Development of highly-reproducible hydrogel based bioink for regeneration of skin-tissues via 3-D bioprinting technology.

3-D Bioprinting is employed as a novel approach in biofabrication to promote skin regeneration following chronic-wounds and injury. A novel bioink composed of carbohydrazide crosslinked {polyethylene oxide-co- Chitosan-co- poly(methylmethacrylic-acid)} (PEO-CS-PMMA) laden with Nicotinamide and human dermal fibroblast was successfully synthesized via Free radical-copolymerization at 73 °C. The developed bioink was characterized in term of swelling, structural-confirmation by solid state 13C-Nuclear Magnetic Resonance (NMR), morphology, thermal, 3-D Bioprinting via extrusion, rheological and interaction with DNA respectively. The predominant rate of gelation was attributed to the electrostatic interactions between cationic CS and anionic PMMA pendant groups. The morphology of developed bioink presented a porous architecture satisfying the cell and growth-factor viability across the barrier. The thermal analysis revealed two-step degradation with 85 % weight loss in term of decomposition and molecular changes in the bioink moieties By applying low pressure in the range of 25-50 kPa, the optimum reproducibility and printability were determined at 37 °C in the viscosity range of 500-550 Pa. s. A higher survival rate of 92 % was observed for (PEO-CS-PMMA) in comparison to 67 % for pure chitosan built bioink. A binding constant of K ≈ 1.8 × 106 M-1 recognized a thermodynamically stable interaction of (PEO-CS-PMMA) with the Salmon-DNA. Further, the addition of PEO (5.0 %) was addressed with better self-healing and printability to produce skin-tissue constructs to replace the infected skin in human.

Role of human papilloma virus in oral leukoplakia.

BACKGROUND: Controversy surrounds regarding the role of human papillomavirus (HPV) in oral precancerous and cancerous lesions in India where smokeless, tobacco consumption is rampant. AIMS: The present study was carried out with an aim to investigate the presence and type of HPV infection in oropharyngeal leukoplakia and to determine the association of HPV positivity with various patient and lesion characteristics. SETTINGS AND DESIGN: Prospective case series. MATERIALS AND METHODS: A total of fifty confirmed cases of oral leukoplakia (OL), aged 18-55 years were enrolled in the study. Specimens were obtained from the site of lesion. All the specimens were subjected to histopathological analysis and HPV-16, 18 detection was done using real-time polymerase chain reaction technique. RESULTS: Mean age of patients was 34.00 ± 8.85. Majority were males (62%), from middle social class (78%) and were educated up to graduation or above (54%). All the patients had one or more adverse habits (betel, chewing tobacco, smoking and alcohol) with mean duration of disease was 3.53 ± 3.05 years. Five patients (10%) had diabetes. Burning sensation (86%) and trismus (36%) were the reported complaints. Maximum were Stage II (50%), sized 2-4 cm2 (60%), homogenous (70%). Floor of mouth and tongue were most commonly involved sites (50%). Majority had mild dysplasia (58%). Acanthosis (66%), hyperplasia (62%), koliocytosis (40%), and keratosis (98%) were quite common. HPV (16/18) could not be detected in any specimen. CONCLUSIONS: The present study highlighted the fact that association of HPV with oral leukoplakia seems to be overestimated and needs to be reexamined with consensus Human papilloma virus (HPV) primers to detect HPV types with more valid empirical relationships.

Endovascular repair of common celiomesenteric trunk stenosis.

A common celiomesenteric trunk (CMT) is one of the several anatomic variations in the mesenteric circulation and occurs when the celiac and superior mesenteric arteries originate from a single common trunk. Because of its rarity, few lesions of the CMT have been reported. We herein present a case of atherosclerotic stenosis of the CMT of an 81-year-old female who presented with symptoms of mesenteric angina. To our knowledge, this represents the first reported case of endovascular treatment of CMT stenosis.

Removal of Co2+ ions from aqueous solution by cation exchange sorption onto NiO.

Batch adsorption technique was used to study the adsorption of cobalt on NiO. The aim of this work was to examine the effect of pH, concentration and temperature on the ion exchange removal of Co2+ from aqueous solution by the NiO surface. We used Langmuir model to interpret the adsorption data. The Kurbatov-type plots were tested to determine the adsorption mechanism. The kinetics of Co2+ adsorption on NiO was best described by film diffusion model. A well-known thermodynamic equation was used to assess the enthalpy and entropy of the system. The thermodynamic data were indicative of the spontaneous nature of the endothermic sorption process of Co2+ onto the NiO.

One new triterpene ester from Nepeta suavis.

One new tetracyclic triterpene ester (1) has been isolated from the chloroform-soluble portion of the whole plant of Nepeta suavis along with two known compounds, namely artemetin (2) and jaceidin (3). The structures of the isolated compounds were assigned on the basis of their (1)H and (13)C NMR spectra including two-dimensional NMR techniques such as COSY, HMQC, and HMBC experiments and comparison with the literature data.

Surface charge properties of Fe2O3 in aqueous and alcoholic mixed solvents.

Iron oxide (Fe2O3) was identified and characterized by surface area, X-ray diffractometry, and FTIR analyses. Surface charge densities, point of zero charge (PZC), and surface ionization constants were determined from the potentiometric titration data in various aqueous and aqueous organic mixed solvents in the temperature range 293-313 K. The surface charge densities were observed to decrease with the increase in temperature and concentration of metal ions in both the aqueous and aqueous organic mixed solvents. The absolute values of the surface charge density were found to change in the order aqueous > aqueous/methanol > aqueous/ethanol. Further, the PZC of the iron oxide was observed to shift to the higher pH values in the order ethanol > methanol > aqueous solution, which indicated a decrease in the acidity of the surface -OH groups. The pKa1 and pKa2 values of iron oxide were also determined and then used for determination of the surface potential (psi0) of the solid in aqueous and aqueous organic mixed solvents. The surface potential-surface charge curves generally supplemented the results derived from psi0-pH curves.

Temperature Effect on the Surface Charge Properties of gamma-Al2O3.

A comprehensive study of the surface properties of the gamma-Al2O3 in KNO3 as a function of temperature was undertaken potentiometrically. Surface charge, ionization and complexation constants, and PZC were calculated from the potentiometric titration data in the temperature range 293-333 K. A difference between the PZC and CIP was observed as a result of the adsorption of NO-3 ions. A simple graphical procedure based on the mass action law was used to determine the number of surface sites and equilibrium constants. Thermodynamic parameters, which showed a decrease in the role of nitrate NO-3 ion in the charging mechanism of gamma-Al2O3, were also evaluated, whereas that of K+ ion increased with the increase in temperature. Copyright 1998 Academic Press.