Impact of Using Pre- and Post-Bronchodilator Spirometry Reference Values in a Chinese Population.

RATIONALE: Spirometry reference equations that are derived from a large, nationally representative, general population are warranted in China and the impact of using pre- and post-BD spirometry reference values has yet to be assessed in Chinese populations. OBJECTIVES: To present both the pre-BD and post-BD spirometry reference values for Chinese adults using the China Pulmonary Health (CPH) study. METHODS: A reference population of 17969 healthy, non-smoking participants in the CPH study was used to calculate the pre- and post-BD reference values for the forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC. Both pre- and post-BD reference values were applied to the entire CPH population (50991 individuals) to illustrate the divergence between the use of references in determining the disease prevalence and severity grading. MEASUREMENTS AND MAIN RESULTS: The prevalence of airflow limitation was 5.36% using pre-BD reference and 8.02% using the post-BD reference. Individuals who had post-BD FEV1/FVC below post-BD but higher than pre-BD reference values were found to have significantly higher rates of self-reported respiratory symptoms, and significantly lower values in spirometry indicators than those above post-BD reference values. An additional 3.51% of participants were identified as grade II-IV COPD using the post-BD FEV1 predicted values. CONCLUSION: This study generated and applied pre- and post-bronchodilator spirometry reference values in a nationally representative Chinese adult population. Post-BD reference values may serve as an additional criterion in identifying individuals at risk for obstructive pulmonary diseases, its diagnostic and prognostic values should be further investigated.

Measuring the orbital angular momentum of generalized higher-order twisted partially coherent beams.

Recently a new family of partially coherent fields incorporating generalized inseparable cross-coupled phases named generalized higher-order twisted partially coherent beams (GHTPCBs) have been introduced. The twist factor u is a key parameter that not only quantifies the strength of the generalized cross-coupled phase for a given order, but also determines the amount of the concomitant orbital angular momentum (OAM). In this paper, we propose a simple and reliable method to measure the factor u using a two-pinhole mask. Without need of complicated optical system, it only requires to capture the far-field diffraction intensity distribution of the GHTPCB passing through the mask. By analyzing the Fourier spectrum of the intensity distribution, the value of twist factor can be derived nearly in real time. The influence of the separation distance between two pinholes and the pinholes' diameter and position on the measurement accuracy are thoroughly studied both in theory and experiment. The experimental results agree well with the theoretical results. Our methodology can also be extended to measure the sole factor of similar position dependent phases such as the topological charge of a vortex phase.

Fast measurement of coherence-orbital angular momentum matrices of random light beams using off-axis holography and coordinate transformation.

We propose an effective protocol to measure the coherence-orbital angular momentum (COAM) matrix of an arbitrary partially coherent beam. The method is based on an off-axis holography scheme and the Cartesian-polar coordinate transformation, which enables to simultaneously deal with all the COAM matrix elements of interest. The working principle is presented and discussed in detail. A proof-of-principle experiment is carried out to reconstruct the COAM matrices of partially coherent beams with spatially uniform and non-uniform coherence states. We find an excellent agreement between the experimental results and the theoretical predictions. In addition, we show that the OAM spectrum of a partially coherent beam can also be directly acquired from the measured COAM matrix.

The Role of Bioactive Small Molecules in COPD Pathogenesis.

Chronic obstructive pulmonary disease (COPD) is recognized as a predominant contributor to mortality worldwide, which causes significant burdens to both society and individuals. Given the limited treatment options for COPD, there lies a critical realization: the imperative for expeditious development of novel therapeutic modalities that can effectively alleviate disease progression and enhance the quality of life experienced by COPD patients. Within the intricate field of COPD pathogenesis, an assortment of biologically active small molecules, encompassing small protein molecules and their derivatives, assumes crucial roles through diverse mechanisms. These mechanisms relate to the regulation of redox balance, the inhibition of the release of inflammatory mediators, and the modulation of cellular functions. Therefore, the present article aims to explore and elucidate the distinct roles played by different categories of biologically active small molecules in contributing to the pathogenesis of COPD.

