Therapeutic Acellular Scaffolds for Limiting Left Ventricular Remodelling-Current Status and Future Directions

Myocardial infarction (MI) is one of the leading causes of heart-related deaths worldwide. Following MI, the hypoxic microenvironment triggers apoptosis, disrupts the extracellular matrix and forms a non-functional scar that leads towards adverse left ventricular (LV) remodelling. If left untreated this eventually leads to heart failure. Besides extensive advancement in medical therapy, complete functional recovery is never accomplished, as the heart possesses limited regenerative ability. In recent decades, the focus has shifted towards tissue engineering and regenerative strategies that provide an attractive option to improve cardiac regeneration, limit adverse LV remodelling and restore function in an infarcted heart. Acellular scaffolds possess attractive features that have made them a promising therapeutic candidate. Their application in infarcted areas has been shown to improve LV remodelling and enhance functional recovery in post-MI hearts. This review will summarise the updates on acellular scaffolds developed and tested in pre-clinical and clinical scenarios in the past five years with a focus on their ability to overcome damage caused by MI. It will also describe how acellular scaffolds alone or in combination with biomolecules have been employed for MI treatment. A better understanding of acellular scaffolds potentialities may guide the development of customised and optimised therapeutic strategies for MI treatment.     

Influence of seed layer treatment on low temperature grown ZnO nanotubes: Performances in dye sensitized solar cells

Non-aligned and highly densely aligned ZnO nanotube (NTs), synthesized by low temperature solution method were applied as photoanode materials for the fabrication of efficient dye-sensitized solar cells (DSSCs). The crystalline and the morphological analysis revealed that the grown aligned ZnO NTs possessed a typical hexagonal crystal structure of outer and inner diameter ∼250 nm and ∼100 nm, respectively. ZnO seeding on FTO substrates is an essential step to achieve the aligned ZnO NTs. A DSSC fabricated with aligned ZnO NTs photoanode achieved high solar-to-electricity conversion efficiency of ∼2.2% with short circuit current (J_SC) of 5.5 mA/cm², open circuit voltage (V_OC) of 0.65 V and fill factor (FF) of 0.61. Significantly, the aligned ZnO NTs photoanode showed three times improved solar-to-electricity conversion efficiency than DSSC fabricated with non-aligned ZnO NTs. The enhanced performances were credited to the aligned morphology of ZnO NTs which executed the high charge collection and the transfer of electrons at the interfaces of ZnO NTs and electrolyte layer.     

Fabrication and Catalytic Characterization of Laccase-Loaded Calcium-Alginate Beads for Enhanced Degradation of Dye-Contaminated Aqueous Solutions

Catalysis Letters - Engineered laccases represent an eco-friendlier and robust biocatalytic tool for the treatment of dye-harboring textile wastewater. This study investigates the immobilization of...     

Synthesis and characterization of high-purity silica nanosphere from rice husk

The work reports the synthesis, characterization, and the properties of high-purity silica nanospheres from low-cost rice husk. Primarily, the rice husk was washed with distilled water (DW) and subjected to acid leaching to remove the impurities. The treated rice husk was annealed at different temperatures (620 and 900 degrees C) for varied time periods to achive the desirable silica nanospheres. The annealing temperature and time considerably affected the properties of the synthesized silica nanospheres. The morphology studies confirmed that the size of nanospheres were of approximately 50-60 nm. The photoluminesence studies revealed that the synthesized silica nanospheres showed less structural defects and good optical properties. On the basis of the formation and the characterization of silica nanospheres a possible mechanism was suggested. Inductively coupled plasma mass spectrometry (ICP-MS) analysis confirmed that the synthesized silica nanospheres contained approximately 99.93% purity.     

