Enzymatic Catalysis in Size and Volume Dual-Confined Space of Integrated Nanochannel-Electrodes Chip for Enhanced Impedance Detection of Salmonella.

Nanochannel-based confinement effect is a fascinating signal transduction strategy for high-performance sensing, but only size confinement is focused on while other confinement effects are unexplored. Here, a highly integrated nanochannel-electrodes chip (INEC) is created and a size/volume-dual-confinement enzyme catalysis model for rapid and sensitive bacteria detection is developed. The INEC, by directly sandwiching a nanochannel chip (60 µm in thickness) in nanoporous gold layers, creates a micro-droplet-based confinement electrochemical cell (CEC). The size confinement of nanochannel promotes the urease catalysis efficiency to generate more ions, while the volume confinement of CEC significantly enriches ions by restricting diffusion. As a result, the INEC-based dual-confinement effects benefit a synergetic enhancement of the catalytic signal. A 11-times ion-strength-based impedance response is obtained within just 1 min when compared to the relevant open system. Combining this novel nanoconfinement effects with nanofiltration of INEC, a separation/signal amplification-integrated sensing strategy is further developed for Salmonella typhimurium detection. The biosensor realizes facile, rapid (<20 min), and specific signal readout with a detection limit of 9 CFU mL-1 in culturing solution, superior to most reports. This work may create a new paradigm for studying nanoconfined processes and contribute a new signal transduction technique for trace analysis application.

WeChat-Based Education and Rehabilitation Program Improves Physical Performance and Quality of Life in Patients with Acute Coronary Syndrome after Percutaneous Coronary Intervention.

WeChat provides the chance for online caring program to improve physical recovery and quality of life (QoL) in patients with cardio/cerebral vascular diseases, especially in special period such as coronavirus disease 2019 (COVID-19) spread time. This study intended to evaluate the influence of the WeChat-based education and rehabilitation program (WERP) on physical performance and QoL in patients with acute coronary syndrome (ACS) post percutaneous coronary intervention (PCI). Totally, 180 patients with ACS after PCI were randomized to the WERP (N = 90) and control care (CC) (N = 90) groups, then received corresponding caring program for 3 months. Short physical performance battery (SPPB) score, 6-minute walking distance (6MWT), EuroQol-5 dimensions (EQ-5D) score, and EuroQol-5 Visual Analog Scale (EQ-VAS) score were assessed at discharge, month (M)1, M2, and M3, respectively. Our study showed that SPPB score at M1 ( P = 0.029), M2 (P = 0.048), and M3 (P = 0.030) was higher in WERP group than in CC group. Besides, 6MWT at M1 (P = 0.026), M2 (P = 0.023), and M3 (P = 0.041) were longer in WERP group than in CC group. Finally, EQ-5D score at M1 (P = 0.022) and M3 (P = 0.023) was lower, while EQ-VAS score at M1 (P = 0.020), M2 (P = 0.013), and M3 (P = 0.039) was higher in WERP group than in CC group. Subgroup analyses further showed that patients with baseline SPPB score ≤ 9 benefited more from WERP. Conclusively, WERP could be an option to improve physical performance and QoL in patients with ACS after PCI.

Changes in orbital angular momentum distribution of a twisted partially coherent array beam in anisotropic turbulence.

Based on the generalized Huygens Fresnel integral, we derive the analytical formula of the cross-spectral density of a twisted partially coherent array beam propagating in non-Kolmogorov anisotropic turbulence, and investigate the changes in orbital angular momentum (OAM). The results show that the anisotropy of the turbulence causes different effects in horizontal and vertical directions. The spectral density distribution of twisted partially coherent array beam in turbulence presents self-splitting and rotation, which combines the interesting effects of the twist phase and coherent structure. Although OAM is conserved, the spatial distribution of OAM flux density can be changed by changing the propagation distance, power and anisotropy of turbulence, and the modulation of the twist phase affects not only the magnitude of OAM but also its distribution. Our work is helpful for exploring new forms of OAM sources, and promote the application of free-space optical communications and optical field modulation.

