Photocytotoxic Lanthanum(III) and Gadolinium(III) Complexes of Phenanthroline Bases Showing Light-Induced DNA Cleavage Activity

Lanthanide complexes of formulation [La(B)(2)(NO3)(3)] (1-3) and [Gd(B)(2)(NO3)(3)] (4-6), where B is a N,N-donor phenanthroline base, namely, 1,10-phenanthroline (phen in 1, 4),dipyrido[3,2-d2',3'-f]quinoxaline (dpq in 2,5) and dipyrido[3,2-a2',3'-c]phenazine (dppz in 3, 6), have been prepared, characterized from physicochemical data, and their photoinduced DNA and protein cleavage activity studied The photocytotoxicity of the dppz complexes 3 and 6 has been studied using HeLa cancer cells. The complexes exhibitligand centered bands in the UV region The dppz complexes show thelowest energy band at 380 nm in N,N-dimethylformamide (DMF) The La(III)complexes are diamagnetic. The Gd(III) complexes (4-6) have magneticmoments that correspond to seven unpaired electrons The complexes are1(.)1 electrolytic in aqueous DMF The dpq and dppz complexes in DMFshow ligand-based reductions. The complexes display moderate binding propensity to calf thymus DNA giving binding constant values in the range of 5.7 x 10(4)-5.8 x 10(5) M-1 with a relative order. 3, 6 (dppz)> 2, 5 (dpq) > 1, 4 (phen) The binding data suggest DNA surface and/or groove binding nature of the complexes. The complexes do not show any hydrolytic cleavage of plasmid supercoiled pUC19 DNA. The dpq and dppz complexes efficiently cleave SC DNA to its nicked circular form onexposure to UV-A light of 365 nm at nanomolar complex concentration. Mechanistic studies reveal the involvement of singlet oxygen (O-1(2)) and hydroxyl radical (HO center dot) as the cleavage active species.The complexes show binding propensity to bovine serum albumin (BSA)protein giving K-BSA values of similar to 10(5) M-1. The dppz complexes 3 and 6 show BSA protein cleavage activity in UV-A light of 365 nm The dppz complexes 3 and 6 exhibit significant photocytotoxicity in HeLa cells giving respective IC50 values of 341 nM and 573 nM in UV-A light of 365 nm for an exposure time of 15 min (IC50 > 100 mu M in dark for both the complexes) Control experiments show significant dark and phototoxicity of the dppz base alone (IC50 = 413 nM in light with 4 h incubation in dark and 116 mu M in dark with 24 h incubation). A significant decrease in the dark toxicity of the dppz base is observedon binding to the lanthanide ions while retaining similar phototoxicity.

Influence of External Light Waves on the Thermoelectric Power Under Strong Magnetic Field in Ultrathin Films, Quantum Wires and Quantum Dots of Optoelectronic Materials

In this paper, an attempt is made to study the influence of external light waves on the thermoelectric power under strong magnetic field (TPSM) in ultrathin films (UFs), quantum wires (QWs) and quantum dots (QDs) of optoelectronic materials whose unperturbed dispersion relation of the conduction electrons are defined by three and two band models of Kane together with parabolic energy bands on the basis of newly formulated electron dispersion laws in each case. We have plotted the TPSM as functions of film thickness, electron concentration, light intensity and wavelength for UFs, QWs and ODs of InSb, GaAs, Hg1-xCdxTe and In1-xGaxAsyP1-y respectively. It appears from the figures that for UFs, the TPSM increases with increasing thickness in quantum steps, decreases with increasing electron degeneracy exhibiting entirely different types of oscillations and changes with both light intensity and wavelength and these two latter types of plots are the direct signature of light waves on opto-TPSM. For QWs, the opto-TPSM exhibits rectangular oscillations with increasing thickness and shows enhanced spiky oscillations with electron concentration per unit length. For QDs, the opto-TPSM increases with increasing film thickness exhibiting trapezoidal variations which occurs during quantum jumps and the length and breadth of the trapezoids are totally dependent on energy band constants. Under the condition of non-degeneracy, the results of opto-TPSM gets simplified into the well-known form of classical TPSM equation which the function of three constants only and being invariant of the signature of band structure.

