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1.
Cryobiology ; 2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36442660

RESUMO

The wood frog, Rana sylvatica (aka Lithobates sylvaticus) is the main model for studies of natural freeze tolerance among amphibians living in seasonally cold climates. During freezing, ∼65% of total body water can be converted to extracellular ice and this imposes both dehydration and hypoxia/anoxia stresses on cells. The current study analyzed the responses of the alpha subunit of the hypoxia-inducible transcription factor (HIF-1), a crucial oxygen-sensitive regulator of gene expression, to freezing, anoxia or dehydration stresses, examining six tissues of wood frogs (liver, skeletal muscle, brain, heart, kidney, skin). RT-PCR revealed a rapid elevation hif-1α transcript levels within 2 h of freeze initiation in both liver and brain and elevated levels of both mRNA and protein in liver and muscle after 24 h frozen. However, both transcript and protein levels reverted to control values after thawing except for HIF-1 protein in liver that dropped to ∼60% of control. Independent exposures of wood frogs to anoxia or dehydration stresses (two components of freezing) also triggered upregulation of hif-1α transcripts and/or HIF-1α protein in liver and kidney with variable responses in other tissues. The results show active modulation of HIF-1 in response to freezing, anoxia and dehydration stresses and implicate this transcription factor as a contributor to the regulation of metabolic adaptations needed for long term survival of wood frogs in the ischemic frozen state.

2.
Nat Commun ; 13(1): 7278, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36446805

RESUMO

Earthquake triggered landslides often pose a great threat to human life and property. Emerging research has been devoted to documenting coseismic landslides failed during or shortly after earthquakes, however, the long-term seismic effect that causes unstable landslides only to accelerate, moderately or acutely, without immediate failures is largely neglected. Here we show the activation and recovery of these earthquake accelerated landslides (EALs) in Central Italy, based on satellite radar observations. Unlike previous studies based on single or discrete landslides, we established a large inventory of 819 EALs and statistically quantified their spatial clustering features against a set of conditioning factors, thus finding that EALs did not rely on strong seismic shaking or hanging wall effects to occur and larger landslides were more likely to accelerate after earthquakes than smaller ones. We also discovered their accelerating-to-recovering sliding dynamics, and how they differed from the collapsed 759 coseismic landslides. These findings contribute to a more comprehensive understanding of the earthquake-triggering landslide mechanism and are of great significance for long-term landslide risk assessment in seismically active areas.

3.
Amyloid ; : 1-12, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36399070

RESUMO

BACKGROUND: Tafamidis inhibits progression of transthyretin (TTR) amyloid cardiomyopathy (ATTR-CM) by binding TTR tetramer and inhibiting dissociation to monomers capable of denaturation and deposition in cardiac tissue. While the phase 3 ATTR-ACT trial demonstrated the efficacy of tafamidis, the degree to which the approved dose captures the full potential of the mechanism has yet to be assessed. METHODS: We developed a model of dynamic TTR concentrations in plasma to relate TTR occupancy by tafamidis to TTR stabilisation. We then developed population pharmacokinetic-pharmacodynamic models to characterise the relationship between stabilisation and measures of disease progression. RESULTS: Modelling individual patient data of tafamidis exposure and increased plasma TTR confirmed that single-site binding provides complete tetramer stabilisation in vivo. The approved dose was estimated to reduce unbound TTR tetramer by 92%, and was associated with 53%, 56% and 49% decreases in the rate of change in NT-proBNP, KCCQ-OS, and six-minute walk test disease progression measures, respectively. Simulating complete TTR stabilisation predicted slightly greater reductions of 58%, 61% and 54%, respectively. CONCLUSIONS: These findings support the value of TTR stabilisation as a clinically beneficial treatment option in ATTR-CM and the ability of tafamidis to realise nearly the full therapeutic benefit of this mechanism. CLINICALTRIALS.GOV IDENTIFIER: NCT01994889.

