The determination of selenium concentration in blood and tumour tissues of breast cancer patients in Syria using instrumental neutron activation analysis

The aim of this study was to investigate the relationship of selenium concentration in blood components and tumour tissues of breast cancer patients and healthy volunteers (control), in Syria, using instrumental neutron activation analysis (INAA). Red blood cells and serum selenium concentrations were determined in 50 healthy volunteers aged 25-70 years and 70 breast cancer patients aged 25-84 years. Selenium levels were also measured in malignant and adjacent normal tissues from breast cancer patients. The accuracy of the analysis was evaluated by co-analyses of international reference materials. The results showed that selenium concentration in serum and RBC was significantly lower among breast cancer patients compared to healthy volunteers (P<0.001). The results also showed that the selenium concentration was significantly higher in the cancer tissues compared to adjacent normal tissues (P<0.001). We conclude that there is a good indication for selenium deviation in blood and malignant tissue of breast cancer patients compared to that of healthy volunteers. This revised version was published online in July 2006 with corrections to the Cover Date.     

Performance evaluation of praseodymium doped fiber amplifiers

Optical Review - In this paper, we report the performance evaluation of praseodymium doped fiber amplifier (PDFA) operating in 1.25–1.35&nbsp;μm band of wavelengths based on...     

Offline estimation of 2D crystal lattice parameters by processing the electron diffraction image

Electron diffraction provides useful information about the internal composition of materials and has been in the use of material scientists for more than fifty years. In order to extract useful information from offline diffraction images, they are manually analyzed by using some photometric technique. Manual analysis is however a cumbersome, laborious and difficult task. To reduce the labors of material scientists one can employ image processing techniques to perform automated analysis, due to the well established popularity and clear evidence of widely used image processing techniques. In this work an image processing technique is being proposed for the extraction of 2D unit cell information from diffraction images on one hand and finding the 2D point group contained by the lattices on the other. The technique employs a morphological shrinking operation to find the center of each spot in the underlying preprocessed diffraction image. This is followed by the extraction of eight points with reference to the spot produced by the transmitted electron beam. The resultant nine points, i.e. the extracted eight plus the reference spot generated by the transmitted electron beam, are then subjected to symmetry operations, rotation symmetry and mirror symmetry, in polar coordinate system, to classify the point group of the lattice produced by the electron diffraction. One of the difficult task, even in manual analysis, is to ascertain the exact spot where the transmitted electron beam hit the sample at the time of realization of the image. This has been accurately and intuitively done by employing the notion that the transmitted spot must have greater number of pixels, with the highest gray value, among the diffracted spots. The proposed strategy has been applied to a sample set of various images and the results shows that the technique is efficient in determining the unit cell in 2D and classify the point group with good accuracy.     

Synthesis and Coordination Behavior of a New Hybrid Bidentate Ligand with Phosphine and Silylene Donors

This work describes the synthesis and coordination behavior of a new mixed-donor ligand PhC(NtBu)₂SiC₆H₄PPh₂ ( 1 ) containing both silylene and phosphine donor sites. Ligand 1 was synthesized from a reaction of ortho-lithiated diphenylphosphinobenzene (LiC₆H₄PPh₂) with chlorosilylene (PhC(NtBu)₂SiCl). Treatment of 1 with Se and GeCl₂ resulted in Si^IV compounds 2 and 3 by selective oxidation of the silylene donor. This strong σ-donor ligand induces dissociation of CuCl and PhBCl₂ leading to formation of ionic complexes 4 and 5 respectively. The reaction of 1 with ZnCl₂ and AlCl₃ resulted in the formation of chelate complexes 5 and 7 , respectively, while treatment with EtAlCl₂ and GaCl₃ forms monodentate complexes 8 and 9 . X-ray analysis of 4 showed that the copper is in the spiro center of the two five-membered rings. Moreover, the copper(I)chloride has not been oxidized but dissociates to Cu⁺ and [CuCl₂]⁻. All the compounds are well characterized by mass spectrometry, elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction studies.     

Mechanistic study of quinone-polyalcohol interaction through cyclic voltammetry

The electrochemistry of some quinones has been focused to determine the mode of interaction in presence of polyalcohols. Three compounds of each family (benzoquinones, naphthoquinones and anthraquinones) were investigated through cyclic voltammetry in the presence of ethylene glycol (a diol)) and glycerol (a triol) in dichloromethane and acetonitrile at 25°C. The observed positive shift in both the waves of the quinone with successive addition of alcohol was attributed to hydrogen bonding in the quinone-alcohol couple. “Two electron one step” electron transfer mechanism was proposed for the increase in the first wave height at the expense of second. The depletion of the first anodic wave at higher concentration of polyalcohol was rationalized in terms of protonation-deprotonation mechanism. A prior peak observed in the presence of glycerol was ascribed to the hydrogen bonding of the alcohol with neutral quinone. The difference in basicity strength within a family as well as among the three quinone families was also addressed in view of the interaction effectiveness.     

