Gisha Elizabeth Luckachan

PLA, TPS and PCL binary and ternary blends: structural characterization and time-dependent morphological changes

One-step melt mixing procedure was used to generate binary and ternary blends containing different compositions of poly-l-lactide (PLA), thermoplastic starch (TPS) and poly(ɛ-caprolactone) (PCL) polymers. The structural characterization of the blends was carried out using X-ray diffraction, Raman and infrared spectroscopy, solid-state nuclear magnetic resonance (NMR) and atomic force microscopy (AFM). In addition, time-dependent evolution in structure and morphology of the blends was studied. Binary blend of PLA50PCL50 exhibited reduction in crystallinity of PLA due to some extent of intermixing of PCL and PLA phases. Diffuse Raman bands, X-ray diffraction signals as well as broadening of crystalline NMR resonances of PLA confirmed the phenomenon. In PLA50TPS50 blend, TPS did not mix with PLA and had no effect on the crystallinity of PLA. In the ternary blends, the addition of PCL was observed to improve the dispersion of TPS in PLA. The ternary blends with different compositions did not exhibit any significant differences among each other, and no strong interactions between the components were observed. Raman mapping was also demonstrated to accurately map the dispersion of components in the blend. Morphology of the blends was observed to exhibit physical aging phenomenon as a function of time. PLA50PCL50 blend had significant changes in topography, reduction of polymer domains and interfacial separation in the aged samples due to the relaxation of the polymer domains. Due to the glassy nature of PLA and TPS phases, the contraction of these phases co-existed with subsequent expansion of PCL phase due to its rubbery state at room temperature. In the ternary blends, the physical aging resulted in similar loss of ultrastructure in PCL and phase separation, although the ultrastructure of PLA and TPS was not significantly affected.

Self-healing protective coatings of polyvinyl butyral/polypyrrole-carbon black composite on carbon steel

Self-healing polyvinyl butyral (PVB) based organic coating formulations were prepared by incorporating polypyrrole-carbon black (PPyCB) composite as an inhibiting pigment. The redox properties and diffusion barrier nature of PPy imparted self-healing to the PVB/PPyCB composite coatings in aggressive environments. PPy induced the formation of a stable passive layer on the metal surface through the interaction of released dopant, from the organic sulfonic acid doped PPy with metal iron oxide. SEM images and Raman spectroscopy confirmed the formation of a protective passive layer on the metal surface. Furthermore, reduced PPy hindered the diffusion of water and oxygen through the coating. The addition of more conducting particles like graphene further enhanced the protective nature of the PVB/PPyCB composite coatings. This work demonstrates a possible application of conducting particles in enhancing the protective nature of organic coatings used widely in industry simply as a barrier coating.

Evaluation of crystallinity variation and phase dispersion in polymer blends and nanocomposites by Raman mapping

Raman mapping technique was used to characterize the crystallinity variations and phase distribution of individual components in polymer blends and polymer nanocomposites. The conformational changes of poly-l-lactide (PLA) and poly-ε-caprolactone (PCL) were analysed in complex structures comprising PLA50PCL50 binary and PLA50TPS30PCL20 ternary blends (TPS = thermoplastic starch). The mapping images of PLA50PCL50 binary blend showed the existence of the PLA component in the amorphous form, whereas well-crystallized PLA was observed in the mapping images of PLA50TPS30PCL20 ternary blend. XRD and solid-state 13C NMR confirmed the Raman findings on these changes of PLA crystallinity in the blends. Causes of these crystallinity changes were revealed from Raman mapping of phase dispersion of blend components which exhibited small domains of PLA phase confined in between large clusters of PCL in the binary blend, whereas an improved dispersion of both phases in the ternary blend resulted owing to the presence of TPS phase. The role of compatibilizer in the dispersion of graphene (G) filler in the polyethylene matrix was also successfully visualized using Raman mapping technique in polyethylene–graphene (PE-G) and PE-G-CPE35 nanocomposites. The dispersion of graphene was less optimum in the PE-G composites, whereas in the PE-G-CPE35 composites, the addition of compatibilizer resulted in improved filler dispersion. The findings from Raman mapping were also corroborated with the TEM analysis of the filler dispersion.