Study on Laser Parameter Measurement System Based on Cone-Arranged Fibers and CCD Camera.

This paper proposes a new laser parameter measuring method based on cone-arranged fibers to further improve the measurable spot size, allowable incident angle range, and spatial sampling resolution. This method takes a conical array composed of flexible fibers to sample and shrink the cross-section spot of the laser beam, facilitating low-distortion shooting with a charge-coupled diode (CCD) camera, and adopts homogenized processing and algorithm analysis to correct the spot. This method is experimentally proven to achieve high-accuracy measurements with a decimeter-level spot-receiving surface, millimeter-level resolution, and high tolerance in order to incite skew angle. Comparing the measured spot under normal incidence with the real one, the root mean square error (RMSE) of their power in the bucket (PIB) curves is less than 1%. When the incident angle change is between -8° and 8°, the RMSE is less than 2% and the measurement error of total power is less than 5% based on the premise that the fiber's numerical aperture (NA) is 0.22. The possibility of further optimizing the measurement method by changing the fiber parameters and array design is also reported.

Simultaneous Extraction of Planetary Boundary-Layer Height and Aerosol Optical Properties from Coherent Doppler Wind Lidar.

Planetary boundary-layer height is an important physical quantity for weather forecasting models and atmosphere environment assessment. A method of simultaneously extracting the surface-layer height (SLH), mixed-layer height (MLH), and aerosol optical properties, which include aerosol extinction coefficient (AEC) and aerosol optical depth (AOD), based on the signal-to-noise ratio (SNR) of the same coherent Doppler wind lidar (CDWL) is proposed. The method employs wavelet covariance transform to locate the SLH and MLH using the local maximum positions and an automatic algorithm of dilation operation. AEC and AOD are determined by the fitting curve using the SNR equation. Furthermore, the method demonstrates the influential mechanism of optical properties on the SLH and MLH. MLH is linearly correlated with AEC and AOD because of solar heating increasing. The results were verified by the data of an ocean island site in China.

Optomechanical Design and Application of Solar-Skylight Spectroradiometer.

Using a solar radiometer is an effective approach for improving the remote sensing of solar irradiance distribution and atmospheric composition. Long-term development of a solar scanning radiometer enables frequent and reliable measurement of atmospheric parameters such as the water vapor column and aerosol optical properties. However, the discrete wavelength radiometer has encountered a bottleneck with respect to its insufficient spectral resolution and limited observation waveband, and it has been unable to satisfy the needs of refined and intelligent on-site experiments. This study proposes a solar-skylight spectroradiometer for obtaining visible and near-IR fine spectrum with two types of measurement: direct-sun irradiance and diffuse-sky radiance. The instrument adopts distributed control architecture composed of the ARM-Linux embedded platform and sensor networks. The detailed design of the measuring light-path, two-axis turntable, and master control system will be addressed in this study. To determine all coefficients needed to convert instrument outputs to physical quantities, integrating sphere and Langley extrapolation methods are introduced for diffuse-sky and direct-sun calibration, respectively. Finally, the agreement of experimental results between spectroradiometers and measuring benchmarks (DTF sun-photometer, microwave radiometer, and Combined Atmospheric Radiative Transfer simulation) verifies the feasibility of the spectroradiometer system, and the radiation information of feature wavelengths can be used to retrieve the characteristics of atmospheric optics.

Cooperation Mode of Outer Surface and Inner Space of Nanochannel: Separation-Detection System Based on Integrated Nanochannel Electrode for Rapid and Facile Detection of Salmonella.