二维配位聚合物[Tb(1,4⁃bdc)1.5(phen)(H2O)]n的合成、晶体结构及对Fe3+离子的荧光检测

通过溶剂热反应成功合成出一种新型2D配位聚合物[Tb(1,4-bdc)_1.5(phen)(H₂O)]_n(1)(1,4-H₂bdc=对苯二甲酸;phen=菲咯啉)。对其进行了单晶X射线衍射、粉末X射线衍射、红外光谱、元素分析、荧光光谱表征。X射线衍射晶体学分析表明,配合物1结晶于三斜晶系P1空间群,2个相邻的Tb(Ⅲ)离子与4个1,4-bdc^2-通过—O—C—O—桥联成双核单元,并进一步通过1,4-bdc^2-桥联成二维层状结构。荧光实验证明配合物1可以通过荧光猝灭机制检测Fe₃₊,Ksv=8.39×10³ L·mol-1,检测限为0.017μmol·L^-1。     

Manganese Dioxide Mediated Stereoselective, One-step Synthesis of Novel Steroidal (6R)-Spiro-1’,2’,4’-triazoline-3’-thiones

Oxidative cyclization of 5α-cholestan-6-one thiosemicarbazone (1), its 3β-chloro (2) and 3β-acetoxy (3) analogues with active manganese dioxide at room temperature afforded selectively the corresponding (6R)-spiro-1’,2’,4’-triazoline-3’-thiones 4—6. This synthesis has the advantages of mild reaction conditions, easy handling, easily available reagent and high yields. The products have been characterized by analytical and spectral data.     

Thermoresponsive copolymer nanofilms for controlling cell adhesion, growth, and detachment

This study reports the development and use of a novel thermoresponsive polymeric nanofilm for controlling cell adhesion and growth at 37 °C, and then cell detachment for cell recovery by subsequent temperature drop to the ambient temperature, without enzymatic cleavage or mechanical scraping. A copolymer, poly(N-isopropylacrylamide-co-hydroxypropyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate) (abbreviated PNIPAAm copolymer), was synthesized by free radical polymerization. The thermoresponses of the copolymer in aqueous solution were demonstrated by dynamic light scattering (DLS) through detecting the sensitive changes of copolymer aggregation against temperature. The DLS measurements revealed the lower critical solution temperature (LCST) at approximately 30 °C. The PNIPAAm film stability and robustness was provided through silyl cross-linking within the film and with the hydroxyl groups on the substrate surface. Film thickness, stability, and reversibility with respect to temperature switches were examined by spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and contact angle measurements. The results confirmed the high extent of thermosensitivity and structural restoration based on the alterations of film thickness and surface wettability. The effective control of adhesion, growth, and detachment of HeLa and HEK293 cells demonstrated the physical controllability and cellular compatibility of the copolymer nanofilms. These PNIPAAm copolymer nanofilms could open up a convenient interfacial mediation for cell film production and cell expansion by nonenzymatic and nonmechanical cell recovery.     

Simple and rapid synthesis of ternary polyaniline/titanium oxide/graphene by simultaneous TiO<Subscript>2</Subscript> generation and aniline oxidation as hybrid materials for supercapacitor applications

This paper reports a simple methodology for the synthesis of a polyaniline/titanium oxide/graphene hybrid (Pani/TiO₂/GN) using a simple methodology, and their application as a supercapacitor electrode material for energy storage. The Pani/TiO₂/GN hybrid was prepared by a simple approach by simultaneous generation of Pani and TiO₂ in situ from aniline and titanium iso-propoxide, respectively, in the presence of GN under ice bath conditions. The incorporation of GN improved the electrical conductivity of Pani and helped to decrease the charge transfer resistance, whereas TiO₂ generation by an in situ method increased the surface area considerably and enhanced the capacitance of the Pani/TiO₂/GN hybrid. TEM showed that Pani and TiO₂ were well incorporated and coated on the GN successfully. The shift of the peaks in the FTIR spectrum and XRD pattern of the Pani/TiO₂/GN hybrid compared to their pure counterparts suggested that TiO₂ and Pani had been perfectly coated on the GN, and there was a strong interaction among Pani, GN, and TiO₂ particles. The electrochemical performance of the as-prepared Pani/TiO₂/GN hybrid electrode showed a high specific capacitance of 403.2 F g^?1 at a current density of 2 A g^?1 and excellent cycling stability for up to 1000 cycles. This suggested that the effective incorporation of GN and TiO₂ into Pani and the high surface area could simultaneously increase the electrochemical capacitance and cyclic stability of the Pani/TiO₂/GN hybrid, leading to superior electrochemical performance.

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Graphical abstract The electrochemical performance of as-prepared Pani/TiO₂/GN hybrid electrode showed a high specific capacitance of 403.2 F g^?-1 at a current density of 2 A g^?-1 and excellent cycling stability for up to 1000 cycles. This suggested that the effective incorporation of GN and TiO₂ into Pani and the high surface area could simultaneously increase the electrochemical capacitance and cycle stability of the Pani/TiO₂/GN hybrid, leading to superior electrochemical performance.