Fatty acid composition in erythrocytes and coronary artery disease risk: a case-control study in China.

Background and aims: There is limited and conflicting evidence about the association of erythrocyte fatty acids with coronary artery disease (CAD), particularly in China where the CAD rates are high. Our study aimed to explore the association between erythrocyte fatty acid composition and CAD risk in Chinese adults. Methods: Erythrocyte fatty acids of 314 CAD patients and 314 matched controls were measured by gas chromatography. Multivariable conditional logistic regression and restricted cubic spline models were used to explore the odds ratio with 95% confidence interval (OR, 95% CI) and potential association between erythrocyte fatty acids and CAD risk. Principal component analysis (PCA) was used to analyze further the potential role of various erythrocyte fatty acid patterns in relation to CAD risk. Results: Significant inverse associations were observed between high levels of erythrocyte total n-3 polyunsaturated fatty acids (n-3 PUFA) [ORT3-T1 = 0.18 (0.12, 0.28)], monounsaturated fatty acids (MUFA) [ORT3-T1 = 0.21 (0.13, 0.32)], and the risk of CAD. Conversely, levels of saturated fatty acids (SFAs) and n-6 polyunsaturated fatty acids (n-6 PUFAs) were positively associated with CAD risk [ORT3-T1 = 3.33 (2.18, 5.13), ORT3-T1 = 1.61 (1.06, 2.43)]. No significant association was observed between CAD risk and total trans fatty acids. Additionally, the PCA identifies four new fatty acid patterns (FAPs). The risk of CAD was significantly positively associated with FAP1 and FAP2, while being negatively correlated with FAP3 and FAP4. Conclusion: The different types of erythrocyte fatty acids may significantly alter susceptibility to CAD. Elevated levels of n-3-PUFAs and MUFAs are considered as protective biomarkers against CAD, while SFAs and n-6 PUFAs may be associated with higher CAD risk in Chinese adults. The risk of CAD was positively associated with FAP1 and FAP2, and negatively associated with FAP3 and FAP4. Combinations of erythrocyte fatty acids may be more important markers of CAD development than individual fatty acids or their subgroups.

Surficial amino groups coupling induced concentration-dependent fluorescence and fluorescence quantum yield of nitrogen-dopped carbon quantum dots via efficient charge transfer.

Modification of surficial functional groups among carbon quantum dots (CQDs) has been considered an efficient approach to regulate the fluorescence emission of CQDs. However, the mechanism of how surficial functional groups affect fluorescence is vague which fundamentally limits the further applications of CQDs. Here we report the concentration-dependent fluorescence and fluorescence quantum yield of nitrogen-dopped carbon quantum dots (N-CQDs). At high concentrations (≥0.188 g/L), fluorescence redshift occurs accompanied with decrease in fluorescence quantum yield. Fluorescence excitation spectra and HOMO-LUMO energy gaps calculations show that energy levels of excited states of N-CQDs are relocated via the coupling of surficial amino groups among N-CQDs. Furthermore, electron density difference maps and broadened fluorescence spectra obtained from both experimental measurement and theoretical calculation further confirm that the coupling of surficial amino groups dominates the fluorescence property and verify the formation of charge-transfer state of N-CQDs complex at high concentrations which provides pathways for efficient charge transfer. Given that charge-transfer state induced fluorescence loss and fluorescence spectra broadening are the typical characteristics of organic molecules, CQDs exhibit the optical properties of both quantum dots and organic molecules.

Radial phased-locked Laguerre-Gaussian correlated schell-model beam array.

A new beam array called radial phased-locked Laguerre-Gaussian correlated Schell-model (LGCSM) beam array is presented, the beamlet of this beam array is partially coherent beam with Laguerre Gaussian-Schell model correlation. The propagation expression of a radial phased-locked LGCSM beam array in free space is derived. It is aimed to give the effect of beam parameters on evolutions of beam array composed by LGCSM beam. The radial phased-locked LGCSM beam array has unique properties on propagation, the intensity of such beam array will evolve from a beam array composed of Gauss beams into a beam array formed of LGCSM beams. Furthermore, the intensity evolutions of such beam array are modulated by coherence length and beam order of beamlets. The obtained results are important in areas such as light field shaping, and free space optical communication.

