Preparation and characterization of mucoadhesive gels containing pentoxifylline loaded nanoparticles for vaginal delivery of genital ulcer

Iranian Polymer Journal - Mucoadhesive gel formulations containing pentoxifylline (PTX)-loaded nanoparticle (NP) for the treatment of genital ulcer were prepared and evaluated. In that context,...     

Synthesis and Characterization of Acrylonitrile-co-Divinylbenzene (AN/DVB) Polymeric Resins for the Isolation of Aroma Compounds and Anthocyanins from Strawberry

In this study, the aroma compounds and anthocyanins were recovered from strawberry by using crosslinked acrylonitrile-co-divinylbenzene (AN/DVB) adsorbent. Suspension polymerization technique was utilized for the synthesis of adsorbent resins with a porous character, and the optimal AN/DVB and diluent/DVB ratios of the adsorbent were determined as 0.5 and 1.5, respectively. After that, packed bed applications were carried out using this adsorbent resin. The adsorption process was accomplished by passing 240 ml strawberry juice through the column, and the desorption process was completed by obtaining the eluate from the column in 20 ml methanol. Aroma compounds analyses were applied to the six samples of the column output and eluate which desorbed from the columns. All experiments were carried out in gas chromatography–mass spectrometry. It was determined from the total peak areas that 90 % of the aroma components of the strawberry juice were isolated by the packed bed column. Total monomeric anthocyanins were determined via the pH differential method, and 279.5 and 256.58 mg Pg-3-glu/kg strawberry were found in the strawberry juice and eluate, respectively. Approximately, 92?±?1 % of the total monomeric anthocyanins were isolated from the sample. Finally, the prepared column system was reused six times by regeneration and each use gave a similar performance.     

Determination of membrane integrity in onion tissues treated by pulsed electric fields: Use of microscopic images and ion leakage measurements

The influence of electrical field strength and number of pulses on cell rupture of onion tissues was investigated by two different methods to understand the changes in cell viability of plant tissues after pulsed electric field (PEF) treatment. The impact of pulsed electric field parameters on cell integrity of 20 mm diameter, 4 mm thick disks of Sabroso onions (Allium cepa L.) was determined by ion leakage measurements and microscopic method. The effect of treatments on cellular integrity was visualized by neutral red staining of the onion cells. Cell rupture is essential for optimal process design before extraction of desirable compounds and/or drying of plant tissues. Experimental results were obtained for onion disks treated with electrical pulses at field strengths of E ≈ 167 V/cm and 333 V/cm, pulse width of ti = 100 μs, frequency of f = 1 Hz and the number of pulses, n = 1 to 100. At 167 V/cm electric field strength treatment cell rupture was not observed however ion leakage increased and air spaces around cell walls disappeared, most likely due to changes in cell membrane permeability. Irreversible cell rupture occurred at 333 V/cm. Ion leakage values and ruptured cells count were increased with increasing pulse number. 92.2 ± 5.9 % of the onion cells were ruptured after 333 V/cm and 100 pulse treatment. Small plant cells that are located near vascular bundles and upper epidermis showed higher resistance to pulsed electric field treatments.Industrial RelevanceThe aim of this study was to determine the response of plant tissues with different cell type to the pulse electric field treatment. Two different methods, neutral red staining and ion leakage, were used to visualize and determine the cell rupture on onion tissues. Industry may choose one of these methods to evaluate treatment efficiency on the basis of cell rupture; especially ion leakage measurements which require lower investment cost and easy to apply or microscopic method for visualize the cells layer by layer. The paper stresses the importance of cell type, size and distribution of cells were found to the ability to resist cell rupture during pulsed electric field treatment. It is critical to explain overall changes caused by PEF on the structure of plant tissue at a cellular level in order to optimize the quality of PEF processed foods.     

High-modulus steels reinforced with ceramic particles through ingot casting process

High Young's modulus steels can be fabricated based on the concept of metal matrix composites. In this paper, a number of reinforcing ceramic phases with high Young's modulus are assessed and selected to design compositions for high-modulus steels based on thermodynamic calculations. The steel matrix composites reinforced with boride and carbide phases are produced through ingot casting and are processed thermomechanically to strips following standard processing routes for automotive products. The results show that the Young's modulus of steels in the as-cast condition can be increased using borides and carbides. However, further down-stream processing via conventional thermomechanical processing leads to a gradual degradation of the Young's modulus due to extensive void formation. The opportunities and challenges of ceramic-reinforced high-modulus steels produced via conventional ingot casting and thermomechanical processing for the automotive market are discussed.     

Surface coating of polyamide reverse osmosis membranes with zwitterionic 3‐(3,4‐dihydroxyphenyl)‐l‐alanine (l‐DOPA) for forward osmosis

To overcome low permeability and fouling problems of membranes used in FO processes, modification is needed to improve the hydrophilicity, permeability and selectivity of membranes. In this work, thin film composite (TFC) commercial polyamide RO membranes (BW30‐LE, SW30‐HR, AG and AC) were functionalized with zwitterionic l ‐DOPA. The effect of l ‐DOPA on the morphology of membranes was determined via SEM, FT‐IR, AFM and contact angle analysis. The l ‐DOPA modified BW30‐LE membrane showed excellent properties with 46° contact angle and 3.8 L/m²hbar water permeability and 0.83 L/m²h salt permeability. Although, l ‐DOPA modified BW30‐LE membrane had the highest water flux and hydrophilicity, l ‐DOPA modified SW30‐HR membrane showed higher FO flux with 9.38 L/m²h than BW 30 membrane with 3.5 L/m²h at 50 g/L NaCl draw solution. Introducing hydroxyl and carboxyl ionic groups on the membrane surface with l ‐DOPA coating enhanced the FO performance and water permeability which provide a new insight in FO applications.     

Pull-out behavior of prestressing strands in steel fiber reinforced concrete

This paper presents the results of an experimental study investigating the effects of steel fibers on the mechanical properties of concrete and the enhancement of bond strength of prestressing strands in steel fiber reinforced concrete (SFRC). The first part of the experimental program consisted of compression, tension and flexural tests on SFRC. Two types of steel fibers with 30 mm and 60 mm fiber lengths were used with five different fiber contents. The second part of the study consisted of simple pull-out tests on 12.7 mm and 15.2 mm diameter seven-wire untensioned prestressing strands embedded in concrete blocks. The pull-out tests were conducted with two different fiber lengths and five different fiber contents for each strand diameter. The steel fibers were observed to improve the pull-out resistance of strands by controlling the crack growth inside concrete blocks.     

An Experience in Testing an Object-Oriented Satellite Control System

This paper presents our experience in testing an object-oriented software: the Telemetry and Telecommand System (TMTC). The TMTC runs along a distributed architecture comprising microcomputers plus a Data Base server inter-connected via LAN under TCP/IP protocol. This in-house developed software was designed according to the Object Modelling Technique (OMT). TMTC's software components represent clusters of classes related to functionality and building blocks of generic services. In order to establish a systematic way for the testing activities we have adapted the Hierarchical Approach (HA), proposed by Shel Siegel, to the experience and culture of the team. The HA, focusing on object-oriented testing, has fitted well with the aim of detecting as many faults as possible in the early phases of the development. In the HA almost all classes are individually tested before being gradually integrated into groups. Groups of classes are defined according to the scenarios specified in the system design phase. This has considerably reduced the testing effort. This paper also discusses the system class number in comparison with the number of stubs and drivers generated for testing. The difficulties to test a distributed application for satellite controlling and monitoring are likewise examined.