Construction of the Au Nanoparticle/Graphene Oxide/Au Nanotube (AuNP/GO/AuNT) Sandwich Membrane for Surface-Enhanced Raman Scattering Sensing.

Au nanotube-based composite membrane served as surface-enhanced Raman scattering (SERS) substrate with an ultralarge aspect ratio possesses an excellent flexibility and widely tunable surface plasmon resonance, and by introducing graphene oxide (GO) as a spacer layer, the SERS enhancement of the composite membrane is obviously better than those from the individual blocks of the Au nanotubes (AuNTS) membrane and the Au nanoparticle/graphene oxide (AuNP/GO) membrane. Such a "sandwich" (AuNP/GO/AuNT) structured membrane has a high SERS sensitivity and a wide tunability by controlling the size of Au nanoparticles and the thickness of graphene oxide, and the detection limits of the AuNP/GO/AuNT substrate for R6G and NBA are as low as 10-12 and 10-7 M, respectively; the large enhancement is attributed to the adsorption and chemical mechanism of graphene oxide and the physical mechanism of the Au nanoparticles and nanotubes (the electromagnetic field coupling between them).

Spreading evolution of a linear phase-locked hollow beam array in atmospheric turbulence.

Based on the generalized Huygens-Fresnel principle, propagation characteristics of a linear phase-locked hollow beam (PLHB) array propagating through atmospheric turbulence are investigated. Analytical expressions of the average intensity and mean-squared beam width of the PLHB array are derived. It is shown that propagation properties of a PLHB array are related to the initial beam parameters (i.e., number of beamlets, size of beam waist, range of wavelength) of the PLHB array and the strength of turbulence. These findings may provide potential applications in free-space optical communications, lidar, remote sensing, and related fields.

Sleep Disturbances Are Associated With Depressive Symptoms in a Chinese Population: The Rugao Longevity and Aging Cohort.

Objective: To investigate the cross-sectional and longitudinal relationships between sleep disturbances and depressive symptoms in older Chinese adults. Methods: This study included baseline and 3.5-year follow-up data of 1,631 Chinese men and women aged 70 years or older from the aging arm of the Rugao Longevity and Aging Study. Depressive symptoms were assessed by the 15-item Geriatric Depression Scale (GDS). Sleep disturbances were assessed by using the Pittsburgh Sleep Quality Index (PSQI). Logistic regression models were used to estimate the odds ratios (ORs) of the associations. Results: In the cross-sectional analysis, individuals with greater total PSQI scores exhibited significantly higher risk of "depressive symptoms" (OR: 1.31, 95% CI: 1.21-1.41) and "some depressive symptoms" (OR: 1.22, 95% CI: 1.17-1.28). Specifically, higher scores on the sleep efficiency PSQI subscale were associated with greater odds for "depressive symptoms" (OR: 1.54, 95% CI: 1.30-1.84) and "some depressive symptoms" (OR: 1.42, 95% CI: 1.29-1.57). Our longitudinal analyses indicated an association between greater PSQI total scores at baseline and greater odds of having "some depressive symptoms" at follow-up (OR: 1.07, 95% CI: 1.00-1.14). Additionally, higher scores on the sleep efficiency PSQI subscale had an association with higher odds for "some depressive symptoms" (OR: 1.21, 95% CI: 1.04-1.41). Conclusions: Poor self-reported global sleep quality and sleep efficiency PSQI subscale scores were associated with levels of depressive symptoms in an older Chinese population, indicating that global sleep quality and sleep efficiency may be risk factors for depression and can possibly predict the levels of depressive symptoms.

Thermal blooming induced phase change and its compensation of a Gaussian beam propagation in an absorbing medium.

A high-power laser beam propagating in an absorbing medium, thermal blooming causes phase distortion, which is severe for the beam quality. In this Letter, a feasible approach for obtaining the phase change induced by thermal blooming is proposed. In addition, based on the aforementioned phase change, an alternative solution of phase compensation near the receiver is provided, which may enrich the previous compensation method (i.e., using an adaptive optics system near the beam transmitter). These findings may have potential applications in optical communication, astronomical imaging, and related areas.

Thermal blooming induced phase change and its compensation of a Gaussian beam propagation in an absorbing medium: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 4304 (2021)OPLEDP0146-959210.1364/OL.437851.

Clinical characteristics of Kawasaki disease and concurrent pathogens during isolation in COVID-19 pandemic.