High-resolution laser induced excitation spectroscopy and decay dynamics of YNbO4:Er3.

The rare earth materials have attracted intensive attention due to their strong luminescent characteristic. However, the split fine Stark levels are difficult to be determined. Here we report a room-temperature detection for Stark levels of YNbO4: Er3+ using established laser-induced spectroscopy system with dye laser of superhigh resolution of wavelength at 0.005 nm. From excitation spectra, six split Stark levels of 4G11/2 (Er3+) were directly detected. Moreover, nonradiative relaxations of 4G9/2→4G11/2 and 4G11/2→2H11/2/ 4S3/2 have been observed with weighed lifetimes of 0.70 µs and 6.15 µs, and characteristic green emission of Er3+ (@555 nm) yields lifetime of 31.78 µs.

Exosomes derived from microRNA-129-5p-modified tumor cells selectively enhanced suppressive effect in malignant behaviors of homologous colon cancer cells.

Exosome-encapsulated microRNAs (miRNAs) are novel diagnostic and predictive markers in colon cancer. Hence, the study of serum exosomal miRNAs in patients with colon cancer may help its diagnosis and treatment. PKH26-labeled exosomal uptake analysis identified whether exosomes transfer miRNA-129-5p to target cells. Transmission electron microscopy and dynamic light scattering analysis were applied to determine exosome morphology and size distribution. The Cell Counting Kit-8, wound healing assay and Transwell assays were used to detect cell proliferation, migration, and invasion after treatment with engineered exosomes. Moreover, the Western blotting was used to quantify the expression of proteins involved in cell apoptosis. In our study, hepatocellular liver carcinoma, cervical cancer and colon cancer cells were selected as the target cells of miRNA-129-5p exosomes. Exosomes containing miRNA-129-5p were found to be significantly more easily absorbed by colon cancer cells, presenting a stronger inhibitory effect on colon cancer cell proliferation. MiRNA-129-5p exosomes induced apoptosis in colon cancer cells while inhibiting their proliferation, migration, and invasion. In conclusion, exosomes derived from miRNA-129-5p-modified tumor cells selectively inhibited colon cancer progression, shedding new insights to therapeutic efficacy of this cancer.

Enhanced light-driven hydrogen generation on carbon quantum dots with TiO2 nanoparticles.

Solar to hydrogen (H2) conversion systems based on carbon nanomaterials have shown great potentials in the clean energy field recently. However, for most systems, energy level alignments and light-induced redox processes are still unclear, which hinder artificial designing for higher efficiency of solar energy conversion and further applications. Here we report 77% enhancement in the light-driven H2 generation efficiency of N,S co-doped carbon quantum dot (N,S-CQD) aqueous system by adding TiO2 nanoparticles. Using steady-state and transient spectroscopy, four specific energy levels of CQDs are confirmed with the band gaps of 3.55 eV (X4), 2.99 eV (X3), 2.76 eV (X2) and 1.75 eV (X1), respectively. The X2 energy band is highly active for H+ reduction with a longer lifetime of 13.38 ns. Moreover, the observed low efficiency of intrinsic transition from X3 to X2 band of N,S-CQDs accounts for the poor performance of solar to H2 conversion for pure N,S-CQDs based on H2 generation and detailed time-resolved spectroscopic results. The mechanism of H2 generation enhancement can be explained by multiple electron transfer processes between N,S-CQDs and TiO2 NPs where TiO2 NPs act as electron intermediates that efficiently transfer electrons from the inert band (X3) to the active band (X2) for H2 generation. This study enriches the fundamental understanding of N,S-CQDs and provides a new pathway toward high-performance N,S-CQD-based solar to H2 conversion systems.

Propagation of partially coherent Lorentz-Gauss vortex beam through oceanic turbulence.

