A biosensor platform based on amine functionalized conjugated benzenediamine-benzodithiophene polymer for testosterone analysis

A novel benzenediamine-benzodithiophene polymer is synthesized for use in biosensor fabrication for the detection of testosterone. The sensory platform is constructed via drop coating on a screen-printed carbon electrode, using poly(benzenediamine-Bis[(2-ethylhexyl)oxy]benzodithiophene) (pBDBT) as the polymer layer. Testosterone antibodies are immobilized on the polymer-coated electrode surface via glutaraldehyde, which binds to the surface through the amino functional groups on the polymer backbone. The changes in the surface features due to testosterone binding are investigated via electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry as well as contact angle measurements. Surface morphology of the modified electrodes is characterized by atomic force microscopy. The linear range and limit of detection of the sensor are calculated. Impact of possible interfering compounds is investigated. Furthermore, the sensory platform is utilized for testosterone analysis in synthetic biological fluids.     

Modeling non-Gaussian time-varying vector autoregressive processes by particle filtering

We present a novel and general methodology for modeling time-varying vector autoregressive processes which are widely used in many areas such as modeling of chemical processes, mobile communication channels and biomedical signals. In the literature, most work utilize multivariate Gaussian models for the mentioned applications, mainly due to the lack of efficient analytical tools for modeling with non-Gaussian distributions. In this paper, we propose a particle filtering approach which can model non-Gaussian autoregressive processes having cross-correlations among them. Moreover, time-varying parameters of the process can be modeled as the most general case by using this sequential Bayesian estimation method. Simulation results justify the performance of the proposed technique, which potentially can model also Gaussian processes as a sub-case.     

EPDM Elastomer and Biothermoplastic Polyester-based Silicate-layered Multifunctional Nanocomposites Incorporated with Poly(MA-alt-α-olefin)-g-APTS-SiO2 NPs and PP-g-MA by Reactive Extrusion Nanotechnology

Multifunctional polymer blend nanocomposites consisting EPDM elastomer as a matrix polymer, bioengineering polyesters (PLA and PCL), PP-g-MA compatibilizer and covalently encapsulated colloidal alternating reactive copolymer-g-γ-aminopropyl trimethoxysilane-silica nanoparticles as reactive compatibilizer nanofillers, and organoclay (reactive ODA-MMT and complexable DMDA-MMT) nanofillers were fabricated in melt by a one-step reactive extrusion nanotechnology. The effects of bioengineering polyesters and their molecular mass, origin of organology, and reactive PP-g-MA compatibilizer were evaluated. Unique nanostructures, lower particle sizes and crystallinity, SEM–TEM morphologies, higher thermal behaviors, good mechanical and rheological properties of thermoplastic multifunctional nanocomposites were evaluated.     

Effects of material and treatment parameters on noise‐control performance of compressed three‐layered multifiber needle‐punched nonwovens

The effects of material and treatment parameters on airflow resistivity and normal‐incidence sound absorption coefficient (NAC) of compressed three‐layer nonwoven composites have been studied. Material parameters included fiber size and porosity, and treatment factors included applied pressure and duration of compression. Fibers used included poly(lactic acid) (PLA), polypropylene (PP), glassfiber, and hemp. Three‐layered nonwoven composites were classified based on material content and fiber blend. LHL and PGP were sandwiched structures consisting of PLA/Hemp/PLA and PP/glassfiber/PP layers, respectively. PGI consisted of three layers of an intimate blend of PP and glassfiber. Statistical models were developed to predict air flow resistivity from material parameters and the change in air flow resistivity from compression parameters. Independent variables in the first model were porosity and fiber size and, in the latter model, were compressibility, pressure, and initial material parameters. An increase in air flow resistivity was found with increased compression. No significant effect of compression duration was detected. Two additional statistical models were developed for the prediction of sound absorption coefficient based on material and treatment parameters. The independent variables of the first model were air flow resistivity, thickness, and frequency, and those of the second model were compressibility, initial thickness, and initial density of the composite, diameter and density of the fiber, compression pressure, and frequency. A decrease in sound absorption coefficient was detected with increasing compression, while no effect of duration was detected. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The influence of thermal treatment on color response of wood materials

