Indolizine‐Based Donors as Organic Sensitizer Components for Dye‐Sensitized Solar Cells

Strong electron‐donating functionality is desirable for many organic donor‐π‐bridge‐acceptor (D‐π‐A) dyes. Strategies for increasing the electron‐donating strength of common nitrogen‐based donors include planarization of nitrogen substituents and the use of low resonance‐stabilized energy aromatic ring‐substituted nitrogen atoms. Organic donor motifs based on the planar nitrogen containing heterocycle indolizine are synthesized and incorporated into dye‐sensitized solar cell (DSC) sensitizers. Resonance active substitutions at several positions on indolizine in conjugation with the D‐π‐A π‐system are examined computationally and experimentally. The indolizine‐based donors are observed to contribute electron density with strengths greater than triarylamines and diarylamines, as evidenced by UV/Vis, IR absorptions, and oxidation potential measurements. Fluorescence lifetime studies in solution and on TiO₂ yield insights in understanding the performance of indolizine‐based dyes in DSC devices.     

Fibrillation of α‐lactalbumin: Effect of crocin and safranal,two natural small molecules from Crocus sativus

Formation of toxic amyloid structures is believed to be associated with various late‐onset neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. The fact that many proteins in addition to those that are associated with clinical conditions have the potential to form amyloid fibrils in vitro provides opportunities for studying the fundamentals of protein aggregation and amyloid formation in model systems. Accordingly, considerable interest and effort has been directed toward developing small molecules to inhibit the formation of fibrillar assemblies and their associated toxicities. In the present study, we investigated the inhibitory effect of crocin and safranal, two principal components of saffron, on fibrillation of apo‐α‐lactalbumin (a‐α‐LA), used as a model protein, under amyloidogenic conditions. In the absence of any ligand, formation of soluble oligomers became evident after 18 h of incubation, followed by subsequent appearance of mature fibrils. Upon incubation with crocin or safranal, while transition phase to monomeric beta structures was not significantly affected, formation of soluble oligomers and following fibrillar assemblies were inhibited. While both safranal and crocin had the ability to bind to hydrophobic patches provided in the intermediate structures, and thereby inhibit protein aggregation, crocin was found more effective, possibly due to its simultaneous hydrophobic and hydrophilic character. Cell viability assay indicated that crocin could diminish toxicity while safranal act in reverse order. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 854–865, 2010.     

In vitro selection and field responses of somaclonal variant plants of rice cv PR113 for drought tolerance

Drought is the major environmental stress that limits rice productivity worldwide. In vitro somaclonal variation using different selection agents has been used for crop improvement. Here, rice plants of cv PR113 were selected in vitro on 30, 50 and 70 g L^-1 polyethylene glycol 6,000 (PEG). Callus growth, proliferation, calli volume (first and second culture) and plantlet regeneration (third culture) were found to be decreased upto a certain level to acquire tolerance to PEG-induced drought. From the field data, 30 g L^-1 PEG lines showed higher vegetative growth (plant height, tiller number, leaf number, shoot weight and root growth) as compared with 50 g L^-1 PEG selected somaclone lines under limited irrigation. The yield parameters-panicle length, panicle weight, grains per panicle, 1,000-grain weight, grain yield per plant, harvest index and grain straw ratio were also higher in 30 g L^-1 PEG lines as compared with 50 g L^-1 PEG lines. The results, therefore indicate that 30 g L^-1 PEG selected somaclone lines were more suited than 50 g L^-1 PEG selected somaclone lines under stress as compared with WT. The finding suggests that rice cv PR113 somaclones generated on PEG are found to be drought tolerant under field condition with better yield.     

Safety and efficacy of granulocyte–colony-stimulating factor administration following autologous intramuscular implantation of bone marrow mononuclear cells: a randomized controlled trial in patients with advanced lower limb ischemia

Background aimsThe aim was to investigate the therapeutic effect of granulocyte–colony-stimulating factor (G-CSF) administration following implantation of autologous bone marrow mononuclear cells (BM MNC) for patients with lower limb ischemia.MethodsThe design was a randomized controlled trial. Fifteen patients with severe chronic limb ischemia were treated with autologous BM MNC [without G-CSF (MNC–G-CSF) or combined with G-CSF administration for 5 days following transplantation (MNC+G-CSF)].ResultsAll clinical parameters, including ankle brachial index, visual analog scale and pain-free walking distance, showed a mean improvement from baseline, which was measured at 4 and 24 weeks after transplantation in both groups. However, in three (20%) patients, the clinical course did not improve and limb salvage was not achieved. No significant difference was observed among the patients treated in the MNC–G-CSF and MNC+G-CSF groups. No severe adverse reactions were reported during the study period. No relationship was observed between both the numbers of viable MNC or CD34⁺ cells and the clinical outcome.ConclusionsAutologous transplantation of BM MNC into ischemic lower limbs is safe, feasible and efficient for patients with severe peripheral artery disease. However, the administration of G-CSF following cell transplantation does not improve the effect of BM MNC implantation and therefore would not have any beneficial value in clinical applications of such cases.