The partially coherent Lorentz-Gauss vortex beam generated by a Schell-model source has been introduced. Based on the extended Huygens-Fresnel principle, the cross-spectral density function of a partially coherent Lorentz-Gauss vortex beam propagating in oceanic turbulence is derived. The influences of coherence length, topological charge M, and oceanic turbulence on the spreading properties and position of the coherence vortex for a partially coherent Lorentz-Gauss vortex beam are analyzed in detail. The results show that a partially coherent Lorentz-Gauss vortex beam propagating in stronger oceanic turbulence will evolve into a Gaussian-like beam more rapidly as the propagation distance increases, and the number of coherent vortices will change.

Propagation properties of a partially coherent Lorentz beam in uniaxial crystal orthogonal to the optical axis.

The cross-spectral density function of a partially coherent Lorentz beam propagating in uniaxial crystal orthogonal to the optical axis is obtained, and the evolution properties and the spectral degree of coherence for a partially coherent Lorentz beam in uniaxial crystal are illustrated by using numerical examples. The influence of coherence length and the ratio of refractive index ne/no on the normalized intensity and spectral degree of coherence for a partially coherent Lorentz beam are analyzed in detail.

Evolution properties of partially coherent four-petal Gaussian vortex beams propagating in uniaxial crystals orthogonal to the optical axis.

The analytical propagation equations for partially coherent four-petal Gaussian vortex beams propagating through uniaxial crystals orthogonal to the optical axis are derived, and the propagation properties are analyzed by numerical examples. The influence of beam order n, topological charge M, the coherence length, and the ratio of refractive index n(e)/n(o) on the normalized intensity distribution of partially coherent four-petal Gaussian vortex beams is discussed.

Evolution properties of partially coherent flat-topped vortex hollow beam in oceanic turbulence.

Employing the theory of coherence, the partially coherent flat-topped vortex hollow beam is first introduced. The analytical propagation equation for a partially coherent flat-topped vortex hollow beam in oceanic turbulence is derived by using the extended Huygens-Fresnel diffraction integral and the spectrum of oceanic turbulence. The influences of coherence length, beam order N, the topological charge M, and the parameters of oceanic turbulence on evolution properties of partially coherent flat-topped vortex hollow beams propagating in oceanic turbulence are obtained by using the numerical examples.

Formation of hydroxyl radical from the photolysis of salicylic acid.

Photodissociation dynamics of salicylic acid (SA) in the gas phase at different photolysis wavelengths (266, 315-317 nm) is investigated by probing the nascent OH photoproduct employing the single-photon laser-induced fluorescence (LIF) technique. At all the photolysis wavelengths it is found that the nascent OH radicals are produced mostly in a vibrationally ground state (υ'' = 0) and have similar rotational state distributions. The two spin-orbit and Λ-doublet states of the OH fragment formed in the dissociation are measured to have a nonstatistical distribution at each photolysis wavelength. The LIF signal of the OH could be observed upon photolysis at 317 nm but not at 317.5 nm. The threshold of OH formation from SA photodissociation is estimated to be 98.2 ± 0.9 kcal/mol. The effect of the phenolic OH group on the dissociation of SA is discussed.

Fluorescence and solvent-dependent phosphorescence studies of o-nitrobenzaldehyde: a combined experimental and theoretical investigation.

The fluorescence and phosphorescence emission studies have been performed to understand the photochemistry of o-nitrobenzaldehyde in solution upon photoexcitation to the first excited singlet state (S(1)). The presence of an energy barrier in the S(1)-state hydrogen transfer potential energy surface is determined experimentally through the observed dual fluorescence emission, and the barrier height is estimated to be about 84-87 kcal mol(-1) by gradually decreasing the excitation energy. The phosphorescence spectra of o-NBA in five different solvents are observed for the first time, providing direct experimental evidence on the existence of triplet manifold in the photoexcitation of o-NBA. Furthermore, the relative phosphorescence quantum yield is found to be solvent dependent. To get further insights into the dynamic process involved in the photochemistry of o-NBA, excited state calculations at the TD-B3LYP/6-311+G(d,p) level of theory with the PCM model are accomplished, which strongly support our experimental findings.

