Search

Retention of guidewire during a neurointervention procedure is extremely rare and potentially lethal. We report a successful operation on an aortic rupture caused by a retained guidewire from a neurointervention procedure 2 years ago. During the operation, we took out the guidewire from both the aortic arch and femoral artery. Postoperative treatment was uneventful. At the 10-month follow-up, the patient remained asymptomatic and computed tomography showed no abnormality. [ABSTRACT FROM AUTHOR]

Five new phenolic polyketides, namely 3- O -methylwailupemycin G ( 1 ), wailupemycin J ( 2 ), R - and S -wailupemycin K ( 3 and 4 ) and wailupemycin L ( 5 ), as well as the known enterocin ( 6 ) and 5-deoxyenterocin ( 7 ) were isolated and identified from the fermentation broth of Streptomyces sp. OUCMDZ-3434 associated with the marine green algae, Enteromorpha prolifera . Their structures including absolute configurations were elucidated according to the spectroscopic analysis, X-ray single crystal diffraction and the Mosher's experiments. Compound 1 showed comparable α -glucosidase inhibition with an IC 50 value of 0.86 mM to acarbose (IC 50 1.12 mM), and compound 4 was cytotoxic on the HeLa cell with an IC 50 value of 8.2 μM. Compounds 2 , 3 and 7 showed anti-H1N1 virus activity with 47.8%, 42.5% and 60.6% inhibitions, respectively at 50 μg/mL (ribavirin, 45.3% inhibition). [ABSTRACT FROM AUTHOR]

In this work, we report a simple, ultrasensitive, and feasible colorimetric assay for metal ion (K + , used as a model) via inherent peroxidase-like enzymatic amplification strategy of gold nanoparticles (AuNPs). It is shown that peroxidase-like activity of AuNPs can be improved dramatically by its surface activation with target-specific aptamer molecules. Whereas when the target exists, the aptamers leave the surface of AuNPs in a target concentration-dependent manner, resulting in a decrease of the nanoenzymatic catalytic ability of AuNPs. Thus, K + can be quantified in the presence of AuNPs by using a colorimetric sensing probe (3,3′,5,5′-tetramethylbenzidine). The color change of the solution is relevant to the dose of the target, and this can be achieved with the naked eyes and monitored by UV–vis spectrometry. A linear dependence between the absorbance and target K + concentration is obtained under optimal conditions in the range from 0. 1 nM to 1 μM with a detection limit (LOD) of 0.06 nM estimated at the 3S blank level . The sensitivity displays to be 2–9 orders of magnitude better than those of other K + detection methods. This sensing strategy may in principle be universally applicable for the detection of a range of environmental or biomedical molecules of interest. [ABSTRACT FROM AUTHOR]

In this contribution, we have developed a rapid method for the highly selective detection of mercury ions (Hg 2+ ) using citrate-stabilized triangular silver nanoplates (AgNPs). The colorimetric sensor strategy is based on the aggregation of Hg 2+ -coated AgNPs with the assistance of two amino groups of lysine, resulting in a color change of AgNP solution from blue to mauve or gray. The sensor enables the analysis of Hg 2+ with a minimum detectable concentration that corresponds to 50 nM. Meanwhile, the strategy offers excellent selectivity toward Hg 2+ against other cations. The validation of this method is carried out by analysis of Hg 2+ in tap water with satisfying recoveries over 91.35–106%. [ABSTRACT FROM AUTHOR]

In this study, a simple and highly sensitive colorimetric assay of H 2 O 2 using triangular Ag nanoplates has been carried out. In the presence of H 2 O 2 , the Ag nanoplates are etched from triangle to round, which leads to the vanishment of the surface plasmon resonance (SPR) absorption at 400 nm and significant decrease the absorbance of the band at 670 nm. The color change of the reaction system from the initial blue to mauve can be observed. This proposed method can determine H 2 O 2 with a dynamic range of 50 nM to 1 μM and a low detection limit of 1.36 nM. The high sensitivity of the triangular nanoplates can be ascribed to highly reactive edges/tips, and strongly tip sharpness and aspect ratio dependent SPR absorption of the triangular nanostructure. This sensing system is further extended to the detection of glucose by H 2 O 2 generated from the enzymatic oxidation of glucose, and thus holds great promises in clinical applications. [ABSTRACT FROM AUTHOR]

