Neonatal exposure to 17 beta-estradiol down-regulates the expression of synaptogenesis related genes in selected brain regions of adult female rats

Aims: Administration of estradiol or compounds with estrogenic activity to newborn female rats results in irreversible masculinization as well as defeminization in the brain and the animals exhibit altered reproductive behavior as adults. The cellular and molecular mechanism involved in inducing the irreversible changes is largely unknown. In the present study, we have monitored the changes in the expression of selected synaptogenesis related genes in the sexually dimorphic brain regions such as POA, hypothalamus and pituitary following 17 beta-estradiol administration to neonatal female rats. Main methods: Female Wistar rats which were administered 17 beta-estradiol on day 2 and 3 after birth were sacrificed 120 days later and the expression levels of genes implicated in synaptogenesis were monitored by semi-quantitative reverse transcription PCR. Since estradiol induced up-regulation of COX-2 in POA is a marker for estradiol induced masculinization as well as defeminization, in the present study only animals in which the increase in expression of COX-2 gene was observed in POA were included in the study. Key findings: Down-regulation of genes such as NMDA-2B, NETRIN-1, BDNF, MT-5 MMP and TNF-alpha was observed in the pre-optic area of neonatally E2 treated female rat brain but not in hypothalamus and pituitary compared to the vehicle- treated controls as assessed by RT-PCR and Western blot analysis. Significance: Our results suggest a possibility that down-regulation of genes associated with synaptogenesis in POA, may be resulting in disruption of the cyclical regulation of hormone secretion by pituitary the consequence of which could be infertility and altered reproductive behavior. (C) 2015 Elsevier Inc. All rights reserved.

Ray tracing based path-length calculations for polarized light tomographic imaging

A ray tracing based path length calculation is investigated for polarized light transport in a pixel space. Tomographic imaging using polarized light transport is promising for applications in optical projection tomography of small animal imaging and turbid media with low scattering. Polarized light transport through a medium can have complex effects due to interactions such as optical rotation of linearly polarized light, birefringence, diattenuation and interior refraction. Here we investigate the effects of refraction of polarized light in a non-scattering medium. This step is used to obtain the initial absorption estimate. This estimate can be used as prior in Monte Carlo (MC) program that simulates the transport of polarized light through a scattering medium to assist in faster convergence of the final estimate. The reflectance for p-polarized (parallel) and s-polarized (perpendicular) are different and hence there is a difference in the intensities that reach the detector end. The algorithm computes the length of the ray in each pixel along the refracted path and this is used to build the weight matrix. This weight matrix with corrected ray path length and the resultant intensity reaching the detector for each ray is used in the algebraic reconstruction (ART) method. The proposed method is tested with numerical phantoms for various noise levels. The refraction errors due to regions of different refractive index are discussed, the difference in intensities with polarization is considered. The improvements in reconstruction using the correction so applied is presented. This is achieved by tracking the path of the ray as well as the intensity of the ray as it traverses through the medium.

Light Induced Metastable State of Silver Nitroprusside Probed by Raman Spectroscopy

Low temperature Raman spectroscopic measurements on silver nitroprusside (AgNP), Ag-2Fe(CN)(5)NO] powders display reversible features of a partially converted metastable state. The results are compared with similarly observed metastable state in case of sodium nitroprusside (NaNP) and the differences have been discussed in terms of possible resistance to metastable state formation offered by silver atoms on the basis of hard soft acid base (HSAB) theory.

Fluoranthene derivatives as blue fluorescent materials for non-doped organic light-emitting diodes

In this study, we report synthesis of symmetrically and non-symmetrically functionalized fluoranthene-based blue fluorescent molecular materials for non-doped electroluminescent devices. The solid state structure of these fluorophores has been established by single crystal X-ray diffraction analysis. Furthermore, a detailed experimental and theoretical study has been performed to understand the effect of substitution of symmetric and non-symmetric functional groups on optical, thermal and electrochemical properties of fluoranthene. These materials exhibit a deep blue emission and high PLQY in solution and solid state. The vacuum deposited, non-doped electroluminescent devices with the device structure ITO/NPD (15 nm)/CBP (15 nm)/EML (40 nm)/TPBI (30 nm)/LiF (1 nm)/Al were fabricated and characterized. A systematic shift in the peak position of EL emission was observed from sky blue to bluish-green with EL maxima from 477 nm to 490 nm due to different functional groups on the periphery of fluoranthene. In addition, a high luminance of >= 2000 cd m(-2) and encouraging external quantum efficiency (EQE) of 1.1-1.4% were achieved. A correlation of the molecular structure with device performance has been established.