OH produced from o-nitrophenol photolysis: a combined experimental and theoretical investigation.

Photodissociation dynamics of o-nitrophenol in the gas phase at different photolysis wavelengths (361-390 nm) is investigated, and the nascent OH radical is observed by the single-photon laser-induced fluorescence technique. At all the photolysis wavelengths, the OH radicals are formed in vibrationally cold state (upsilon(")=0) and have similar rotational state distributions. The average rotational temperature for all the photolysis wavelengths is approximately 970+/-120 K, corresponding to a rotational energy of 1.9+/-0.2 kcal mol(-1). The spin orbit and Lambda-doublet states of the OH fragments formed in the dissociation are measured to have nonstatistical distributions. To get an insight into the dissociative mechanism leading to OH formation in the photolysis of o-nitrophenol, the potential energy surfaces of the OH-forming channels are mapped by ab initio theoretical calculations. According to both experimental and theoretical results, a possible mechanism for OH formation is proposed.

Photolysis of o-nitrobenzaldehyde in the gas phase: a new OH* formation channel.

Photolysis of gaseous o-nitrobenzaldehyde (o-NBA) with selected different excitation wavelengths (355-400 nm) is investigated, and the nascent OH radical is detected by the single-photon laser-induced fluorescence (LIF) technique. The relative quantum yield and rotational excitation of OH formation are found to be dependent on the excitation energy. The distributions of rotational, spin-orbit, and Lambda-doublet states are obtained at 355-400 nm by analyzing the experimental data. The OH radicals are found to be vibrationally cold at all photolysis wavelengths. The spin-orbit and Lambda-doublet states have nonstatistical distributions. To understand the dissociative process involved in the OH-generating channel, DFT calculations are performed. Based on both experimental and theoretical results, possible photolysis channels of o-NBA leading to the OH fragment are proposed and discussed.

Dynamics of OH formation in the photodissociation of o-nitrobenzoic acid at 295 and 355 nm.

Photodissociation dynamics of o-nitrobenzoic acid at 295 and 355 nm is studied by probing the nascent OH photoproduct employing the single-photon laser-induced fluorescence technique. At both of the photolysis wavelengths, the OH fragments are found to be vibrationally cold but have different rotational state distributions. Upon photolysis at 295 nm, the relative population of OH in different rotational states does not follow the Boltzmann equilibrium distribution, whereas upon photolysis at 355 nm, a Boltzmann distribution is observed with a rotational temperature of 1010 +/- 100 K. Between the two spin-orbit states, (2)Pi(3/2) and (2)Pi(1/2), the former is found to be preferentially populated, and the distribution of the Pi(A') state for the Lambda-doublet is dominant at both of the wavelengths studied. Several possible dissociation pathways of o-nitrobenzoic acid leading to formation of the OH fragment are investigated computationally. On the basis of the theoretical and experimental studies, a possible mechanism of OH formation from the photodissociation of o-nitrobenzoic acid at 295 and 355 nm is proposed.

Photodissociation dynamics of alkyl nitrites at 266 and 355 nm: the OH product channel.

Photodissociation of methyl nitrite and n-butyl nitrite at 266 and 355 nm has been investigated in the gas phase at room temperature. OH photoproducts were observed, and their internal state distributions were measured by the one-photon laser-induced fluorescence (LIF) technique. It was found that the nascent OH from the 266 nm photolysis of methyl nitrite was vibrationally cold, and its rotational state distribution conformed to a Boltzmann behavior with a rotational temperature of T(rot) = 2200 +/- 150 K. In contrast, the nascent OH from the 266 nm photolysis of n-butyl nitrite was found to be vibrationally excited, and the measured relative population of v'' = 0:1 was 0.78:0.22. The rotational state distribution of the OH v'' = 1 state conformed to Boltzmann behavior, with a rotational temperature of T(rot) = 1462 +/- 120 K. However, a simple Boltzmann distribution was not found for the OH v'' = 0 state. In the photolysis of n-butyl nitrite at 355 nm, the OH fragment was found to be vibrationally cold and its rotational state distribution showed non-Boltzmann behavior. A photodissociation mechanism involving an intramolecular hydrogen atom transfer process is proposed for the OH product pathway for methyl nitrite, which has been compared with the potential energy surfaces obtained from density functional theory (DFT) calculations. A photodissociation mechanism of n-butyl nitrite is also proposed for the OH product pathway, which differs from that of methyl nitrite due to the effects of the different alkoxy substituents.