BACKGROUND: The aim of this study is to explore the characteristics of Kawasaki disease (KD) and concurrent pathogens due to a stay-at-home isolation policy during coronavirus disease 2019 (COVID-19) epidemic. METHODS: All patients with KD admitted between February and April in 2015-2020, were classified into before (group 1, in 2015-2019) and after (group 2, in 2020) isolation groups. A total of 4742 patients [with KD (n = 98) and non-KD (n = 4644)] referred to Mycoplasma pneumoniae (MP) and virus detection were analyzed in 2020. Clinical characteristics, laboratory data, and 13 pathogens were analyzed retrospectively. RESULTS: Group 2 had a significantly increased incidence of KD (0.11%) with 107 patients compared to that of group 1 (0.03%) with 493 patients. The comparisons of oral mucosal change, strawberry tongue, desquamation of the fingertips, cervical lymphadenopathy and neutrophil percentage decreased in group 2 compared to group 1. The infection rate of MP increased significantly in group 2 (34.7%) compared to group 1 (19.3%), while the positive rate of viruses decreased significantly in group 2 (5.3%) compared to group 1 (14.3%). In 2020, the positive rate of MP infection increased significantly in patients with KD compared to the increase in patients with non-KD. The infection rate of MP for younger children aged less than 3 years old was higher in group 2 than in group 1. CONCLUSION: Compared with the characteristics of KD from 2015 to 2019 years, the incidence of KD was increased in 2020 and was accompanied by a high incidence of MP infection, especially in younger children (less than 3 years old) during the isolation due to COVID-19 pandemic.

Genome-wide DNA methylation analysis of peripheral blood cells derived from patients with first-episode schizophrenia in the Chinese Han population.

Schizophrenia is a severe neuropsychiatric disorder with core features including hallucinations, delusions, and cognition deficits. Accumulating evidence has implicated abnormal DNA methylation in the development of schizophrenia. However, the mechanisms by which DNA methylation changes alter the risk for schizophrenia remain largely unknown. We recently carried out a DNA methylome study of peripheral blood samples from 469 first-episode patients with schizophrenia and 476 age- and gender-matched healthy controls of Han Chinese origin. Genomic DNA methylation patterns were quantified using an Illumina Infinium Human MethylationEPIC BeadChip. We identified multiple differentially methylated positions (DMPs) and regions between patients and controls. The most significant DMPs were annotated to genes C17orf53, THAP1 and KCNQ4 (KV7.4), with Bonferroni-adjusted P values of [Formula: see text], [Formula: see text], and [Formula: see text], respectively. In particular, KCNQ4 encodes a voltage-gated potassium channel of the KV7 family, which is linked to neuronal excitability. The genes associated with top-ranked DMPs also included many genes involved in nervous system development, such as LIMK2 and TMOD2. Gene ontology analysis of the differentially methylated genes further identified strong enrichment of neuronal networks, including neuron projection extension, axonogenesis and neuron apoptotic process. Finally, we provided evidence that schizophrenia-associated epigenetic alterations co-localize with genetic susceptibility loci. By focusing on first-episode schizophrenia patients, our investigation lends particularly strong support for an important role of DNA methylation in schizophrenia pathogenesis unconfounded by the effects of long-term antipsychotic medication or disease progression. The observed DNA methylation aberrations in schizophrenia patients could potentially provide a valuable resource for identifying diagnostic biomarkers and developing novel therapeutic targets to benefit schizophrenia patients.

Health status and associated factors of HIV-infected patients in Kunming, China.

OBJECTIVE: To assess health status of HIV-positive patients and to examine its predictors in Kunming, China. METHODS: HIV-positive patients were recruited from a general hospital and an infection hospital in 2015. Health status of the patients was evaluated using standardized questions on eight health domains (mobility, self-care, pain and discomfort, cognition, interpersonal activities, vision, sleep and energy, and emotional distress) of the WHO World Health Survey. A multivariate linear regression model was employed to explore the predictors of health status. RESULTS: A total of 1,363 HIV patients were recruited. The mean (SD) health status score was 73.4 (18.2), with the prevalence of reporting problems ranging from 17.6% (self-care problems) to 86.3% (vision problems). CD4 count, occupation, household income, accessibility to healthcare services, and healthcare expenditures were found to be significant predictors of health status. CONCLUSIONS: Healthcare services for HIV patients may assist improvement of interpersonal activities and relieve emotional distress, and efforts are needed to continually increase accessibility to the services. Special attention should be given to those at low socioeconomic level and those suffering from low CD4 count.

Nuclear Norm Clustering: a promising alternative method for clustering tasks.

Clustering techniques are widely used in many applications. The goal of clustering is to identify patterns or groups of similar objects within a dataset of interest. However, many cluster methods are neither robust nor sensitive to noises and outliers in real data. In this paper, we present Nuclear Norm Clustering (NNC, available at https://sourceforge.net/projects/nnc/), an algorithm that can be used in various fields as a promising alternative to the k-means clustering method. The NNC algorithm requires users to provide a data matrix M and a desired number of cluster K. We employed simulated annealing techniques to choose an optimal label vector that minimizes nuclear norm of the pooled within cluster residual matrix. To evaluate the performance of the NNC algorithm, we compared the performance of both 15 public datasets and 2 genome-wide association studies (GWAS) on psoriasis, comparing our method with other classic methods. The results indicate that NNC method has a competitive performance in terms of F-score on 15 benchmarked public datasets and 2 psoriasis GWAS datasets. So NNC is a promising alternative method for clustering tasks.