Photocytotoxic luminescent lanthanide complexes of DTPA-bisamide using quinoline as photosensitizer

Lanthanide complexes Ln(DTPAAQ)(DMF)] (1-3) (Ln - Pr (1), Eu (2), Tb (3), H(3)DTPAAQ - N, N `'-bis(3-amidoquinolyl) diethylenetriamine-N, N', N `'-triacetic acid, DMF - N, N-dimethylformamide) were studied for their structures, photophysical properties, DNA and protein binding, DNA photocleavage, photocytotoxicity and cellular internalization. The crystal structures of complexes Ln(DTPAAQ)(DMF)] (1-3) display a discrete mononuclear nine-coordinate {LnN(3)O(6)} tricapped-trigonal prism (TTP) coordination geometry. The europium and terbium complexes show strong luminescence properties in the visible region having a long luminescence lifetime (tau = 0.51-0.64 ms). The conjugated 3-aminoquinoline moieties act as efficient light harvesting antennae, which upon photoexcitation transfer their energy to Eu(III) or Tb(III) for their characteristic D-5(0) -> F-7(J) or D-5(4) -> F-7(J) f-f transitions respectively. The complexes display efficient binding affinity to DNA (K-b = 3.4 x 10(4) - 9.8 x 10(4) M-1) and BSA (KBSA = 3.03 x 10(4) - 6.57 x 10(4) M-1). Europium and terbium complexes give enhanced luminescence upon interacting with CT-DNA suggesting possible luminescence-based sensing applications for these complexes. Complexes 1-3 show moderate cleavage of supercoiled (SC) DNA to its nicked circular (NC) form on exposure to UV-A light of 312 nm involving formation of singlet oxygen (O-1(2)) and hydroxyl radicals (cOH) in type-II and photoredox pathways. Eu(III) and Tb(III) complexes exhibit remarkable photocytotoxicity with human cervical cancer cell line (HeLa) (IC50 = 20.7-28.5 mM) while remaining essentially noncytotoxic up to 150 mM in the dark. Complexes are nontoxic in nature thus suitable for designing cellular imaging agents. Fluorescence microscopy data reveal primarily cytosolic localization of the Eu(III) and Tb(III) complexes in HeLa cells.

The cis-Diammineplatinum(II) Complex of Curcumin: A Dual Action DNA Crosslinking and Photochemotherapeutic Agent

Pt(cur)(NH3)(2)](NO3) (1), a curcumin-bound cis-diammineplatinum(II) complex, nicknamed Platicur, as a novel photoactivated chemotherapeutic agent releases photoactive curcumin and an active platinum(II) species upon irradiation with visible light. The hydrolytic instability of free curcumin reduces upon binding to platinum(II). Interactions of 1 with 5'-GMP and ct-DNA indicated formation of platinum-bound DNA adducts upon exposure to visible light (lambda = 400-700 nm). It showed apoptotic photocytotoxicity in cancer cells (IC50 approximate to 15 mu M), thus forming (OH)-O-center dot, while remaining passive in the darkness (IC50 > 200 mu M). A comet assay and platinum estimation suggest Pt-DNA crosslink formation. The fluorescence microscopic images showed cytosolic localization of curcumin, thus implying possibility of dual action as a chemo-and phototherapeutic agent.

Instability in an amorphous In-Ga-Zn-O field effect transistor upon water exposure

The instability of an amorphous indium-gallium-zinc oxide (IGZO) field effect transistor is investigated upon water treatment. Electrical characteristics are measured before, immediately after and a few days after water treatment in ambient as well as in vacuum conditions. It is observed that after a few days of water exposure an IGZO field effect transistor (FET) shows relatively more stable behaviour as compared to before exposure. Transfer characteristics are found to shift negatively after immediate water exposure and in vacuum. More interestingly, after water exposure the off current is found to decrease by 1-2 orders of magnitude and remains stable even after 15 d of water exposure in ambient as well as in vacuum, whereas the on current more or less remains the same. An x-ray photoelectron spectroscopic study is carried out to investigate the qualitative and quantitative analysis of IGZO upon water exposure. The changes in the FET parameters are evaluated and attributed to the formation of excess oxygen vacancies and changes in the electronic structure of the IGZO bulk channel and at the IGZO/SiO2 interface, which can further lead to the formation of subgap states. An attempt is made to distinguish which parameters of the FET are affected by the changes in the electronic structure of the IGZO bulk channel and at the IGZO/SiO2 interface separately.