Electrical and structural characterization of plasma polymerized polyaniline/TiO2 heterostructure diode: a comparative study of single and bilayer TiO2 thin film electrode

A heterostructure was fabricated using p-type plasma polymerized polyaniline (PANI) and n-type (single and bilayer) titanium dioxide (TiO2) thin film on FTO glass. The deposition of single and bilayer TiO2 thin film on FTO substrate was achieved through doctor blade followed by dip coating technique before subjected to plasma enhanced polymerization. To fabricate p-n heterostructure, a plasma polymerization of aniline was conducted using RF plasma at 13.5 MHz and at the power of 120 W on the single and bilayer TiO2 thin film electrodes. The morphological, optical and the structural characterizations revealed the formation of p-n heterostructures between PANI and TiO2 thin film. The PANI/bilayer TiO2 heterostructure showed the improved current-voltage (I-V) characteristics due to the substantial deposition of PANI molecules into the bilayer TiO2 thin film which provided good conducting pathway and reduced the degree of excitons recombination. The change of linear I-V behavior of PANI/TiO2 heterostructure to non linear behavior with top Pt contact layer confirmed the formation of Schottky contact at the interfaces of Pt layer and PANI/TiO2 thin film layers.     

Aluminum silicate fibers impregnated acrylonitrile butadiene rubber composites: Ablation,thermal transport/stability,and mechanical inspection

Variant concentrations of ceramic fibers (CerFs) were incorporated into acrylonitrile butadiene rubber (NBR) to fabricate elastomeric ablative composites for ultrahigh temperature applications. The CerFs introduction into the polymer matrix has enhanced the ablation resistance up to 59% and successfully reduced the backface temperature of the polymer composite up to 110^oC during the ultrahigh temperature ablation investigation. Thermal decomposition of the polymer composites was diminished up to 10% with increasing fiber concentration in the rubber matrix. Thermal conductivity was reduced equal to 63% while thermal impedance was enhanced up to 84% with the utmost fiber incorporation into the NBR matrix. The CerFs have adversely affected the mechanical properties of NBR matrix due to their brittle/inert nature and weak interface bonding with the host matrix. Scanning electron microscopy along with the energy dispersive x‐ray spectroscopy was used to examine the ablated specimens and the fiber dispersion within the host matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4392–4400, 2013     

Cardiomyocyte Proliferation as a Source of New Myocyte Development in the Adult Heart

Cardiac diseases such as myocardial infarction (MI) can lead to adverse remodeling and impaired contractility of the heart due to widespread cardiomyocyte death in the damaged area. Current therapies focus on improving heart contractility and minimizing fibrosis with modest cardiac regeneration, but MI patients can still progress to heart failure (HF). There is a dire need for clinical therapies that can replace the lost myocardium, specifically by the induction of new myocyte formation from pre-existing cardiomyocytes. Many studies have shown terminally differentiated myocytes can re-enter the cell cycle and divide through manipulations of the cardiomyocyte cell cycle, signaling pathways, endogenous genes, and environmental factors. However, these approaches result in minimal myocyte renewal or cardiomegaly due to hyperactivation of cardiomyocyte proliferation. Finding the optimal treatment that will replenish cardiomyocyte numbers without causing tumorigenesis is a major challenge in the field. Another controversy is the inability to clearly define cardiomyocyte division versus myocyte DNA synthesis due to limited methods. In this review, we discuss several studies that induced cardiomyocyte cell cycle re-entry after cardiac injury, highlight whether cardiomyocytes completed cytokinesis, and address both limitations and methodological advances made to identify new myocyte formation.     

Modification of cotton fabric for textile dyeing: industrial mercerization versus gamma irradiation

The current research is intended to investigate the effect of gamma radiation on the cotton fabric and compare the dyeability of gamma irradiated fabric with that of chemically mercerized fabric using reactive dye, Reactive Violet H3R. The gray cotton fabric samples were desized and bleached, before being mercerized or irradiated, followed by dyeing with reactive dye. The cotton fabric was exposed to variable absorbed doses of 2–10 kGy. The color strength values at various levels of temperature, pH, dyeing time, and salt concentration were evaluated using optimal conditions of mercerization and gamma-ray treatment. The comparison of color strength values for the mercerized and the gamma irradiated cotton fabric showed that the irradiated fabric had high color strength at 60 °C using dye bath of pH10 in the presence of 6 g/L of exhausting agent while dyeing for 40 min. Both mercerization and irradiation increased the surface area of fibers that substantially elevated the dyeing performance and fastness properties.