Evaluation of solute-solvent interactions from solvent blue-shifts of n → π* transitions of C=O, C=S, NO2 and N=N groups: hydrogen bond energies of various donor-acceptor systems

Effects of non-polar, polar and proton-donating solvents on the n → π* transitions of C=O, C=S, NO2 and N=N groups have been investigated. The shifts of the absorption maxima in non-polar and polar solvents have been related to the electrostatic interactions between solute and solvent molecules, by employing the theory of McRAE. In solvents which can donate protons the solvent shifts are mainly determined by solute-solvent hydrogen bonding. Isobestic points have been found in the n → π* bonds of ethylenetrithio-carbonate in heptane-alcohol and heptane-chloroform solvent systems, indicating the existence of equilibria between the hydrogen bonded and the free species of the solute. Among the different proton-donating solvents studied water produces the largest blue-shifts. The blue-shifts in alcohols decrease in the order 2,2,2-trifluoroethanol, methanol, ethanol, isopropanol and t-butanol, the blue-shift in trifluoroethanol being nearly equal to that in water. This trend is exactly opposite to that for the self-association of alcohols. It is suggested that electron-withdrawing groups not merely decrease the extent of self-association of alcohols, but also increase the ability to donate hydrogen bonds. The approximate hydrogen-bond energies for several donor-acceptor systems have been estimated. In a series of aliphatio ketones and nitro compounds studied, the blue-shifts and consequently the hydrogen bond energies decrease with the decrease in the electron-withdrawing power of the alkyl groups. It is felt that electron-withdrawing groups render the chromophores better proton acceptors, and the alcohols better donors. A linear relationship between n → π* transition frequency and the infrared frequency of ethylenetrithiocarbonate has been found. It is concluded that stabilization of the electronic ground states of solute molecules by electrostatic and/or hydrogen-bond interactions determines the solvent shifts.

Rough Justice or Zero Tolerance? - Reassessing the Nature of Copyright in Light of Collective Licensing (Part I)

Starting point in the European individualistic copyright ideology is that an individual author creates a work and controls the use of it. However, this paper argues that it is (and has always been) impossible to control the use of works after their publication. This has also been acknowledged by the legislator, who has introduced collective licensing agreements because of this impossibility. Since it is impossible to rigorously control the use of works this writing "Rough Justice or Zero Tolerance - Reassessing the Nature of Copyright in Light of Collective Licensing" examines what reality of copyright is actually about. Finding alternative (and hopefully more "true") ways to understand copyright helps us to create alternative solutions in order to solve possible problems we have as it comes e.g. to use of content in online environment. The paper makes a claim that copyright is actually about defining negotiation points for different stakeholders and that nothing in the copyright reality prevents us from defining e.g. a new negotiation point where representatives of consumers would meet representatives of right holders in order to agree on the terms of use for certain content types in online environment.

The RATAS-project, in the Light of 25 Years of Development Towards Computer-Integrated Construction

In smaller countries where the key players in construction IT development tend to know each other personally and where public R&D funding is concentrated to a few channels, IT roadmaps and strategies would seem to have a better chance of influencing development than in the bigger industrial countries. In this paper Finland and the RATAS-project is presented as a historical case illustrating such impact. RATAS was initiated as a construction IT roadmap project in 1985, involving many of the key organisations and companies active in construction sector development. Several of the individuals who took an active part in the project have played an important role in later developments both in Finland and on the international scene. The central result of RATAS was the identification of what is nowadays called Building Information Modelling (BIM) technology as the central issue in getting IT into efficient use in the construction sector. BIM, which earlier was referred to as building product modelling, has been a key ingredient in many roadmaps since and the subject of international standardisation efforts such as STEP and IAI/IFCs. The RATAS project can in hindsight be seen as a forerunner with an impact which also transcended national borders.

Phonon-mediated two-magnon light scattering from ferromagnetic insulators

An indirect mechanism of light scattering from spin-waves in ferromagnetic insulators via two-magnon one-phonon process is proposed. Following linear response theory, an expression has been derived for the differential scattering cross-section in the mean-field-approximation.

On Using Projective Relations for Calibration and Estimation in a Structured-Light Scanner

For structured-light scanners, the projective geometry between a projector-camera pair is identical to that of a camera-camera pair. Consequently, in conjunction with calibration, a variety of geometric relations are available for three-dimensional Euclidean reconstruction. In this paper, we use projector-camera epipolar properties and the projective invariance of the cross-ratio to solve for 3D geometry. A key contribution of our approach is the use of homographies induced by reference planes, along with a calibrated camera, resulting in a simple parametric representation for projector and system calibration. Compared to existing solutions that require an elaborate calibration process, our method is simple while ensuring geometric consistency. Our formulation using the invariance of the cross-ratio is also extensible to multiple estimates of 3D geometry that can be analysed in a statistical sense. The performance of our system is demonstrated on some cultural artifacts and geometric surfaces.