4.
Dis Markers ; 2022: 3132824, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35855849

RESUMO

Benign epilepsy in childhood with centrotemporal spikes (VBECT) has been associated with electroencephalography (EEG), but the relationship of VBECT with zinc, magnetic resonance spectroscopy (MRS), and intelligence quotient (IQ) tests is unclear. The aim of this study was to investigate the association of VBECT with zinc, MRS, EEG, and IQ tests. In this retrospective study, we selected 58 children with variable benign epilepsy with centrotemporal spikes as the experimental group. A total of 120 children with typical benign childhood epilepsy with centrotemporal spikes were selected as the control group. The zinc, MRS, EEG, and IQ test results of 178 children were measured and analyzed. The results showed that the zinc, MRS, and IQ test results of the patients in the experimental group decreased significantly. The spinal slow wave results in the experimental group showed a significant upward trend. Linear correlation analysis of zinc with MRS, EEG, and IQ tests showed that 13 pairs of indicators were significantly negatively correlated. Our results suggest the importance of zinc, MRS, EEG, and IQ during VBECT.


Assuntos
Epilepsia Rolândica , Criança , Eletroencefalografia/métodos , Humanos , Espectroscopia de Ressonância Magnética , Estudos Retrospectivos , Zinco
5.
IEEE Trans Cybern ; 52(4): 2505-2517, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32697729

RESUMO

In this article, distributed algorithms are developed to search the generalized Nash equilibrium (NE) with global constraints. Relations between the variational inequality and the NE are investigated via the Karush-Kuhn-Tucker (KKT) optimal conditions, which provide the underlying principle for developing the distributed algorithms. Two time-varying consensus schemes are proposed for each agent to estimate the actions of others, by which a distributed framework is established. The algorithm with fixed-gains is designed with certain system knowledge, while the adaptive algorithm is proposed to address the problem when the system parameters are not available. The asymptotic convergence to the NE is established through the Lyapunov theory and the consensus theory. The power control problem in a femtocell network is formulated as a Nash game and is solved by the proposed algorithms. The simulation results are provided to verify the effectiveness of theoretical development.

6.
IEEE Trans Cybern ; 52(1): 620-629, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32275637

RESUMO

This article considers the bearing-only formation control problem, where the control of each agent only relies on relative bearings of their neighbors. A new control law is proposed to achieve target formations in finite time. Different from the existing results, the control law is based on a time-varying scaling gain. Hence, the convergence time can be arbitrarily chosen by users, and the derivative of the control input is continuous. Furthermore, sufficient conditions are given to guarantee almost global convergence and interagent collision avoidance. Then, a leader-follower control structure is proposed to achieve global convergence. By exploring the properties of the bearing Laplacian matrix, the collision avoidance and smooth control input are preserved. A multirobot hardware platform is designed to validate the theoretical results. Both simulation and experimental results demonstrate the effectiveness of our design.

7.
J Environ Manage ; 302(Pt B): 114082, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34775335

RESUMO

Apple is one of the most important cash crops in China. However, negative economic, environmental and social impacts are associated with its production. This study aims to apply a holistic systems perspective to understand existing problems associated with apple production in China and use this information to improve its sustainability. A structured survey was administered to farmers (n = 245) in Shandong and Shanxi provinces, combined with semi-structured interviews with apple supply chain stakeholders (n = 25). Themes, dimensions and relationships were identified based on an inductive thematic analysis of interview data, and then triangulated against the survey data. Interpretive Structural Modelling and Cross-Impact Matrix Multiplication Applied to Classification methods were applied to investigate interrelationships and effects of the elicited elements within the system. The results indicated that various environmental, economic and social problems are associated with apple production in China, including environmental and health risks associated with synthetic input applications, yield instability, deterioration of apple quality, farmers' uncertainty about accessing routes to market, and the ageing farming workforce. The interaction of socio-economic and supply chain issues has contributed to the system "lock-in" to unsustainable practices within the apple production system. Existing agricultural policies were ineffective as they did not include policy leverage to mitigate the multiple factors driving lock-in to unsustainable practices within the system. The research has provided evidence to enable policymakers to develop effective and targeted strategies to facilitate sustainable production within the apple production system. In particular, the future policy mix should consider the entirety of the food system including perspectives and requirements of different stakeholders. The three-stage approach applied has demonstrated its feasibility of investigating sustainability issues facing a particular industry within a specific cultural and policy context.