In this study, the influence of thermal treatment on color changes of six different wood materials was investigated. Test specimens were subjected to three different temperatures (160, 180, and 200°C) and durations (3, 5, and 7 h). The data obtained were analyzed using variance analysis, and then the statistical analysis of Tukey's test was conducted. After this treatment, the results showed that the color values of the six wood materials changed significantly. It was determined that L* (lightness) values decreased; the minimum change in L* was ～4% for Juniper wood, and the maximum change in L* was ～64% for Beech wood. The values of a* (red coordinate) and b* (yellow coordinate) showed varying levels of increase when the heat treatment conditions were 160°C for 3 to 7 h (not including Cherry wood), but the values began to decrease slowly after treatment at 160°C for 5 h. The ratios of the minimum and maximum color change in a* and b* were determined at 180°C for 3 h in Plane wood, 200°C for 5 h in Hazelnut wood, and 160°C for 3 h and 200°C for 7 h in Beech wood. As temperature and duration were increased, the minimum total color change (ΔE) was ～3.5% for 160°C at 3 h in Cypress wood, and the maximum total color change (ΔE) was ～50% for 200°C at 7 h in Cypress wood. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Ovarian Cancer: In Search of Better Marker Systems Based on DNA Repair Defects

Ovarian cancer is the fifth most common female cancer in the Western world, and the deadliest gynecological malignancy. The overall poor prognosis for ovarian cancer patients is a consequence of aggressive biological behavior and a lack of adequate diagnostic tools for early detection. In fact, approximately 70% of all patients with epithelial ovarian cancer are diagnosed at advanced tumor stages. These facts highlight a significant clinical need for reliable and accurate detection methods for ovarian cancer, especially for patients at high risk. Because CA125 has not achieved satisfactory sensitivity and specificity in detecting ovarian cancer, numerous efforts, including those based on single and combined molecule detection and “omics” approaches, have been made to identify new biomarkers. Intriguingly, more than 10% of all ovarian cancer cases are of familial origin. BRCA1 and BRCA2 germline mutations are the most common genetic defects underlying hereditary ovarian cancer, which is why ovarian cancer risk assessment in developed countries, aside from pedigree analysis, relies on genetic testing of BRCA1 and BRCA2. Because not only BRCA1 and BRCA2 but also other susceptibility genes are tightly linked with ovarian cancer-specific DNA repair defects, another possible approach for defining susceptibility might be patient cell-based functional testing, a concept for which support came from a recent case-control study. This principle would be applicable to risk assessment and the prediction of responsiveness to conventional regimens involving platinum-based drugs and targeted therapies involving poly (ADP-ribose) polymerase (PARP) inhibitors.     

Photoluminescent electrospun polymeric nanofibers incorporating germanium nanocrystals

The photoluminescent germanium nanocrystals (Ge-NCs) were successfully incorporated into electrospun polymeric nanofiber matrix in order to develop photoluminescent nanofibrous composite web. In the first step, the synthesis of Ge-NCs was achieved by nanosecond pulsed laser ablation of bulk germanium wafer immersed in organic liquid. The size, the structural and the chemical characteristics of Ge-NCs investigated by TEM, XPS, XRD and Raman spectroscopy revealed that the Ge-NCs were highly pure and highly crystalline having spherical shape within 3–20 nm particle size distribution. In the second step, Ge-NCs were mixed with polyvinyl alcohol (PVA) polymer solution, and then, Ge-NC/PVA nanofibers were obtained via electrospinning technique. The electrospinning of Ge-NCs/PVA nanoweb composite structure was successful and bead-free Ge-NCs/PVA nanofibers having average fiber diameter of 185 ± 40 nm were obtained. The STEM analysis of the electrospun Ge-NCs/PVA nanofibers elucidated that the Ge-NCs were distributed homogeneously in the polymeric nanofiber matrix. The UV–Vis absorption and photoluminescence spectroscopy studies indicated the quantum confinement effect of Ge-NCs on the optical properties of the electrospun Ge-NCs/PVA nanoweb.     

Effects of sizing materials on the properties of carbon fiber‐reinforced polyamide 6,6 composites

This article aims to study the effect of the sizing materials type on the mechanical, thermal, and morphological properties of carbon fiber (CF)‐reinforced polyamide 6,6 (PA 6,6) composites. For this purpose, unsized CF and sized CFs were used. Thermogravimetric analysis was performed, and it has been found that certain amounts of polyurethane (PU) and PA sizing agents decompose during processing. The effects of sizing agent type on the mechanical and thermomechanical properties of all the composites were investigated using tensile, Izod impact strength test, and dynamic mechanical analysis. Tensile strength values of sized CF‐reinforced composites were higher than that of unsized CF‐reinforced composites. PA and polyurethane sized CF‐reinforced composites exhibited the highest impact strength values among the other sized CF‐reinforced composites. PU and PA sized CF‐reinforced composites denoted higher storage modulus and better interfacial adhesion values among the other sizing materials. Scanning electron microscope studies indicated that CFs which were sized with PU and PA have better interfacial bonding with PA 6,6 matrix among the sized CFs. All the results confirmed that PA and PU were suitable for CF's sizing materials to be used for PA 6,6 matrix. POLYM. COMPOS., 34:1583–1590, 2013. © 2013 Society of Plastics Engineers