A process control method for the electric current-activated/assisted sintering system based on the container-consumed power and temperature estimation

Journal of Thermal Analysis and Calorimetry - In this paper, the current, voltage and temperature of the container of an electric current-activated/assisted sintering (ECAS) system are measured and...     

Anodic Voltammetric Determination of an Atypical Antipsychotic Drug Amisulphide in Pharmaceutical Dosage Forms Using Electrochemical fsDNA Biosensor

Russian Journal of Electrochemistry - In this study, a new biosensor for amisulpride (ASP) determination is defined. The interaction between ASP and fish sperm double-stranded DNA (FSdsDNA) was...     

Effect of external pressure on the Kβ/Kα X-ray intensity ratios of 3d metals

The occupation numbers of the 3d transition metals are calculated as a function of pressure by means of the linear muffin-tin-orbital method. This data is used with the multiconfiguration Dirac-Fock (MCDF) X-ray intensity ratios (R) to estimate the variation of the intensity ratios of 3d metals with pressure. It is found that R decreases with pressure for the early 3d metals whereas it increases for the heavier 3d transition metals.     

Natural Melanin Nanoparticle‐decorated Screen‐printed Carbon Electrode: Performance Test for Amperometric Determination of Hexavalent Chromium as Model Trace

A biosensor was prepared with natural melanin nanoparticles (MNP) decorated on a screen‐printed carbon electrode (SPCE). Hexavalent chromium was selected as a well‐known heavy metal ion to be detected for testing the performance of novel biosensor. Natural MNP was extracted from cuttlefish (Sepia officinalis) ink. Surface decoration of SPCEs with MNP was performed by two different methods. The first one was layer‐by‐layer assembly (LBL‐A) for different cycle times(n). In the second one, plasma treatment of SPCE incorporated with evaporation‐induced self‐assembly (EI‐SA) techniques including different incubation times in MNP solutions. The performance of both modified SPCEs were tested for amperometric detection of Cr(VI) in various water samples, and peak reduction of Cr(VI) was determined at 0.33 V. Amperometric results showed wide linear ranges of 0.1–2 μM and 0.1–5 μM of Cr(VI) for SPCEs modified with 14n‐LBL‐A and 12h‐EI‐SA, respectively. The sensitivities of SPCEs modified with 14n‐LBL‐A and 12h‐EI‐SA techniques were 0.27 μA μM^?1 and 0.52 μA μM^?1, respectively. In addition, both modified SPCEs selectively detected Cr(VI) in a model aqueous system composed of certain other heavy metals and minerals, and tap and lake water samples. The LOD and LOQ values for 12h‐EI‐SA were 0.03 μM and 0.1 μM, respectively. This showed that MNP‐modified‐SPCEs generated via EI‐SA techniques have the potential to be an alternative to conventional detection methods such as ICP‐MS.     

Preparation and antimicrobial properties of LL‐37 peptide immobilized lignin/caprolactone polymer film

The use of biopolymers has gained priority in tissue engineering and biotechnology, both as dressing material and for enhancing treatment efficiency. There is a demand for new biopolymers designed with protease inhibitors and antimicrobials. LL‐37 is an important antimicrobial peptide in human skin and exhibits a broad spectrum of antimicrobial activity against bacteria, fungi, and viral pathogens. Using lignin which is an abundant carbohydrate polymer in nature and a polyacrylic acid, we prepared a lignin/caprolactone biodegradable film by plastifying caprolactone and polyacyrlic acid. Lignin/caprolactone biodegradable film was activated with CDI and then immobilized LL‐37 peptide. The structure was elucidated in terms of its functional groups by attenuated total reflectance‐fourier transform infrared spectroscopy (ATR‐FTIR), and the morphology of the lignin/caprolactone biodegradable film was characterized by scanning electron microscopy (SEM) before and after the immobilization process. The amount of LL‐37 immobilized was determined by ELISA method. It was found that 97% of LL‐37 peptide was successfully immobilized onto the lignin/caprolactone biodegradable film. Antimicrobial activity was determined in the lignin/caprolactone biodegradable film samples by quantitative antimicrobial activity method. According to the results, LL‐37 immobilized lignin/caprolactone biodegradable film samples were effective on test organisms; Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli. In bio‐compatibility assays, the ability to support tissue cell integration was detected by using 3 T3 mouse fibroblasts. Samples were examined under transverse microscope, non‐immobilized sample showed a huge cellular death, whereas LL‐37 immobilized lignin/caprolactone biodegradable film had identical cellular growth with the control group. This dual functional lignin/caprolactone biodegradable film with enhanced antibacterial properties and increased tissue cell compatibility may be used to design new materials for various types of biological applications.     

Antitumoral and MMP-2 inhibition activity of raloxifene or tamoxifen loaded nanoparticles containing dimethyl-β-cyclodextrin

A new nanoparticle formulation has been developed by using dimethyl-β-cyclodextrin (DM-β-CD) with raloxifene HCl or tamoxifene citrate. Both drugs are insoluble in water and represent as low bioavailibilities when given orally. Tamoxifen has an FDA approval for breast cancer prevention and the treatment. Raloxifene is approved for osteoprosis treatment. Both drugs were selected as a model drug antitumoural activity and MMP-2 inhibition studies were evaluated on breast cancer cell lines MCF-7 and MDA-MB 231. MMP-2 is known to be responsible for tumour invasion and initation the of angiogenesis. DM-β-CD and sodium taurocholate (NaTC) have been used as absorption enhancers to increase penetration effect of raloxifene/tamoxifen on the tumour cells and aimed to provide high antitumoral activity and MMP-2 inhibition results by developed nanoparticle formulations. The effects of two absorption enhancers were compared. The highest antitumoral activity was observed for DM-β-CD—raloxifene HCl nanoparticle formulation and also MMP-2 enzyme inhibit effectively.     

Selective detection of dopamine with poly(diphenylamine sulfonic acid) modified electrode in the presence of ascorbic acid

A glassy carbon electrode was modified with electropolymerized film of diphenylamine sulfonic acid (DPASA). Electropolymerization was performed by cyclic voltammetry in 0.1 M KCl solution. The modified electrode showed an excellent electrocatalytic effect towards oxidation of dopamine (DA) and ascorbic acid (AA). Electrostatic interaction between the negatively charged poly(DPASA) film and either cationic DA species or anionic AA species favorably contributed to the redox response of DA and AA. Anodic peaks of DA and AA in their mixture were well separated by ca 168 and −11.8 mV. The proposed modified electrode was utilized for selective determination of dopamine in the concentration range of 5.0 × 10^t7–2.0 × 10⁻⁵ M in the presence of high concentration of ascorbic acid. Detection limit was 6.5 × 10⁻⁹ M.     

Polyaniline/Maleic Acid Copolymers Composites: Synthesis and Characterization

Summary: Polyaniline/maleic acid copolymers composites were synthesized by chemical in situ polymerization of aniline using ammonium peroxidisulfate as oxidant, in the presence of water soluble copolymers containing carboxylic groups. Fine dispersions of composite materials, soluble in N,N-dimethylformamide or dimethyl sulfoxide were obtained which can be processed as thin films and membranes for application as proton-conductive materials for electrolyte membranes of fuel cells. The composites were characterized by FTIR spectroscopy and thermal methods.