Photocatalytic activity of tin-substituted TiO2 in visible light

Ultrafine powders of (Ti1-xSnx)O2, 0

Towards optimum diffraction efficiency for methylene blue sensitized dichromated gelatin holograms

A systematic investigation has been carried out into the optimization of diffraction efficiency (η) of methylene blue sensitized dichromated gelatin (MBDCG) holograms. The influence of the following parameters on η have been studied: prehardener concentration (CH), concentrations of ammonium dichromate (CA) and methylene blue (CM) as photosensitizers, and exposure (E). This study revealed that with CH similar, equals 0.5, CA similar, equals 30, CM similar, equals 0.3, and E similar, equals 400–600, optimum diffraction efficiency of over 80%, can be easily achieved in MBDCG holograms.

Assessment of ultrasound modulation of near infrared light on the quantification of scattering coefficient

Purpose: To assess the effect of ultrasound modulation of near infrared (NIR) light on the quantification of scattering coefficient in tissue-mimicking biological phantoms.Methods: A unique method to estimate the phase of the modulated NIR light making use of only time averaged intensity measurements using a charge coupled device camera is used in this investigation. These experimental measurements from tissue-mimicking biological phantoms are used to estimate the differential pathlength, in turn leading to estimation of optical scattering coefficient. A Monte-Carlo model base numerical estimation of phase in lieu of ultrasound modulation is performed to verify the experimental results. Results: The results indicate that the ultrasound modulation of NIR light enhances the effective scattering coefficient. The observed effective scattering coefficient enhancement in tissue-mimicking viscoelastic phantoms increases with increasing ultrasound drive voltage. The same trend is noticed as the ultrasound modulation frequency approaches the natural vibration frequency of the phantom material. The contrast enhancement is less for the stiffer (larger storage modulus) tissue, mimicking tumor necrotic core, compared to the normal tissue. Conclusions: The ultrasound modulation of the insonified region leads to an increase in the effective number of scattering events experienced by NIR light, increasing the measured phase, causing the enhancement in the effective scattering coefficient. The ultrasound modulation of NIR light could provide better estimation of scattering coefficient. The observed local enhancement of the effective scattering coefficient, in the ultrasound focal region, is validated using both experimental measurements and Monte-Carlo simulations. (C) 2010 American Association of Physicists in Medicine. [DOI: 10.1118/1.3456441]

Analysis of effects of ambients (temperature and light intensity) on the electrical breakdown in bipolar transistors

This paper presents an analysis of the effects of ambients-temperature and light intensity on the V-l characteristics of bipolar transistors under electrical breakdown. The analysis is based on the transportation and storage of majority carriers in the base region. It is shown that this analysis can explain the observed shift in the V-l characteristics to lower voltages with increase in either temperature or light intensity.

Interaction of 3-hydroxybenzoate-6-hydroxylase with cibacron blue

Cibacron blue is a potent inhibitor of 3-HBA-6-hydroxylase at a concentration < 1 mu M. Kinetic analyses revealed that at a concentration below 0.5 mu M the dye behaves as an uncompetitive inhibitor with respect to 3-HBA and competes with NADH for the same site on the enzyme. The alteration of the near-UV CD spectrum and quenching of the emission fluorescence of the enzyme by cibacron blue indicates a significant alteration in the environment of aromatic amino acid residues due to a stacking interaction and subtle conformatiodnal changes in the enzyme. The concentration-dependent quenching of the intrinsic fluorescence of the enzyme by cibacron blue was employed to determine the binding parameters such as association constant (K-a) and stoichiometry (r) for the enzyme-dye complex.

New phase unwrapping strategy for rapid and dense 3D data acquisition in structured light approach

Sinusoidal structured light projection (SSLP) technique, specifically-phase stepping method, is in widespread use to obtain accurate, dense 3-D data. But, if the object under investigation possesses surface discontinuities, phase unwrapping (an intermediate step in SSLP) stage mandatorily require several additional images, of the object with projected fringes (of different spatial frequencies), as input to generate a reliable 3D shape. On the other hand, Color-coded structured light projection (CSLP) technique is known to require a single image as in put, but generates sparse 3D data. Thus we propose the use of CSLP in conjunction with SSLP to obtain dense 3D data with minimum number of images as input. This approach is shown to be significantly faster and reliable than temporal phase unwrapping procedure that uses a complete exponential sequence. For example, if a measurement with the accuracy obtained by interrogating the object with 32 fringes in the projected pattern is carried out with both the methods, new strategy proposed requires only 5 frames as compared to 24 frames required by the later method.