查看更多>>摘要：In this study, a new cyanine-based photosensitizer Cy-N-Rh was developed for photodynamic therapy. Based on fluorescence resonance energy transfer (FRET) mechanism, utilizing the absorption of the donor rhodamine (Rh), the acceptor heptamethine cyanine unit (Cy) was indirectly excited to produce singlet oxygen (O-1(2)). The efficiency of energy transfer from the donor Rh to the acceptor Cy was 78.5%. Meanwhile, the singlet oxygen yield of Cy-N-Rh (Phi(delta) = 12.00%) was much higher than that of the acceptor Cy (Phi(delta) = 4.35%) without FRET. Moreover, the dual cation gave Cy-N-Rh with excellent mitochondria targeting ability with Pearson's correlation coefficients of 0.90 and 0.91, respectively. In the MTT test, Cy-N-Rh had low dark cytotoxicity with cell survival rate above 90% and high photo cytotoxicity with cell survival rate below 40%. The cell apoptosis assay also demonstrated the role of the photosensitizer Cy-N-R visually. More importantly, Cy-N-Rh fulfilled two-photon excitation fluorescence imaging under the 800 nm femtosecond laser. All results indicate that this design strategy provides a new method for the development of higher-level cyanine photosensitizers. (C) 2022 Elsevier B.V. All rights reserved.
Bermudez, C.Motiyenko, R. A.Cabezas, C.Ilyushin, V. V....
9页
查看更多>>摘要：The rotational spectrum (4-40 GHz and 50-330 GHz) has been measured and analyzed for trifluoroacetaldehyde, also known as fluoral (CF3CHO), which is one of the degradation products of the fluorinated contaminants emitted into the atmosphere. The complexity of the spectroscopic analysis of this molecule arises from the strong coupling between the internal rotation motion of CF3 group and the overall rotation of the molecule. The value obtained for its coupling constant (p = 0.91723481(49)) is comparable to the corresponding value of methanol (CH3OH, p = 0.81), which is known for its complex spectrum. A total of 12,322 transitions of the ground, the first and second excited torsional states (delta E-1ut = 62.0183(13) cm(-1); delta E-2ut = 120.3315(13)cm(-1)) with J <= 50 were included in the analysis that was performed employing the rho-axis-method (RAM), and the RAM36 code. A fit within experimental error (root mean square deviation equals to 35 kHz) has been achieved for this dataset using 47 parameters of the RAM torsion-rotation Hamiltonian. In the course of the analysis, it became evident that for such high p value, as it is determined for fluoral, a larger than usual torsional basis set at the first diagonalization step of the two-step diagonalization procedure is required for achieving a fit within experimental error. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
查看更多>>摘要：In order to classify imported frozen fish, effectively a spectral data compression method was presented based on two-dimensional correlation spectroscopy. In the experiment, the near-infrared spectral data of Oncorhynchus keta, Oncorhynchus nerka and Oncorhynchus gorbuscha of Salmonidae were collected. And two-dimensional correlation spectroscopy among the three fish samples was constructed. The study found that the auto-correlation peaks intensities at 650 nm, 1724 nm and 1908 nm were almost zero, which were taken as the separation point of the spectra. Therefore, each spectral data is divided into 4 segments and the integral of each segment is obtained. The original spectra of 201 points in each group were compressed into 4 points. Then, the compressed spectral data were input into the support vector machine to establish the discriminant model of three kinds of frozen fish. At the same time, the Competitive Adaptive Reweighted Sampling and the Successive Projections Algorithm were used to screen the original spectra. The classification results were compared with the result of the spectral data compression method of two-dimensional correlation spectroscopy. The result shows: the compression rate of the proposed method is 98.01%; the accuracy rate of support vector machine training set is 100%; the accuracy rate of validation set is up to 100%. The results shows that the proposed spectral data compression method based on two-dimensional correlation spectral technology has high compression rate and accurate classification.(c) 2022 Published by Elsevier B.V.
