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1.
J Environ Manage ; 361: 121265, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38820788

ABSTRACT

Rapid urban expansion and economic development challenges to the sustainability of ecosystem services (ESs), a solid understanding of the mechanisms that drive ESs helps policymakers to respond. However, few existing studies on ES-driven mechanisms emphasize the integration of natural and cultural services, with most neglecting spatial non-stationarity at the geographic scale. Here, we improved the ROS model to quantify cultural ecosystem services (CES) and developed a comprehensive ecosystem services index (CESI) by coupling CES with 6 typical natural ESs (carbon storage (CS), water yield (WY), nitrogen export (NE), soil conservation (SC), habitat quality (HQ), food supply (FS)), subsequently, Spearman's correlation and MGWR were employed to reveal the CESI-driven mechanism considering geographic scales. The results showed that: (1) From 2000 to 2020, CS, WY, SC, and HQ exhibited decline, which contrasts with the significant increase in CES. (2) The CESI showed a decreasing trend (3.28-3.70) while the coefficient of variation was increasing over time (0.11-0.15). The overall spatial distribution of CESI shows higher northwest than southeast, with strong spatial autocorrelation. (3) The CESI exhibits synergistic associations with CS, SC, HQ, and CES (0.54-0.83), and forms trade-offs with WY, NE, and FS. (4) Climate, vegetation, landscape, human, and topography have significant effects on CES and CESI with a significantly geographic scale differences, especially areas closer to the sea exhibit heightened sensitivity. Besides, the combined effects of multiple factors are stronger than any individual driver. The results emphasize the necessity of introducing ecological land in coastal cities and establishing natural reserves in high CESI areas to maintain diversity. The study improves the CES assessment methodology and proposes an integrated analytical framework that combines natural and cultural ESs with geographic-scale drivers, providing a new perspective on the analysis of ESs mechanisms.


Subject(s)
Conservation of Natural Resources , Ecosystem , China , Cities , Soil/chemistry
2.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 41(3): 535-543, 2024 Jun 25.
Article in Zh | MEDLINE | ID: mdl-38932540

ABSTRACT

Magnetic resonance imaging (MRI) plays a crucial role in the diagnosis of ischemic stroke. Accurate segmentation of the infarct is of great significance for selecting intervention treatment methods and evaluating the prognosis of patients. To address the issue of poor segmentation accuracy of existing methods for multiscale stroke lesions, a novel encoder-decoder architecture network based on depthwise separable convolution is proposed. Firstly, this network replaces the convolutional layer modules of the U-Net with redesigned depthwise separable convolution modules. Secondly, an modified Atrous spatial pyramid pooling (MASPP) is introduced to enlarge the receptive field and enhance the extraction of multiscale features. Thirdly, an attention gate (AG) structure is incorporated at the skip connections of the network to further enhance the segmentation accuracy of multiscale targets. Finally, Experimental evaluations are conducted using the ischemic stroke lesion segmentation 2022 challenge (ISLES2022) dataset. The proposed algorithm in this paper achieves Dice similarity coefficient (DSC), Hausdorff distance (HD), sensitivity (SEN), and precision (PRE) scores of 0.816 5, 3.668 1, 0.889 2, and 0.894 6, respectively, outperforming other mainstream segmentation algorithms. The experimental results demonstrate that the method in this paper effectively improves the segmentation of infarct lesions, and is expected to provide a reliable support for clinical diagnosis and treatment.


Subject(s)
Algorithms , Image Processing, Computer-Assisted , Ischemic Stroke , Magnetic Resonance Imaging , Humans , Magnetic Resonance Imaging/methods , Ischemic Stroke/diagnostic imaging , Image Processing, Computer-Assisted/methods , Multimodal Imaging/methods , Neural Networks, Computer
3.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(12): 3397-400, 2014 Dec.
Article in Zh | MEDLINE | ID: mdl-25881446

ABSTRACT

The LIBS of one kind of household fuel coal was obtained with the first harmonic output 532 nm of an Nd·YAG laser as radiation source. With the assignment of the spectral lines, it was found that besides the elements C, Si, Mg, Fe, Al, Ca, Ti, Na and K, which are reported to be contained in coal, the presented sample also contains trace elements, such as Cd, Co, Hf, Ir, Li, Mn, Ni, Rb, Sr, V, W, Zn, Zr etc, but the spectral lines corresponding to O and H elements did not appear in the spectra. This is owing to the facts that the transition probability of H and O atoms is small and the energy of the upper level for transition is higher. The results of measurement also show that the intensity of spectral line increases with the laser pulse energy and self-absorption of the spectral lines K766.493 nm and K769.921 nm will appear to some extent. Increasing laser energy further will make self-absorption more obvious. The presence of self-absorption can be attributed to two factors. One is the higher transition rate of K atoms, and the other is that the increase in laser intensity induces the enhancement of the particle number density in the plasma.

