Synthesis and Changes of Conductivities and Thermal Stabilities of 4,4′-Oxybis [N-(3,4-Dihydroxybenzilidene) Aniline] Chelate Polymers

In this study novel metal coordination polymers were synthesized such as poly-4,4′-oxybis[N-(3,4-dihydroxybenzilidene)aniline] (P-3,4-HBA) containing Cu, Co, Pb, Ni, Zn, Cd, Cr, Mn and Zr metals in the polymer backbone. The polymers are abbreviated as P-3,4-HBA-Cu, P-3,4-HBA-Co, P-3,4-HBA-Pb, P-3,4-HBA-Ni, P-3,4-HBA-Zn, P-3,4-HBA-Cd, P-3,4-HBA-Cr, P-3,4-HBA-Mn and P-3,4-HBA-Zr, respectively. To confirm the structures FT-IR, UV-vis, ¹H and ¹³C-NMR spectral techniques were used. Additional characterization of the polymers was made by size exclusion chromatography (SEC), TGA-DTA and solubility tests. By TGA analysis, P-3,4-HBA-Zr was the most stable polymer against thermal degradation among those synthesized. In addition, it was found that, with exception of P-3,4-HBA-Cr, the other synthesized polymers have little solubility in many organic solvents and water. According to SEC results, P-3,4-HBA-Cr has a single fraction containing 21–22 mer units. Electrical conductivities of the monomer and polymers were measured by the four-point probe technique. The polymers were semiconductors; and, some of their conductivities can be increased via doping with iodine. According to the electrical conductivities of the undoped P-3,4-HBA-Cr and P-3,4-HBA-Zr polymers have nearly ten-times higher conductivities in comparison to the others. From UV-vis measurements, the optical band gaps (E _g ) of 3,4-HBA and P-3,4-HBA-Cr were 2.58 and 2.39 eV, respectively. This result indicates that P-3,4-HBA-Cr has a lower band gap and consequently higher electrical conductivity than 3,4-HBA. Thus, with good solubility, high electrical conductivity and high thermal stability P-3,4-HBA-Cr may be considered as the most useful metal coordination polymer among those synthesized.     

Composition of the essential oil of Stachys sericantha,S. gaziantepensis,and S. mardinensis (Lamiaceae) from Turkey

The genus Stachys L. one of the largest genera of Lamiaceae and Stachys species are used by many people for the therapeutic value of their essential oils. In this study, water-distilled essential oil of three species of Stachys was analysed. The analysis was performed by using gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) systems simultaneously. The major components found were hexadecanoic acid (23.7%), dodecanoic acid (11.3%), and caryophyllene oxide (10.7%) for S. sericantha P.H. Davis (endemic); α-pinene (53%), β-pinene (8.2%) for S. gaziantepensis M. Dinc and S. Do?u (endemic); Menthyl acetate (15.3%), isomenthone (15.0%), pulegone (10%), spathulenol (7.0%), and caryophyllene oxide (6.7%) for S. mardinensis (Post) R. Mill.     

The effects of different levels of orange fiber and fat on microbiological, physical, chemical and sensorial properties of sucuk

The effects of orange fiber and fat levels on the physical, chemical and microbiological properties of sucuk (Turkish dry-fermented sausage) were investigated. Different levels of orange fiber (0, 2 and 4%) were added to sucuk batters with different levels of fat (10, 15 and 20%). Sucuk samples were analyzed during ripening. Lactic acid bacteria, Micrococcus/Staphylococcus and pH value were effected very significantly by orange fiber. Orange fiber caused a decrease in residual nitrite levels and an increase in the TBARS values. L^∗ and b^∗ values of sucuk samples increased with the use of fiber. Fiber use also decreased the cooking loss. No statistically significant difference was found between control and 2% fiber groups in terms of texture, color, odor taste and general acceptability scores. While fat levels had significant effects on cooking loss, taste and L^∗ values, ripening time effected all analyzed parameters.     

A Supervised Constant Modulus Algorithm for Blind Equalization

Blind equalization is a technique for adaptive equalization of a communication channel without the aid of the usual training sequence. Although the Constant Modulus Algorithm (CMA) is one of the most popular adaptive blind equalization algorithms, it suffers from slow convergence rate. A novel enhanced blind equalization technique based on a supervised CMA (S-CMA) is proposed in this paper. The technique is employed to initialize the coefficients of a linear transversal equalizer (LTE) filter in order to provide a fast startup for blind training. It also presents a computational study and simulation results of this newly proposed algorithm compared to other CMA techniques such as conventional CMA, Normalized CMA (N-CMA) and Modified CMA (M-CMA). The simulation results have demonstrated that the proposed algorithm has considerably better performance than others.     