Optimizing Photovoltaic Response by Tuning Light-Harvesting Nanocrystal Shape Synthesized Using a Quick Liquid-Gas Phase Reaction

The electron recombination lifetime in a sensitized semiconductor assembly is greatly influenced by the crystal structure and geometric form of the light-harvesting semiconductor nanocrystal. When such light harvesters with varying structural characteristics are configured in a photoanode, its interface with the electrolyte becomes equally important and directly influences the photovoltaic efficiency. We have systematically probed here the influence of nanocrystal crystallographic structure and shape on the electron recombination lifetime and its eventual influence on the light to electricity conversion efficiency of a liquid junction semiconductor sensitized solar cell. The light-harvesting cadmium sulfide (CdS) nanocrystals of distinctly different and controlled shapes are obtained using a novel and simple liquid gas phase synthesis method performed at different temperatures involving very short reaction times. High resolution synchrotron X-ray diffraction and spectroscopic studies respectively exhibit different crystallographic phase content and optical properties. When assembled on a mesoscopic TiO2 film by a linker molecule, they exhibit remarkable variation in electron recombination lifetime by 1 order of magnitude, as determined by ac-impedance spectroscopy. This also drastically affects the photovoltaic efficiency of the differently shaped nanocrystal sensitized solar cells.

Phase dependent photocatalytic activity of Ag loaded TiO2 films under sun light

Well-crystallized anatase and mixed (anatase-rutile) phase TiO2 thin films were deposited by DC magnetron sputtering technique at various DC powers in the range of 80-140 W. Pure anatase phase was observed in the TiO2 films deposited at low power of 80 W. Films deposited at 120 W were composed of both anatase and rutile phases. At higher power of 140 W, the films are rutile dominated and the rutile percentage increased from 0 to 82% with increase of DC power. The same results of phase change were confirmed by Raman studies. The surface morphology of the TiO2 films showed that the density of the films increased with increase of sputter power. The optical band gap of the films varied from 3.35 to 3.14 eV with increase of DC power. The photocatalytic activity of the TiO2 films increased with increasing DC power up to 120 W and after that it decreases. We found that the TiO2 films deposited at 120 W with 48% of rutile phase, exhibited high photocatalytic activity (43% of degradation) under UV light compared with other TiO2 films. After loading the optimized Ag nanoparticles on the mixed phase TiO2 films, the photocatalytic activity shifted from UV to visible region with enhancement of photocatalytic activity (55% of degradation). (C) 2015 Elsevier B.V. All rights reserved.

Optimizing Photovoltaic Response by Tuning Light-Harvesting Nanocrystal Shape Synthesized Using a Quick Liquid-Gas Phase Reaction

The electron recombination lifetime in a sensitized semiconductor assembly is greatly influenced by the crystal structure and geometric form of the light-harvesting semiconductor nanocrystal. When such light harvesters with varying structural characteristics are configured in a photoanode, its interface with the electrolyte becomes equally important and directly influences the photovoltaic efficiency. We have systematically probed here the influence of nanocrystal crystallographic structure and shape on the electron recombination lifetime and its eventual influence on the light to electricity conversion efficiency of a liquid junction semiconductor sensitized solar cell. The light-harvesting cadmium sulfide (CdS) nanocrystals of distinctly different and controlled shapes are obtained using a novel and simple liquid gas phase synthesis method performed at different temperatures involving very short reaction times. High resolution synchrotron X-ray diffraction and spectroscopic studies respectively exhibit different crystallographic phase content and optical properties. When assembled on a mesoscopic TiO2 film by a linker molecule, they exhibit remarkable variation in electron recombination lifetime by 1 order of magnitude, as determined by ac-impedance spectroscopy. This also drastically affects the photovoltaic efficiency of the differently shaped nanocrystal sensitized solar cells.

