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101.
Dual‐Sensitized Luminescent Europium(ΙΙΙ) and Terbium(ΙΙΙ) Complexes as Bioimaging and Light‐Responsive Therapeutic Agents
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Srikanth Dasari Swati Singh Prof. Dr. Sri Sivakumar Prof. Dr. Ashis K. Patra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17387-17396
Dual‐photosensitized stable EuΙΙΙ and TbΙΙΙ complexes, namely [Eu(dpq)(tfnb)3] ( 1 ) and [Tb(dpq)(tfnb)3] ( 2 ), in which dpq=dipyrido[3,2‐d:2′,3′‐f]quinoxaline and Htfnb=4,4,4‐trifluoro‐1‐(2‐napthyl)‐1,3‐butanedione, were designed as bioimaging and light‐responsive therapeutic agents. Their X‐ray structures, photophysical properties, biological interactions, photoinduced DNA damage, photocytotoxicity, and cellular uptake properties were studied. Discrete mononuclear complexes adopt an eight‐coordinated {LnN2O6} distorted square antiprism geometry with bidentate N,N‐donor dpq and O,O‐donor tfnb ligands. The designed probes have the advantage of dual‐sensitizing antennae (dpq, Htfnb) to modulate their desirable optical properties for cellular imaging and light‐responsive intracellular damage. The remarkable photostability, absence of inner‐sphere water (q<1), and longer excited‐state lifetimes of the complexes make them suitable as cellular‐imaging probes. The dpq 3T state is well located energetically to allow efficient energy transfer (ET) to the emissive 5D0 and 5D4 states of EuΙΙΙ and TbΙΙΙ. This leads to higher quantum yields (φ=0.15–0.20) in aqueous media and makes these compounds suitable cellular‐imaging probes. The complexes display significant binding ability toward DNA and bovine serum albumin (K≈105 m ?1). They effectively cleave supercoiled DNA to its nicked circular form at λ=365 nm through photoredox pathways. The cellular internalization studies showed cytosolic and nuclear localization. The remarkable photocytotoxicity of these probes offers a strategy towards developing photoresponsive LnΙΙΙ probes as cellular‐imaging and phototherapeutic agents. 相似文献
102.
Christian Rapp Edwin Kreuzer N. Sri Namachchivaya 《Archive of Applied Mechanics (Ingenieur Archiv)》2012,82(3):297-315
Nearly every cargo that is transported by ship is boxed in standardized containers. The land to ship and ship to land handling
of containers is performed by container cranes. These cranes dominate the throughput of the containers in ports. The operators
need to be well-trained and skilled because of the requirements of the task to load or unload the ships. During container
handling, the crane-load system can be compared to a pendulum of rope length L and deflection f{\phi} . It is referred to as an underactuated system. Whenever the fixed point of the pendulum is displaced, the load starts oscillating.
In the nonlinear dynamics literature, one finds the field of resonant coupling to transfer energy from actuated controllable
modes to underactuated uncontrollable modes. This work presents a novel normal form approach in order to identify the mode
coupling. The proposed method decomposes a nonlinear control system into controllable and uncontrollable subsystem. Only the
normal form terms in the controllable subsystem are utilized to design a general controller. Simulation results are given
to highlight the load oscillation suppression. 相似文献
103.
Iserles et al. (J. Approx. Theory 65:151–175, 1991) introduced the concepts of coherent pairs and symmetrically coherent pairs of measures with the aim of obtaining Sobolev
inner products with their respective orthogonal polynomials satisfying a particular type of recurrence relation. Groenevelt
(J. Approx. Theory 114:115–140, 2002) considered the special Gegenbauer-Sobolev inner products, covering all possible types of coherent pairs, and proves certain
interlacing properties of the zeros of the associated orthogonal polynomials. In this paper we extend the results of Groenevelt,
when the pair of measures in the Gegenbauer-Sobolev inner product no longer form a coherent pair.
This research is supported by grants from CNPq and FAPESP. 相似文献
104.