Nanochannels hold great prospects in intelligent systems; however, current research focuses on the inner space of the nanochannel while the outer surface is rarely explored. Here, we report on a cooperation mode of the outer surface and inner space of the nanochannel using an integrated nanochannel-electrode (INCE) and its application as a separation-detection system for rapid and facile detection of foodborne bacteria. Unlike conventional nanochannel systems, the INCE integrates two electrodes as a sensitive electrochemical interface and the nanochannel itself as nanofilter, generating a novel separation-detection system. The system is examined in a biosensing strategy based on magnetic nanoparticles (MNPs). Salmonella typhimurium (St) is taken as the target due to its severe threat to human health and food safety. By electrochemically probing the MNPs-St complex themselves on the surface of INCE, this method eliminates the requirement on additional signal labels. The biosensor presents a linear detection range from 102 to 107 CFU mL-1 and a limit of detection of 50 CFU mL-1, being comparable or even better than those of analogues with complicated signal amplification designs. Moreover, the biosensor exhibits good specificity against four types of interfering bacteria. This concept may bring new insight into the development of nanochannel research and contribute a new way to the fields of separation and detection.

Mesoscale optical turbulence simulations above Tibetan Plateau: first attempt.

The vertical distributions of optical turbulence (C n2 profiles) are a major factor in defining the capabilities of ground-based telescopes and interferometers. As site-testing campaigns are extremely expensive and instruments only provide the local atmospheric parameter, atmospheric modeling might represent an advance prediction result in astronomical sites. The key meteorological parameters and the integrated astroclimatic parameters (Fried parameter r0, seeing ɛ, isoplanatic angle θAO and wavefront coherence time τAO) related to the C n2 profiles above the Tibetan Plateau are investigated for astronomical applications by using the Weather Research and Forecasting (WRF) model. Radiosonde measurements from a field campaign at Lhasa station above the Tibetan Plateau are used to quantify the ability of this model. The results show that the C n2 profile decreases rapidly in the surface layer, increasing with height from the boundary layer to low stratosphere, and decreases gradually in the high free atmosphere. From the whole campaign measurements above the Tibetan Plateau, the mean r0 is 8.64 cm, the mean ɛ is 1.55'', the mean θAO is 0.42'' and the mean τAO is 1.89 ms, and the comparison with the other world's leading observatory sites have been presented. In addition, such as the bias and the root-mean-squared error are used to quantify the performance of the WRF model. In spite of the model performance in reconstructing the meteorological parameters is reasonable in general, the uncertainty in quantifying the C n2 profiles and the integrated parameters are not negligible in some cases. The main results of this study tell us that the WRF model could provide a useful resource to design, monitor the performance of, and even optimize the operation of sophisticated Adaptive Optics (AO) systems.

Estimating and measurement of atmospheric optical turbulence according to balloon-borne radiosonde for three sites in China.

The distribution of optical turbulence (Cn2 profiles) is the fundamental parameter closely related to the design and application of optoelectronic systems. Since systematic direct measurements of optical turbulence for many climates and seasons are not available, it is useful to estimate Cn2 effectively from the routine meteorological parameters. The Cn2 profiles are estimated by routine meteorological parameters based on the Tatarskii model, and the estimated results are compared with the corresponding radiosonde measurements from the field campaigns at Rongcheng (122.37∘E, 37.15∘N), Taizhou (121.42∘E, 28.62∘N), and Dachaidan (95.35∘E, 37.74∘N) in China. The agreement between the estimation model and the measurement is very close, except for a portion of the atmosphere where it showed considerable difference. Additionally, statistical operators are used to quantify the performance of the estimated model, and the statistical results also show that the estimated and measured Cn2 profiles are consistent well. Furthermore, the integrated parameters (such as the Fried parameter, r0) from radiosonde measurement are 7.92 cm, 5.39 cm, and 3.68 cm at Rongcheng, Taizhou, and Dachaidan, respectively. Therefore, the Cn2 profiles and their characteristics in these typical climate sites provide useful information to assess the effect of laser transmission in the atmosphere, which are usually used in the design of optoelectronic systems and astronomical site testing.

Maternal ß-HCG concentrations in early IVF pregnancy: association with the embryo development stage of blastocysts.

