Investigation on Au-nano incorporated pH-sensitive (itaconic acid/acrylic acid/triethylene glycol) based polymeric biocompatible hydrogels.

The pH-sensitive gold nano hydrogel based on itaconic acid, acrylic acid and triethylene glycol (GIAT) has been prepared by free radical polymerization viz. organic solventless approach with different monomer ratios. The nature of bonding and structural identification of GIAT hydrogels were characterized by FT-IR spectroscopy. The surface morphology of gold gel was examined using scanning electron microscopy (SEM). In addition, transmission electron microscopy (TEM) was used to identify the size of gold nano particles. The in vitro biocompatibility of GIAT hydrogel has been evaluated in 3T3 fibroblast cell lines. The obtained results show that gold nano particle incorporated hydrogel possess ~99% of cell proliferation. Followed by, the impact of gold nano particles on swelling, surface morphology was studied. The consecutive preparation of hydrogel, effect of different pH conditions, and stoichiometry of monomeric units have also been discussed. The degree of swelling was measured in carbonate buffer solutions for 24h period with varying pH such as 1.2, 6.0, 7.4 and 10.0. The obtained results showed that the stoichiometry of itaconic acid and gold nano particles plays an essential role in modifying the nature of GIAT polymeric hydrogels. In conclusion, promising Au-nano incorporated pH-sensitive bio polymeric hydrogels were prepared and characterized. The unique properties of these Au-nano hydrogel make them attractive use in biomedical applications.

Non toxic, antibacterial, biodegradable hydrogels with pH-stimuli sensitivity: Investigation of swelling parameters.

In this work, a series of pH-sensitive hydrogels were synthesized from Sodium alginate (SA), Ethylene glycol (EG) and Acrylic acid (AA). Biodegradability of hydrogel was tested against soil burial test for 35days and in vitro phosphate buffer solution test for 10days respectively. Degradation of the sample might be due to the breakdown of ester linkage and hydrophilic pendant functionality present in hydrogel. The progression of biodegradation was examined by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Detailed swelling parameters such as swelling equilibrium Seq (%) at various pH, biological fluids (distilled water (DW), physiological saline 0.89% NaCl (PS), iso-osmotic phosphate buffer at pH 7.4 (PB)) and equilibrium water content (EWC) have also been investigated, which revealed that dynamic compassion of hydrogels. The hydrogel has shown strong antibacterial activity against Escherichia coli (gram negative) and Staphylococcus aureus (gram positive) bacteria's. Cytotoxic assays, using MTT Assay in 3T3 fibroblast Cell line was performed. At 10µg/ml, cell viability was in the range of 92-94%. However, the cell viability (%) decreases with increasing concentration of sample. The synergistic effect of biodegradable hydrogels possessing excellent swelling properties, high water content, biocompatibility and wound healing tendency using in vivo test can be made as suitable candidate for biomedical applications. In vivo wound healing studies conducted on a Wister albino rat model of incision wound performed for 9days. The results revealed that more accelerated wound healing have been observed even in shorter duration. Thus, the synthesized hydrogel with great pH-responsiveness and excellent drug delivery may have a great opening for biomedical applications.

Effects of low back disability status on lower back discomfort during sustained and cyclical trunk flexion.

A laboratory study was conducted to determine the effects of back disability status on endurance time and perceived discomfort during trunk flexion. Eighty participants (40 with chronic or recurrent low back pain (CRLBP), 40 pain-free) were tested. The trunk was flexed to 15 degrees, 30 degrees, 45 degrees and 60 degrees under three conditions: 1) continuous static flexion; 2) cyclical flexion with 20% rest; and 3) cyclical flexion with 40% rest. Each condition was performed for up to 600 s or until the participant reached his/her pain tolerance limit. Dependent variables included time to distracting discomfort (TDD), total endurance time (TET) and perceived discomfort. For continuous exertions, CRLBP participants had lower TDD (p < 0.001), lower TET (p < 0.001) and greater discomfort (p < 0.001) compared to pain-free controls. In both groups, TDD and TET decreased and perceived discomfort increased as the flexion angle increased. For intermittent exertions, CRLBP participants reported greater discomfort than pain-free participants (p < 0.001). Increasing rest from 20 to 40% reduced discomfort in CRLBP participants, but produced no consistent benefit in pain-free participants. To accommodate persons with CRLBP, consideration should be given to reducing both the magnitude (angle) and duration of trunk flexion required by their jobs.

Influence of frame rate and image delay on virtual driving performance.

The control and navigation of unmanned ground vehicles (UGVs) by humans requires a thorough understanding of the limitations in human perception and performance. Images of the external world recorded by cameras mounted on the UGV are presented as a video display to the operator, who then remotely manipulates the vehicle using a standard control. Operator performance is directly proportional to the computational complexity associated with the processing of video data. This work studies the effects of frame rate and image delay (lag) on remote driving performance. Experiments were conducted with five subjects using a driving simulator with a 1 dof force feedback steering wheel control. After sufficient training on the simulator, subjects drove a virtual car on a standard track under varying settings of frame rate and lag. Performance was measured by the duration to complete the course. Comparison of performance both within and between subjects showed characteristic driving patterns at different settings. Implications of the findings are discussed in relation to video data presentation for remote driving applications.