Herein, a label-free and highly sensitive electrochemical aptasensor for the detection of angiogenin was proposed based on a conformational change of aptamer and amplification by poly(diallyldimethyl ammonium chloride) (PDDA)-functionalized graphene/gold nanoparticles (AuNPs) composites-modified electrode. PDDA-functionalized graphene (P-GR) nanosheets as the building block in the self-assembly of GR nanosheets/AuNPs heterostructure enhanced the electrochemical detection performance. The electrochemical aptasensor has an extraordinarily sensitive response to angiogenin in a linear range from 0.1 pM to 5 nM with a detection limit of 0.064 pM. The developed sensor provides a promising strategy for the cancer diagnosis in medical application in the future. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hourglass-like Ni(OH)2 was prepared via a simple and facile route in solution. [•] The sensor has a detection limit of 80nM. [•] The sensor shows much better catalytic performance compared with bulk material. [•] The sensor shows a great potential for practicable applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] A signal-off architecture for lysozyme detection was designed. [•] The sensor has a linear range (7–30nM) with a detection limit of 1nM. [•] The sensor shows a high sensitivity, good selectivity and satisfactory stability. [•] The sensor shows a great potential for practicable applications. [Copyright &y& Elsevier]

Highlights: [•] The preparation method of flower-shaped Ni/Al layered double hydroxide (LDH) is quite simple. [•] The Ni/Al-LDH has great adsorption capacity owing to its flower-shaped nature. [•] The very good linear relationship toward glucose can be obtained in two regions: 1–100μM and 0.5–21mM. [•] The sensor has a detection limit of 0.11μM. [•] The sensor possesses high sensitivity, good stability and excellent repeatability. [•] The sensor shows a great potential for practicable applications. [ABSTRACT FROM AUTHOR]

Abstract: A one-step electrochemical sensor for sensing of potassium ion (K+) based on the conformational change of a single stranded DNA (ssDNA) with G-rich sequence was presented. The introduction of K+ induced folding of the aptamer, and the Fc moiety approached the electrode surface to produce measurable electrochemical signals. The aptasensor had a lower detection limit at 0.1nM, which was an excellent sensitivity compared with other methods for K+ detection. The proposed approach showed high selectivity and minimized the nonspecific adsorption, so that it was used for the detection of target K+ in the human serum sample. [Copyright &y& Elsevier]

We have proposed a colorimetric sensing assay exploiting the formation of gold amalgamation, combining with Hg 2+ mediated the growth of gold nanoparticles (AuNPs) for rapid detecting Hg 2+ ions with highly sensitivity and selectivity. In our developed approach, Hg 2+ is reduced to elemental mercury by citrate-capped AuNPs, forming gold amalgamation on the surface of AuNPs. AuNP-Hg 2+ interaction modulates the growth of AuNPs which is formed in the HAuCl 4 /NH 2 OH reaction. The rate of AuNP growth is highly dependent on the target concentration. AuNPs with low Hg coverage grow into spherical AuNPs with slow growth rate, which generates red-colored solutions. Whereas, AuNPs with high Hg coverage accelerate the growth of spherical AuNPs with a larger particle size, which generates blue colored solutions. At higher concentration, however, the growth rate of AuNPs begins to decrease. As the concentration of Hg 2+ increases till the saturation of Hg onto the surface of AuNPs, the growth of the AuNPs is inhibited due to full coverage of Hg on the AuNP surface. On the basis of this principle, Hg 2+ can be well determined ranging from 0.5 to 10 nM with a 0.26 nM of the detection limit. [ABSTRACT FROM AUTHOR]

In this work, we report an ultrasensitive colorimetric sensing strategy for Cu 2+ based on the Cu 2+ catalyzed TMB-H 2 O 2 reaction, and the signal amplification induced by aptamer-K + -Cu 2+ complex. It is demonstrated that Cu 2+ exhibits an intrinsic peroxidase-like catalytic activity. Thus, we utilize the catalytic activity of Cu 2+ to TMB-H 2 O 2 reaction for direct colorimetric visualization of Cu 2+ for the first time. The limit of detection (LOD) is 2.6 μM. To further improve the sensitivity of Cu 2+ detection, we utilized G-quadruplex-Cu 2+ metalloenzyme complex formed by K + , G-rich DNA, and Cu 2+ to amplify colorimetric signal of TMB-H 2 O 2 reaction. The LOD is as low as 0.076 μM, which is 34-fold lower than that of only Cu 2+ -catalyzed TMB-H 2 O 2 system (2.6 μM). The LOD shows excellent potential for monitoring ultralow levels of Cu 2+ in water samples. [ABSTRACT FROM AUTHOR]

An ultrasensitive colorimetric assay for Hg 2+ detection was presented based on synergistic catalytic effect of gold nanoparticles (AuNPs) and Hg. The AuNPs could catalyze the reduction of Hg 2+ by surface-capping citrate. The effect of Hg 2+ uptake implied amalgam formation and increased the surface area of AuNPs, leading to remarkable catalytic amplification of the peroxidase-like activity of AuNPs. On the basis of this effect, 3,3′,5,5′-tetramethylbenzidine (TMB) as colorimetric probes could be catalyzed into a black blue product in the presence of H 2 O 2 . The detection limit of the colorimetric assay for Hg 2+ is 0.1 nM. Furthermore, the detection limit of Hg 2+ in river water samples and tap water samples are 0.66 nM, and 0.43 nM, respectively. The results are far below the World Health Organization (WHO) permissible limit (30 nM). The assay is highly sensitive, specific, and able to detect Hg 2+ rapidly without requiring sophisticated equipment. In addition, our strategy could also be used as a promising and convenient approach for detection of the target in environmental protection. [ABSTRACT FROM AUTHOR]