RESEARCH QUESTION: Does the blastocyst development stage on embryo transfer day affect serum ß-human chorionic gonadotrophin (ß-HCG) concentration 9 and 16 days after embryo transfer in women whose pregnancy progresses beyond 13 weeks? DESIGN: Retrospective study involving 204 cases where pregnancy progressed beyond 13 weeks of single blastocyst transfer in fresh (n = 66) or frozen embryo transfer (FET) (n = 138) cycles from January 2015 to September 2016. RESULTS: ß-HCG concentrations 9 and 16 days after embryo transfer in FET cycles (median 223 IU/l and 4378 IU/l, respectively) were significantly (P < 0.001) higher than in fresh cycles (157 IU/l and 2813 IU/l). Among fresh cycles, faster-growing blastocysts (expanded + hatching + hatched blastocysts) produced significantly (P < 0.001) higher ß-HCG concentrations 9 days after embryo transfer (191 IU/l) than slower-growing blastocysts (cavitating + full blastocyst, 106 IU/l); however no significant difference was found between the faster- and slower-growing groups by day 16 (2359 IU/l and 3025 IU/l, respectively). Among FET cycles, there was no difference in ß-HCG concentration between blastocysts of different development stages 9 and 16 days after transfer. CONCLUSIONS: Faster-growing blastocysts produced significantly higher serum ß-HCG concentrations 9 days after transfer than slower-growing blastocysts in fresh cycles, but the difference was not significant by day 16 after transfer. Also, ß-HCG concentrations 9 and 16 days after embryo transfer in FET cycles were higher than in fresh embryo transfer cycles. Interpretation of ß-HCG results 9 days after blastocyst transfer should consider the blastocyst growth rate and whether fresh or cryopreserved embryo was transferred.

Influence of Spatial Inhomogeneity of Detector Temporal Responses on the Spectral Fidelity in Continuous Wave Cavity Ringdown Spectroscopy.

Due to their advantages of having a wide bandwidth, low cost, and being easy to obtain, traditional photodetectors (PDs) are being widely applied in measurements of transient signals. The spatial inhomogeneity of such PD temporal responses was measured directly to account for the PD spatial effect of decay rate due to poor alignment in continuous wave cavity ringdown spectroscopy (CW-CRDS) experiments. Based on the measurements of three PDs (i.e., model 1611 (Newport), model 1811 (Newport), and model PDA10CF-EC (Thorlabs)), all the temporal responses followed a tendency of declining first and then rising, and steady platforms existed for the last two PDs. Moreover, as we expected, the closer the PD center was, the faster the response. On the other hand, the initial shut-off amplitude generally reached a larger value for a faster temporal response. As a result, the spatial effect can strongly influence the spectral line shape and value, which will introduce more errors into the precise measurements of spectral parameters using the CRDS technique if this effect is not considered. The defined effective detection area (EDA) of the PDs, which was close to the active area given by manufacturers, was the key parameter that should be paid more attention by researchers. Therefore, the PD should be aligned perfectly to make sure that the EDA covers the laser spot completely.

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.

Estimating the surface layer refractive index structure constant over snow and sea ice using Monin-Obukhov similarity theory with a mesoscale atmospheric model.

Since systematic direct measurements of refractive index structure constant ( Cn2) for many climates and seasons are not available, an indirect approach is developed in which Cn2 is estimated from the mesoscale atmospheric model outputs. In previous work, we have presented an approach that a state-of-the-art mesoscale atmospheric model called Weather Research and Forecasting (WRF) model coupled with Monin-Obukhov Similarity (MOS) theory which can be used to estimate surface layer Cn2 over the ocean. Here this paper is focused on surface layer Cn2 over snow and sea ice, which is the extending of estimating surface layer Cn2 utilizing WRF model for ground-based optical application requirements. This powerful approach is validated against the corresponding 9-day Cn2 data from a field campaign of the 30th Chinese National Antarctic Research Expedition (CHINARE). We employ several statistical operators to assess how this approach performs. Besides, we present an independent analysis of this approach performance using the contingency tables. Such a method permits us to provide supplementary key information with respect to statistical operators. These methods make our analysis more robust and permit us to confirm the excellent performances of this approach. The reasonably good agreement in trend and magnitude is found between estimated values and measurements overall, and the estimated Cn2 values are even better than the ones obtained by this approach over the ocean surface layer. The encouraging performance of this approach has a concrete practical implementation of ground-based optical applications over snow and sea ice.

