Review of Nanobiopolymers for Controlled Drug Delivery

Biodegradable polymeric nanoparticles have attracted attention as potential drug delivery devices due to its bioavailability, biocompatibility, encapsulation, controlled drug release and in drug targeting to organs/tissues, as carriers of DNA in gene therapy, deliver proteins, peptides and genes. Controlled release systems increases therapeutic activity reducing the number of drug administration. This review presents the most outstanding contributions in the field of biodegradable polymeric nanoparticulate systems including poly (lactic-co-glycolic acid), polylactic acid, chitosan, gelatin, poly hydroxy alkaonates, poly caprolactone and poly alkyl cyanoacrylate used as drug delivery system, their synthesis, encapsulation process and drug release mechanisms.     

Polyhydroxy propionate-co-hydroxy dodecanoate-co-hydroxy octadecanoate for in vitro cell culture

This study is novel to report the utilization of molasses for the production of polyhydroxy propionate-co-hydroxy dodecanoate-co-hydroxy octadecanoate from Pseudomonas sp. LDC-5 as prospective biomaterial. Thermal analysis revealed its potential for thermal permanence and melt processing. 3T3 fibroblasts were cultured on these different scaffolds and their proliferation was compared. Giemsa and acridine orange/ethidium bromide staining revealed that there was no distinct change in morphology. Polyhydroxyalkanoate:poly ethylene glycol blend was found to be the most promising for extracellular matrix secretion, a key thrust function of 3D culture. Lactate dehydrogenase assay indicated the membrane integrity. DNA fragmentation analysis showed that the scaffold did not damage DNA. Thus the prepared scaffold can serve as a promising biomaterial.     

Experimental Investigation of the Thermal Performance of Graphite Foam for Evaporator Enhancement in Both Pool Boiling and an FC-72 Thermosyphon

High-conductivity graphite foam is investigated for use as a surface enhancement for improved thermal performance in both pool boiling and an FC-72 thermosyphon. The influences of heat load and fluid level on the overall system thermal performance including surface superheat, effective heat transfer coefficient, and thermal resistance are examined. The thermal resistance of the foam heat sink is found to be extremely low at a minimum of 0.024 K/W, well below that of many other methods. The featured low thermal resistance is the primary benefit of this system. The thermal resistance is found to rise with increasing heat flux, but still remains advantageously low and exhibits excellent potential for high heat flux dissipation with low surface superheat, making it suitable for thermal management of advanced electronics.     

Equilibrium pressure measurements in the Li-N-H system by static manometric method

The equilibrium pressure over the phase mixture (Li₂NH + LiNH₂ + LiH) was measured from 343 to 683 K by static manometric method. The plot of ln (p_eq/p⁰) versus (1/T) showed three distinct temperature regions with different slopes. Analysis of the equilibrium gas composition in each temperature regions revealed that the equilibrium gas is a mixture of H₂, NH₃ and N₂ below 443 K whereas above 443 K, the equilibrium gas is mainly H₂. The enthalpy and entropy of the reaction of H₂ with Li₂NH to form LiNH₂ and LiH are found to be −55.0 ± 1.3 kJ?mol⁻¹ and −86 ± 2 J?K⁻¹?mol⁻¹, respectively at 523 K, where LiNH₂ exists in the solid state and −18.5 ± 0.5 kJ?mol⁻¹ and −26 ± 1 J?K⁻¹?mol⁻¹, respectively at 658 K, where LiNH₂ exists in the liquid state. The enthalpy and entropy of melting of solid LiNH₂ are calculated as 36.5 ± 1.4 kJ?mol⁻¹ and 60 ± 2 J?K⁻¹?mol⁻¹, respectively.     

A comparative study on in vitro behavior of calcium silicate ceramics synthesized from biowaste resources

Calcium silicate ceramics have received significant attention for biomedical applications for their excellent bioactivity and osteoconduction properties. Sol-gel process is extensively used for the fabrication of calcium silicates. In sol-gel process, calcium nitrate tetra hydrate (Ca(NO₃)₂·4H₂O) and tetraethylorthosilicate (TEOS) are used as precursors. However, these precursors are expensive. The objective of this work was to compare in vitro behavior of calcium silicate (CaSiO₃) produced using biowaste such as rice husk ash (RHA) and eggshells (coded; NCS) with CaSiO₃ prepared using TEOS and Ca(NO₃)₂·4H₂O (coded; CCS). Thermal investigation results revealed that the crystallization temperature for NCS is relatively lower (772°C) than for CCS (870°C). Bioactivity was studied in vitro using simulated body fluid (SBF) with respect to mineralization rate of hydroxyapatite. Mineralization of a greater hydroxyapatite was observed on NCS ceramics than CCS ceramics after incubation for 3, 7, 14 days in SBF solution, which was confirmed using X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy-energy dispersive spectroscopy. Degradation studies were conducted in Tris-HCl solution and the test results revealed that NCS ceramics has lower dissolution rate than CCS ceramics. The antimicrobial assay has shown that NCS samples exhibit significant zone of inhibition against Escherichia coli and Staphylococcus aureus which confirmed that the CaSiO₃ prepared from RHA and eggshell can prevent bacteria from adhering to the surface. In addition cell culture studies revealed that NCS ceramics possess good cytocompatibility with MG-63 cells and significantly promoted cell proliferation.     

Immunogenic properties of rabbit haemorrhagic disease virus structural protein VP60 expressed by a recombinant baculovirus: an efficient vaccine

We have constructed a recombinant baculovirus containing the gene encoding the structural protein VP60 from the Spanish field isolate AST/89 of rabbit haemorrhagic disease virus (RHDV). Infection of cultured Spodoptera frugiperda Sf9 cells with this recombinant virus resulted in the production of high yields of VP60 protein which did not seem to assemble to form virus like particles, but was antigenically similar to the corresponding viral protein obtained from purified virions. A VP60-dose study showed that the recombinant protein was able to elicit a protective response in rabbits against a nasal challenge with 100 LD50 of RHDV. The effective dose able to protect 50% of the animals in the absence of adjuvant was found to be 10-25 micrograms of recombinant VP60.     

Effect of substitution of quartz by rice husk ash and silica fume on the properties of whiteware compositions

Active silica from rice husk ash (RHA) and silica fume (SF) were progressively incorporated in a whiteware composition in substitution of quartz. The Influence of the addition on the thermo-mechanical properties, vitrification behavior and microstructure has been investigated. It has been found that replacement of quartz by RHA+ SF (1:1) reduced drastically both the maturing temperature (50–100 °C) and the thermal expansion (3.24–14.6%) at 600 °C with the improvement in the fired strength. Maximum improvement in the fired MOR (20.8%) was observed in a whiteware composition containing 10% (RHA+silica fume). On complete replacement of quartz (25%) by RHA+SF, the fired strength was noticed around 14.95% in whiteware body matured at lower temperature by 100 °C.The improvement in the properties is attributed to sharp changes in the microstructural features as a result of significant reduction in the content of the quartz phase and the simultaneous increase in glassy phase. The findings would be helpful to improve the properties of whiteware as well as to reduce the energy consumption during firing process.