Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate

Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 μg·l-1

Combination of thymosin α1 with conventional therapy improves APC and IL-1R1 levels in children with severe pneumonia

Purpose: To investigate the effect of a combination of thymosin α1 with  conventional regimen on APC and IL-1R1 levels in children with severe pneumonia, and to provide a reference for its clinical treatment.Methods: A total of 96 children with severe pneumonia over a period of two years were divided into control and observation groups (48 cases per  group) by random number table method. The patients consisted of 46 males and 50 females within the age range of 0.1 - 6 years (mean age = 3.0 ± 1.2 years), and mean duration of 13.4 ± 2.2 days). Their acute physiology and chronic health evaluation II (APACHE II) was 20.3 ± 3.2 points. Patients in the control group were placed on conventional treatment programs, while those in the observation group, in addition to the  conventional treatments, received thymosin α1 (subcutaneous injection of thymosin α1 at a dose of 1.5 mg per injection) twice daily for the first 3 days, then once daily until the 7th day, after which the adverse reactions were observed and treated. Pulmonary function indices, and levels of APC, and IL-1R1 were also determined in the patients’ sera before and after the treatment regime.Results: The clinical efficacy of the observation group was significantly better (p < 0.05) than that of control. There were no significant differences (p > 0.05) in the indices of pulmonary function (maximal inspiratory and expiratory pressure, and peak expiratory flow) between the two groups before treatment. However, after treatment they were significantly higher (p < 0.05) in the observation group than in control. There were no significant differences (p > 0.05) in APC and IL-1R1 levels between the two groups before treatment, but after treatment, while the level of APC in the observation group was significantly increased (p < 0.05), the IL-1R1 level was significantly decreased (p < 0.05), when compared to the control group. Both groups showed no obvious adverse reactions during the treatmentregime.Conclusion: Combining thymosin α1 with routine treatment in the  management of children with severe pneumonia can significantly alleviate the symptoms of patients, greatly stimulate recovery of pulmonary function, improve APC and IL-1R1 levels, and prevent inflammation.Keywords: Pneumonia, Thymosin α1, Routine treatment, Inflammatory factors, Pulmonary functio

Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate

<p>Abstract</p> <p>Surface-enhanced Raman scattering (SERS) has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag) nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates) for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO₃/BuNH₂) and reaction time. A Ag nanoparticles (AgNPs) double-layer was formed by directly reducing Ag⁺ions on the glass surfaces, while a top layer (3rd-layer) of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm^-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm^-1band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD) of arsenate was determined to be approximately 5 &#956;g&#183;l^-1.</p

Quantitatively in Situ Imaging Silver Nanowire Hollowing Kinetics

We report the in situ investigation of the morphological evolution of silver nanowires to hollow silver oxide nanotubes using transmission X-ray microscopy (TXM). Complex silver diffusion kinetics and hollowing process via the Kirkendall effect have been captured in real time. Further quantitative X-ray absorption analysis reveals the difference between the longitudinal and radial diffusions. The diffusion coefficient of silver in its oxide nanoshell is, for the first time, calculated to be 1.2 × 10^–13 cm²/s from the geometrical parameters extracted from the TXM images

Carbonate orientational order and superlattice structure in vaterite

© 2014 Elsevier B.V. All rights reserved. Vaterite is considered to play an important role as a precursor phase in the formation of calcium carbonate phases, including those related to biomineralization. An accurate description of vaterite\u27s structure associated with the order of carbonate groups is essential to understanding the formation, stabilization, and functionality of vaterite in organisms. Molecular dynamics simulations, synchrotron X-ray diffraction, and transmission electron microscopy have been combined in order to investigate the structure of vaterite. The electrostatic interactions between Ca and neighboring CO3 groups promote local and long-range ordering of CO3 groups, which may result in a superstructure of vaterite. Molecular dynamics simulations show that the superstructure (P6522) with ordered carbonate ions has a relatively lower energy than the disordered structure. The kinetics of the disorder-to-order transition suggests that the transition is rapid and that the superstructure is expected to form. X-ray diffraction data confirm the presence of the P6522 superstructure. The measured diffraction peaks are consistent with the calculated diffraction peaks, especially those weak peaks predicted as a result of the superstructure. Transmission electron microscopy also reveals minor satellite electron diffraction peaks with the more intense peaks of the primary pattern, suggesting a superlattice structure resulted from ordering in both crystallographic ab plan and c direction, which is consistent with the proposed superstructure