Analysis of an optical turbulence profile using complete ensemble empirical mode decomposition.

We obtain an intrinsic optical turbulence model using a data-driven method named complete ensemble empirical mode decomposition. First, the measured profile of a refractive index structure parameter is decomposed into a set of intrinsic mode functions and a residue. The components are tested against white noise to determine the statistical significance. Meanwhile, the physical meanings of the IMFs are revealed using meteorological data that agrees with previous research. Second, the effect of noisy oscillations, quasi-cyclical variations, and the trend on the overall profile are evaluated by the variance contribution rate. Third, the intrinsic optical turbulence model is defined. The combination of different IMFs with the residue forms intrinsic optical turbulence profiles, by which the stratification structures on different scales are embedded into the model. Comparison with other models highlights the virtue of the intrinsic optical turbulence model.

Aerosol absorption measurement at SWIR with water vapor interference using a differential photoacoustic spectrometer.

Atmospheric aerosol plays an important role in atmospheric radiation balance through absorbing and scattering the solar radiation, which changes local weather and global climate. Accurate measurement is highly requested to estimate the radiative effects and climate effects of atmospheric aerosol. Photoacoustic spectroscopy (PAS) technique, which observes the aerosols on their natural suspended state and is insensitive to light scattering, is commonly recognized as one of the best candidates to measure the optical absorption coefficient (OAC) of aerosols. In the present work, a method of measuring aerosol OAC at the wavelength where could also be absorbed by water vapor was proposed and corresponding measurements of the absorption properties of the atmospheric aerosol at the short wave infrared (SWIR, 1342 nm) wavelength were carried out. The spectrometer was made up of two high performance homemade photoacoustic cells. To improve the sensitivity, several methods were presented to control the noise derived from gas flow and vibration from the sampling pump. Calibration of the OAC and properties of the system were also studied in detail. Using the established PAS instrument, measurement of the optical absorption properties of the atmospheric aerosol were carried out in laboratory and field environment.

Equivalent refractive-index structure constant of non-Kolmogorov turbulence.

The relationship between the non-Kolmogorov refractive-index structure constant and the Kolmogorov refractive-index structure constant is derived by using the refractive-index structure function and the variance of refractive-index fluctuations. It shows that the non-Kolmogorov structure constant is proportional to the Kolmogorov structure constant and the scaling factor depends on the outer scale and the spectral power law. For a fixed Kolmogorov structure constant, the non-Kolmogorov structure constant increases with a increasing outer scale for the power law less than 11/3, the trend is opposite for the power law greater than 11/3. This equivalent relation provides a way of obtaining the non-Kolmogorov structure constant by using the Kolmogorov structure constant.

Toward a new radiative-transfer-based model for remote sensing of terrestrial surface albedo.

This Letter formulates a simple yet accurate radiative-transfer-based theoretical model to characterize the fraction of radiation reflected by terrestrial surfaces. Emphasis is placed on the concept of inhomogeneous distribution of the diffuse sky radiation function (DSRF) and multiple interaction effects (MIE). Neglecting DSRF and MIE produces a -1.55% mean relative bias in albedo estimates. The presented model can elucidate the impact of DSRF on the surface volume scattering and geometry-optical scattering components, respectively, especially for slant illuminations with solar zenith angles (SZA) larger than 50°. Particularly striking in the comparisons between our model and ground-based observations is the achievement of the agreement level, indicating that our model can effectively resolve the longstanding issue in accurately estimating albedo at extremely large SZAs and is promising for land-atmosphere interactions studies.