4.
Insights Imaging ; 14(1): 207, 2023 Nov 27.
Article in English | MEDLINE | ID: mdl-38010567

ABSTRACT

OBJECTIVES: This study aims to evaluate the efficacy of multi-model incorporated by radiomics, deep learning, and transcriptomics features for predicting pathological grade and survival in patients with clear cell renal cell carcinoma (ccRCC). METHODS: In this study, data were collected from 177 ccRCC patients, including radiomics features, deep learning (DL) features, and RNA sequencing data. Diagnostic models were then created using these data through least absolute shrinkage and selection operator (LASSO) analysis. Additionally, a multi-model was developed by combining radiomics, DL, and transcriptomics features. The prognostic performance of the multi-model was evaluated based on progression-free survival (PFS) and overall survival (OS) outcomes, assessed using Harrell's concordance index (C-index). Furthermore, we conducted an analysis to investigate the relationship between the multi-model and immune cell infiltration. RESULTS: The multi-model demonstrated favorable performance in discriminating pathological grade, with area under the ROC curve (AUC) values of 0.946 (95% CI: 0.912-0.980) and 0.864 (95% CI: 0.734-0.994) in the training and testing cohorts, respectively. Additionally, it exhibited statistically significant prognostic performance for predicting PFS and OS. Furthermore, the high-grade group displayed a higher abundance of immune cells compared to the low-grade group. CONCLUSIONS: The multi-model incorporated radiomics, DL, and transcriptomics features demonstrated promising performance in predicting pathological grade and prognosis in patients with ccRCC. CRITICAL RELEVANCE STATEMENT: We developed a multi-model to predict the grade and survival in clear cell renal cell carcinoma and explored the molecular biological significance of the multi-model of different histological grades. KEY POINTS: 1. The multi-model achieved an AUC of 0.864 for assessing pathological grade. 2. The multi-model exhibited an association with survival in ccRCC patients. 3. The high-grade group demonstrated a greater abundance of immune cells.

5.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(3): 742-5, 2011 Mar.
Article in Zh | MEDLINE | ID: mdl-21595231

ABSTRACT

With 532 nm laser as excitation source, the excitation and relaxation process of NO2 molecule was investigated by the technique of photoacoustic and fluorescence emission spectra. The results show that NO2 molecules will be pumped to the first excited electronic state by laser photon. When the sample pressure is lower, some of the excited molecules relax to the ground state by radiation process directly; the other parts are redistributed to a few of the excited rovibronic energy levels by the process of fast internal energy transfer. With the increase in the sample pressure, continual collisions dominate the relaxation process gradually. This makes the excited molecules to be redistributed to many excited rovibronic energy levels. Emission from these excited levels forms a continuous spectrum. Just then, the efficiency of fluorescence emission from laser excited level decreases and the fluorescence intensity on the long wavelength side increases. The intensity of PA signals increases also. These phenomena indicate that besides the relaxation process of radiation, there is a strong relaxation process of continual collision under the condition of higher sample pressure. It converts vibration energy of the excited molecules into translation one. This induces the increase in gas temperature and a sound wave is produced.

6.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(2): 297-300, 2010 Feb.
Article in Zh | MEDLINE | ID: mdl-20384110

ABSTRACT

The technique of photoacoustic (PA) spectrum is based on the conversion of photon to acoustic energy by collision quenching of the excited molecules. It holds the characteristic of higher detection sensitivity, wide detection spectral region, no damage to the sample etc. It is used in many scientific observation areas such as gas composition analysis, research on chemistry and biology, environmental monitor and so on In the present paper, the analytic formula of the PA signal produced from the in teraction of intense laser with gas system was deduced by solving the dynamic rate equation about the interaction of photon and material. The results show that the magnitude of the PA signal depends on the factors of molecular absorption cross-section, laser intensity, photon number absorbed by the molecule and collision relaxation rate. With the aid of the relation of the PA signal versus laser intensity, the PA spectrum of NO molecule in the wavelength region of 420.0-470.0 nm is ascribed to the transition of X 2 pi (v" = 0) --> A 2 sigma (v' = 0, 1) and X 2 pi (v" = 0) --> E 2 sigma (v' = 2, 3, 4), F 2 sigma (v' = 1, 2, 3) and R 2 sigma (v' = 0, 1). These transitions are realized via two or three-photon process. The vibration constants of NO A 2 sigma, E 2 sigma, F 2 sigma and R 2 sigma electronic states were calculated from the wavelength of the spectral peaks. They are 2 346, 2 342, 2 397 and 2 381 cm(-1) respectively. The results are consistent with the one of other method. The phenomenon of saturation appears when the buffer gas pressure is high enough. This is owing to the finite excited molecules.

