Comparison Study ofHydrogels Properties Synthesized with Micro- andNano- Size Bacterial Cellulose Particles Extracted from Nata de coco

The effect of different size of bacterial cellulose particles used in the production of hydrogel was investigated. Bacterial cellulose was extracted from nata de coco, a local dessert origin from the Philippines. Micro size particle was prepared by conventional grinding of dried sheet of bacterial cellulose whereas cellulose nanoparticle was prepared by acid hydrolysis treatment. Both were then used in hydrogels formulation with acrylic acid (in ratio of 70% of bacterial cellulose dispersion to 30% acrylic acid) and exposed to electron beam irradiation (40 kGy). TEM observation showed nano cellulose particle, having range of dimension of 80 – 160 nm in length and 13 – 22 nm in diameter. It was found that hydrogel with nano cellulose has higher glass transition temperature (39°C) as compared to micro cellulose hydrogel (32°C). SEM observation revealed that swollen nano cellulose hydrogel has smaller and homogenous pores arrangement while micro cellulose has bigger and irregular pores thus affecting their swelling degree

The remarkable three-dimensional network structure of bacterial cellulose for tissue engineering applications

Cellulose is a natural homopolymer, composed of \u3b2-1,4- anhydro-D-glucopyranose units. Unlike plant cellulose, bacterial cellulose (BC), obtained from species belonging to the genera of Acetobacter, Rhizobium, Agrobacterium, and Sarcina through various cultivation methods and techniques, is produced in its pure form. BC is produced in the form of gel-like, never dry sheet with tremendous mechanical properties. Containing up to 99% of water, BC hydrogel is considered biocompatible thus finding robust applications in the health industry. Moreover, BC three-dimensional structure closely resembles the extracellular matrix (ECM) of living tissue. In this review, we focus on the porous BC morphology particularly suited to host oxygen and nutrients thus providing conducive environment for cell growth and proliferation. The remarkable BC porous morphology makes this biological material a promising templet for the generation of 3D tissue culture and possibly for tissueengineered scaffolds

Association between serum 25-hydroxyvitamin D level and anthropometric indices among institutionalized elderly people in Kelantan, Malaysia

Elderly people in institutionalized home care might have the risk of getting certain nutrient deficiencies  due  to  lack  of food intake  and  comorbidities.  This  study  was  intended  to investigate the prevalence of vitamin D deficiency among institutionalized elderly people and association between anthropometric indices with serum 25(OH)D level. 47 elderly people from Kelantan, age 60 years and above were interviewed for socio-demographic data and anthropometry measurements. The mean serum 25(OH)D level among elderly was 54.9 ± 19.4 nmol/l shows most of the elderly in this study were in hypovitaminosis D status (83%), but none were classified having vitamin D deficiency. In conclusion, vitamin D deficiency was not prevalent among institutionalized elderly in Malaysia and nutritional status has no or less effect on serum 25(OH)D level.Keywords: elderly people; serum vitamin D; serum 25(OH)D; institutionalized elderly peopl

Analysis of toothbrush rig parameter estimation using different model orders in Real-Coded Genetic Algorithm (RCGA)

System identification is a method to build a model for a dynamic system from the experimental data. In this paper, optimization technique was applied to optimize the objective function that lead to satisfying solution which obtain the dynamic model of the system. Realcoded genetic algorithm (RCGA) as a stochastic global search method was applied for optimization. Hence, the model of the plant was represented by the transfer function from the identified parameters obtained from the optimization process. For performance analysis of toothbrush rig parameter estimation, there were six different model orders have been considered where each of model order has been analyzed for 10 times. The influence of conventional genetic algorithm parameter - generation gap has been investigated too. The statistical analysis was used to evaluate the performance of the model based on the objective function which is the Mean Square Error (MSE). The validation test-through correlation analysis was used to validate the model. The model of model order 2 is chosen as the best model as it has fulfilled the criteria involved in selecting the accurate model. Generation gap used was 0.5 has shorten the algorithm convergence time without affecting the model accuracy

Topological characterization of a bacterial cellulose-acrylic acid polymeric matrix

This paper focuses on the micro- and nano-topological organization of a hydrogel, constituted by a mixture of bacterial cellulose and acrylic acid, and intended for biomedical applications. The presence of acrylic acid promotes the formation of two interpenetrated continuous phases: the primary "pores phase" (PP) containing only water and the secondary "polymeric network phase" (PNP) constituted by the polymeric network swollen by the water. Low field Nuclear Magnetic Resonance (LF NMR), rheology, Scanning Electron Microscopy (SEM) and release tests were used to determine the characteristics of the two phases. In particular, we found that this system is a strong hydrogel constituted by 81% (v/v) of PP phase the remaining part being occupied by the PNP phase. Pores diameters span in the range 10-100 \u3bcm, the majority of them (85%) falling in the range 30-90 \u3bcm. The high PP phase tortuosity indicates that big pores are not directly connected to each other, but their connection is realized by a series of interconnected small pores that rend the drug path tortuous. The PNP is characterized by a polymer volume fraction around 0.73 while mesh size is around 3 nm. The theoretical interpretation of the experimental data coming from the techniques panel adopted, yielded to the micro- and nano-organization of our hydrogel. \ua9 2014 Elsevier B.V. All rights reserved

Antibacterial drug release from a biphasic gel system: Mathematical modelling

Bacterial infections represent an important drawback in the orthopaedic field, as they can develop either immediately after surgery procedures or after some years. Specifically, in case of implants, they are alleged to be troublesome as their elimination often compels a surgical removal of the infected implant. A possible solution strategy could involve a local coating of the implant by an antibacterial system, which requires to be easily applicable, biocompatible and able to provide the desired release kinetics for the selected antibacterial drug. Thus, this work focusses on a biphasic system made up by a thermo-reversible gel matrix (Poloxamer 407/water system) hosting a dispersed phase (PLGA micro-particles), containing a model antibacterial drug (vancomycin hydrochloride). In order to understand the key parameters ruling the performance of this delivery system, we developed a mathematical model able to discriminate the drug diffusion inside micro-particles and within the gel phase, eventually providing to predict the drug release kinetics. The model reliability was confirmed by fitting to experimental data, proposing as a powerful theoretical approach to design and optimize such in situ delivery systems