Synthesis,Characterization, Cytotoxicity and Detailed HSA Interaction of New Zinc(II) Complexes Containing Dithiocarbamate and Heterocyclic N-donor Ligands

[Zn(ph-dtc)(bpy)]Cl (1) and [Zn(ph-dtc)(phen)]Cl (2) (where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline and ph-dtc = phenylacetichydrazidedithiocarbamate) were synthesized and characterized by elemental analysis and spectroscopic methods (FT–IR, UV–Vis and ¹H NMR). Zn(II) complexes were examined in biological tests in vitro using MCF-7 breast cancer cell line. Both complexes showed significant cytotoxic activity against human breast cancer MCF-7 cells. The interaction of above compounds with Human Serum Albumin (HSA) was investigated by means of various spectroscopic (at pH ～ 7.4 in Tris–HCl buffer medium) and molecular docking methods. The fluorescence data showed that 1 and 2 quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constants (K_b) and the number of binding sites (n ～ 1) were calculated. The thermodynamic analysis suggested that hydrophobic interaction played major roles in the binding of 1 or 2 to HSA. The distance r between protein and the above-mentioned compounds was obtained according to fluorescence resonance energy transfer. The conformational changes of protein secondary structure in the presence of Zn(II) complexes were proven using UV–Vis absorption and circular dichroism techniques. Also, docking results confirmed the spectroscopic results.     

Photodynamic Antimicrobial Cellulosic Material Through Covalent Linkage of Protoporphyrin IX onto Lyocell Fibers

Here, we report the preparation of porphyrin-functionalized Lyocell fibers according to an azide-alkyne click concept. First, azido-modified Lyocell fibers and alkynylated protoporphyrin building blocks were prepared through alkoxysilane chemistry and Steglich esterification, respectively. Lyocell fibers were pre-activated by swelling in organic solvents in order to increase the accessibility of hydroxyl groups in the subsequent silanization process. The azide-equipped cellulosic matrix reacted with the propargyl groups of the protoporphyrin IX derivative in a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC), by which protoporphyrin IX was introduced onto the surface of the Lyocell fibers. The modified building blocks and the final functionalized cellulosic materials were comprehensively characterized by FTIR, NMR, UV/Vis spectroscopy and elemental analysis. Photo-bactericidal activity of modified fibers against 2?gram-positive bacteria strains, including Staphylococcus aureus and Bacillus subtilis, were investigated and compared to those of unmodified and azido-modified Lyocell fibers. The results confirmed the photo-antibacterial activity of the synthesized fibers against both bacteria strains.     

Efficient synthesis of novel bis(arylmethylidenes) of the 2,2-dimethyl-1,3-dithian-5-one system

In a mixture consisting of catalytic quantities of diethylamine, sodium dodecyl sulfate, and a zirconium salt in water, 2,2-dimethyl-1,3-dithian-5-one undergoes double aldol condensation with two folds of aromatic aldehydes at 50^oC to yield the respective bisarylmethylidene derivatives efficiently within 2?h. The products precipitate in the reaction mixtures spontaneously, perhaps due to high polarity of the medium, avoiding time-consuming and expensive chromatographic separations. Thus, products are isolated easily by a simple filtration and recrystallization from ethyl acetate, while the filtrate was recycled successfully for subsequent reactions.     

Statistical factor-screening and optimization in slurry phase bioremediation of 2,4,6-trinitrotoluene contaminated soil

Since slurry phase bioremediation is a promising treatment for recalcitrant compounds such as 2,4,6-trinitrotoluene (TNT), a statistical study was conducted for the first time to optimize TNT removal (TR) in slurry phase. Fractional factorial design method, 2(IV)(7-3), was firstly adopted and four out of the seven examined factors were screened as effective. Subsequently, central composite design and response surface methodology were employed to model and optimize TR within 15 days. A quadratic model (R(2) = 0.9415) was obtained, by which the optimal values of 6.25 g/L glucose, 4.92 g/L Tween 80, 20.23% (w/v) slurry concentration and 5.75% (v/v) inoculum size were estimated. Validation experiments at optimal factor levels resulted in 95.2% TR, showing a good agreement with model prediction of 96.1%. Additionally, the effect of aeration rate (0-4 vvm) on TR was investigated in a 1-liter bioreactor. Maximum TR of 95% was achieved at 3 vvm within 9 days, while reaching the same removal level in flasks needed 15 days. This reveals that improved oxygen supply in bioreactor significantly reduces bioremediation time in comparison with shake flasks.     

One-step synthesis of tenorite (CuO) nano-particles from Cu4 (SO4) (OH) 6 by direct thermal-decomposition method

In this research work, CuO nano-particles were synthesized at 750 °C (for 2 h) by the direct thermal-decomposition method using the brochantite as precursor. The nano-particles were characterized using X-ray diffraction (XRD), energy dispersive spectra (EDS), infrared spectrum (IR), and scanning electron microscope (SEM). SEM image showed that the CuO nano-particles were of rod shape with diameter and length of 235 ± 5 nm and 856 ± 5 nm, respectively. As a result, this method could be used at an industrial scale as a cheap and convenient way in production of pure tenorite nano-particles.     