Calcitonin gene-related peptide inhibits neuronal apoptosis in heatstroke rats via PKA/p-CREB pathway.

PURPOSE: The incidence of heatstroke (HS) is not particularly high; however, once it occurs, the consequences are serious. It is reported that calcitonin gene-related peptide (CGRP) is protective against brain injury in HS rats, but detailed molecular mechanisms need to be further investigated. In this study, we further explored whether CGRP inhibited neuronal apoptosis in HS rats via protein kinase A (PKA)/p-cAMP response element-binding protein (p-CREB) pathway. METHODS: We established a HS rat model in a pre-warmed artificial climate chamber with a temperature of (35.5 ± 0.5) °C and a relative humidity of 60% ± 5%. Heatstress was stopped once core body temperature reaches above 41 °C. A total of 25 rats were randomly divided into 5 groups with 5 animals each: control group, HS group, HS+CGRP group, HS+CGRP antagonist (CGRP8-37) group, and HS+CGRP+PKA/p-CREB pathway blocker (H89) group. A bolus injection of CGRP was administered to each rat in HS+CGRP group, CGRP8-37 (antagonist of CGRP) in HS+CGRP8-37 group, and CGRP with H89 in HS+CGRP+H89 group. Electroencephalograms were recorded and the serum concentration of S100B, neuron-specific enolase (NSE), neuron apoptosis, activated caspase-3 and CGRP expression, as well as pathological morphology of brain tissue were detected at 2 h, 6 h, and 24 h after HS in vivo. The expression of PKA, p-CREB, and Bcl-2 in rat neurons were also detected at 2 h after HS in vitro. Exogenous CGRP, CGRP8-37, or H89 were used to determine whether CGRP plays a protective role in brain injury via PKA/p-CREB pathway. The unpaired t-test was used between the 2 samples, and the mean ± SD was used for multiple samples. Double-tailed p < 0.05 was considered statistically significant. RESULTS: Electroencephalogram showed significant alteration of θ (54.50 ± 11.51 vs. 31.30 ± 8.71, F = 6.790, p = 0.005) and α wave (16.60 ± 3.21 vs. 35.40 ± 11.28, F = 4.549, p = 0.020) in HS group compared to the control group 2 h after HS. The results of triphosphate gap terminal labeling (TUNEL) showed that the neuronal apoptosis of HS rats was increased in the cortex (9.67 ± 3.16 vs. 1.80 ± 1.10, F = 11.002, p = 0.001) and hippocampus (15.73 ± 8.92 vs. 2.00 ± 1.00, F = 4.089, p = 0.028), the expression of activated caspase-3 was increased in the cortex (61.76 ± 25.13 vs. 19.57 ± 17.88, F = 5.695, p = 0.009) and hippocampus (58.60 ± 23.30 vs. 17.80 ± 17.62, F = 4.628, p = 0.019); meanwhile the expression of serum NSE (5.77 ± 1.78 vs. 2.35 ± 0.56, F = 5.174, p = 0.013) and S100B (2.86 ± 0.69 vs. 1.35 ± 0.34, F = 10.982, p = 0.001) were increased significantly under HS. Exogenous CGRP decreased the concentrations of NSE and S100B, and activated the expression of caspase-3 (0.41 ± 0.09 vs. 0.23 ± 0.04, F = 32.387, p < 0.001) under HS; while CGRP8-37 increased NSE (3.99 ± 0.47 vs. 2.40 ± 0.50, F = 11.991, p = 0.000) and S100B (2.19 ± 0.43 vs. 1.42 ± 0.30, F = 4.078, p = 0.025), and activated the expression caspase-3 (0.79 ± 0.10 vs. 0.23 ± 0.04, F = 32.387, p < 0.001). For the cell experiment, CGRP increased Bcl-2 (2.01 ± 0.73 vs. 2.15 ± 0.74, F = 8.993, p < 0.001), PKA (0.88 ± 0.08 vs. 0.37 ± 0.14, F = 20.370, p < 0.001), and p-CREB (0.87 ± 0.13 vs. 0.29 ± 0.10, F = 16.759, p < 0.001) levels; while H89, a blocker of the PKA/p-CREB pathway reversed the expression. CONCLUSIONS: CGRP can protect against HS-induced neuron apoptosis via PKA/p-CREB pathway and reduce activation of caspase-3 by regulating Bcl-2. Thus CGRP may be a new target for the treatment of brain injury in HS.

