Characterization of minocycline loaded chitosan/polyethylene glycol/glycerol blend films as antibacterial wound dressings

Wound care has been a challenging subject for medical teams and researchers. Bacterial infections are one of the most serious complications in injured skins that often affect healing process. Antibacterial wound dressings can be used to facilitate wound healing process. The purpose of this study is to fabricate chitosan (Chito)/polyethylene glycol (PEG) antibacterial wound dressing doped with minocycline, and to evaluate the influence of composition ratio on the blending properties of the films. To improve the mechanical properties of these films, we examined various amounts of glycerol as a plasticizer. Moreover, we investigated morphological and mechanical aspects, water uptake, degradation, water vapor transmission and wettability properties of the films prepared with various ratios of Chito/PEG/Gly. Assessment of mechanical properties revealed that film containing 80:20 ratio Chito/PEG with 40 PHR Gly content exhibits the highest ultimate tensile strength and elongation at break (9.74 MPa and 45.73% respectively). Furthermore, results demonstrated that upon increasing PEG and Gly contents, degradability and hydrophilicity of the films increased whereas water uptake decreased. Water vapor transmission rate of the films was close to the range of 530–1200 g/m²d, indicating that the as formed films are possible candidates for dressing low exudate wounds or burns. Minocycline loaded films exhibited a biphasic drug release profile and it was more effective on gram-positive bacteria than on gram-negative bacteria. The polymeric film with the highest amount of loaded drug (2%) exhibited insignificant cytotoxicity (88%) against normal fibroblast cell line.     

Evaluation of Centrifugal Casting Process Parameters for In Situ Fabricated Functionally Gradient Fe-TiC Composite

A gradient Fe-TiC composite was successfully produced via combination of in situ reaction with centrifugal casting techniques. Additionally, some of the effective parameters of the centrifugal casting process have been studied. Cast iron and ferrotitanium, which were used as raw materials, were melted using a high-frequency induction furnace coupled with centrifugal equipment. The microstructure and phase characterization of the fabricated composite was studied by scanning electron microscopy, optical microscopy, and X-ray diffraction. The results show that the production of a pearlite matrix composite reinforced by TiC particles is feasible. The distribution of TiC in the pearlitic matrix is completely uneven as a result of density difference between molten medium and TiC in the centrifugal casting process.     

Calculation of equilibrium composition in combustion products

For a specific combustion problem involving calculations of several species at equilibrium, it is much simpler to write a special computer program and calculate the concentrations, rather than to use a generalized computer program. To calculate these concentrations, one must solve a set of non-linear algebraic equations. This work describes a procedure in which the Newton-Raphson method and the successive substitution method are combined. It is was found that for these types of problems the value of unknowns and the nature of the equations are such that by adopting the two procedures simultaneously a much faster and reliable convergence is achieved. This study also shows what possible species should be considered for these calculations.     

Radiation pattern design of photonic crystal LED optimized by using multi-objective grey wolf optimizer

Photonic Network Communications - This paper proposes an effective method for shaping the radiation pattern intensity of photonic crystal (PhC) light-emitting diode (LED). In this method, the...     

Analytical cracking load estimation of Laminated Veneer Lumber (LVL) beams with holes

Predicting the load-carrying capacity of timber beams with holes cannot be performed by usual analysis methods if the failure of the beam is governed by the crack initiation and propagation around the hole at low load levels. Predicting the cracking load is an important design issue because it corresponds to the load-carrying capacity of the timber beam before the crack propagation. One of the models that can be used for the fracture formulation is that of a beam on elastic foundation. In this model a part of the beam is assumed to follow the conditions of beam with elastic foundation which has spring stiffness equal to the fracture properties of the material in the crack surface. Based on beam on elastic foundation model, the cracking load prediction is the target of the paper. Some closed form solutions for the beam with hole are presented. The formulation has been derived for two cases of pure shear and pure bending moment. Finally a semi-empirical formulation for combination of shear and bending moment in the section is presented. The model predictions are compared with the results of an experimental program showing good correlation. The analytical model can therefore be proposed for future revisions of codes of practice such as the Eurocode 5.     

The role of hydrocolloids in the development of gluten-free cereal-based products for coeliac patients: a review

A growing number of diseases in association with gluten intake, such as coeliac disease, have led to increasing demand for gluten-free products as a crucial economic and health issue. Gluten-free products, because of the absence of gluten, usually have a poor texture, taste and appearance. Therefore, the production of good quality gluten-free products with substances that can somehow mimic the viscoelastic properties of gluten is an important challenge. Recently, hydrocolloids are widely used to improve the quality and shelf-life of gluten-free products. In this study, the effect of hydrocolloids on the production of gluten-free cereal-based products, such as breads, cakes and muffins, biscuits and cookies, pasta and noodles, has been reviewed as well as their nutritional values. In general, this study could suggest key factors in the improvement of gluten-free products.     

An algorithm on sign words extraction and recognition of continuous Persian sign language based on motion and shape features of hands

Sign language is the most important means of communication for deaf people. Given the lack of familiarity of non-deaf people with the language of deaf people, designing a translator system which facilitates the communication of deaf people with the surrounding environment seems to be necessary. The system of translating the sign language into spoken languages should be able to identify the gestures in sign language videos. Consequently, this study provides a system based on machine vision to recognize the signs in continuous Persian sign language video. This system generally consists of two main phases of sign words extraction and their classification. Several stages, including tracking and separating the sign words, are conducted in the sign word extraction phase. The most challenging part of this process is separation of sign words from video sequences. To do this, a new algorithm is presented which is capable of detecting accurate boundaries of words in the Persian sign language video. This algorithm decomposes sign language video into the sign words using motion and hand shape features, leading to more favorable results compared to the other methods presented in the literature. In the classification phase, separated words are classified and recognized using hidden Markov model and hybrid KNN-DTW algorithm, respectively. Due to the lack of proper database on Persian sign language, the authors prepared a database including several sentences and words performed by three signers. Simulation of proposed words boundary detection and classification algorithms on the above database led to the promising results. The results indicated an average rate of 93.73 % for accurate words boundary detection algorithm and the average rate of 92.4 and 92.3 % for words recognition using hands motion and shape features, respectively.