Effects of modified atmosphere and vacuum packaging on microbiological and chemical properties of rainbow trout (Oncorynchus mykiss) fillets

Microbial (psychrotrophic, mesophilic aerobic bacteria and Enterobacteriacae counts), and chemical analysis [pH, total volatile bases nitrogen (TVB-N), lipid oxidation (Thiobarbituric acid reactive substance, TBARS)] of rainbow trout (Oncorynchus mykiss) fillets in air (control), vacuum and modified atmosphere packaging (MAP) with various gas mixtures conditions at 4+/-1 degrees C were determined. The gas mixtures evaluated were 100% CO2, 2.5% O2+7.5% N2+90% CO2 and 30% O2+30% N2+40% CO2. Psychrotrophic bacteria count was above 1 x 10(7) cfu/g on the 12th day in 100% CO2. However; mesophilic bacteria count was below 1 x 10(6) cfu/g at the end of the 14-day storage period. Enterobacteriaceae count was significantly lower in samples packaged with MAP. Lipid oxidation increased rapidly after 6 days of storage in the samples containing 30% O2. While minimum TBARS values were recorded in fillets containing 100% CO2 and vacuumed fillets, the lowest TVB-N values were obtained in fillets with 100% CO2.     

A Novel Strategy as a Potential Rapid Therapy Modality in the Treatment of Corneal Ulcers: Fluconazole/Vancomycin Dual Drug-Loaded Nanofibrous Patches

Corneal ulcer, which is brought on by a breach in the epithelial barrier, is a dangerous infection of the avascular corneal stroma. New treatment strategies are needed, suppressing the aggressive nature of the disease and including a combination of different drugs. In this study, vancomycin (VAN) and fluconazole (FLU) dual-drug loaded dual-layered polyvinyl alcohol and gelatin (PVA/GEL) nanofibrous patches are produced by electrospinning. Scanning electron microscopy (SEM) images show smooth surfaces are obtained for both pure and drug-loaded nanofibrous patches. The tensile test results report that loading the FLU and VAN separately into the PVA/GEL patches decrease both the tensile strength and elongation at break and it is further reduced when combining two drug-loaded layers in one patch. According to drug release results, the FLU and VAN-loaded nanofibrous patches show a controlled release profile extending up to 96 h. Moreover, PVA/GEL/FLU, PVA/GEL/VAN, and PVA/GEL/FLU/VAN nanofibrous patches display significant antimicrobial activity against Candida albicans and Staphylococcus aureus. SEM, 4'-6diamidynofenyloindol (DAPI) staining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay show that PVA/FLU and PVA/GEL/FLU/VAN nanofibrous patches have a superior effect on NIH3T3 cell spreading and proliferation. The novelty of this study lays in the development of a potential dual drug rapid treatment for corneal ulcers of aggressive nature.     

Experimental and Numerical Modal Characterization for Additively Manufactured Triply Periodic Minimal Surface Lattice Structures: Comparison between Free-Size and Homogenization-Based Optimization Methods

Homogenization-based topology optimization (HMTO) is one of the most extensively used grading methods to generate functionally graded lattice structures (FGLs). However, it requires a precharacterization of the lattices, which is time-consuming. As a remedy, free-size optimization-based graded lattice generation (FOGLG) is explored as an alternative method to generate the FGLs. This article builds on the authors’ previous work in which the HMTO and FOGLG approaches are studied to improve the dynamic characteristic of a design by using a single lattice type, namely, double gyroid (DG) structure. To show applicability of the proposed methods, different lattice types including diamond (D), gyroid (G), and I-WP are employed to create FGLs herein. The frequency response analysis is performed, and the results from HMTO and FOGLG are compared in terms of their accuracy and efficiency. The optimized designs are then reconstructed by relative density mapping (RDM) and enhanced relative density mapping (ERDM) methods. The fabricated test samples made of cobalt–chromium using the direct metal laser melting (DMLM) technique are then experimentally validated using a laser vibrometer. The results reveal that HMTO and FOGLG can be used on the lattice types with a variety of configurations and relative densities.     

Rapid Biocatalytic Synthesis of Aromatic Acid CoA Thioesters by Using Microbial Aromatic Acid CoA Ligases

Chemically labile ester linkages can be introduced into lignin by incorporation of monolignol conjugates, which are synthesized in planta by acyltransferases that use a coenzyme A (CoA) thioester donor and a nucleophilic monolignol alcohol acceptor. The presence of these esters facilitates processing and aids in the valorization of renewable biomass feedstocks. However, the effectiveness of this strategy is potentially limited by the low steady-state levels of aromatic acid thioester donors in plants. As part of an effort to overcome this, aromatic acid CoA ligases involved in microbial aromatic degradation were identified and screened against a broad panel of substituted cinnamic and benzoic acids involved in plant lignification. Functional fingerprinting of this ligase library identified four robust, highly active enzymes capable of facile, rapid, and high-yield synthesis of aromatic acid CoA thioesters under mild aqueous reaction conditions mimicking in planta activity.