Real-time optical imaging and tracking of micron-sized particles

We report real-time imaging and dynamics monitoring of micrometer predefined and random sized particles by time-space-wavelength mapping technology using a single-detector. Experimentally, we demonstrate real-time line imaging of a 5 μm polystyrene microsphere, glass powder particles and patterns such as fingerprints with up to 5 μm resolution at 1 line/50 ns capture rate. By using the same setup, real-time displacement tracking of micrometer-size glass particles with 50 ns temporal resolution and up to 5 μm spatial resolution is achieved. We also show that existing correlation spectroscopy algorithms can be adopted to extract dynamic information in a complex environment.     

Tetrakis‐phthalocyanines bearing electron‐withdrawing fluoro functionality: Synthesis,spectroscopy, and electrochemistry

In this study, 2,9,16,23‐tetrakis‐4′‐(2,3,5,6‐tetrafluoro)‐phenoxy‐phthalocyaninatometalfree and metal(II) complexes, (H₂PcBzF₁₆, ZnPcOBzF₁₆, CuPcOBzF₁₆, and CoPcOBzF₁₆) (Bz: Benzene) (2H, Zn, Cu, and Co), have been prepared directly from the corresponding 4′‐(2,3,5,6‐fluorophenylthio)‐phthalonitrile compounds in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in high boiling quinoline solvent. Tetrafluoro atoms on 2,3,5,6‐position of benzene at the peripheral sites of phthalocyanines (Pcs) give rise interesting solubility to tetrakismetallophthalocyanines. Although all complexes were soluble in DCM, CHCl₃, THF, DMF, and DMSO with increasing order, complexes synthesized, particularly H₂PcBzF₁₆, CuPcOBzF₁₆, have very limited solubility in DMF and DMSO. The complexes have been characterized by elemental analysis, FTIR, ¹H NMR, UV–vis, and MALDI–TOF mass spectral data. The cyclic voltammetry and differential pulsed voltammetry of the complexes show that while H₂PcBzF₁₆, CuPcOBzF₁₆, and ZnPcOBzF₁₆ give ligand‐based reduction and oxidation processes, CoPcOBzF₁₆ gives both ligand and metal‐based redox processes, in harmony with the common metallophthalocyanine complexes. Redox processes due to both aggregated and disaggregated species were simultaneously observed during the first reduction process. The nature of the metal‐based redox processes was confirmed using spectroelectrochemical measurements. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:262–271, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20545     

Synthesis, characterization and electro-spectroelectrochemical studies of four macrocyclic Schiff-base Co(II) complexes having N2O2 set of donor atoms

Four macrocyclic Schiff-base cobalt complexes, [CoL¹][NO₃]₂ · 3H₂O, [CoL²][NO₃]₂ · 4H₂O, [CoL³][NO₃]₂ · 4H₂O and [CoL⁴][NO₃]₂ · 2H₂O, were synthesized by reaction of salicylaldehyde derivatives with 1,4-bis(3-aminopropoxy)butane or (±)-trans-1,2-diaminocyclohexane and Co(NO₃)₂ · 6H₂O by template effect in methanol. The metals to ligand ratio of the complexes were found to be 1:1. The Co(II) complexes are proposed to be tetrahedral geometry. The macrocyclic Co(II) complexes are 1:2 electrolytes as shown by their molar conductivities (Λ_M) in DMF (dimethyl formamide) at 10^?3 M. The structure of Co(II) complexes is proposed from elemental analysis, Ft-IR, UV–visible spectra, magnetic susceptibility, molar conductivity measurements and mass spectra. Electrochemical and thin-layer spectroelectrochemical studies of the complexes were comparatively studied in the same experimental conditions. The electrochemical results revealed that all complexes displayed irreversible one reduction processes and their cathodic peak potential values (E _pc) were observed in around of ?1.14 to 0.95 V. It was also seen that [CoL¹][NO₃]₂ · 3H₂O and [CoL²][NO₃]₂ · 4H₂O exhibited one cathodic wave without corresponding anodic wave but, [CoL³][NO₃]₂ · 4H₂O and [CoL⁴][NO₃]₂ · 2H₂O showed one cathodic wave with corresponding anodic wave, probably due to the presence of different ligand nature even if the complexes have the same N₂O₂ donor set. In view of spectroelectrochemical studies [CoL³][NO₃]₂ · 4H₂O showed distinctive spectral changes in which the intensity of the band (λ = at 316 nm, assigned to n → π* transitions) decreased and a new broad band in a low intensity about 391 nm appeared as a result of the reduction process based on the cobalt center in the complex.     

Synthesis,characterisation and dosimetric evaluation of MgB4O7 glass as thermoluminescent dosimeter

This study presumably reports the dosimetric properties of MgB₄O₇ glass system. A series of MgB₄O₇ glass samples with nominal compositions XMgO-(100-X) B₂O₃, with X?=?35, 40 and 45?mol% was successfully synthesied using conventional melt quenching method. The presence of broad humps and absence of any sharp peak in typical X-ray diffraction patterns confirm the amorphous nature of the synthesised glass samples. Good glass forming ability, 0.55, of the mixture resulting in a glass with excellent glass stability, 1.4, was observed. Thermoluminescence glow curve was observed to be simple with a single well defined dosimetric peak around 200°C. The dose response was found to be linear from 6?µGy to 0.5?kGy when irradiated to Cs-137 gamma rays. Considerably satisfying thermoluminescent (TL) characteristics suggests that the MgB₄O₇ glass could be recommended as a TL dosimeter.     