Sinan Demir Vitaly Bychkov Sri Hari Ramakrishna Chalagalla 《Combustion Theory and Modelling》2017,21(6):997-1022
To reveal the inner mechanisms of a combustion accident in a coalmine, the key stages and characteristics of premixed flame front evolution such as the flame shapes, propagation speeds, acceleration rates, run-up distances and flame-generated velocity profiles are scrutinised. The theories of globally spherical, expanding flames and of finger-flame acceleration are combined into a general analytical formulation. Two-dimensional and cylindrical mining passages are studied, with noticeably stronger acceleration found in the cylindrical geometry. The entire acceleration scenario may promote the total burning rate by up to two orders of magnitude, to a near-sonic value. Starting with gaseous combustion, the analysis is subsequently extended to gaseous-dusty environments. Specifically, combustible dust (e.g. coal), inert dust (e.g. sand), and their combination are considered, and the influence of the size and concentration of the dust particles is quantified. In particular, small particles influence flame propagation more than large ones, and flame acceleration increases with the concentration of a combustible dust, until the concentration attains a certain limit. 相似文献
105.
Debarjoyti Choudhuri B. Sri Padmavati 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2010,61(2):317-328
A general method to discuss the problem of an arbitrary Stokes flow (both axisymmetric and non-axisymmetric flows) of a viscous, incompressible fluid past a sphere with a thin coating of a fluid of a different viscosity is considered. We derive the expressions for the drag and torque experienced by the fluid coated sphere and also discuss the conditions for the reduction of the drag on the fluid coated sphere. In fact, we show that the drag reduces compared to the drag on a rigid sphere of the same radius when the unperturbed velocity is either harmonic or purely biharmonic, i.e., of the form ${r^2\vec{\textbf{v}}}$ , where ${\vec{\textbf{v}}}$ is a harmonic function. Previously Johnson (J Fluid Mech 110:217–238, 1981), who considered a uniform flow showed that the drag on the fluid coated sphere reduces compared to the drag on the uncoated sphere when the ratio of the surrounding fluid viscosity to the fluid-film viscosity is greater than 4. We show that this result is true when the undisturbed velocity is harmonic or purely biharmonic, uniform flow being a special case of the former. However, we illustrate by an example that the drag may increase in a general Stokes flow even if this ratio is greater than 4. Moreover, when the unperturbed velocity is harmonic or purely biharmonic, and the ratio of the surrounding fluid viscosity to the fluid-film viscosity is greater than 4 for a fixed value of the viscosity of the ambient fluid, we determine the thickness of the coating for which the drag is minimum. 相似文献
106.
Sri Krishna Nimmagadda Mingyu Liu Malkanthi K. Karunananda De‐Wei Gao Omar Apolinar Jason S. Chen Peng Liu Keary M. Engle 《Angewandte Chemie (International ed. in English)》2019,58(12):3923-3927
A palladium(II)‐catalyzed enantioselective α‐alkylation of azlactones with nonconjugated alkenes is described. The reaction employs a chiral BINOL‐derived phosphoric acid as the source of stereoinduction, and a cleavable bidentate directing group appended to the alkene to control the regioselectivity and stabilize the nucleopalladated alkylpalladium(II) intermediate in the catalytic cycle. A wide range of azlactones were found to be compatible under the optimal reaction conditions to afford products bearing α,α‐disubstituted α‐amino‐acid derivatives with high yields and high enantioselectivity. 相似文献
107.
One considers an elastic halfspace with depth (x1) dependent density Q and Lamé moduli (λ,m?). Impulsive stresses τli = δ(x2, x3)δ(t) for x1 = 0 are applied with displacement responses ui = gi(t, x2, x3) at x1 = 0 (i = 1, 2, 3). Let vi(t, x1) = ∫∫uidx2dx3 (i = 1, 2 is enough) and set w(t, x1) = ∫∫x2u1dx2dx3. One obtains a system of 3 differential equations for v1, v2, and w to which the spectral techniques of inverse scattering theory are applied as in [25]. The inverse problems for the uncoupled vi can then be solved to produce 2 functions A1 and A2 involving (Q, λ, μ) as functions of “bound” variables y1 and y2 containing (Q, λ, μ), between which a relation then is determined. Analysis of the coupled equation for w then leads to a Fredholm integral equation whose solution provides an additional relation between (Q, λ, μ) from which (Q, λ, μ) can be determined as functions of x1. The integral equation is reduced to a Volterra type equation by results and techniques of transmutation and then solved by a modification of standard techniques. A number of features and results of independent mathematical interest arise from the transmutation theory. 相似文献
108.