Orbital angular momentum spectra of twisted Laguerre-Gaussian Schell-model beams propagating in weak-to-strong Kolmogorov atmospheric turbulence.

The presence of atmospheric turbulence in a beam propagation path results in the spread of orbital angular momentum (OAM) modes of laser beams, limiting the performance of free-space optical communications with the utility of vortex beams. The knowledge of the effects of turbulence on the OAM spectrum (also named as spiral spectrum) is thus of utmost importance. However, most of the existing studies considering this effect are limited to the weak turbulence that is modeled as a random complex "screen" in the receiver plane. In this paper, the behavior of the OAM spectra of twisted Laguerre-Gaussian Schell-model (TLGSM) beams propagation through anisotropic Kolmogorov atmospheric turbulence is examined based on the extended Huygens-Fresnel integral which is considered to be applicable in weak-to-strong turbulence. The discrepancies of the OAM spectra between weak and strong turbulence are studied comparatively. The influences of the twist phase and the anisotropy of turbulence on the OAM spectra during propagation are investigated through numerical examples. Our results reveal that the twist phase plays a crucial role in determining the OAM spectra in turbulence, resisting the degeneration of the detection mode weight by appropriately choosing the twist factor, while the effects of the anisotropic factors of turbulence on the OAM spectra seem to be not obvious. Our findings can be applied to the analysis of OAM spectra of laser beams both in weak and strong turbulence.

Generation of optical 3D unpolarized lattices in a tightly focused random beam.

We study the three-dimensional (3D) polarization properties of a tightly focused partially coherent vector beam whose initial spatial coherence structure exhibits a lattice distribution. By examining the 3D degree of polarization and the polarimetric dimension of the tightly focused field, we demonstrate that this initial spatial coherence structure induces a 3D isotropically unpolarized beam lattice in the focal plane. Along the longitudinal direction, we observe the formation of nearly 3D unpolarized channels spanning 16 wavelengths in length near the focal region. We demonstrate that the spatial distribution of the 3D unpolarized lattice can be conveniently controlled through engineering the spatial coherence structure of the incident beam.

Herbal active small molecule as an immunomodulator for potential application on resistance of common carp against SVCV infection.

Herbal immunomodulators are an important part of prevention and control on viral diseases in aquaculture because of their propensity to improve immunity in fish. The present study was conducted to evaluate the immunomodulatory effect and antiviral activity of a synthesized derivative (serial number: LML1022) against spring viremia of carp virus (SVCV) infection in vitro and in vivo. The antiviral data suggested that LML1022 at 100 µM significantly inhibited the virus replication in epithelioma papulosum cyprini (EPC) cells, and may completely inhibit the infectivity of SVCV virion particles to fish cells by affecting the viral internalization. The results in the related stability of water environments also demonstrated that LML1022 had an inhibitory half-life of 2.3 d at 15 °C, which would facilitate rapid degradation of LML1022 in aquaculture application. For in vivo study, the survival rate of SVCV-infected common carp was increased 30% at least under continuous oral injection of LML1022 at 2.0 mg/kg for 7 d treatment. Additionally, pretreatment of LML1022 on fish prior to SVCV infection also obviously reduced the viral loads in vivo as well as an improved survival rate, showing that LML1022 was potential as an immunomodulator. As an immune response, LML1022 significantly upregulated the immune-related gene expression including IFN-γ2b, IFN-I, ISG15 and Mx1, indicating that its dietary administration may improve the resistance of common carp against SVCV infection.

