Crystallographic,morphological and photoluminescent investigations of Tb3+-doped YAlO3 perovskites for lighting applications

Terbium(III)-doped yttrium aluminate perovskite (YAP:xTb³⁺) (x = 0.01–0.08 mol) was synthesized using a simple gel-combustion method. Structural elucidations were performed using X-ray diffraction (XRD) and Rietveld analysis. Fourier-transform infrared spectral studies validated the efficient synthesis of designed doped samples. Transmission electron microscopic images showed the agglomerated irregular dimensions of the synthesized nanocrystalline materials. When excited at 251 nm, a strong emissive line attributed to ⁵D₄ → ⁷F₅ electronic transition was observed at 545 nm (green emission). The maximum luminescence was found at the optimized concentration (0.05 mol) of Tb³⁺ ions; this emission was quenched by dipolar–dipolar (d–d) interactions. Chromaticity (x and y) and correlated colour temperature parameters were obtained by analysing the emission profiles. Finally, the colour coordinates of nanophosphors were closer to the National Television Standards Committee green coordinates, which replicates their potency in the design and architecture of R-G-B-based white LEDs.     

D-M-D Plasmonic Anti-Reflector for Next-Generation Thin c-Si Solar Cell Applications

Plasmonics - In this paper, focus is on the light trapping surface in crystalline silicon (c-Si) solar cells where thinner c-Si wafers are expected to be used by industry to reduce the cost of cell...     

In-vivo dose measurements with MOSFET dosimeters during MV portal imaging

BackgroundThe purpose of this study was to investigate the feasibility of MOSFET dosimeter in measuring eye dose during 2D MV portal imaging for setup verification in radiotherapy.Materials and methodsThe in-vivo dose measurements were performed by placing the dosimeters over the eyes of 30 brain patients during the acquisition of portal images in linear accelerator by delivering 1 MU with the field sizes of 10 × 10 cm² and 15 × 15 cm².ResultsThe mean doses received by the left and right eyes of 10 out of 30 patients when both eyes were completely inside the anterior portal field were found to be 2.56 ± 0.2 cGy and 2.75 ± 0.2, respectively. Similarly, for next 10 patients out of the same 30 patients the mean doses to left and right eyes when both eyes were completely out of the anterior portal fields were found to be 0.13 ± 0.02 cGy and 0.17 ± 0.02 cGy, respectively. The mean doses to ipsilateral and contralateral eye for the last 10 patients when one eye was inside the anterior portal field were found to be 3.28 ± 0.2 cGy and 0.36 ± 0.1 cGy, respectively.ConclusionThe promising results obtained during 2D MV portal imaging using MOSFET have shown that this dosimeter is well suitable for assessing low doses during imaging thereby enabling to optimize the imaging procedure using the dosimetric data obtained. In addition, the documentation of the dose received by the patient during imaging procedure is possible with the help of an in-built software in conjunction with the MOSFET reader module.     

The pygmy hog is a unique genus: 19th century taxonomists got it right first time round

The pygmy hog, Sus salvanius, the smallest and rarest extant suid was first described as the only member of the genus Porcula. It is currently regarded as member of the genus Sus and a sister taxon of the domestic pig/Eurasian wild boar (Sus scrofa). Phylogenetic analyses of 2316 bp from three mtDNA loci (control-region, cytochrome b, 16S) by Bayesian inference and statistical testing of alternative phylogenetic hypotheses all support the original classification of the pygmy hog as a unique genus. Thus, we propose that the species name Porcula salvania should be resurrected. The reclassification will heighten awareness of the need for the future protection and survival of this unique species.     

Tumor-Endothelial Cell Three-dimensional Spheroids: New Aspects to Enhance Radiation and Drug Therapeutics

Classic cancer research for several decades has focused on understanding the biology of tumor cells in vitro. However, extending these findings to in vivo settings has been impeded owing to limited insights on the impact of microenvironment on tumor cells. We hypothesized that tumor cell biology and treatment response would be more informative when done in the presence of stromal components, like endothelial cells, which exist in the tumor microenvironment. To that end, we have developed a system to grow three-dimensional cultures of GFP-4T1 mouse mammary tumor and 2H11 murine endothelial cells in hanging drops of medium in vitro. The presence of 2H11 endothelial cells in these three-dimensional cocultures was found to sensitize 4T1-GFP tumor cells to chemotherapy (Taxol) and, at the same time, protect cells from ionizing radiation. These spheroidal cultures can also be implanted into the dorsal skinfold window chamber of mice for fluorescence imaging of vascularization and disease progression/treatment response. We observed rapid neovascularization of the tumor-endothelial spheroids in comparison to tumor spheroids grown in nude mice. Molecular analysis revealed pronounced up-regulation of several proangiogenic factors in the tumor tissue derived from the tumor-endothelial spheroids compared with tumor-only spheroids. Furthermore, the rate of tumor growth from tumor-endothelial spheroids in mice was faster than the tumor cell-only spheroids, resulting in greater metastasis to the lung. This three-dimensional coculture model presents an improved way to investigate more pertinent aspects of the therapeutic potential for radiation and/or chemotherapy alone and in combination with antiangiogenic agents.     