Leakage suppression in human airway tree segmentation using shape optimization based on fuzzy connectivity method

Human airway tree segmentation from computed tomography (CT) images is a very important step for virtual bronchoscopic applications. Imaging artifacts or thin airway walls decrease the contrast between the air and airway wall and make the segmented region to leak from inside of the airway to the parenchyma. This in turn begins the leakage phenomenon to build and then large parts of the lung parenchyma might be erroneously marked as the airway tree instead. Unfortunately, existing methods typically do not sufficiently extract the necessary peripheral airways needed to plan a procedure. In this article, we propose a new shape based human airway segmentation scheme to suppress the leakage into surrounding area which is based on fuzzy connectivity (FC) method. Complex medical image features such as weak boundary edges in the CT images of the lung parenchyma have fuzzy properties and can be described by FC in many extents. Our method aims to embed a mathematical shape optimization approach in a FC algorithm. Using the partial derivatives of the image data that is minimized with respect to the polar angle and cylindrical axis direction, a proper cost function based on cylindrical features of the airway branches is proposed. This approach retains the cylindrical properties of the airway branches during the segmentation process. The proposed cost function includes two parts named cylindrical‐shape feature and smoothed final error term. The former term arranges the underlying voxels on a cylindrical shape and the latter term controls and smoothes the final error considering the local minima's problem. To evaluate the efficiency of our proposed optimization technique in term of segmentation accuracy, the cost function is first applied to the simulated data with the spongy shape of leakage and the leakage origin. The impact of each term of the proposed cost function on the final error and the convergence of the algorithm are also evaluated. Then, the cost function with best proper parameters is applied to real image dataset. Comparisons of the results on multidetector CT chest scans show that our segmentation algorithm outperforms the fuzzy region growing algorithm. Quantitative comparisons with manually segmented airway trees also indicate high sensitivity of our segmentation algorithm on peripheral airways. On the basis of the results, it is concluded that the proposed method is able to detect more branches up to the sixth generation with no leakage which provides 2–3 more generations of airways than several other methods do. The extracted airway trees enable image‐guided bronchoscopy to go deeper into the human lung periphery than past studies. The novelty of our proposed method is to apply a shape optimization approach embedded in an efficient FC segmentation algorithm. Hence, our method prevents leakage from its origination in contrast to most previously published works that just set their algorithms to repeat the segmentation steps to reduce leakage. As our results indicate leakage suppression in human airway segmentation instead of readjusting the segmentation parameters, more airway branches can be extracted with correct shape. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 71–84, 2013     

The effect of 3-(triethoxy silyl) propyl amine concentration on surface modification of multiwall carbon nanotubes

Abstract

The influence of 3-(triethoxy silyl) propyl amine (TESPA) concentration on Multi Wall Carbon Nanotubes (MWCNTs) modification, is experimentally investigated. The MWCNTs modification were performed by 150, 75 and 25 weight percent (wt.%) of TESPA with respect to MWCNTs weight and the properties of the prepared samples were compared with each other and pristine MWCNTs. The MWCNTs silylation has been confirmed by Fourier Transformation Infrared Spectroscopy due to O-H stretching absorption peak disappearing. The 75?wt.% silyl grafted MWCNTs with increasing at about 26.7% in mean value diameters size owns more uniform morphology among the samples based on Scanning Electron Microscopy images. Also, Thermo Gravimetric Analysis shows that this sample has higher thermal stability because of lower weight loss (9.97%) in coupling agent decomposition temperature range at about 119.5–480?°C. Furthermore, X-Ray Diffraction indicates that the mentioned sample has higher level of amorphous structure with 39% reduction in crystallite size in comparison with the pristine MWCNTs. So, the 75?wt.% of TESPA introduced as the optimal concentration for this type of MWCNTs modification.

• Highlights

• Introduction of silyl compounds as a proper coupling agent to modify the carbon nanotube surfaces

• Determination of optimal silyl compounds concentration to modify the carbon nanotube surface

• Cristallinity in XRD pattern can determine the success of CNTs grafted with silyl compounds

     

Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering

Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber–hydrogel composite for GAG content and in two-layer electrospun fiber–hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering.     

Preferred orientation and shape of electrodeposited nanocrystalline Al-Mg alloy dendrites

Al-Mg electrodeposition yielded face centered cubic (fcc)-Al(Mg) nanocrystalline featherlike dendrites consisting a stem and several arms exhibiting strong morphological anisotropy and microtexture. Various morphological features and preferred orientations lead to a crystallographic model suggesting that the stem and arms contain nanograins with their high energy {011} and {001} planes perpendicular to the growth directions. The dendrites grow with both low ({111}) and high ({001}) energy planes of nanograins as growth planes. The shape of these dendrites was explained using preferred orientations of nanograins within.