Light-Emitting Devices – Luminescence from Low-Dimensional Nanostructures

[no abstract available

Transdifferentiation of Human Dental Pulp Stem Cells Into Oligoprogenitor Cells

Introduction: The nerve fibers in central nervous system are surrounded by myelin sheet which is formed by oligodendrocytes. Cell therapy based on oligodendrocytes and their precursors transplantation can hold a promising alternative treatment for myelin sheet repair in demyelinating diseases. Methods: Human Dental Pulp Stem Cells (hDPSCs) are noninvasive, autologous and easy available source with multipotency characteristics, so they are in focus of interest in regenerative medicine. In the present study, hDPSCs were differentiated into oligoprogenitor using glial induction media, containing Retinoic Acid (RA), basic Fibroblast Growth Factor (bFGF), Platelet- Derived Growth Factor (PDGF), N2 and B27. The differentiated Oligoprogenitor Cells (OPCs) were evaluated for nestin, Olig2, NG2 and O4 using immunocytochemistry. Also, the expression of nestin, Olig2 and PDGFR-alpha gens (neuroprogenitor and oligoprogenitor markers) were investigated via RT-PCR technique. Results: The results indicate that glial differentiation medium induces the generation of oligoprogenitor cells as revealed via exhibition of specific glial markers, including Olig2, NG2 and O4. The expersion of nestin gene (neuroprogenitor marker) and Olig2 and PDGFR-alpha genes (oligoprogentor markers) were detected in treated hDPSCs at the end of the induction stage. Conclusion: hDPSCs can be induced to transdifferentiate into oligoprogenitor cells and respond to the routinely applied regents for glial differentiation of mesanchymal stem cells. These data suggest the hDPSCs as a valuable source for cell therapy in neurodegenerative diseases

The effect of precursor aging on optical and electrochromic properties of WO3 thin films for making smart windows

This paper proposes a suitable method for increasing effective surface area of electrodeposited WO3 thin films. This is done because effective surface area improves optical and electrochromic properties in smart windows. Therefore, we investigated precursor aging atperoxytungstate precursor (0, 24, 48 and 72 h). Experiments showed by increasing aging time of the precursor solution, larger aggregates were formed. Their morphology, optical and cyclic voltammogram characterization showed that increasing aging time improves optical and electrochromic properties of WO3 thin films in 1M LiClO4-PC electrolyte. The WO3 films with aging time of 72 h exhibited a noticeable EC performance with variation of transmittance up to 72% at 633nm. The result indicated that using two electrochromic materials with complementary properties could improve the function of the devic

Investigation of developed clay-nanocomposite packaging film on quality of peach fruit (Prunus persica Cv. Alberta) during cold storage

A nanocomposite packaging film (NPF) prepared by blending polyethylene (PE) with nanoclay (closite 20A) was used. The effects of NPF on the quality parameters of mature peach fruit were investigated during 42 d of storage at 2 °C. The results showed that barrier properties of active film properly suited fruit respiration and significantly inhibited bacterial growth. The weight loss, softening and internal browning of peach fruit were also significantly inhibited by 42%, 28%, and 15%, respectively, which indicated that NPF could delay peach ripening. In addition, pH, total soluble solid, and titratable acidity of fruit in the neat PE film and the unpacked fruit changed more significantly compared with the NPF-packed fruit. Additionally, peach in NPF exhibited lower polyphenol oxidase and higher peroxidase and catalase activities than the others. These results shown that NPF may be an applicable method to control fruit loss and prolong quality of peach during storage. Practical applications: In this study a clay-nanocomposite film with modified barrier and unti-microbial properties on storage of peach fruit was investigated. The barrier properties of the nanocomposite film improved compared to the neat LDPE film so that causes to decrease the respiration rate of the product. Also it is capable to increase the shelf life and storage life of the product. In addition this nanocomposite film can be used as an active packaging with anti-microbial property. Furthermore, the melt blending extrusion for developing of the nanocomposite film can be used as an industrial and cost effective method for reduction of the product losses in postharvest period

Influence of Well-Width Fluctuations on the Electronic Structure of GaN/Al x

Experimental and computation results based on chemical composition assessment of metal-organic chemical vapour deposition grown undoped GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N multiquantum well structures in the low composition limit of x = 0.07 and wide wells demonstrate composition fluctuations in the barrier layers which lead to large-scale nonuniformities and inequivalence of the different wells. As a consequence the experimental photoluminescence spectra at low temperature show a double peak structure indicative of well-width fluctuations by one lattice parameter (2 monolayers)

Light-Emitting Devices – Luminescence from Low-Dimensional Nanostructures

[no abstract available

Influence of Well-Width Fluctuations on the Electronic Structure of GaN/Alx\text{}_{x}Ga1−x\text{}_{1-x}N Multiquantum Wells with Graded Interfaces

Experimental and computation results based on chemical composition assessment of metal-organic chemical vapour deposition grown undoped GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N multiquantum well structures in the low composition limit of x = 0.07 and wide wells demonstrate composition fluctuations in the barrier layers which lead to large-scale nonuniformities and inequivalence of the different wells. As a consequence the experimental photoluminescence spectra at low temperature show a double peak structure indicative of well-width fluctuations by one lattice parameter (2 monolayers)