Assuntos
Malus , Agricultura , Produtos Agrícolas , Fazendeiros , Fazendas , Humanos
8.
Cancers (Basel) ; 13(6)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805661

RESUMO

The limitations of the biomarker prostate-specific antigen (PSA) necessitate the pursuit of biomarkers capable of better identifying high-risk prostate cancer (PC) patients in order to improve their therapeutic management and outcomes. Aggressive prostate tumors characteristically exhibit high rates of glycolysis and lipogenesis. Glycerol 3-phosphate phosphatase (G3PP), also known as phosphoglycolate phosphatase (PGP), is a recently identified mammalian enzyme, shown to play a role in the regulation of glucose metabolism, lipogenesis, lipolysis, and cellular nutrient-excess detoxification. We hypothesized that G3PP may relieve metabolic stress in cancer cells and assessed the association of its expression with PC patient prognosis. Using immunohistochemical staining, we assessed the epithelial expression of G3PP in two different radical prostatectomy (RP) cohorts with a total of 1797 patients, for whom information on biochemical recurrence (BCR), metastasis, and mortality was available. The association between biomarker expression, biochemical recurrence (BCR), bone metastasis, and prostate cancer-specific survival was established using log-rank and multivariable Cox regression analyses. High expression of G3PP in PC epithelial cells is associated with an increased risk of BCR, bone metastasis, and PC-specific mortality. Multivariate analysis revealed high G3PP expression in tumors as an independent predictor of BCR and bone metastasis development. High G3PP expression in tumors from patients eligible for prostatectomies is a new and independent prognostic biomarker of poor prognosis and aggressive PC for recurrence, bone metastasis, and mortality.

9.
J Rheumatol ; 48(5): 760-766, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33060303

RESUMO

OBJECTIVES: This study aimed to expand knowledge about soluble low-density lipoprotein receptor-related protein 1 (sLRP1) in juvenile idiopathic arthritis (JIA) by determining associations of sLRP1 levels in nonsystemic JIA patients with clinical and inflammatory biomarker indicators of disease activity. METHODS: Plasma sLRP1 and 44 inflammation-related biomarkers were measured at enrollment and 6 months later in a cohort of 96 newly diagnosed Canadian patients with nonsystemic JIA. Relationships between sLRP1 levels and indicators of disease activity and biomarker levels were analyzed at both visits. RESULTS: At enrollment, sLRP1 levels correlated negatively with age and active joint counts. Children showed significantly higher levels of sLRP1 than adolescents (mean ranks: 55.4 and 41.9, respectively; P = 0.02). Participants with 4 or fewer active joints, compared to those with 5 or more active joints, had significantly higher sLRP1 levels (mean ranks: 56.2 and 40.7, respectively; P = 0.006). At enrollment, considering the entire cohort, sLRP1 correlated negatively with the number of active joints (r = -0.235, P = 0.017). In the entire cohort, sLRP1 levels at enrollment and 6 months later correlated with 13 and 6 pro- and antiinflammatory biomarkers, respectively. In JIA categories, sLRP1 correlations with inflammatory markers were significant in rheumatoid factor-negative polyarticular JIA, oligoarticular JIA, enthesitis-related arthritis, and psoriatic arthritis at enrollment. Higher sLRP1 levels at enrollment increased the likelihood of absence of active joints 6 months later. CONCLUSION: Plasma sLRP1 levels correlate with clinical and biomarker indicators of short-term improvement in JIA disease activity, supporting sLRP1 as an upstream biomarker of potential utility for assessing JIA disease activity and outcome prediction.