Quantitative (upsilon, N, Ka) product state distributions near the triplet threshold for the reaction H2CO --> H + HCO measured by Rydberg tagging and laser-induced fluorescence.

In this paper, we report quantitative product state distributions for the photolysis of H2CO --> H + HCO in the triplet threshold region, specifically for several rotational states in the 2(2)4(3) and 2(3)4(1) H2CO vibrational states that lie in this region. We have combined the strengths of two complementary techniques, laser-induced fluorescence for fine resolution and H atom Rydberg tagging for the overall distribution, to quantify the upsilon, N, and Ka distributions of the HCO photofragment formed via the singlet and triplet dissociation mechanisms. Both techniques are in quantitative agreement where they overlap and provide calibration or benchmarks that permit extension of the results beyond that possible by each technique on its own. In general agreement with previous studies, broad N and Ka distributions are attributed to reaction on the S0 surface, while narrower distributions are associated with reaction on T1. The broad N and Ka distributions are modeled well by phase space theory. The narrower N and Ka distributions are in good agreement with previous quasi-classical trajectory calculations on the T1 surface. The two techniques are combined to provide quantitative vibrational populations for each initial H2CO vibrational state. For dissociation via the 2(3)4(1) state, the average product vibrational energy (15% of E(avail)) was found to be about half of the rotational energy (30% of E(avail)), independent of the initial H2CO rotational state, irrespective of the singlet or triplet mechanism. For dissociation via the 2(2)4(3) state, the rotational excitation remained about 30% of E(avail), but the vibrational excitation was reduced.

OH fragment from benzoic acid monomer photolysis: threshold and product state distribution.

Photodissociation dynamics of benzoic acid monomer (BAM) at different ultraviolet excitation wavelengths (280-295 nm) has been investigated. The nascent OH product state distributions were measured using the laser-induced fluorescence (LIF) technique. The rotational state distributions, the Lambda-doublet-state ratio, and spin-orbit state distributions of the OH fragment were also measured at 280-294 nm. The OH fragments are vibrationally cold, and their rotational state distributions are peaked at J'' = 3.5 at each photolysis wavelength. No LIF signal of OH fragments was observed at 295 nm. The photodissociation threshold is determined to be 102.5-103.9 kcal/mol for OH channel. The dissociative state and mechanism have been discussed for OH produced from the photodissociation of BAM.

Spectroscopy of the A(1B2)-X(1A1) transition of jet-cooled fluorobenzene: laser-induced fluorescence, dispersed fluorescence, and pathological Fermi resonances.

A detailed study of the S1((1)B2)-S0((1)A1) electronic transition of jet-cooled fluorobenzene has been carried out using laser-induced fluorescence and dispersed fluorescence (DF) spectroscopies. Analysis of over 40 single vibronic level DF spectra resulted in the assignment of 16 fundamental frequencies in the excited electronic state. Progressions in totally symmetric modes, particularly in the ring-breathing mode nu9, feature in both types of fluorescence spectrum. There is also significant activity in non-totally-symmetric modes, with activity in Franck-Condon (FC)-allowed overtones, FC-forbidden combinations induced by Duschinsky mixing, and symmetry-forbidden transitions induced by the same Herzberg-Teller vibronic coupling mechanism that induces the benzene S1-S0 transition. Fermi resonances (FRs) are extensive throughout the spectrum, especially in the important FC-active a1 modes. A consequence of these extensive FRs is that several important previous assignments are shown to be incorrect and have been reassigned here. Ab initio and density functional theory calculations have also been performed to support the experimental assignments.