AgNOR increase in buccal epithelial cells of trisomy 21 infants

The aim of this study is to compare the Argilophilic Nucleolus Organizer Regions (AgNORs) level between Down syndrome (DS) patients and controls in a tissue sharing the same embryonic origin with the central nervous system and compare the results with those obtained recently by us from DS's lymphocytes. For this, buccal desquamating epithelial cells well known as the ectodermic origin were used. Since the AgNOR staining intensity is an indicator of the ribosomes biosynthesis rate, comparison of the image analysis values of the AgNOR area/total nuclear area (NORa/TNa) in buccal desquamating epithelial cells of DS patients and controls provided a plausible conclusion about the regulation/deregulation of the rRNA genes (rDNA) in these cells of DS babies/infants. The (NORa/TNa) proportion was calculated using an in-house computer program. Fifty buccal desquamating cells were analysed for each individual to determine the average NORa/TNa value per individual. In contrast to healthy controls, NORa/TNa proportion value of buccal epithelial cells from DS patients found significantly higher than that of the controls: (4.08 ± 1.16)% and (2.13 ± 0.55)%, respectively. This 92% increase is far higher than the expected value due to the extra rRNA genes on the extra-chromosome 21. Finally DS babies/infants exhibit very higher AgNOR expression increase in their buccal epithelial cells compared to controls. This is the first study that is available on the comparison of AgNOR expression levels in buccal epithelial cells between DS infants and their controls.     

A multibody-based dynamic simulation method for electrostatic actuators

A numerical simulation method is developed to analyze the dynamic responses of electrostatic actuators, which are electromechanically-coupled systems. The developed method can be used to determine the dynamic responses of cantilever-type switches, which are an example of typical MEMS (Micro-Electro-Mechanical System) devices driven by an electrostatic force. We propose the approach that adopts a point charge to deal with electric field effects between electrodes. This approach may be considered as a lumped parameter model for the electrostatic interactions. An advantage of this model may be the easy incorporation of the electrostatic effects between electrodes into a multibody dynamics analysis algorithm. The resulting equations contain the variables for position, velocity, and electric charge to describe the motion of the masses and the charges on the electrodes in a system. By solving these equations simultaneously, the dynamic response of an electrostatically-driven system can be correctly simulated. In order to realize this approach, we implement the procedures into RecurDyn, the multibody dynamics software developed by the authors. The developed numerical simulation tool was evaluated by applying it to cantilever-type electrostatic switches in many different driving conditions. The results suggest that the developed tool may be useful for predicting behaviors of electrostatic actuators in testing as well as in design.     

One‐Step Microfluidic Coating of Phospholipid Microbubbles with Natural Alginate Polymer as a Delivery System for Human Epithelial Lung Adenocarcinoma

In this study, the neoplastic drug frequently used in the treatment of lung cancer, carboplatin is loaded to microbubbles via a microfluidic platform. In order to increase the drug loading capacity of microbubbles, carboplatin is encapsulated into alginate polymer layer. The phospholipid microbubbles (MBs) are synthesized by MicroSphere Creator, which is connected with T‐junction and micromixer for the treatment with CaCl₂ solution to provide gelation of the alginate coated phospholipid microbubbles (AMBs). The carboplatin loaded alginate coated phospholipid microbubbles (CAMBs) result in 12.2 ± 0.21 µm mean size, obtained by mixing with 0.05% CaCl₂ using T‐junction. The cytotoxic activities of the synthesized MBs, AMBs, and CAMBs are also investigated with the 3‐(4,5‐Dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) (MTT) and live/dead fluorescent dying assays in the A549 and BEAS‐2B cell lines. The one‐step microfluidic coating of lipid microbubbles with natural alginate polymer appears to be a promising strategy for enhanced drug reservoir properties.     

Enhanced activity and stability of Pt catalysts on functionalized graphene sheets for electrocatalytic oxygen reduction

Electrocatalysis of oxygen reduction using Pt nanoparticles supported on functionalized graphene sheets (FGSs) was studied. FGSs were prepared by thermal expansion of graphite oxide. Pt nanoparticles with average diameter of 2 nm were uniformly loaded on FGSs by impregnation methods. Pt-FGS showed a higher electrochemical surface area and oxygen reduction activity with improved stability as compared with the commercial catalyst. Transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical characterization suggest that the improved performance of Pt-FGS can be attributed to smaller particle size and less aggregation of Pt nanoparticles on the functionalized graphene sheets.     

Prepared and characterization of new macrocyclic Schiff bases and their binuclear copper complexes

The new five macrocyclic ligands were synthesized by reaction of 2,6-diaminopyridine and various dialdehydes. Then, their copper(II) perchlorate complexes were synthesized by template effect by reaction of 2,6-diaminopyridine, Cu(ClO(4))(2).6H(2)O and aldehydes. The ligands and their complexes have been characterized by elemental analysis, IR, (1)H and (13)C NMR, UV-vis spectra, magnetic susceptibility, conductivity measurements, mass spectra. All complexes are diamagnetic and binuclear. The diamagnetic behaviour of the binuclear complexes may be explained by a very strong anti-ferromagnetic interaction in the Cu-Cu pair.