7.
Guang Pu Xue Yu Guang Pu Fen Xi ; 28(12): 2900-3, 2008 Dec.
Article in Zh | MEDLINE | ID: mdl-19248509

ABSTRACT

Investigation of the optical absorption and fluorescence of NO2 molecule has long been of interest because it is not only one of the key substances of air pollution, but also a stable molecule of nonzero spin and has many special properties such as that the vibronic levels of the first excited state are coupled strongly to the high vibration levels of the ground state, so that once NO2 molecules are excited, they must undergo complicated quenching process. The quenching mechanism influences the lifetime of the excited molecule severely. In the present paper, the fluorescence lifetime of NO2 excited electronic states are observed experimentally by the technique of LIF time decay spectroscopy and with an optical parameter generator and amplifier pumped by a Nd:YAG laser as excitation source. The results show that the fluorescence lifetime of excited NO2 molecules depends on the excitation wavelength and sample pressure. The time decay curves present a property of bi-exponential when the excitation wavelength is selected as 429.0, 452.0, 509.0 and 532.0 nm, respectively. This indicates that the fluorescence is composed of two components. One has a long lifetime, while the other has a short one. The short-lived component comes from the radiation of the molecules excited by A2B2, B2B1<--X2 A1 transition And the long one is owing to the radiation of the molecules excited to the high rovibronic levels of the ground electronic state. These levels are correlated with A2B2 state. The de-excitation mechanism of the excited molecules is investigated by measuring the variation in fluorescence lifetime versus the sample pressure. The conclusion is that the excited molecules corresponding to the short lifetime quench mainly through the process of radiation and fast inner conversion. As to the excited molecules with long lifetime, the de-excitation process is not only radiation, but also the non-radiation process of collision.

8.
Spectrochim Acta A Mol Biomol Spectrosc ; 78(5): 1567-71, 2011 May.
Article in English | MEDLINE | ID: mdl-21388865

ABSTRACT

The electronic quenching rate constants of NO A(2)Σ (υ'=0, 1), E(2)Σ (υ'=2, 3, 4) and F(2)Δ (υ'=1, 2, 3) states by gas air are reported. The experiments were carried out by measuring the total fluorescence intensity of A(2)Σ (υ'=0, 1)→X(2)Π (υ″) transition at various air pressures. It gives the Stern-Volmer plots. The quenching rate constants of A(2)Σ (υ'=0, 1) states are obtained from the slope of Stern-Volmer plots and the known radiative lifetime. Based on the primary results of the work, we have measured the quenching rate constants of high excited E(2)Σ (υ'=2, 3, 4), F(2)Δ (υ'=1, 2, 3) states for the first time with the technique of photo-acoustic (PA) spectroscopy. It is shown that the electronic quenching rate constants of NO E (υ') and F (υ') states are in the order of 10(-10)cm(3)/molecules. They are much larger than those of A(2)Σ (υ') state, whose rate constants are in the order of 10(-13)cm(3)/molecules. For E (υ') and F (υ') states, it is also found that the quenching rate constants increase with the vibrational energy levels. Similar result has been reported also for A(2)Σ (υ'≥2) states in existing literatures. The agreement indicates the potential use of PA spectroscopy for measuring the electronic quenching rate.


Subject(s)
Acoustics , Electrons , Light , Molecular Conformation , Nitric Oxide/chemistry , Fluorescence , Kinetics , Lasers , Pressure
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 77(1): 141-5, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20537581

ABSTRACT

Laser induced fluorescence (LIF) emission spectrum of SO(2) in the range of 270.0-470.0 nm has been obtained with the quadruple harmonic output (266 nm) of a pulsed Nd:YAG laser as excitation source. The spectrum is composed of a continuous envelope in the short wavelength side, while it shows the character of banded structure superimposed on a continuous one in the long wavelength region. Fluorescence emission from the hybrid states of A(1)A(2)+B(1)B(1) and X(1)A(1)+B(1)B(1) forms the continuous envelope and phosphorescence emission from the triplet state a(3)B(1) forms the banded progression. It is also found that direct emission from laser excited states is very weak. The primary portion of the emission is from the energy levels populated by collision relaxation or collision induced intersystem crossing process. The harmonic frequencies and inharmonic coefficients of the symmetric stretching vibration and the bending vibration of X(1)A(1) state are derived from the ascription of the phosphorescence progression.


Subject(s)
Lasers , Sulfur Dioxide/chemistry , Kinetics , Luminescent Measurements , Spectrometry, Fluorescence , Time Factors
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