查看更多>>摘要：Mechanochromic luminophors with strong solid-state emission are promising candidates for highcontrast mechanochromic luminescence materials. Meanwhile, mechanically responsive luminogenic molecules with tricolor switching are highly desirable but are seldom reported. In this work, three anthracene-based donor-acceptor-pi-donor (D-A -pi-D) type benzothiadiazole derivatives were designed and synthesized. These luminogens showed remarkable aggregation-induced emission (AIE) or aggregation-induced emission enhancement (AIEE) effect. Furthermore, these luminogens exhibited bright and different solid state fluorescence involving yellow-green, yellow and orange colors, and the fluorescence of their solids could be effectively regulated by mechanical grinding. For luminogen 1, its solid displayed reversible two-color mechanofluorochromic property. As for luminogens 2 and 3, their solids displayed fluorescent colors change from yellow to yellow-green upon slight grinding, and the yellow-green light-emitting solids were converted into orange fluorescent solids after heavy grinding, demonstrating interesting three-color mechanofluorochromism features.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this paper, a theoretical study has been made on the intermolecular interactions of the H-2-CuF complex, including binding energy, intermolecular vibrations, isotope effects, and rotational structure. Based on different bond lengths of H-2 and CuF monomers, three intermolecular potential energy surfaces (PESs) were constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. A global minimum on the PESs show that H-2-CuF complex belongs to C-2 nu point group with a T-shaped structure. The obtained binding energy ranges from 8890 to 10050 cm(-1), which increases as the increment of H-H bond length, but opposite case has been determined as the increment of Cu-F bond length. The accuracy of PESs was examined by the available data of 1(01)-0(00) transition. The predicted rotational transition frequency obtained from bound state calculations can reproduce the experimental observation very well, and the predicted error is 0.1% based on the PES1 constructed with r(H2) and r(CuF) fixed at 0.838 and 1.7409 angstrom. By analyzing the wave function of the bound state, the intermolecular vibrational modes were assigned unambiguously. Isotope effects were also studied and the largest error is also 0.1% compared with the available 1(01)-0(00) transition data. A set of spectroscopic parameters were obtained for six isotopologues to determine rotational structure of H-2-CuF complex. Upon the complex formation, the obtained structure parameters show that H-H bond length is elongated by 0.081 angstrom, while Cu-F value is shortened by 0.008 angstrom from the respective average bond lengths of free monomer. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A novel two-photon fluorogenic probe has been developed to detect formaldehyde with fast response, low cytotoxicity, and excellent selectivity. This probe exhibits a strong turn-on fluorescence response to formaldehyde under excitation at 370 nm and has been successfully applied to detect formaldehyde in living cells. Theoretical calculations at the B3LYP/6-31 + G(d,p), APFD/6-311++G, and APFD/6-311 + G(2d,p) levels of theory for the absorption and emission wavelengths of the probes were in agreement with those obtained experimentally.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Femtosecond time-resolved photoelectron spectroscopy was employed to investigate the ultrafast non-adiabatic dynamics of diethylamine (DEA). Following the direct excitations of the two main conformational structures (i.e., TT and TG) of DEA to the 3p Rydberg states at 200 nm, DEA undergoes internal conversion to the 3s state with similar to 68 fs, which is similar to previously relaxation pathways of several secondary and tertiary amines. Subsequent dynamics on the 3s Rydberg state evolves along the N-H stretching coordinate and is then accompanied by the breaking of the N-H bond in about 120 fs, rather than the cleavage of the N-C, or C-C bonds as well as the conformational transformations between the TT and TG conformers on the 3s states. Theoretically, we reveal the pre-dissociative n sigma* character evolving along the N-H stretching coordinate within the 3s state as DEA dissociates to yield H atom products. As contrasted to the well-known conformational N-C bond rotation motions in systems such as tertiary amines, the non-adiabatic relaxation of the 3s state of DEA is predominantly characterized by the N-H bond dissociation process.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Here, we report the existence of a pentameric water cluster in the host framework of [Cu(cyclam)(N-3)(2)]center dot 4H(2)O, that is stable upto 167 degrees C, well above the boiling point of water. The pentameric cluster structure embedded in the host framework is evident from the single crystal studies. The high thermal stability is confirmed by TGA and temperature dependent confocal Raman microscopic studies, where loss of water bands is well captured between 167 and 170 degrees C, besides its existence through SCXRD studies. To the best of our knowledge, this is the first report where temperature dependent confocal Raman microscopic investigation is used to study the stability of water in crystal environment. The study promises that temperature dependent confocal Raman microscopy can be an efficient tool to investigate the existence and stability of small water clusters, precisely in restricted environments. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：5-lipoxygenase (5-LOX) was a key enzyme involved in many inflammatory diseases. Sec-Oglucosylhamaudol (SOG) was a chromone found in Saposhnikovia divaricata (Turcz.) Schischk (S. divaricate). The potato-derived 5-LOX (p-5-LOX) and human recombinant 5-LOX (h-5-LOX) were selected as model protein due to their simple usability and high stability in this study. Thus, the binding interactions of p-5-LOX and h-5-LOX with SOG were investigated by multi-spectroscopy and molecular docking. As a result, the fluorescence intensities of the two 5-LOX were quenched statically by SOG. However, the binding ability of SOG to h-5-LOX was higher than that of p-5-LOX at the same temperature. The results of multi-spectroscopy revealed that the conformation and micro-environment of the two 5-LOX proteins were changed after binding with SOG. Fluorescence assay and molecular docking indicated that hydrogen bond and electrostatic gravitation were the main forces between the two 5-LOX and SOG. Our results here suggested that SOG may exert anti-inflammatory effect by inhibiting 5-LOX activity. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Binary strontium borate host glass together with samples doped with 0.25 %WO3 and one of the rare - earth ions (0.125% Eu3+, Dy3+ or Pr3+) were prepared by conventional melting - annealing technique. DTA analysis of the host base glass was carried out to derive the proper temperatures which are necessary to convert glasses into their corresponding glass-ceramic through controlled thermal heat -treatment regime. Measurements of optical, FTIR, and PL spectra were carried out with special analysis of the spectral properties. The identity of glass - ceramic derivatives were investigated through x-ray diffraction, and TEM & SEM tools to identify their crystalline morphological features. The absorption spectrum of WO3 (-) doped glass refers to the existence of dominant hexavalent tungsten ions. The RE-doped glass reveal characteristic visible - NIR absorption peaks due to the respective rare earth ions. FTIR spectra show absorption bands due to both triangular and tetravalent borate groups (BO3, BO4). PL spectra reveal excitation and emission characteristic peaks due to each specific rare earth ions. XRD indicate the preference of the host glass to form strontium pyroborate (SrB4O7) crystalline phase. This facilitates the clear knowledge of the crystallization behavior and hence can justify the effect of the crystallization on the studied properties. (C) 2022 Elsevier B.V. All rights reserved.
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