Cloning and DNA sequence of plasmid determinant iss, coding for increased serum survival and surface exclusion, which has homology with lambda DNA

Summary Escherichia coli K12 cells carrying a cloned 1.4 kb HindIII fragment from plasmid ColV2-K94, showed increased survival in guinea pig serum. The recombinant plasmid also conferred group II surface exclusion, i.e. the cells were reduced in recipient ability towards the incoming plasmid R538drd in conjugation experiments. Southern blotting suggested homology with bacteriophage lambda DNA and to the insertion element IS2. Determination of the DNA sequence of the fragment demonstrated the presence of a truncated IS2 (165 bp), separated by 250 bp from a 900 bp stretch of homology with lambda DNA, beginning within the Rz gene and continuing in the rightward direction on the lambda map. A 97 amino acid open reading frame (ORF) adjacent to Rz and on the opposite strand, remained intact in iss, with several amino acid changes. The ORF in iss is preceded by sequences resembling prokaryotic ribosome binding sites and promoters.     

NADPH production from NADP+ with a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans

Summary A convenient and efficient method of NADPH production from NADP⁺ has been established using a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans IFO 3172. Using airdried cells of the bacterium, the optimum conditions for NADPH production were examined, including the cell and glucose concentrations, NADP⁺ concentration, pH, buffer and reaction temperature. Under suitable conditions, the conversion ratio and the amount of NADPH accumulated reached about 100% and 73 mg/ml of the reaction mixture, respectively, after 1-h reaction. Intact cells of the bacterium also showed high NADPH production even in the reaction mixture without a surfactant. The addition of Triton X-100 to the reaction mixture and freeze-thawing treatment of intact cells enhanced the production. The NADPH production method was further improved by using cells of the bacterium immobilized by entrapment in a -carrageenan gel lattice. The immobilized cells had almost the same enzymatic properties as the air-dried cells. The conditions for the continuous production of NADPH with an immobilized cell column were also investigated. NADPH was produced in a good yield (about 95%) with this continuous process.     

Copper-thioarylazoimidazole complexes: Structures, photochromism and redox interconversion between Cu(II) ↔ Cu(I) and correlation with DFT calculation

Reaction of Cu(ClO₄)₂·6H₂O, SRaaiNR′ (1-alkyl-2-[(o-thioalkyl)phenylazo]imidazole) and NH₄SCN (1:1:2 mol ratio) affords distorted square pyramidal, [Cu^II(SRaaiNR′)(SCN)₂] (3) compound while identical reaction with [Cu(MeCN)₄](ClO₄) yields -SCN- bridged coordination polymer, [Cu^I(SRaaiNR′)(SCN)]_n (4). These two redox states [Cu^II and Cu^I] are interconvertible; reduction of [Cu^II(SRaaiNR′)(SCN)₂] by ascorbic acid yields [Cu^I(SRaaiNR′)(SCN)]_n while the oxidation of [Cu^I(SRaaiNR′)(SCN)]_n by H₂O₂ in presence of excess NH₄SCN affords [Cu^II(SRaaiNR′)(SCN)₂]. They are structurally confirmed by single crystal X-ray diffraction study. Cyclic voltammogram of the complexes show Cu(II)/Cu(I) redox couple at ∼0.4 V and azo reductions at negative to SCE. UV light irradiation in MeCN solution of [Cu^I(SRaaiNR′)(SCN)]_n (4) show trans-to-cis isomerisation of coordinated azoimidazole. The reverse transformation, cis-to-trans, is very slow with visible light irradiation while the process is thermally accessible. Quantum yields (?_t→c) of trans-to-cis isomerisation are calculated and free ligands show higher ? than their Cu(I) complexes. The activation energy (E_a) of cis-to-trans isomerisation is calculated by controlled temperature experiment. Copper(II) complexes, 3, do not show photochromism. DFT and TDDFT calculation of representative complexes have been used to determine the composition and energy of molecular levels and results have been used to explain the solution spectra, photochromism and redox properties of the complexes.     

Domain swapping reveals complement control protein modules critical for imparting cofactor and decay-accelerating activities in vaccinia virus complement control protein

Vaccinia virus encodes a structural and functional homolog of human complement regulators named vaccinia virus complement control protein (VCP). This four-complement control protein domain containing secretory protein is known to inhibit complement activation by supporting the factor I-mediated inactivation of complement proteins, proteolytically cleaved form of C3 (C3b) and proteolytically cleaved form of C4 (C4b) (termed cofactor activity), and by accelerating the irreversible decay of the classical and to a limited extent of the alternative pathway C3 convertases (termed decay-accelerating activity [DAA]). In this study, we have mapped the VCP domains important for its cofactor activity and DAA by swapping its individual domains with those of human decay-accelerating factor (CD55) and membrane cofactor protein (MCP; CD46). Our data indicate the following: 1) swapping of VCP domain 2 or 3, but not 1, with homologous domains of decay-accelerating factor results in loss in its C3b and C4b cofactor activities; 2) swapping of VCP domain 1, but not 2, 3, or 4 with corresponding domains of MCP results in abrogation in its classical pathway DAA; and 3) swapping of VCP domain 1, 2, or 3, but not 4, with homologous MCP domains have marked effect on its alternative pathway DAA. These functional data together with binding studies with C3b and C4b suggest that in VCP, domains 2 and 3 provide binding surface for factor I interaction, whereas domain 1 mediates dissociation of C2a and Bb from the classical and alternative pathway C3 convertases, respectively.