Association between obstructive sleep apnea severity and depression risk: a systematic review and dose-response meta-analysis.

Obstructive sleep apnea (OSA) has received considerable attention as a potential risk factor for depressive symptoms. The systematic review was conducted to confirm the dose‒response connection between OSA severity and depression risk. A systematic literature search of English and Chinese articles published in PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), and SinoMed databases from their inception to 28 August 2023 was conducted. An evaluation using the Newcastle‒Ottawa Scale was performed. A meta-analysis was used to evaluate the impact of OSA severity. A random-effects dose‒response model was conducted to evaluate the linear and nonlinear dose‒response connections. We evaluated publication bias by funnel plots, and symmetry by Egger's test. We identified 18 cross-sectional researches. 3143 participants which were involved in the dose‒response meta-analysis. Contrasted with mild OSA, individuals with severe OSA had a higher adjusted risk of depression (rate ratio: 1.34, 95% confidence interval = 1.05-1.70), with substantial heterogeneity (I2 = 70.9%, Pheterogeneity<0.001). There is a significant linear connection between OSA severity and depression risk. The depression risk increased by 0.4% for every 1 event per hour increase in the apnea-hypopnea index (AHI). The protocol for this unfunded research was drafted and registered at PROSPERO (ID CRD42023474097).

Trajectory analysis for low-order harmonic generation in two-color strong laser fields.

Focusing two-color laser fields in gas-phase medium produces ultrashort ultra-broadband low-order harmonics spanning from terahertz to extreme ultraviolet regime. The low-order harmonic generation can be explained by both macroscopic photocurrent model and microscopic strong field approximation theory. Here, we analytically build a bridge between the macroscopic and microscopic theories by means of the trajectory method, which manifests correspondences between macroscopic and microscopic theories. And we demonstrate the trajectory analysis to explain phase-dependent terahertz and third-harmonic generations, and contribute the phase-dependent yields and spectral shapes to the coherent superposition of electron trajectories released at distinct ionization instants, reflecting electron interfering with itself in radiation process. The trajectory method readily connects the low-order harmonics characteristics and behaviors of electron wavepacket, which has potential for reconstructing ultrafast electron dynamics by means of low-harmonics observations.

Coulomb potential determining terahertz polarization in a two-color laser field.

The orientation and ellipticity of terahertz (THz) polarization generated by a two-color strong field not only casts light on underlying mechanisms of laser-matter interaction, but also plays an important role for various applications. We develop the Coulomb-corrected classical trajectory Monte Carlo (CTMC) method to well reproduce the joint measurements, that the THz polarization generated by the linearly polarized 800 nm and circularly polarized 400 nm fields is independent on two-color phase delay. The trajectory analysis shows that the Coulomb potential twists the THz polarization by deflecting the orientation of asymptotic momentum of electron trajectories. Further, the CTMC calculations predict that, the two-color mid-infrared field can effectively accelerate the electron rapidly away from the parent core to relieve the disturbance of Coulomb potential, and simultaneously create large transverse acceleration of trajectories, leading to the circularly polarized THz radiation.

Research misconduct knowledge and associated factors among nurses in China: A national cross-sectional survey.

AIM: To measure the knowledge level of research misconduct and explore its associated factors among nurses. BACKGROUND: Engagement in research misconduct by nurses may transfer to professional misconduct in the clinical setting, thereby jeopardizing the quality of patient care. We still know little about the research misconduct situation among nurses. Previous attempts also hardly reflected participants' real knowledge level of research misconduct. METHODS: We applied multistage sampling (province, hospital, and participants) in this cross-sectional survey, and recruited 4112 nurses from 200 tertiary hospitals in 25 provinces. RESULTS: The average knowledge score of the participants was 15.99 ± 5.79. Associated factors of scientific misconduct knowledge score included career situation, educational level, fertility status, research activities index, and perceived consequences for research misconduct. CONCLUSION: It is urgent and necessary to design continuing research integrity training for nurses. Hospital managers and policy-makers should pay more attention to key trainees, including newcomers, nurses from less developed groups and institutions, and those from clinical departments. Training designers should also consider how to help nurses with offspring balance their family and work, and should not neglect the training for nurses with extensive research experience. In addition to conveying knowledge and information, the training can integrate cognitive education of research misconduct to improve the effect.

Attention-based neural network for polarimetric image denoising.

In this Letter, we propose an attention-based neural network specially designed for the challenging task of polarimetric image denoising. In particular, the channel attention mechanism is used to effectively extract the features underlying the polarimetric images by rescaling the contributions of channels in the network. In addition, we also design the adaptive polarization loss to make the network focus on the polarization information. Experiments show that our method can well restore the details flooded by serious noise and outperforms previous methods. Moreover, the underlying mechanism of channel attention is revealed visually.

