A highly sensitive sensor of paracetamol based on zinc-layered hydroxide-<Emphasis Type="Italic">L</Emphasis>-phenylalanate-modified multiwalled carbon nanotube paste electrode

A new zinc-layered hydroxide-L-phenylalanate (ZLH-LP)-modified multiwalled carbon nanotube (MWCNT) was prepared as a new material of paste electrode for the detection of paracetamol (PCM) in 1.0?×?10^?1 M phosphate buffer solution and at pH 7.5. The electrochemical characterization of the MWCNTs/ZLH-LP paste electrode was characterized by square wave voltammetry, electrochemical impedance spectroscopy, and cyclic voltammetry while the morphology properties of the MWCNTs, ZLH-LP, and MWCNTs/ZLH-LP were investigated using transmission electron microscopy and scanning electron microscopy. Under optimized conditions, the MWCNTs/ZLH-LP paste electrode demonstrated an excellent electrocatalytic activity towards oxidation of PCM in the linear responses’ ranges from 7.0?×?10^?7 M to 1.0?×?10^?4 M (correlation coefficient, 0.996) with the limit of detection obtained at 8.3?×?10^?8 M. As a conclusion, the MWCNTs/ZLH-LP paste electrode revealed good repeatability, reproducibility, and stability, and was found to be applicable for use in pharmaceutical tablet samples.

Open image in new window

Graphical abstract ?

     

Preconcentration and selective extraction of chromium species in water samples using amino modified mesoporous silica

Speciation and separation of chromium (VI) and chromium (III) from aqueous solutions were investigated using amino-propyl functionalised mesoporous silica (AP-MCM-41) as an adsorbent. The as-synthesised adsorbent was produced following a simple synthesis method at room temperature prior to template removal using microwave digestion. The maximum adsorption capacity at 111.1mg/g was calculated according to the Langmuir isotherm model, suggesting a 1:1 monolayer adsorption mechanism. Moreover, AP is a simple chelate, yet it can extract Cr (VI) exclusively from solutions containing other mixed metal ions simply by tuning the solution pH. Recovery of Cr (VI) from loaded sorbents is equally easy to perform with 100% extraction efficiencies allowing reuse of the sorbent and recovery of Cr (VI) from aqueous solutions containing a complex mixture of ions. The material would find use in environmental remediation applications, as a selective adsorbent of Cr (VI) or even as a solid-phase extraction stationary phase to remove and pre-concentrate Cr (VI) from aqueous solutions; this study demonstrates enrichment factors of 100 although higher levels are also possible.     

Graphene-encapsulated Fe3O4 nanoparticles with 3D laminated structure as superior anode in lithium ion batteries

Fe₃O₄–graphene composites with three‐dimensional laminated structures have been synthesised by a simple in situ hydrothermal method. From field‐emission and transmission electron microscopy results, the Fe₃O₄ nanoparticles, around 3–15 nm in size, are highly encapsulated in a graphene nanosheet matrix. The reversible Li‐cycling properties of Fe₃O₄–graphene have been evaluated by galvanostatic discharge–charge cycling, cyclic voltammetry and impedance spectroscopy. Results show that the Fe₃O₄–graphene nanocomposite with a graphene content of 38.0 wt % exhibits a stable capacity of about 650 mAh g^?1 with no noticeable fading for up to 100 cycles in the voltage range of 0.0–3.0 V. The superior performance of Fe₃O₄–graphene is clearly established by comparison of the results with those from bare Fe₃O₄. The graphene nanosheets in the composite materials could act not only as lithium storage active materials, but also as an electronically conductive matrix to improve the electrochemical performance of Fe₃O₄.     

Proteome profile of zebrafish caudal fin based on one-dimensional gel electrophoresis LCMS/MS and two-dimensional gel electrophoresis MALDI MS/MS analysis

Zebrafish (Danio rerio) is the widely used vertebrate model animal for understanding the complexity of development and disease process. Zebrafish has been also extensively used in understanding the mechanism of regeneration for its extensive capability of regenerating fins and other tissues. We have analyzed the proteome profile of zebrafish caudal fin in its native state based on one-dimensional gel electrophoresis LCMS/MS and two-dimensional gel electrophoresis MS/MS analyses. A total of 417 proteins were identified as zebrafish fin tissue specific, which includes 397 proteins identified based on one-dimensional gel electrophoresis LCMS/MS analysis and 101 proteins identified based on two-dimensional gel electrophoresis MALDI MS/MS. The proteins mapped to the zebrafish fin tissue were shown to be involved in various biological activities related to development, apoptosis, signaling and metabolic process. Focal adhesion, regulation of actin cytoskeleton, cancer-related pathways, mitogen-activated protein kinase signaling, antigen processing and presentation, and proteasome are some of the important pathways associated with the identified proteome data set of the zebrafish fin.     

Study of (1−x)ZnAl2O4–xSiO2 spinel structures as microwave dielectric materials

Sol–gel method was used to synthesize zinc aluminate (ZnAl₂O₄) dispersed into silica matrix with different compositions of x. Morphological structure of (1?x)ZnAl₂O₄–xSiO₂ samples were investigated by field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD). The FESEM images showed spherical structures and agglomerated particles occurred inside the samples. XRD analysis indicated the cubic phase formation of the samples. The crystallite size, D was calculated and it was found that the crystallite size are slightly increased from 8 to 17 nm. FTIR spectra analysis shows that the water presence in the samples and also the presence of nitrate group. The dielectric properties have been measured, ε _r value was found to be around 13.0. The S₁₁ parameter analysis shows the samples was resonated at 2.40 GHz and gives different values of bandwidth for microstrip patch antenna application.     

Numerical solutions of the Kawahara type equations using radial basis functions

This study is carried out to investigate the numerical solutions of the Kawahara, KdV‐Kawahara, and the modified Kawahara equations by using the meshless method based on collocation with radial basis functions. Results of the meshless method with different radial basis functions are presented for the travelling wave solution of the Kawahara type equations. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 542–553, 2012     

Backbending Phenomena in Even–Even $${}^{\boldsymbol{162{-}172}}$$ Hf Isotopes

Physics of Atomic Nuclei - This study probes the backbending phenomena in even–even $${}^{162{-}172}$$ Hf isotopes. Experimental ground-state rotational energies up to $$J^{\pi}=36^{+}$$...     

Experimental study of the influence of silica nanoparticles on the bulk stability of SDS-foam in the presence of oil

The influence of silica nanoparticles on the bulk stability of SDS-foam in the presence of oil was investigated in this study using KRÜSS dynamic foam analyzer. The bulk foam static stability was evaluated from half-decay time, liquid drainage, bubble size distribution, and change in total height and volume of the generated foams with respect to time. Results clearly showed that foam stability in the presence of oil mainly depends on the viscosity and density of the oil. Foam stability increased with the addition of silica nanoparticles due to the aggregation of the nanoparticles at the thin lamellae of the foam, which prevents spreading of the oil at the gas–liquid interface. Moreover, optimum foam stability was obtained with the modified nanosilica–SDS mixtures, while slower liquid drainage from the foam did not generally result in high foam stability.