Phase dependent photocatalytic activity of Ag loaded TiO2 films under sun light

Well-crystallized anatase and mixed (anatase-rutile) phase TiO2 thin films were deposited by DC magnetron sputtering technique at various DC powers in the range of 80-140 W. Pure anatase phase was observed in the TiO2 films deposited at low power of 80 W. Films deposited at 120 W were composed of both anatase and rutile phases. At higher power of 140 W, the films are rutile dominated and the rutile percentage increased from 0 to 82% with increase of DC power. The same results of phase change were confirmed by Raman studies. The surface morphology of the TiO2 films showed that the density of the films increased with increase of sputter power. The optical band gap of the films varied from 3.35 to 3.14 eV with increase of DC power. The photocatalytic activity of the TiO2 films increased with increasing DC power up to 120 W and after that it decreases. We found that the TiO2 films deposited at 120 W with 48% of rutile phase, exhibited high photocatalytic activity (43% of degradation) under UV light compared with other TiO2 films. After loading the optimized Ag nanoparticles on the mixed phase TiO2 films, the photocatalytic activity shifted from UV to visible region with enhancement of photocatalytic activity (55% of degradation). (C) 2015 Elsevier B.V. All rights reserved.

White light emissive molecular siblings

The design and synthesis of two structurally close and complementarily fluorescent boron based molecular siblings 2 and 3 are reported. The luminescence properties of individual triads are modulated to complement each other by controlling the intramolecular energy transfer in 2 and 3. The binary mixture of 2 and 3 emits white-light.

Mitochondria-Targeting Iron(III) Catecholates for Photoactivated Anticancer Activity under Red Light

Iron(III) catecholates Fe(R-bpa)(R-dopa)Cl] (1, 2) with a triphenylphosphonium (TPP) moiety, where R-bpa is 2-(TPP-N,N-bis((pyridin-2-yl)methyl)ethanamine) chloride (TPPbpa) and R-dopa is 4-{2-(anthracen-9-yl)methylamino]ethyl}benzene-1,2-diol (andopa, 1) or 4-{2-(pyren-1-yl)-methylamino]ethyl}benzene-1,2-diol (pydopa, 2), were synthesized and their photocytotoxicity studied. Complexes 3 and 4 with phenyl-N,N-bis(pyridin-2-yl)methyl]methanamine (phbpa) were used as controls. The catecholate complexes showed an absorption band near 720 nm. The 5e(-) paramagnetic complexes showed a Fe-III/Fe-II irreversible response near -0.45 V and a quasi-reversible catechol/semiquinone couple near 0.5 V versus saturated calomel electrode (SCE) in DMF/0.1 M tetrabutylammonium perchlorate. They showed photocytotoxicity in red/visible light in HeLa, HaCaT, MCF-7, and A549 cells. Complexes 1 and 2 displayed mitochondrial localization, reactive oxygen species (ROS) generation under red light, and apoptotic cell death. Control complexes 3 and 4 exhibited uniform distribution throughout the cell. The complexes showed DNA photocleavage under red light (785 nm), forming hydroxyl radicals as the ROS.

Novel synergistic photocatalytic degradation of antibiotics and bacteria using V-N doped TiO2 under visible light: the state of nitrogen in V-doped TiO2

We report the synthesis of vanadium and nitrogen co-doped TiO2 for photocatalysis mainly emphasizing the state of nitrogen doping into TiO2 in the presence of vanadium ions. Considering the increase in antibiotic resistance developed by microbes due to the excess of pharmaceutical waste in the ecosystem, the photocatalytic activity was measured by degrading an antibiotic, chloramphenicol. A novel experiment was conducted by degrading the antibiotic and bacteria in each other's vicinity to focus on their synergistic photo-degradation by V-N co-doped TiO2. The catalysts were characterized using XRD, DRS, PL, TEM, BET and XPS analysis. Both interstitial and substitutional nitrogen doping were achieved with V-TiO2, showing high efficiency under visible light for antibiotic and bacterial degradation. In addition, the effect of doping concentration of nitrogen and vanadium in TiO2 and catalyst loading was studied thoroughly. Reusability experiments show that the prepared V-N co-doped TiO2 was stable for many cycles.