Intensity-surged and bandwidth-extended terahertz radiation in two-foci cascading plasmas.

The two-color strong-field mixing in gas medium is a widely used approach to generate bright broadband terahertz (THz) radiation. Here, we present a new, to the best of our knowledge, and counterintuitive method to promote THz performance in the two-color scheme. Beyond our knowledge that the maximum THz generation occurs with two-color foci overlapped, we found that, when the foci of two-color beams are noticeably separated along the propagation axis resulting in cascading plasmas, the THz conversion efficiency is surged by one order of magnitude and the bandwidth is stretched by more than two times, achieving 10-3 conversion efficiency and >100 THz bandwidth under the condition of 800/400 nm, ∼35 fs driving lasers. With the help of the pulse propagation equation and photocurrent model, the observations can be partially understood by the compromise between THz generation and absorption due to the spatial redistribution of laser energy in cascading plasmas. The present method can be extended to a mid-infrared driving laser, and new records of THz peak power and conversion efficiency are expected.

Charge-encoded multi-photoion coincidence for three-body fragmentation of CO2 in the strong laser fields.

The photoion-photoion coincidence (PIPICO) is a simple and effective approach for the selection of correlated fragments in a specific dissociating channel in molecules. We propose here a charge-encoded multi-photoion coincidence (cMUPICO) method, in analogy to traditional PIPICO, however in which the charge of individual fragments is taken into account. The cMUPICO method allows for clearly displaying coincident channels for dissociation channels containing three more fragments with unequal charge states, invisible in the traditional PIPICO. As a demonstration, three-body fragmentation dynamics of CO2 in strong IR laser fields is analyzed, and 11 dissociation channels are effectively identified, five of which are first found with cMUPICO. The present results show that cMUPICO is a powerful and practical tool for distinguishing various dissociation channels with multiply charged multi-photoions.

Third-order harmonic generation in a bi-chromatic elliptical laser field.

The low-order harmonic generation induced by a strong laser field produces a bright, ultrashort, supercontinuum radiation ranging from the terahertz to ultraviolet band. By controlling the phase-delay and ellipticity of the bi-chromatic laser fields, the third harmonic generation is experimentally and theoretically investigated for elucidating the mechanism of the low-order harmonics. The third harmonic generation is found to be strongly suppressed in the counter-rotating bi-chromatic laser field due to the selection rule for harmonic emissions. The continuum-continuum transition in the strong field approximation is extended to explain the third harmonic generation as a function of the phase delay and ellipticity of the bi-chromatic laser fields. Compared with the semi-classical photocurrent model, the continuum-continuum transition on the basis of quantum-mechanical treatment achieves better agreement with the experimental observations. Our work indicates that the overlapping in continuum states via different quantum paths of a single electron plays a role in low-order harmonics generation under elliptical bi-chromatic laser fields.

Frequency interferometric localization microscopy.

We propose a new super-resolution microscopy, named frequency interferometric localization microscopy (FILM). FILM is implemented by incorporating a Michelson interferometer into wide-field fluorescence microscope, which introduces coherence time as a new auxiliary axis to obtain the spectral information of individual fluorophores. After the time-wavelength transformation, the homogeneous linewidth of individual fluorophores can be isolated from the inhomogeneous broadening distribution of the fluorophore ensemble. Thus, the nearby fluorophores with a distinguishable central wavelength can be separated in the frequency domain and localized with accuracy beyond the diffraction limit. The principle of the method, experimental schematics, and reconstruction algorithm are numerically demonstrated. With properly prepared fluorophores, FILM has the potential to reach, in principle, molecular-scale spatial resolution.

Experimental evidence for terahertz emission of continuum electrons in the dual-color laser field.

Terahertz (THz) wave generation (TWG) in a dual-color laser is investigated with joint measurements between THz and third-harmonic generation, where the relative phase delay of dual-color fields is determined in situ in sub-wavelength accuracy, allowing for the clarification of the TWG mechanism in a direct comparison with various theoretical predictions. The delay- and polarization-dependent experiment validates that the continuum-continuum transition within the escaped electron wavepacket in the single atom gives birth to THz emission, while the bound energetic level does not contribute to TWG. TWG from atoms and molecules would provide an all-optical, vacuum-free, and ultrafast tool to record the spatiotemporal evolution of tunneling electron wavepackets.

Calcium phosphate precipitation inhibits mitochondrial energy metabolism.