Effects of Chlorogenic Acid on Lowering IgE-Binding Capacity of Soybean 7S: Comparison between Covalent and Noncovalent Interaction.

Allergenicity of soybean 7S protein (7S) troubles many people around the world. However, many processing methods for lowering allergenicity is invalid. Interaction of 7S with phenolic acids, such as chlorogenic acid (CHA), to structurally modify 7S may lower the allergenicity. Hence, the effects of covalent (C-I, periodate oxidation method) and noncovalent interactions (NC-I) of 7S with CHA in different concentrations (0.3, 0.5, and 1.0 mM) on lowering 7S allergenicity were investigated in this study. The results demonstrated that C-I led to higher binding efficiency (C-0.3:28.51 ± 2.13%) than NC-I (N-0.3:22.66 ± 1.75%). The C-I decreased the α-helix content (C-1:21.06%), while the NC-I increased the random coil content (N-1:24.39%). The covalent 7S-CHA complexes of different concentrations had lower IgE binding capacity (C-0.3:37.38 ± 0.61; C-0.5:34.89 ± 0.80; C-1:35.69 ± 0.61%) compared with that of natural 7S (100%), while the noncovalent 7S-CHA complexes showed concentration-dependent inhibition of IgE binding capacity (N-0.3:57.89 ± 1.23; N-0.5:46.91 ± 1.57; N-1:40.79 ± 0.22%). Both interactions produced binding to known linear epitopes. This study provides the theoretical basis for the CHA application in soybean products to lower soybean allergenicity.

Statistical analysis of the spatial-temporal distribution of aerosol extinction retrieved by micro-pulse lidar in Kashgar, China.

The spatial-temporal distribution of dust aerosol is important in climate model and ecological environment. An observation experiment of the aerosol vertical distribution in the low troposphere was made using the micro-pulse lidar system from Sept. 2008 to Aug. 2009 at the oasis city Kashgar, China, which is near the major dust source area of the Taklimakan desert. The monthly averaged temporal variation of aerosol extinction profiles are given in the paper. The profile of aerosol extinction coefficient suggested that the dust aerosol could be vertically transported from the ground level to the higher altitude of above 5 km around the source region, and the temporal distribution showed that the dust aerosol layer of a few hundred meters thick appeared in the seasons of early spring and summer near the ground surface.

Development and external validation of a mixed-effects deep learning model to diagnose COVID-19 from CT imaging.

Background: The automatic analysis of medical images has the potential improve diagnostic accuracy while reducing the strain on clinicians. Current methods analyzing 3D-like imaging data, such as computerized tomography imaging, often treat each image slice as individual slices. This may not be able to appropriately model the relationship between slices. Methods: Our proposed method utilizes a mixed-effects model within the deep learning framework to model the relationship between slices. We externally validated this method on a data set taken from a different country and compared our results against other proposed methods. We evaluated the discrimination, calibration, and clinical usefulness of our model using a range of measures. Finally, we carried out a sensitivity analysis to demonstrate our methods robustness to noise and missing data. Results: In the external geographic validation set our model showed excellent performance with an AUROC of 0.930 (95%CI: 0.914, 0.947), with a sensitivity and specificity, PPV, and NPV of 0.778 (0.720, 0.828), 0.882 (0.853, 0.908), 0.744 (0.686, 0.797), and 0.900 (0.872, 0.924) at the 0.5 probability cut-off point. Our model also maintained good calibration in the external validation dataset, while other methods showed poor calibration. Conclusion: Deep learning can reduce stress on healthcare systems by automatically screening CT imaging for COVID-19. Our method showed improved generalizability in external validation compared to previous published methods. However, deep learning models must be robustly assessed using various performance measures and externally validated in each setting. In addition, best practice guidelines for developing and reporting predictive models are vital for the safe adoption of such models.