Biopolymer nanocomposites for engineering applications

Background: In 1967 a few years after the first working laser was invented, EndreMester in Semmelweis University Budapest, Hungary wanted to find out if laser might cause cancer. He took some mice, shaved the hair off their backs, divided them into two groups and gave a laser treatment with a low powered ruby laser to one group. They did not get cancer and to his surprise the hair on the treated group grew back more quickly than the untreated group. That was how “laser biostimulation” effects were discovered. Purpose of the work: The effects of pulsed monochromatic light, with fixed pulsations and wavelengths, on the healing of pressure ulcers were evaluated in this prospective, randomized, controlled study. Method: A placebo-controlled, double-blind study using low energy photon therapy (LLLT) was performed in ten patients with bedsore on the back. Treatment was given three times a week for 10 weeks, using monochromatic (red) optical sources; diode 660nm (GaAl-660). The patients who were randomized to placebo treatment received sham therapy from an identical-appearing light source from the same delivery system. Results: Ten patients with bedsore were randomized to receive LLLT or placebo therapy. At the conclusion of the study, the percentage of the initial ulcer area remaining unhealed in the LLLT and placebo groups was 24.4% and 84.7%, respectively (P = 0.0008). The decrease in ulcer area (compared to baseline) observed in the LLLT and placebo groups was 193.0 mm2 and 14.7 mm2, respectively (P = 0.0002). One patient dropped out of the study, complaining of lack of treatment efficacy; he was found to be randomized to the placebo group. There were no adverse effects. Conclusions: In this placebo-controlled, double-blind study LLLT was an effective modality for the treatment of bedsore which were resistant to conventional medical management. The results are encouraging as pulsed monochromatic light increased healing rate and shortened healing time. This will positively affect the quality of life in elderly patients with pressure ulcers. 1Head-Biomedical Science and Medical Biotechnology Department, Shaheed Suhrawardy Medical College andHospital, Dhaka-1207. Bangladesh. 2Dept. of Medical Radiation Physics, Kreiskrankenhaus Gummersbach, Teaching Hospital of the University of Cologne, 51643, Germany. And-Dept. of Medical Physics and Biomedical Engineering, Gono Bishwabidyalay (Gono University), Nayarhat, Savar, Dhaka-1344, Bangladesh. 3Department of Orthopedic and Trauma Surgery, Shaheed Suhrawardy Medical College and Hospital,Dhaka-1207, Bangladesh. 4Department of Surgery, Shaheed Suhrawardy Medical College and Hospital, Dhaka-1207, Bangladesh. *Corresponding author Nazrulislam, Head-Biomedical Science And Medical Biotechnology Department, Shaheed Suhrawardy Medical College and Hospital, Dhaka-1207. Bangladesh. Submitted: 29 July 2017; Accepted: 07 Aug 2017; Published: 07 Sep 2017E hot and dusty weather and modern inactive life style of Kingdom of Saudi Arabia is one of the major contributors in chronic kidney disease (CKD). Now it is a major health problem in the kingdom. The number of people infected with CKD is growing, that is becoming a major challenge for health professionals and on the health care system as well. For improving medical practitioners knowledge and awareness about CKD and the risk factors in Saudi Arabia, we propose an eHealth system for chronic kidney disease that will empowered patients to self-manage the disease at different stage. This eHealth management system will also help them to determine high risk groups and provide early management to delay progression of the disease. It will provide patients with IT tools for monitoring, training and self-management which will improve outcomes in kidney disease. This management system offers innovative solutions to inform, engage, and communicate with individuals with CKD in the Kingdom.T study proposes a method for the estimation of peripheral vascular occlusion (PVO) in diabetic foot using sprott chaos synchronization (SCS) classifier with the wolf pack search (WPS) algorithm. The long-term presence of elevated blood sugar levels commonly results in peripheral neuropathy, peripheral vascular disease, nephropathy and retinopathy in patients with type-2 diabetes mellitus. Patients with PVO disease have decreased walking capability and life quality in diabetes mellitus and poor peripheral circulation of PVO causes morbidity like infection and amputation of the legs or feet of diabetics. This progressively vascular occlusion is often ignored by the patients and primary care physicians in early stage. Therefore, a reliable method of diagnostic assistance is crucial for early diagnosis and monitoring of PVO and prevention of amputation. Photoplethysmography (PPG) is a non-invasive technique for detecting blood volume changes in peripheral vascular bed. Literature indicates that the pulse transit time increases and waveform shape changes increase in PPG of the vascular occlusion. PPG pulses of feet gradually become asynchronous due to the different speed of deteriorating patency and collateral circulation in the peripheral arteries. We utilized synchronizing chaotification to compare the bilateral similarity and asymmetry of PPG signals and applied SCS to estimate three degrees of PVO. Among 30 subjects tested, this classification technique could recognize various butterfly motion patterns representing severities successfully including normal condition, lower-degree disease and higher-degree disease. The proposed method has potential for providing diagnostic assistance for PVO of diabetics and other high-risk populations with efficiency and higher accuracy.O compounds (OPs), a group of neurotoxins, are widely used as pesticides and insecticides. They not only pollute the environment but also deteriorate human health. Owing to their destructive effects, these compounds should be strictly regulated and monitored. Therefore, emphasis should be put on developing methods for immediate detection and effective elimination. In our previous study, a novel biosensor utilizing Organophosphorus Hydrolase (OPH) for OPs degradation and detection was proposed. M13 filamentous bacteriophage served as a vector carrying OPH on the surface of its pVIII coat protein via leucine zippers. Moreover, a mild steel-binding peptide was attached on its pIII coat protein for immobilization on mild steel electrode surface. The activity of OPH/ M13 phage/mild steel biosensor was determined via electrochemical analysis and spectrophotometer. To our knowledge, the most important improvement is that the produced phage can be easily recovered by centrifugation rather than labor waste procedure. These results demonstrated the capability of proposed sensor may be useful in further development since both the specificity and activity of genetically engineered M13 phage are better compared to the wild-one.

Identification of selective oxidation of TiC/SiC composite with X-ray diffraction and Raman spectroscopy

Open cell 3D titanium carbide/silicon carbide (TiC/SiC) composite was oxidised to titanium oxide/silicon carbide (TiO2/SiC) following different temperature profiles in a thermal gravimetric analysis (TGA) instrument in continuous air-flow and static air (oven) environments. The TiC oxidation to anatase, starting at temperatures over 450°C, was confirmed by Raman spectroscopy and X-Ray diffraction (XRD). By increasing the temperature, the mass fraction of anatase diminished, while the mass fraction of rutile increased. SiC oxidation started at 650°C when a mixture of TiO2/SiO2/SiC could be observed by Raman, XRD and HRTEM.