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Naresh Dadhich Josep M. Pons Kartik Prabhu 《General Relativity and Gravitation》2012,44(10):2595-2601
The necessary and sufficient condition for the thermodynamical universality of the static spherically symmetric Lovelock black hole is that it is the Nth order pure Lovelock Λ-vacuum solution. By universality we mean the thermodynamical parameters: temperature and entropy always bear the same relation to the horizon radius for d = 2N + 1, 2N + 2 dimensions for all N which is the degree of the Lovelock polynomial. For instance, the entropy always goes in terms of the horizon radius as r h and r h 2, respectively for the odd and even dimensions. Not only that the universality uniquely identifies the pure Lovelock black hole with Λ, it is the characterizing property of this class of black holes. 相似文献
73.
Low-noise, tunable wavelength-conversion through nondegenerate four-wave mixing Bragg scattering in SiN(x) waveguides is experimentally demonstrated. Finite element method simulations of waveguide dispersion are used with the split-step Fourier method to predict device performance. Two 1550 nm wavelength band pulsed pumps are used to achieve tunable conversion of a 980 nm signal over a range of 5 nm with a peak conversion efficiency of ≈5%. The demonstrated Bragg scattering process is suitable for frequency conversion of quantum states of light. 相似文献
74.
Sagar B. Tolani Michael Craig Robert K. DeLong Kartik Ghosh Adam K. Wanekaya 《Analytical and bioanalytical chemistry》2009,393(4):1225-1231
We report the electrochemical deposition of poly(pyrrolepropylic acid) nanowires, their covalent modification with antibodies
and their conversion into potential functional sensor devices. The nanowires and the devices were characterised by optical
microscopy, fluorescence microscopy, electron microscopy and electrical measurements. Fluorescence images, current–voltage
(I–V) profiles and real-time sensing measurements demonstrated a rapid and highly sensitive and selective detection of human serum
albumin (HSA), a substance that has been used to diagnose incipient renal disease. The detection is based on the selective
binding of HSA onto anti-HSA that is covalently attached to the nanowires. The binding changes the electrical properties of
the nanowires thus enabling the real-time detection. Whilst the utility of the research was demonstrated for protein binding/detection,
the technology could easily be designed for the detection of other analytes by the modification of polymer nanowires with
other analyte-specific molecules/biomolecules. Therefore, the technology has the potential to positively impact broad analytical
applications in the biomedical, environmental and other sectors.
Figure Real-time dynamic current response on sequential exposure of buffer, bovine serum albumin (BSA) and human serum albumin (HSA)
onto anti-HSA modified poly (pyrrolepropylic acid) nanowires. Fluorescence images of poly(pyrrolepropylic acid) nanowire (top
right) and polypyrrole nanowire control (bottom right) after sequential treatment with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide
hydrochloride (EDC), anti HSA and fluorophore-labeled HSA. 相似文献
75.
Synthesis,Characterization, and Theoretical Investigation of Two‐Coordinate Palladium(0) and Platinum(0) Complexes Utilizing π‐Accepting Carbenes 下载免费PDF全文
Dr. Sudipta Roy Dr. Kartik Chandra Mondal Dipl.‐Chem. Jann Meyer Dipl.‐Chem. Benedikt Niepötter Christian Köhler Dr. Regine Herbst‐Irmer Prof. Dr. Dietmar Stalke Dr. Birger Dittrich Dr. Diego M. Andrada Prof. Dr. Gernot Frenking Prof. Dr. Herbert W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(26):9312-9318
An elegant general synthesis route for the preparation of two coordinate palladium(0) and platinum(0) complexes was developed by reacting commercially available tetrakis(triphenylphosphine)palladium/platinum with π‐accepting cyclic alkyl(amino) carbenes (cAACs). The complexes are characterized by NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction. The palladium complexes exhibit sharp color changes (crystallochromism) from dark maroon to bright green if the C‐Pd‐C bond angle is sharpened by approximately 6°, which is chemically feasible by elimination of one lattice THF solvent molecule. The analogous dark orange‐colored platinum complexes are more rigid and thus do not show this phenomenon. Additionally, [(cAAC)2Pd/Pt] complexes can be quasi‐reversibly oxidized to their corresponding [(cAAC)2Pd/Pt]+ cations, as evidenced by cyclic voltammetry measurements. The bonding and stability are studied by theoretical calculations. 相似文献
76.