Use of weather research and forecasting model outputs to obtain near-surface refractive index structure constant over the ocean.

The methods to obtain atmospheric refractive index structure constant (Cn2) by instrument measurement are limited spatially and temporally and they are more difficult and expensive over the ocean. It is useful to forecast Cn2 effectively from Weather Research and Forecasting Model (WRF) outputs. This paper introduces a method that WRF Model is used to forecast the routine meteorological parameters firstly, and then Cn2 is calculated based on these parameters by the Bulk model from the Monin-Obukhov similarity theory (MOST) over the ocean near-surface. The corresponding Cn2 values measured by the micro-thermometer which is placed on the ship are compared with the ones forecasted by WRF model to determine how this method performs. The result shows that the forecasted Cn2 is consistent with the measured Cn2 in trend and the order of magnitude as a whole, as well as the correlation coefficient is up to 77.57%. This method can forecast some essential aspects of Cn2 and almost always captures the correct magnitude of Cn2, which experiences fluctuations of two orders of magnitude. Thus, it seems to be a feasible and meaningful method that using WRF model to forecast near-surface Cn2 value over the ocean.

Average intensity of M × N Gaussian array beams in oceanic turbulence.

Based on the power spectrum of oceanic turbulence proposed by Nikishov, the analytical expressions for average intensity of M×N Gaussian array beams propagating in oceanic turbulence are derived, where the coherent and incoherent combinations are considered. Using the focused beam, the intensity can be received at the same point. The changes of the average intensity versus three oceanic parameters are investigated.

Influence of oceanic turbulence on propagation of a radial Gaussian beam array.

The analytical expression for the root-mean-square (Rms) beam width of the radial Gaussian beam array propagating in oceanic turbulence is derived, where the coherent combination is considered. Meanwhile, the analytical expression for effect of the turbulence on the beam F is also obtained. Giving a comparison of results of F calculated by the analytical expression and the previously integrating one, it can be seen that the two results are in agreement with each other exactly. Further, the influences of the rate of dissipation of mean-squared temperatureχ(T), the rate of dissipation of kinetic energy per unit mass of seawater εand the ratio of temperature to salinity contribution to the refractive index spectrum w are investigated. The results indicate that the Rms beam width increases as χ(T) increases, εdecreases and the salinity-induced turbulence dominates. Moreover, the changings of effective radius of curvature with mentioned above parameters are studied. The strength of turbulence determines the value of effective radius of curvature, and which decreases asχ(T) and w increases, and εdecreases.

Two-wavelength ghost imaging through atmospheric turbulence.

Recent work has indicated that ghost imaging might find useful application in standoff sensing where atmospheric turbulence is a serious problem. There has been theoretical study of ghost imaging in the presence of turbulence. However, most work has addressed signal-wavelength ghost imaging. Two-wavelength ghost imaging through atmospheric turbulence is theoretically studied in this paper. Based on the extended Huygens-Fresnel integral, the analytical expressions describing atmospheric turbulence effects on the point spread function (PSF) and field of view (FOV) are derived. The computational case is also reported.

Adaptive optical ghost imaging through atmospheric turbulence.

We demonstrate for the first time (to our knowledge) that a high-quality image can still be obtained in atmospheric turbulence by applying adaptive optical ghost imaging (AOGI) system even when conventional ghost imaging system fails to produce an image. The performance of AOGI under different strength of atmospheric turbulence is investigated by simulation. The influence of adaptive optics system with different numbers of adaptive mirror elements on obtained image quality is also studied.

Propagation of Gaussian-Schell beam in turbulent atmosphere of three-layer altitude model.

We propose a method that is used to derive the moment radius of intensity distribution in a turbulent atmosphere. From this study, we have found that the second moment radius is affected only by the first-order expansion coefficient of the wave structure function. If our attention is directed to a higher moment radius, a higher order approximation of the expansion needs to be used. As an example, the propagation of a Gaussian-Schell beam in a slant path has been studied based on the turbulent atmosphere of a three-layer model. The variation of some beam properties, such as the relative waist width, angular spread, and kurtosis parameter with the initial waist width, wavelength, and zenith angle, has been analyzed and discussed in detail. The study shows that there is little difference between the three-layer model and the Kolmogorov model in studying uplink propagation, and the difference is large for downlink propagation. The intensity profile of the Gaussian beam in turbulence does not keep a Gaussian shape unless the beam spreading due to turbulence is very large or very small.

Light filaments with higher-order Kerr effect.

The influence mechanism of higher-order Kerr effect on the propagation of laser beam is investigated by a modified model, which indicates that a collapsing wave will transform into a universe blowup profile. The analysis of higher-order terms of the nonlinear refractive index shows that the filamentation process can be induced by Kerr self-focusing without the occurrence of the ionization effect. The determining role of the combination of self-focusing and spontaneous defocusing and the energy reservoir in formation of lengthy filament is confirmed visually.