Facile Synthesis and Multiple Application of Ultralong-Afterglow Room Temperature Phosphorescence Aggregate Carbon Dots from Simple Raw Materials.

Owing to the ultralong afterglow, room temperature decay phosphorescence nanomaterials have aroused enough attention. In the work, by simple one-pot solid-state thermal decomposition reaction, aggregate carbon dots (CDs) was prepared from trimesic and boric acid. Based on the intermolecular hydrogen bonds and intramolecular π-π stacking weak interaction from precursors, CDs was encapsulated in boron oxide matrix and formed aggregation. The aggregate state of CDs facilitated the triplet excited states (Tn), which could induce the room temperature decay phosphorescence properties. By careful investigation, under different excitation wavelengths at 254 and 365 nm, the aggregate CDs showed > 15 s and > 3 s room temperature phosphorescence emission in the naked eye, which was associated with 1516.12 ms and 718.62 ms lifetime respectively. And the aggregate CDs exhibited widespread application in encoding encryption, optical anti-counterfeiting and fingerprint identification etc. The interesting aggregate CDs revealed unexpected ultralong-afterglow room temperature decay phosphorescence properties and the work opened a window for constructing ultralong-afterglow room temperature decay phosphorescence aggregate CDs nanomaterials.

Fabrication of Supramolecular System Derived from Poly ß-cyclodextrin Coupling Quinoline Dderivative and Its Fluorescence Sensing of Zinc Ion in Pure Water Environment.

Cyclodextrin (CD) is an important guest material owing to the water solubility and biocompatibility. In the paper, an organic small molecule was synthesized. According to supramolecular self-assembly, the organic molecule was bounded to the cavity of Poly ß-cyclodextrin, which was characterized by IR, SEM and TEM et al. After self-assembly interaction, the morphology has changed obviously comparing with precursors. Simultaneously, the supramolecular self-assembly complex exhibited good water solubility. Moreover, By Gaussian calculation, the high binding activity between organic molecule and cyclodextrin was confirmed. By fluorescence investigation, the supramolecular system showed high fluorescence sensing activity for Zn2+ in pure water environment, which could track the dynamic change of Zn2+ in organisms. In addition, the supramolecular system exhibited low cytotoxicity. The work provided an interesting pathway for constructing water-soluble and low cytotoxic fluorescence sensor for Zn2+.

Expression of RNA-m6A-related genes correlates with the HIV latent reservoir level and the CD4+ and CD8+T cell profiles of patients with AIDS.

The HIV latent reservoir is the main obstacle to the eradication of AIDS. Recent studies have shown that the RNA m6A is involved in the regulation of HIV-1 replication. However, no relevant study has reported the relationship between RNA m6A and HIV latent reservoir. For this purpose, peripheral blood mononuclear cell (PBMC) was collected from 36 HIV-infected patients at 1, 24, and 48 weeks after treatment initiation. The number of CD4+ and CD8+ T cells was detected by flow cytometry. Amount of HIV DNA in the PBMC samples one week after treatment initiation was detected by Q-PCR. The expression levels of 23 RNA-m6A-related genes were detected by Q-PCR and Pearson's correlation analysis was performed. Results showed that there was a negative correlation between HIV DNA concentration and the number of CD4+ T cells (r=-0.32, p=0.05; r=-0.32, p=0.06) and a positive correlation with the number of CD8+ T cells (r=0.48, p=0.003; r=0.37, p=0.03). Furthermore, a negative correlation was observed between HIV DNA concentration and the CD4+/CD8+ T cell ratio (r=-0.53, p=0.001; r=-0.51, p=0.001). RNAm6A related genes which correlated with HIV DNA concentration includedALKBH5 (r=-0.45, p=-0.006), METTL3 (r=0.73, p=2.76e-7), METTL16 (r=0.71, p=1.21e2.76e-06), YTHDF1 (r=0.47, p=0.004). Moreover, they have different degrees of correlation with numbers ofCD4+ and CD8+ T cell subsets, and the CD4+/CD8+T cell ratio. In addition, the expression of RBM15 was not correlated with HIV DNA concentration but was significantly negatively correlated with the number of CD4+T cells (r=-0.40, p=0.02). In conclusion, the expression of ALKBH5, METTL3, and METTL16 is correlated with the HIV DNA level, the levels of CD4+ and CD8+ T cell counts, and the CD4+/CD8+ T cell ratio. RBM15 is independent of HIV DNA level and negatively correlated with the number of CD4+T cells.