New types of hybrid material have been synthesized by using four different methods of immobilization of humic acid (HA) on chitin. The most stable hybrid material toward the change of medium acidity was then utilized as sorbent for Cr(III).The HA was extracted from peat soil of Gambut District, South Kalimantan, Indonesia, using the recommended procedure of International Humic Substances Society (IHSS), while the chitin was isolated from crab shell waste through deproteination using 3.5% (w/v) NaOH and followed by removal of inorganic impurities using 1 M HCl. The four methods of immobilization of HA on chitin were (i) Method A: chitin powder (4 g) was gently poured into the stirred solution of 0.4 g HA in 40 mL of 0.01 M NaOH. After overnight stirring, the solid was separated, washed with water, and dried in oven at 70 °C. (ii) Method B: gelatinous chitin (40 g) in 250 mL of 0.5 M HCl was reacted with HA (4 g) in 500 mL of 0.5 M NaOH and aged for 24 h. The product was washed with water and dried. (iii) Method C: HA powder (0.5 g) was mixed with the stirred gel of chitin (2.5 g) in 60 mL of CaCl2 saturated methanol and the mixture was then washed with the mixed solution of 25 mL of 2 M sodium citrate and ethylene glycol 1:1. The solid was separated, washed with water, and dried. (iv) Method D: the solution of HA (0.056 g) in 10 mL of 0.01 M NaOH was reacted with the gel of chitin (0.2 g) in 10 mL of CaCl2 saturated methanol. After 24 h stirring, the solid was separated from the reaction medium, washed with the mixed solution of 2 M sodium citrate and ethylene glycol 1:1, and followed by washing with water and drying. Parameters investigated in this study consisted of the stability test of the immobilized HA, as well as the rate constant (k1), capacity (b), and energy (E) of sorption as well as the rate constant of desorption (k−1). The k1 and k−1 were determined according to a kinetic model of first order sorption reaching equilibrium, while the b and E were determined according to the Langmuir isotherm model.Compared to HA, Methods, A, C, and D; Method B produced the most stable immobilization of HA on chitin. The hybrid material (Chitin-HA) synthesized through Method B was stable in the acidity range that equivalent to pH 2.0-11.0. At the acidity giving maximum sorption, i.e. pH 5, the presence of immobilized HA on the Chitin-HA enhanced more than three times the k1 and k−1, i.e. from 0.057 min−1 and 8.51 × 10−4 (min−1) (mol/L) for chitin to 0.183 min−1 and 3.27 × 10−3 (min−1) (mol/L) for the Chitin-HA. On the contrary, the presence of HA on Chitin-HA only gave small increase on b and small decrease on E. The values of b and E for Cr(III) on chitin were 1.45 × 10−2 mol/g and 23.12 kJ/mol, respectively, while those on Chitin-HA were 1.78 × 10−2 mol/g and 19.95 kJ/mol, respectively. 相似文献
109.
Endoori Srinivas anna Venkateswara Rao Gulipalli Kali Charan Bodige Srinu Pommidi Anil Kumar Surapureddi Sri Ramakrishna Seelam Nareshvarma 《Russian Journal of General Chemistry》2022,92(9):1775-1784
Russian Journal of General Chemistry - A novel series of imidazo[1,2-a]pyridine linked 1,2,3-triazole derivatives has been designed, synthesized and the structures have been confirmed by 1H and 13C... 相似文献
110.
Dileep Kommula Sri Rama Murty Madugula 《Journal of the Iranian Chemical Society》2017,14(8):1665-1671
An efficient, simple, ecofriendly and cost-effective method has been developed for the synthesis of benzimidazole/benzothiazole derivatives by a two-component reaction, involving 1,2-diamino benzene/2-amino thiophenol and substituted aromatic aldehydes using recyclable nano-Fe2O3 catalyst (10 mol%) in water afforded with excellent yields (75–85%). The most important feature of this protocol is short reaction times, high yields, aqueous reaction medium, efficient recycling and high stability of the catalyst. 相似文献