Early studies have shown that moderate levels of calcium overload can cause lower oxidative phosphorylation rates. However, the mechanistic interpretations of these findings were inadequate. And while the effect of excessive calcium overload on mitochondrial function is well appreciated, there has been little to no reports on the consequences of low to moderate calcium overload. To resolve this inadequacy, mitochondrial function from guinea pig hearts was quantified using several well-established methods including high-resolution respirometry and spectrofluorimetry and analyzed using mathematical modeling. We measured key mitochondrial variables such as respiration, mitochondrial membrane potential, buffer calcium, and substrate effects for a range of mitochondrial calcium loads from near zero to levels approaching mitochondrial permeability transition. In addition, we developed a computer model closely mimicking the experimental conditions and used this model to design experiments capable of eliminating many hypotheses generated from the data analysis. We subsequently performed those experiments and determined why mitochondrial ADP-stimulated respiration is significantly lowered during calcium overload. We found that when calcium phosphate levels, not matrix free calcium, reached sufficient levels, complex I activity is inhibited, and the rate of ATP synthesis is reduced. Our findings suggest that calcium phosphate granules form physical barriers that isolate complex I from NADH, disrupt complex I activity, or destabilize cristae and inhibit NADH-dependent respiration.

Organocatalytic C3-functionalization of indolizines: synthesis of biologically important indolizine derivatives.

A Brønsted acid-catalyzed C3-alkylation of indolizines has been established with different electrophiles such as ortho-hydroxybenzyl alcohols, other precursors of para-quinone methides and ortho-quinone methides, and 2-indolylmethanol as well. By using this approach, a series of C3-functionalized indolizines were synthesized in overall good yields (up to 89%). These examples demonstrate that the Brønsted acid-catalyzed C3-alkylation of indolizines has a wide applicability, which can serve as a useful method for synthesizing C3-functionalized indolizine derivatives with structural diversity. This reaction has fulfilled the task of developing organocatalytic C3-functionalization of indolizines for the synthesis of biologically important indolizine derivatives.

Reconstruction and control of a time-dependent two-electron wave packet.

The concerted motion of two or more bound electrons governs atomic and molecular non-equilibrium processes including chemical reactions, and hence there is much interest in developing a detailed understanding of such electron dynamics in the quantum regime. However, there is no exact solution for the quantum three-body problem, and as a result even the minimal system of two active electrons and a nucleus is analytically intractable. This makes experimental measurements of the dynamics of two bound and correlated electrons, as found in the helium atom, an attractive prospect. However, although the motion of single active electrons and holes has been observed with attosecond time resolution, comparable experiments on two-electron motion have so far remained out of reach. Here we show that a correlated two-electron wave packet can be reconstructed from a 1.2-femtosecond quantum beat among low-lying doubly excited states in helium. The beat appears in attosecond transient-absorption spectra measured with unprecedentedly high spectral resolution and in the presence of an intensity-tunable visible laser field. We tune the coupling between the two low-lying quantum states by adjusting the visible laser intensity, and use the Fano resonance as a phase-sensitive quantum interferometer to achieve coherent control of the two correlated electrons. Given the excellent agreement with large-scale quantum-mechanical calculations for the helium atom, we anticipate that multidimensional spectroscopy experiments of the type we report here will provide benchmark data for testing fundamental few-body quantum dynamics theory in more complex systems. They might also provide a route to the site-specific measurement and control of metastable electronic transition states that are at the heart of fundamental chemical reactions.

Ultrafast Mapping of Coherent Dynamics and Density Matrix Reconstruction in a Terahertz-Assisted Laser Field.

A time-resolved spectroscopic protocol exploiting terahertz-assisted photoionization is proposed to reconstruct transient density matrix. Population and coherence elements are effectively mapped onto spectrally separated peaks in photoionization spectra. The beatings of coherence dynamics can be temporally resolved beyond the pulse duration, and the relative phase between involved states is directly readable from the oscillatory spectral distribution. As demonstrated by a photoexcited multilevel open quantum system, the method shows potential applications for subfemtosecond time-resolved measurements of coherent dynamics with free electron lasers and tabletop laser fields.

Catalyst-free [4 + 2] cyclization of para-quinone methide derivatives with homophthalic anhydrides.

The title reaction has been established, which offers a useful method for the construction of dihydrocoumarin frameworks in generally good chemical yields (up to 99%) and high diastereoselectivities (up to >95 : 5 dr). This reaction represents a good example of [4 + 2] cyclizations of para-quinone methide derivatives with electron-rich reaction partners under catalyst-free conditions.

Catalytic Asymmetric [2+3] Cyclizations of Azlactones with Azonaphthalenes.