Assuntos
Artrite Juvenil , Artrite Psoriásica , Adolescente , Artrite Juvenil/diagnóstico , Canadá , Criança , Humanos , Lipoproteínas LDL , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade
10.
IEEE Trans Neural Syst Rehabil Eng ; 28(12): 3113-3120, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33186119

RESUMO

EMG-based continuous wrist joint motion estimation has been identified as a promising technique with huge potential in assistive robots. Conventional data-driven model-free methods tend to establish the relationship between the EMG signal and wrist motion using machine learning or deep learning techniques, but cannot interpret the functional relationship between neuro-commands and relevant joint motion. In this paper, an EMG-driven musculoskeletal model is proposed to estimate continuous wrist joint motion. This model interprets the muscle activation levels from EMG signals. A muscle-tendon model is developed to compute the muscle force during the voluntary flexion/extension movement, and a joint kinematic model is established to estimate the continuous wrist motion. To optimize the subject-specific physiological parameters, a genetic algorithm is designed to minimize the differences of joint motion prediction from the musculoskeletal model and joint motion measurement using motion data during training. Results show that mean root-mean-square-errors are 10.08°, 10.33°, 13.22° and 17.59° for single flexion/extension, continuous cycle and random motion trials, respectively. The mean coefficient of determination is over 0.9 for all the motion trials. The proposed EMG-driven model provides an accurate tracking performance based on user's intention.


Assuntos
Articulação do Punho , Punho , Eletromiografia , Humanos , Movimento (Física) , Movimento , Amplitude de Movimento Articular , Tendões
11.
Proc Math Phys Eng Sci ; 476(2242): 20200248, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33214759

RESUMO

Real-time centimetre-level precise positioning from Global Navigation Satellite Systems (GNSS) is critical for activities including landslide, glacier and coastal erosion monitoring, flood modelling, precision agriculture, intelligent transport systems, autonomous vehicles and the Internet of Things. This may be achieved via the real-time kinematic (RTK) GNSS approach, which uses a single receiver and a network of continuously operating GNSS reference stations (CORS). However, existing CORS networks have often been established simply by attempting regular spacing or in clusters around cities, with little consideration of weather, climate and topography effects, which influence the GNSS tropospheric delay, a substantial GNSS positional error and which prevents homogeneous RTK accuracy attainment. Here, we develop a framework towards optimizing the design of CORS ground infrastructure, such that tropospheric delay errors reduce to 1.5 mm worth of precipitable water vapour (PWV) globally. We obtain average optimal station spacings of 52 km in local summer and 70 km in local winter, inversely related to the atmospheric PWV variation, with denser networks typically required in the tropics and in mountainous areas. We also consider local CORS network infrastructure case studies, showing how after network modification interpolated PWV errors can be reduced from around 2.7 to 1.4 mm.

12.
J Med Chem ; 63(12): 6489-6498, 2020 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-32130005

RESUMO

Drug precipitation in the nephrons of the kidney can cause drug-induced crystal nephropathy (DICN). To aid mitigation of this risk in early drug discovery, we developed a physiologically based in silico model to predict DICN in rats, dogs, and humans. At a minimum, the likelihood of DICN is determined by the level of systemic exposure to the molecule, the molecule's physicochemical properties and the unique physiology of the kidney. Accordingly, the proposed model accounts for these properties in order to predict drug exposure relative to solubility along the nephron. Key physiological parameters of the kidney were codified in a manner consistent with previous reports. Quantitative structure-activity relationship models and in vitro assays were used to estimate drug-specific physicochemical inputs to the model. The proposed model was calibrated against urinary excretion data for 42 drugs, and the utility for DICN prediction is demonstrated through application to 20 additional drugs.


Assuntos
Descoberta de Drogas , Avaliação Pré-Clínica de Medicamentos , Drogas em Investigação/efeitos adversos , Cálculos Renais/induzido quimicamente , Preparações Farmacêuticas/metabolismo , Animais , Simulação por Computador , Cães , Humanos , Cálculos Renais/patologia , Modelos Biológicos , Preparações Farmacêuticas/química , Relação Quantitativa Estrutura-Atividade , Ratos
13.
Sensors (Basel) ; 19(18)2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31533327

