graphene growth occurs through the formation of tantalum carbide, which exhibits catalytic properties ...towards cracking of hydrocarbons. We found that excessive carbon, not involved in carbide formation, forms self-limiting layer of graphene on the surface. The layer of tantalum carbide and graphene provides an efficient protective layer against chemical corrosion and high temperature oxidation.
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Macrophage death in advanced atherosclerosis promotes necrosis and plaque destabilization. A likely cause of macrophage death is accumulation of free cholesterol (FC) in the ER, leading to activation ...of the unfolded protein response (UPR) and C/EBP homologous protein (CHOP)-induced apoptosis. Here we show that p38 MAPK signaling is necessary for CHOP induction and apoptosis. Additionally, two other signaling pathways must cooperate with p38-CHOP to effect apoptosis. One involves the type A scavenger receptor (SRA). As evidence, FC loading by non-SRA mechanisms activates p38 and CHOP, but not apoptosis unless the SRA is engaged. The other pathway involves c-Jun NH₂-terminal kinase (JNK)2, which is activated by cholesterol trafficking to the ER, but is independent of CHOP. Thus, FC-induced apoptosis requires cholesterol trafficking to the ER, which triggers p38-CHOP and JNK2, and engagement of the SRA. These findings have important implications for understanding how the UPR, MAPKs, and the SRA might conspire to cause macrophage death, lesional necrosis, and plaque destabilization in advanced atherosclerotic lesions.
The microwave-induced chemical functionalization of single-walled carbon nanotubes (SWNTs) is reported. The major advantage of this high-energy procedure is that it reduced the reaction time to the ...order of minutes and the number of steps in the reaction procedure compared to that of conventional functionalization processes. Two successful model reactions, namely amidation and 1,3-dipolar cycloaddition of SWNTs were carried out. The amidation was completed in two steps as compared to three in the conventional approach. The step involving acid chloride formation was eliminated here, and the yield remained the same. The 1,3-dipolar cycloaddition of SWNTs was carried out in 15
min under microwave conditions, and the results were similar to what was achieved in 5
days using conventional methods. This finding opens the door to fast and inexpensive processing to produce functional SWNTs, which is extremely important for their use in real-world applications.
Chronological, geochemical and Sr-Nd-Pb isotopic analyses have been carried out on the Mesozoic plutons in western Shandong with the aim of characterizing crustal-mantle evolution during the ...tectono-thermal reactivation of the craton. Detailed SHRIMP zircon U-Pb dating reveals two main periods of Mesozoic activity with contrasting compositions. The older magmatic pulse is manifested by monzonites and monzodiorites from Tongshi for which zircon rims yield a concordant age of 177+/-4 Ma and the cores have a discordant age of ca. 2.5 Ga. Low MgO and Cr, high Na2O contents and especially their isotopic compositions (87Sr/86Sr < 0.7042, 206Pb/204Pb < 16.8 and Nd ~ -12) are consistent with derivation from late Archean-Paleoproterozoic lower crust. Relatively high HREE contents in these Jurassic plutons indicate a garnet-free source (<32 km), in contrast to the garnet-bearing source (>40 km) of the late Mesozoic high Sr and low Y granitoids from the same region. Distinctively different depths of crustal melting suggest dynamic thickening of the crust by magmatic underplating during the Jurassic and Cretaceous. The younger dioritic plutons from Laiwu and Yinan were emplaced at 132-126 Ma and show relatively high MgO and Cr contents and large isotopic variability. They were likely derived from enriched lithospheric mantle source and were subjected to crustal contamination during magma evolution. Early Cretaceous mantle melting is coeval with the widespread late Yanshanian granitic magmatism in North China. Early Cretaceous time may correspond to a critical period when a temperature increase due to lithospheric thinning allowed the intersection of the local geotherm and the wet peridotite solidus. While some mantle-derived magmas were erupted, most were trapped at variable crustal depths, triggering large-scale concomitant melting of the crust. Lithospheric thinning must have continued until the late Cretaceous because of the change in the source of mafic magmas from lithospheric to asthenospheric at that time. It is proposed that removal of the lithospheric keel beneath the North China craton may have been initiated as early as the Jurassic, but with the most intense period in the Cretaceous between 130-75 Ma. Such a relatively long timescale (~100 Ma) emphasizes the role of thermomechanical erosion by convective mantle in lithospheric thinning beneath this region. PUBLICATION ABSTRACT
Abstract
Lin28a is a pluripotent factor that promotes somatic cell reprogramming. Unlike other pluripotent factors, Lin28a expression is transient and accumulated in primed embryonic stem (ES) cells, ...but its exact function and mechanism in the conversion of ES cells from naïve to primed state remain unclear. Here, we present evidence for Dppa3, a protein originally known for its role in germ cell development, as a downstream target of Lin28a in naïve–primed conversion. Using rescue experiment, we demonstrate that Dppa3 functions predominantly downstream of Lin28a during naïve–primed state conversion. Higher level of Lin28a prevents let-7 maturation and results in Dnmt3a/b (target of let-7) upregulation, which in turn induces hypermethylation of the Dppa3 promoter. Dppa3 demarcates naïve versus primed pluripotency states. These results emphasize that Lin28a plays an important role during the naïve–primed state conversion of ES cells, which is partially mediated by a Lin28a–let-7–Dnmt3a/b–Dppa3 axis.
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