COVID-19 vaccine uptake and hesitancy in Chinese patients with asthma.

OBJECTIVE: Both patients and physicians may be hesitant toward vaccination in patients with asthma, which may result in lower vaccine uptake. The aim of this work was to investigate the vaccination rate, the adverse reactions, as well as the factors associated with vaccine acceptance and hesitancy toward COVID-19 vaccination among asthmatic patients in Beijing. METHODS: A multi-center, cross-sectional face-to-face survey was conducted in patients with asthma consecutively recruited from December 2021 to April 2022. The survey included asthma status, COVID-19 vaccine uptake and adverse reactions, and knowledge of and attitude toward COVID-19 vaccination. RESULTS: A total of 261 patients were enrolled. The rate of COVID-19 vaccination during the study period was 73.6%, as compared to 87.64% in the general population in China. Patients who were currently working, had received other vaccines in the past, and had had no adverse reactions to other vaccines, showed a higher rate of COVID-19 vaccination. Patients believing that the vaccination of family members and colleagues had a positive impact on their decision to get vaccinated, were more likely to get the COVID-19 vaccines. The COVID-19 vaccination rate was lower in those with poorly monitored asthma and those using biologic therapies. The adverse effects of COVID-19 vaccines in asthmatic patients were similar to those in the general population. CONCLUSION: The COVID-19 vaccination rate in asthmatic patients was lower than the general population in China. Active measures should be taken to control asthma and increase vaccination rates in these patients.

Validation of COPD Population Screener Questionnaire in Chinese Population: A National Multicenter Study.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is highly prevalent and underdiagnosed worldwide. The validity and reliability of COPD Population Screening (COPD-PS) questionnaire are not properly known in a large-sample Chinese population. METHODS: This is a national multicenter prospective study that enrolled 1,824 outpatients from 12 hospital sites in China. Scores of the Chinese version of COPD-PS questionnaire, demographic data, and clinical information were collected. The validity and the test-retest reliability were evaluated. RESULTS: 1,824 participants were involved in this study, and 404 (22.1%) were diagnosed with COPD. The overall area under the curve (AUC) of the receiver operating characteristic (ROC) for COPD-PS questionnaire was 0.761 (95% CI: 0.734-0.787). A cut-off point of 4 was recommended, corresponding to a sensitivity of 74.50% and a specificity of 64.37%. The COPD-PS questionnaire showed an overall Pearson's correlation of 0.88. CONCLUSIONS: The COPD-PS questionnaire can be used in screening COPD patients from the general Chinese population with respiratory symptoms.

Long-Term Ozone Exposure and Small Airway Dysfunction: The China Pulmonary Health (CPH) Study.