RESUMO

This study aims to efficiently estimate the crop water content of winter wheat using high spatial and temporal resolution satellite-based imagery. Synthetic-aperture radar (SAR) data collected by the Sentinel-1 satellite and optical imagery from the Sentinel-2 satellite was used to create inversion models for winter wheat crop water content, respectively. In the Sentinel-1 approach, several enhanced radar indices were constructed by Sentinel-1 backscatter coefficient of imagery, and selected the one that was most sensitive to soil water content as the input parameter of a water cloud model. Finally, a water content inversion model for winter wheat crop was established. In the Sentinel-2 approach, the gray relational analysis was used for several optical vegetation indices constructed by Sentinel-2 spectral feature of imagery, and three vegetation indices were selected for multiple linear regression modeling to retrieve the wheat crop water content. 58 ground samples were utilized in modeling and verification. The water content inversion model based on Sentinel-2 optical images exhibited higher verification accuracy (R = 0.632, RMSE = 0.021 and nRMSE = 19.65%) than the inversion model based on Sentinel-1 SAR (R = 0.433, RMSE = 0.026 and nRMSE = 21.24%). This study provides a reference for estimating the water content of wheat crops using data from the Sentinel series of satellites.

14.
Sensors (Basel) ; 19(16)2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31426396

RESUMO

The water and shadow areas in SAR images contain rich information for various applications, which cannot be extracted automatically and precisely at present. To handle this problem, a new framework called Multi-Resolution Dense Encoder and Decoder (MRDED) network is proposed, which integrates Convolutional Neural Network (CNN), Residual Network (ResNet), Dense Convolutional Network (DenseNet), Global Convolutional Network (GCN), and Convolutional Long Short-Term Memory (ConvLSTM). MRDED contains three parts: the Gray Level Gradient Co-occurrence Matrix (GLGCM), the Encoder network, and the Decoder network. GLGCM is used to extract low-level features, which are further processed by the Encoder. The Encoder network employs ResNet to extract features at different resolutions. There are two components of the Decoder network, namely, the Multi-level Features Extraction and Fusion (MFEF) and Score maps Fusion (SF). We implement two versions of MFEF, named MFEF1 and MFEF2, which generate separate score maps. The difference between them lies in that the Chained Residual Pooling (CRP) module is utilized in MFEF2, while ConvLSTM is adopted in MFEF1 to form the Improved Chained Residual Pooling (ICRP) module as the replacement. The two separate score maps generated by MFEF1 and MFEF2 are fused with different weights to produce the fused score map, which is further handled by the Softmax function to generate the final extraction results for water and shadow areas. To evaluate the proposed framework, MRDED is trained and tested with large SAR images. To further assess the classification performance, a total of eight different classification frameworks are compared with our proposed framework. MRDED outperformed by reaching 80.12% in Pixel Accuracy (PA) and 73.88% in Intersection of Union (IoU) for water, 88% in PA and 77.11% in IoU for shadow, and 95.16% in PA and 90.49% in IoU for background classification, respectively.

15.
Sensors (Basel) ; 19(11)2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151259

RESUMO

Synthetic Aperture Radar (SAR) scene classification is challenging but widely applied, in which deep learning can play a pivotal role because of its hierarchical feature learning ability. In the paper, we propose a new scene classification framework, named Feature Recalibration Network with Multi-scale Spatial Features (FRN-MSF), to achieve high accuracy in SAR-based scene classification. First, a Multi-Scale Omnidirectional Gaussian Derivative Filter (MSOGDF) is constructed. Then, Multi-scale Spatial Features (MSF) of SAR scenes are generated by weighting MSOGDF, a Gray Level Gradient Co-occurrence Matrix (GLGCM) and Gabor transformation. These features were processed by the Feature Recalibration Network (FRN) to learn high-level features. In the network, the Depthwise Separable Convolution (DSC), Squeeze-and-Excitation (SE) Block and Convolution Neural Network (CNN) are integrated. Finally, these learned features will be classified by the Softmax function. Eleven types of SAR scenes obtained from four systems combining different bands and resolutions were trained and tested, and a mean accuracy of 98.18% was obtained. To validate the generality of FRN-MSF, five types of SAR scenes sampled from two additional large-scale Gaofen-3 and TerraSAR-X images were evaluated for classification. The mean accuracy of the five types reached 94.56%; while the mean accuracy for the same five types of the former tested 11 types of scene was 96%. The high accuracy indicates that the FRN-MSF is promising for SAR scene classification without losing generality.