A Strongly Spin‐Frustrated FeIII7 Complex with a Canted Intermediate Spin Ground State of S=7/2 or 9/2 下载免费PDF全文
Dr. Kartik Chandra Mondal Dr. Valeriu Mereacre Dr. George E. Kostakis Dr. Yanhua Lan Dr. Christopher E. Anson Dr. Ion Prisecaru Prof. Dr. Oliver Waldmann Prof. Dr. Annie K. Powell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10835-10842
A disk‐shaped [FeIII7(Cl)(MeOH)6(μ3‐O)3(μ‐OMe)6 (PhCO2)6]Cl2 complex with C3 symmetry has been synthesised and characterised. The central tetrahedral FeIII is 0.733 Å above the almost co‐planar FeIII6 wheel, to which it is connected through three μ3‐oxide bridges. For this iron‐oxo core, the magnetic susceptibility analysis proposed a Heisenberg–Dirac–van Vleck (HDvV) mechanism that leads to an intermediate spin ground state of S=7/2 or 9/2. Within either of these ground state manifolds it is reasonable to expect spin frustration effects. The 57Fe Mössbauer (MS) analysis verifies that the central FeIII ion easily aligns its magnetic moment antiparallel to the externally applied field direction, whereas the other six peripheral FeIII ions keep their moments almost perpendicular to the field at stronger fields. This unusual canted spin structure reflects spin frustration. The small linewidths in the magnetic Mössbauer spectra of polycrystalline samples clearly suggest an isotropic exchange mechanism for realisation of this peculiar spin topology. 相似文献
77.
Benedikt Niepötter Dr. Regine Herbst‐Irmer Dr. Daniel Kratzert Dr. Prinson P. Samuel Dr. Kartik Chandra Mondal Prof. Dr. Herbert W. Roesky Paul Jerabek Prof. Dr. Gernot Frenking Prof. Dr. Dietmar Stalke 《Angewandte Chemie (International ed. in English)》2014,53(10):2766-2770
An experimental and theoretical charge density study confirms the interpretation of (cAAC)2Si as a silylone to be valid. Two separated VSCCs present in the non‐bonding region of the central silicon are indicative for two lone pairs. In the experiment, both the two crystallographically independent Si? C bond lengths and ellipticities vary notably. It is only the cyclohexyl derivative that shows significant differences in these values, both in the silylones and the germylones. Only by calculating increasing spheres of surrounding point charges we were able to recover the changes in the properties of the charge density distribution caused by weak intermolecular interactions. The nitrogen–carbene‐carbon bond seems to have a significant double‐bond character, indicating a singlet state for the carbene carbon, which is needed for donor acceptor bonding. Thus the sum of bond angles at the nitrogen atoms seems to be a reasonable estimate for singlet versus triplet state of cAACs. 相似文献
78.
A three-component highly regio- and diastereoselective 1,3-dipolar cycloaddition reaction between isatin, a series of primary amino acids (10 nos), and exocyclic α,β-unsaturated ketones was developed towards the synthesis of a small library of bispirooxindole (20 nos) at ambient temperature. The developed reaction afforded highly substituted 3,2′-pyrrolidine-bispirooxindole with two vicinal spiro-quaternary and four contiguous stereocenters from the cheap and abundant starting materials. The products were obtained with good to excellent yields (50–95%) and as a single diastereoisomer in the majority of the cases. Primary amino acids were served as amine component for the in-situ generation of azomethine ylides from isatin. Molecular docking studies were carried out to explore the synthesized bispirooxindoles as inhibitors of the epidermal growth factor receptor (EGFR). Two compounds exhibited excellent binding affinity towards EGFR receptor. 相似文献
79.
Mondal KC Kostakis GE Lan Y Wernsdorfer W Anson CE Powell AK 《Inorganic chemistry》2011,50(22):11604-11611
Two pairs of Ni(2)Dy(2) and Ni(2)Tb(2) complexes, [Ni(2)Ln(2)(L)(4)(NO(3))(2)(DMF)(2)] {Ln = Dy (1), Tb (2)} and [Ni(2)Ln(2)(L)(4)(NO(3))(2)(MeOH)(2)]·3MeOH {Ln = Dy (3), Tb (4)} (H(2)L is the Schiff base resulting from the condensation of o-vanillin and 2-aminophenol) possessing a defect-dicubane core topology were synthesized and characterized. All four complexes are ferromagnetically coupled, and the two Dy-analogues are found to be Single Molecule Magnets (SMMs) with energy barriers in the range 18-28 K. Compound 1 displays step-like hysteresis loops, confirming the SMM behavior. Although 1 and 3 show very similar structural topologies, the dynamic properties of 1 and 3 are different with blocking temperatures (3.2 and 4.2 K at a frequency of 1500 Hz) differing by 1 K. This appears to result from a change in orientation of the nitrate ligands on the Dy(III) ions, induced by changes in ligands on Ni(II). 相似文献
80.
Subhajit Saha Pritam Kumar Roy Kartik Maity Prof. Mahitosh Mandal Prof. Kumar Biradha 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(9):e202103830
Selective detection of H2S in the cellular systems using fluorescent CPs/MOFs is of great scientific interest due to their outstanding aqueous stability, biocompatibility and real-time detection ability. Fabrication of such materials using complete biologically essential elements and applying them as an efficient biosensor is still quite challenging. In this context, two newly synthesized CPs containing biologically essential metal ion (Zn) and nitro/azido functional groups into the framework to sense extracellular and intracellular H2S by reducing into respective amines are presented. The CP- 1 containing the azide group acted as an efficient fluorescent turn-on probe with the lowest detection limit (7.2 μM) and shortest response time (30 s) among the Zn-based probes reported till date. Moreover, CP- 1 exhibited green luminescence in live cells after imaging a very low concentration of H2S, whereas the nitro analogue CP- 2 could not detect the target analyte due to its framework disruption. 相似文献