Rationale: It remains unknown whether long-term ozone exposure can impair lung function. Objectives: To investigate the associations between long-term ozone exposure and adult lung function in China. Methods: Lung function results and diagnosis of small airway dysfunction (SAD) were collected from a cross-sectional study, the China Pulmonary Health Study (N = 50,991). We used multivariable linear and logistic regression models to examine the associations of long-term ozone exposure with lung function parameters and SAD, respectively, adjusting for demographic characteristics, individual risk factors, and longitudinal trends. We then performed a stratification analysis by chronic obstructive pulmonary disease (COPD). Measurements and Main Results: We observed that each 1 SD (4.9 ppb) increase in warm-season ozone concentrations was associated with a 14.2 ml/s (95% confidence interval [CI], 8.8-19.6 ml/s] decrease in forced expiratory flow at the 75th percentile of vital capacity and a 29.5 ml/s (95% CI, 19.6-39.5 ml/s) decrease in mean forced expiratory flow between the 25th and 75th percentile of vital capacity. The odds ratio of SAD was 1.09 (95% CI, 1.06-1.11) for a 1 SD increase in warm-season ozone concentrations. Meanwhile, we observed a significant association with decreased FEV1/FVC but not with FEV1 or FVC. The association estimates were greater in the COPD group than in the non-COPD group. Conclusions: We found independent associations of long-term ozone exposure with impaired small airway function and higher SAD risks, while the associations with airflow obstruction were weak. Patients with COPD appear to be more vulnerable.

Synthesis and anti-parasites efficacy of coumarin derivatives against Dactylogyrus intermedius.

Dactylogyrus is one of the most common parasitic diseases in fish and causes huge losses to the aquaculture industry. With the advantages of safety, low toxicity and easy degradation, plant-derived drugs are ideal for the creation of green aquatic ingredients. The use of plant-derived drugs in aquaculture is limited by their low content and high processing costs, which is a challenge that can be solved by the chemical synthesis of plant-derived drugs. Eleven new coumarin derivatives were synthesized and assessed for their anthelmintic activity in this study. Among them, the derivative 7-((1-tosyl-1H-1,2,3-triazol-4-yl)methoxy)-2H-chromen-2-one (N11) has good anthelmintic activity and its mean anthelmintic efficacy against D. intermedius at a concentration of 10 µM reached 99.84%, which is even better than the anthelmintic activity of the positive control mebendazole. Further studies showed that N11 had concentration values of 3.31 and 1.94 µM for 50% maximal effect (EC50 ) against D. intermedius at 24 and 48 h, respectively. Furthermore, scanning electron microscopy revealed that N11 caused damage to D. intermedius. What is more noteworthy is that a substantial reduction in the ATP content of the parasite was observed following in vitro and in vivo administration of N11. Moreover, it was also found that N11 was able to inhibit the horizontal transmission of D. intermedius. Furthermore, real-time quantitative PCR analysis was utilized to determine the expression profile of genes associated with anti-inflammatory cytokines (IL-10, TGF-ß and IL-4) in goldfish. In all examined organs, it was observed that the expression of anti-inflammatory cytokines increased subsequent to treatment with N11, according to the results. Thus, these results all suggest that N11 possesses good anthelmintic activity and is a potentially effective agent for the control of D. intermedius.

Tailored Supramolecular Cage for Efficient Bio-Labeling.

Fluorescent chemosensors are powerful imaging tools used in a broad range of biomedical fields. However, the application of fluorescent dyes in bioimaging still remains challenging, with small Stokes shifts, interfering signals, background noise, and self-quenching on current microscope configurations. In this work, we reported a supramolecular cage (CA) by coordination-driven self-assembly of benzothiadiazole derivatives and Eu(OTf)3. The CA exhibited high fluorescence with a quantum yield (QY) of 38.57%, good photoluminescence (PL) stability, and a large Stokes shift (153 nm). Furthermore, the CCK-8 assay against U87 glioblastoma cells verified the low cytotoxicity of CA. We revealed that the designed probes could be used as U87 cells targeting bioimaging.

Microbiota associations with inflammatory pathways in asthma.