Core MZ01 from the mud area on the inner shelf of the East China Sea (ECS) was studied to detect millennial climate changes during the Holocene based on a modified version of accelerator mass spectrometry (AMS) 14 C dating age model, sediment grain size, oxygen isotopes and the Mg/Ca ratio of benthic foraminifera shells. On the basis of multiproxies of this core, eight abrupt cooling events were identified that occurred at 8.2, 7.2, 6.2, 5.1, 4.2, 3.2, 2.3 and 1.2 ka BP, within the uncertainties of the revised age model. The timing of the abrupt Holocene surface hydrographic events reconstructed from the core, particularly 8.2 ka, expressed pronouncedly in the mud area on the inner shelf of the ECS appear to be coincident with the records from the North Atlantic, the South China Sea and an adjacent land cave and Greenland ice cores, suggesting global climatic teleconnections. The abrupt climate changes during the Holocene displays periodicities of 820–830 years and 350–420 years, which may be related to solar activity but suggests a robust regional feature of hydrographic changes in the western tropical Pacific. We conclude that the singularity of the particular hydrographic patterns and mechanisms responsible for the patterns and periodicities of these abrupt events merits further studies by more intensive dating controls and novel proxy reconstructions. [ABSTRACT FROM AUTHOR]

[Display omitted] • We developed a sensor array based on Co-N-C single-atom nanozymes for colorimetric discrimination of antioxidants. • Under two pH conditions, Co-N-C nanozymes produce different catalytic effects on the reaction between H 2 O 2 and TMB. • Linear discriminant analysis (LDA) was used to successfully analyze the 7 antioxidants. • The sensing strategy had excellent specificity and good application in human serum samples. Here we develop a simple and effective nose/tongue sensor array based on Co-N-C single-atom nanozymes-3,3′,5,5′-tetramethylbenzidine (TMB)-H 2 O 2 for colorimetric discrimination of antioxidants, which makes use of the color reaction of TMB oxidation by H 2 O 2 in two different pH (3.8 and 4.6) environments under the catalysis of Co-N-C nanoenzyme with peroxidase-like activity. Different antioxidants have varying reducing ability to the oxidation products of TMB (oxTMB), thus resulting in differential absorbance and color changes. Linear discriminant analysis (LDA) results indicate that the sensor array successfully identified 7 antioxidants, i.e., glutathione (GSH), ascorbic acid (AA), cysteine (Cys), tannin (TA), Catechin (C), dopamine (DA), and uric acid (UA) in both buffer and even serum samples. Additionally, the performance of the sensor array was validated with antioxidant mixtures, individual antioxidants with different concentrations, and target antioxidants and interfering substances. In general, the versatile sensor array based on Co-N-C single-atom nanozymes provides an excellent strategy for identifying a variety of antioxidants, which exhibits a broad application prospect in medical diagnosis. [ABSTRACT FROM AUTHOR]

• We propose a simple but sensitive colorimetric method for the detection of P 2 O 7 4−and PPase. • By counting the IOD of red dots in the dark-field images, P2O74− concentration can be determined. • The linear range of P2O74−concentrations (0.1 nM - 10 mM) and a LOD (0.0324 nM) were obtained. We propose a sensitive colorimetric method for the detection of P 2 O 7 4− and pyrophosphatase (PPase). Without Na 4 P 2 O 7 and PPase, under the catalysis of gold nanoparticles (AuNPs), Cu(II) can be reduced to Cu by nicotinamide adenine dinucleotide (NADH), leading to the Cu-coating onto the surfaces of AuNPs, accompanied by the color change from green to red under the dark-field microscope observation. While in the presence of Na 4 P 2 O 7 , the formation of Au@Cu NPs is suppressed due to the strong complexation reaction between Cu(II) and Na 4 P 2 O 7. Thus, the NPs exhibit uniform green color in the dark-field image. By quantitatively counting the integrated optical density (IOD) of red dots in the dark-field images, P 2 O 7 4− concentration can be accurately determined. A linear logarithmic dependence on P 2 O 7 4− concentrations from 0.1 nM to 10 mM with a limit of detection (LOD) of 0.0324 nM was obtained. The addition of PPase to the Na 4 P 2 O 7 -triggered dispersed AuNPs restores the formation of Au@Cu NPs owing to the hydrolysis of Na 4 P 2 O 7 into sodium phosphate under the catalysis of PPase, resulting in reliable quantification of color change of NPs from red to green in the dark-field images. The LOD is as low as 0.0007 U/mL with a linear dynamic range of 0.005–10 U/mL. [ABSTRACT FROM AUTHOR]