16.
AAPS J ; 21(3): 43, 2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30887138

RESUMO

There is considerable interest in developing methods to predict the asymmetric distribution of unbound drug into tissues. The liver is of particular interest due to the multitude of expressed transporters with potential implications for pharmacokinetics, pharmacodynamics, and toxicology. Empirical correlations of in vitro unbound hepatocyte-to-media partition coefficient (in vitro Kpuu) and in vivo unbound liver-to-plasma partition coefficient (in vivo Kpuu) have been reported without considering the theoretical aspects which might confound the interpretation of such observations. To understand the theoretical basis for the translation of Kpuu between in vitro and in vivo systems, we simulated in vitro hepatocyte and in vivo liver Kpuu values using mechanistic mathematical models of these systems. Theoretical comparisons of steady-state Kpuu between in vitro and in vivo systems were performed using liver models which assumed a number of segments ranging from one (i.e., a permeability-limited well-stirred model) to infinity (i.e., a permeability-limited parallel tube model). Using a five-segment model, the effect of zonal differences in metabolism was also explored in this context. The results across the range of examined models indicated that theoretical differences between in vitro and in vivo Kpuu estimates exist and are expected to increase with an increasing degree of extraction across the liver. However, differences were relatively small using what is perhaps the most physiologically relevant, permeability-limited parallel tube model, suggesting that direct correlations are reasonably valid and that the permeability-limited parallel tube model is perhaps the most appropriate physiologically based pharmacokinetic (PBPK) construct for supporting studies of this nature.


Assuntos
Fígado/metabolismo , Modelos Biológicos , Plasma/metabolismo , Animais , Linhagem Celular , Hepatócitos/metabolismo , Humanos , Permeabilidade , Ratos , Distribuição Tecidual
17.
Semin Nephrol ; 39(2): 176-189, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30827340

RESUMO

Exposure is a critically important aspect to consider in the study and management of drug-induced kidney injury. Although blood concentrations of kidney toxicants often may provide a valid surrogate measure of kidney exposure, the kidney has several unique physiological and biochemical properties that lend themselves to accumulation or exclusion of some drugs at sites of toxicity. In such cases, an understanding of these pharmacokinetic mechanisms can be as important as understanding the underlying mechanisms of toxicity. Physiologically based pharmacokinetic models, which mathematically codify such mechanisms in a biologically plausible form, increasingly are being used for developing an understanding of pharmacokinetics across patient populations, drug-drug interactions, and pharmacokinetic-pharmacodynamic relationships. This perspective provides a review of the physiological and biochemical mechanisms as well as the physiochemical properties that theoretically could drive drug accumulation or exclusion within the kidney, along with examples in which these mechanisms have proven important in driving the manifestation of toxicity in vivo. In addition, an overview of the structure, applications, and limitations of existing kidney physiologically based pharmacokinetic models is provided. Finally, a perspective on gaps and associated challenges to such models in the field of toxicology is discussed briefly.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Rim/metabolismo , Injúria Renal Aguda/metabolismo , Interações Medicamentosas , Humanos , Modelos Biológicos , Farmacocinética , Medição de Risco
18.
Sensors (Basel) ; 19(2)2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30650620

RESUMO

To analyze the influence factors of hyperspectral remote sensing data processing, and quantitatively evaluate the application capability of hyperspectral data, a combined evaluation model based on the physical process of imaging and statistical analysis was proposed. The normalized average distance between different classes of ground cover is selected as the evaluation index. The proposed model considers the influence factors of the full radiation transmission process and processing algorithms. First- and second-order statistical characteristics (mean and covariance) were applied to calculate the changes for the imaging process based on the radiation energy transfer. The statistical analysis was combined with the remote sensing process and the application performance, which consists of the imaging system parameters and imaging conditions, by building the imaging system and processing models. The season (solar zenith angle), sensor parameters (ground sampling distance, modulation transfer function, spectral resolution, spectral response function, and signal to noise ratio), and number of features were considered in order to analyze the influence factors of the application capability level. Simulated and real data collected by Hymap in the Dongtianshan area (Xinjiang Province, China), were used to estimate the proposed model's performance in the application of mineral mapping. The predicted application capability of the proposed model is consistent with the theoretical analysis.