BACKGROUND: The airway microbiota plays an important role in asthma pathophysiology. However, the relationship between the airway microbiota and asthma phenotypes is still poorly understood. OBJECTIVE: We aimed to characterize the airway microbiota in asthma patients and determine its correlation with airway inflammatory phenotypes and other phenotypic characteristics. METHODS: The microbial composition of induced sputum specimens collected from asthma patients was determined using 16S rDNA gene sequencing. RESULTS: Patients with asthma had a higher abundance of bacterial taxa associated with Bacteroidetes, Fusobacteria and Proteobacteria and a reduced abundance of Firmicutes and Actinobacteria compared to healthy controls. This study classified the asthma-associated lung microbiota into three community types based on DMM models, which were defined as three pulmotypes (P1, P2 and P3). The lungs of patients with pulmotype 3 (P3) were dominated by Faecalibacterium and Bacteroides, while patients with pulmotype 1 (P1) had a greater abundance of Pasteurellaceae, Streptococcus and Rothia. P1 patients were older (p = .045) and had lower blood TGF levels (p = .028). P3 patients had fewer eosinophils (p = .016) and more neutrophils (p = .039) in induced sputa than P1 patients. CONCLUSIONS: Differences in asthma-associated airway microbiota pulmotypes are associated with and might influence asthma, particularly inflammatory phenotypes.

Orientation-selective sub-Rayleigh imaging with spatial coherence lattices.

The Rayleigh resolution criterion sets the minimum separation for two-point objects to be distinguishable in a classical optical imaging system. We demonstrate that the sub-Rayleigh resolution can be achieved in a telecentric imaging system with the help of a partially coherent illumination whose spatial coherence has lattice-like distribution. We show that the orientation-selective sub-Rayleigh imaging can be realized by controlling the spatial distribution of the coherence lattice into different symmetries. We carry out a proof-of-principle experiment to demonstrate the orientation-selective sub-Rayleigh imaging for a 1951 USAF resolution target. Our results indicate a flexible orientation-selective high-resolution imaging with spatial coherence engineering of the partially coherent light.

Super cosh-Gauss nonuniformly correlated radially polarized beam and its propagation characteristics.

In this paper, a new kind of partially coherent vector beam termed as super cosh-Gauss nonuniformly correlated radially polarized (SCNRP) beam is introduced. Such beam source exhibits almost perfect coherence between two points that are within the beam center region or located on a ring concentric with the beam center. However, the coherence drops or even vanishes when the two points leave the central region and are located on the concentric rings with different radii. The second-order statistical properties, such as the spectral density, the state of polarization (SOP), and the degree of polarization (DOP) of such beam upon free-space propagation are studied through numerical examples. Our results reveal that the beam displays a self-focusing property during propagation. The focusing ability can be enhanced with increasing the beam index and decreasing the beam's spatial coherence width, whereas the DOP and SOP remain unchanged on propagation. Meanwhile, we establish an experimental system with the use of a radial polarization converter and a digital micro-mirror device to synthesize the SCNRP beam with controllable beam index and spatial coherence width. The spectral density and polarization properties of the synthesized beam during propagation are measured and analyzed in the experiment. The experimental results agree well with our theoretical predictions.

Fast calculation of orbital angular momentum flux density of partially coherent Schell-model beams on propagation.

Optical coherence has recently become a degree of freedom to modulate the orbital angular momentum (OAM) flux density of a partially coherent beam during propagation. However, the calculation of the OAM flux density for the partially coherent beam involves partial differential and four-dimensional integral operations, which poses drawbacks for its fast numerical calculations. In this paper, we present an efficient numerical protocol for calculating the OAM flux density of any partially coherent Schell-model beam propagating through a paraxial ABCD optical system by only adopting two-dimensional (2D) Fourier transforms. The general formalism is established in detail for the fast numerical calculation of the OAM flux density. It is found that the operation number in the developed algorithm is independent on the spatial coherence states of the beam. To demonstrate the validity of our algorithm, we calculate the OAM flux density of the partially coherent Laguerre-Gaussian beams during propagation with both the analytical and numerical methods. The obtained results are consistent well with each other. Moreover, the OAM flux density properties of two other classes of Schell-model beams, having no analytical solutions, are investigated as the specific examples. Our method provides a convenient way for studying the correlation-induced OAM density changes for any Schell-model beam propagation through a paraxial optical system.