The first catalytic asymmetric [2+3] cyclization of azlactones with azonaphthalenes has been established. This strategy allowed the synthesis of a variety of chiral isatin derivatives in generally good yields and excellent enantioselectivities (up to 99 % yield, 98 % ee). The developed reaction has not only established a catalytic enantioselective [2+3] cyclization using azlactones as two-carbon building blocks, but also enriches the chemistry of catalytic asymmetric cyclizations of azonaphthalenes. In addition, this protocol will provide a useful method for constructing enantioenriched 3,3'-disubstituted isatin-type frameworks.

Post-processing phase-correction algorithm in two-dimensional electronic spectroscopy.

In a typical two-dimensional electronic spectroscopy (2DES) experiment, the timing errors of the coherence and emission time when determining the absolute time zeros usually introduce extraneous spectral phase slopes and distort the 2D spectrum. In this work, a phase-correction method that merely relies on the data post-processing algorithm is proposed. The method allows reconstructing the spectrum by simply subtracting the artificial linear spectral-phase slopes from the phase component of the 2D spectrum along both coherence and emission frequency axes. The new method has the advantages of ease of implementation and no need for the supplementary experiments and iterative fitting algorithm as commonly-used phasing methods, which may improve the phasing issue in 2DES and serve as a cross-check of now available phasing methods.

Precise phase determination with the built-in spectral interferometry in two-dimensional electronic spectroscopy.

A new method determining the precise phase of pulse sequences in two-dimensional electronic spectroscopy (2DES) is proposed merely using the already built-in spectral interferometry. The approach is easily implemented without the supplementary instrumental construction, only at the expense of a few additional scanning and data-fitting processes. This method is executed with the sample in place, effectively avoiding the phase ambiguities of the beam propagation in samples, thus calibrating the absolute phase at the exact interaction region. The new proposed method is expected to improve the phasing procedure in 2DES in a more convenient way.

LC-MS/MS analysis of Gegen Qinlian Decoction and its pharmacokinetics after oral administration to rats.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of 12 constituents of Gegen Qinlian Decoction (GQD), namely puerarin, daidzein, baicalin, wogonoside, wogonin, liquiritin, liquiritigenin, berberine, jatrorrhizine, palmatine, coptisine and glycyrrhetic acid, in rat plasma. The plasma samples were spiked with the internal standard (IS) carbamazepine acidified with HCl and extracted by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved on a Shiseido Capcell PAK C18 column utilizing a gradient elution profile and a mobile phase consisting of (A) 0.1% formic acid in water and (B) acetonitrile. Detection was performed in the multiple reaction monitoring mode using electrospray ionization in the positive ion mode at a flow rate of 0.3 mL/min and a run time of 8 min. All of the calibration curves gave good linearity (r > 0.9930) over the concentration range from 0.6-360 to 16.2-9720 ng/mL for all components. The intra- and inter-day precisions were <15.0% in terms of the relative standard deviation, and the accuracies were within ±13.7% in terms of the relative error. The method was successfully applied to investigate the pharmacokinetics of the major active compounds of Gegen Qinlian Decoction after its oral administration to rats.

[Effect of Gegen Qinlian decoction on hepatic cytochrome CYP450 isozymes in rats by HPLC-MS/MS].

To study the effect of Gegen Qinlian decoction and its major effective components on five hepatic microsomal CYP450 isozymes in rats. The in vitro hepatic microsomal incubation technique was used to co-culture Gegen Qinlian decoction and its major effective components together with each probe substrate. HPLC-MS/MS was used to establish the analytical method for metabolites of the five isoform probe substrates of CYP450 isozymes, detect the linearity among micoromal protein concentration, incubation time and metabolite formation amount. And HPLC-MS/MS was applied to determine the formation rate (V) of corresponding metabolites (acetaminophen, 4-OH-chlorzoxazone, dextrophan, 6-OH-chlorzoxazone and 6ß-hydroxytestosterone) specific probe substrates of the five isoform probe substrates of CYP450 isozymes (phenacetin, polbutamide, dextromethorphan, chlorzoxazone, testosterone), in order to determine the activity of each isozyme. The result showed good linearity among acetaminophen, 4-OH-tolbutamide, dextrophan, 6-OH-chlorzoxazone and 6ß-hydroxytestosterone, satisfactory precision, stability and average recovery, suggesting the method was feasible. The optimized in vitro microsomal incubation conditions conformed to the requirements in the guideline of drug-drug interaction. Gegen Qinlian decoction showed different degrees of inhibitor effect on 5 CYP450 isoforms (CYP1A2, CYP2C11, CYP2D2, CYP2E1, CYP3A1/2). Its major effective component berberine could inhibit each CYP450 isoform at high concentrations (except for CYP1A2, CYP3A1/2).