19.
Sci Rep ; 8(1): 17122, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30459420

RESUMO

The Sansha Yongle Blue Hole (SYBH) is the deepest blue hole found anywhere to date. Study of the SYBH can provide insight into the interactions between hole wall morphology and many geological/hydrological mechanisms. A comprehensive investigation of the SYBH was carried out for the first time in 2017 using a professional-grade underwater remotely operated vehicle (ROV) to obtain accurate depth and three-dimensional (3D) topographic data. The SYBH resembles a ballet dancer's shoe and has a volume of ~499609 m3. The observed deepest portion of the SYBH is at 301.19 m below the local 10-year mean sea level. The cave bottom laterally deviates from its entrance by 118 m at an azimuth of 219 degrees. The cave entrance is shaped like a comma and has an average width of 130 m; the widest part is 162.3 m wide, while the narrowest part is 26.2 m wide and is at 279 mbsl (meters below sea level). The 3D topography of the SYBH and underwater photography revealed two large transitions at ~76 to 78 mbsl and at 158 mbsl, indicating that the initiation of the blue hole was likely a step wise process and that the hole wall morphology was subsequently remolded through a paleo-sea level stillstand (at or near Younger Dryas). The topographic data also indicated that the blue hole is situated within an isolated environment with no water or material exchange with the outside open sea.

20.
Exp Ther Med ; 16(1): 127-132, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29896232

RESUMO

The aim of the present study was to establish a recurrent convulsion model during the developmental stage using inhalation of flurothyl, and to observe the relationship between the changes in mitochondrial function in hippocampal neurons and hippocampal neuronal apoptosis after recurrent convulsion. A total of 36 Sprague-Dawley male rats were selected and randomly divided into the control (NS) group and recurrent-seizure (RS) group for 0, 1.5, 3, 12 and 24 h. After the last seizure the rats were subdivided with 6 animals in each group. Rats in the seizure group inhaled flurothyl repeatedly to induce status convulsivus, 30 min once daily, for 7 consecutive days, while the same operation was conducted in the control group without inhalation of flurothyl. At each time-point after the last seizure, blood was taken from the heart, followed by decapitation and immediate removal of the brain. Half of the brain tissue was immediately fixed in 10% paraformaldehyde to prepare paraffin-embedded tissues for hematoxylin and eosin (H&E) histological staining. Hippocampus was taken from the other half of the brain and stored at -80°C. Changes in mitochondrial membrane potential (ΔΨm) in hippocampal neurons were detected by flow cytometer. Dynamic changes of mitochondrial fusion and division-related genes, mitochondrial fusion protein 2 (Mfn2) and dynamin-related protein 1 (Drp1), in the hippocampus after recurrent convulsion were observed using reverse transcription-polymerase chain reaction (RT-PCR)and western blot analysis. The expression of caspase-3 and cytochrome c (Cyt c) was determined by RT-PCR and western blot analysis. After successful establishment of the recurrent convulsion model in rats during developmental stage using flurothyl, H&E staining results exhibited that in the CA1 region of hippocampus in the NS group, karyopyknosis occurred in nucleus that was stained to be brown and yellow, and the expression peak of apoptotic cells mainly existed at 24 h after the last convulsion. RT-PCR and western analysis revealed that apoptosis-related gene caspase-3 expression in the RS group was elevated at 1.5 h after the last convulsion, and lasted 24 h after convulsion. Detection results of mitochondrial ΔΨm revealed a significant reduction 1.5, 3 and 12 h after convulsion in hippocampal neurons of experimental rats, which reached the trough at 12 h, and rapidly increased after 24 h. The expression of Mfn2 mRNA in the RS group was significantly lower than that in the control group, while the expression of Drp1 mRNA in RS group was distinctly higher than that in the control group. RT-PCR and western blot analysis revealed that, mitochondrial apoptosis-related gene Cyt c expression was increased at 3 h after the last convulsion, and lasted 24 h after convulsion. Correlation analysis showed that the changes in mitochondrial function were closely related to neuronal apoptosis. The results of the study show that apoptosis exists in the hippocampus of rats after recurrent convulsion, which is closely related to the changes in mitochondrial function.

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