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1.
Sensors (Basel) ; 19(9)2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067712

RESUMO

Spaceborne multistatic synthetic aperture radar (SAR) tomography (SMS-TomoSAR) systems take full advantage of the flexible configuration of multistatic SAR in the space, time, phase, and frequency dimensions, and simultaneously achieve high-precision height resolution and low-deformation measurement of three-dimensional ground scenes. SMS-TomoSAR currently poses a series of key issues to solve, such as baseline optimization, spatial transmission error estimation and compensation, and the choice of imaging algorithm, which directly affects the performance of height-dimensional imaging and surface deformation measurement. This paper explores the impact of baseline distribution on height-dimensional imaging performance for the baseline optimization issue, and proposes a feasible baseline optimization method. Firstly, the multi-base multi-pass baselines of an SMS-TomoSAR system are considered equivalent to a group of multi-pass baselines from monostatic SAR. Secondly, we establish the equivalent baselines as a symmetric-geometric model to characterize the non-uniform characteristic of baseline distribution. Through experimental simulation and model analysis, an approximately uniform baseline distribution is shown to have better SMS-TomoSAR imaging performance in the height direction. Further, a baseline design method under uniform-perturbation sampling with Gaussian distribution error is proposed. Finally, the imaging performance of different levels of perturbation is compared, and the maximum baseline perturbation allowed by the system is given.

2.
Sensors (Basel) ; 18(5)2018 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-29772743

RESUMO

Severe sidelobe interference is one of the major problems with traditional Synthetic Aperture Radar (SAR) imaging. In the observation scene of sea areas, the number of targets in the observation scene is so small that targets can be regarded as sparse. Taking this into account, a method of sidelobe suppression, on the basis of sparsity constraint regularization, is proposed to reduce sidelobes of Gaofen-3 (GF-3) images in sea areas of the image domain. This proposed method has a prominent sidelobe suppression effect with resolution maintenance and without destruction of amplitude and phase information. This method can also be applied to SAR images of other satellites. In addition to the employment of peak sidelobe ratio (PSLR) and integrated sidelobe ratio (ISLR) in evaluating sidelobe suppression level, AE (amplitude error) and PE (phase error) are firstly defined for the evaluation of amplitude and phase-preserving quality, respectively. Through the proposed method, AE and PE values are nearly unchanged and the PSLR and ISLR are significantly reduced. The method, as an important part of the quality-improvement project of GF-3, has been successfully applied to the sidelobe suppression of GF-3 data.

3.
J Biomech Eng ; 136(11)2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25084767

RESUMO

Increasing interests have been raised toward the potential applications of biodegradable poly(lactic-co-glycolic acid) (PLGA) coatings for drug-eluting stents in order to improve the drug delivery and reduce adverse outcomes in stented arteries in patients. This article presents a mathematical model to describe the integrated processes of drug release in a stent with PLGA coating and subsequent drug delivery, distribution, and drug pharmacokinetics in the arterial wall. The integrated model takes into account the PLGA degradation and erosion, anisotropic drug diffusion in the arterial wall, and reversible drug binding. The model simulations first compare the drug delivery from a biodegradable PLGA coating with that from a biodurable coating, including the drug release profiles in the coating, average arterial drug levels, and arterial drug distribution. Using the model for the PLGA stent coating, the simulations further investigate drug internalization, interstitial fluid flow in the arterial wall, and stent embedment for their impact on drug delivery. Simulation results show that these three factors, while imposing little change in the drug release profiles, can greatly change the average drug concentrations in the arterial wall. In particular, each of the factors leads to significant and yet distinguished alterations in the arterial drug distribution that can potentially influence the treatment outcomes. The detailed integrated model provides insights into the design and evaluation of biodegradable PLGA-coated drug-eluting stents for improved intravascular drug delivery.


Assuntos
Artérias , Materiais Biocompatíveis/química , Simulação por Computador , Portadores de Fármacos/química , Stents Farmacológicos , Ácido Láctico/química , Ácido Poliglicólico/química , Anisotropia , Materiais Biocompatíveis/metabolismo , Transporte Biológico , Difusão , Desenho de Fármacos , Liberação Controlada de Fármacos , Ácido Láctico/metabolismo , Ácido Poliglicólico/metabolismo , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
4.
BMC Complement Altern Med ; 14: 323, 2014 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-25175096

RESUMO

BACKGROUND: Electroacupuncture (EA) is a traditional Chinese medicine treatment guided by meridian theory. As it gradually gains more worldwide acceptance, a clarification of its mechanisms is extremely urgent. We observed variations in transcutaneous oxygen pressure/carbon dioxide pressure (tcpO2/tcpCO2) and microcirculation blood perfusion units (BPU) along the pericardium meridian, and cardiac function during EA at Neiguan (PC6) to explore variations in energy metabolism and its relationship with visceral function adjustments during EA. METHODS: Twenty-two healthy volunteers participated in this study. Three channel laser Doppler flowmetry and tcpO2/tcpCO2 detection systems were used to detect tcpO2/tcpCO2 and microcirculation BPU along the pericardium meridian. A hemodynamic monitor was used to detect cardiac function. RESULTS: In the normal state, the microcirculatory BPU along the pericardium meridian were significantly higher than that of their bilateral corresponding control points (p < 0.05). During EA at PC6, the values of the microcirculatory BPU along the pericardium meridian did not vary, and few increased. In the normal state, the values of tcpO2 along the pericardium meridian were significantly higher than those of their bilateral corresponding control points (p < 0.05). In addition, the values of tcpCO2 along the pericardium meridian were lower than those of their bilateral corresponding control points. In comparison with the normal state, EA could decrease tcpO2 along the meridian significantly (p < 0.05) and increase tcpCO2. During EA at PC6 in healthy volunteers treated by artificial acute mild hypoxia, cardiac output and cardiac index (p < 0.05) decreased and systemic vascular resistance increased significantly (p < 0.05). CONCLUSIONS: In the normal state, the values of microcirculatory BPU and tcpO2 along the pericardium meridian were both higher than those of their bilateral corresponding control points. Energy metabolism was vigorous along the meridian. During EA, the decrease in oxygen partial pressure along the pericardium meridian might be a result of strengthened energy metabolism of associated tissue and increased oxygen consumption. The variations in energy metabolism along the pericardium meridian during the course of EA had a close relationship with visceral function adjustments. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTRTRC13003193.


Assuntos
Eletroacupuntura , Metabolismo Energético , Meridianos , Pericárdio/metabolismo , Pontos de Acupuntura , Adulto , Animais , Dióxido de Carbono/metabolismo , Feminino , Coração/fisiologia , Humanos , Masculino , Microcirculação , Oxigênio/metabolismo , Adulto Jovem
5.
China CDC Wkly ; 6(20): 457-462, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38846359

RESUMO

Objective: The goal of this study is to analyze the epidemiological patterns of dengue fever across different districts and counties in Yunnan Province from 2010 to 2021. Methods: In this study, we employed joinpoint regression analysis, spatial autocorrelation analysis, and space-time scan analysis to illustrate the spatio-temporal propagation and demographic influence of dengue fever, using both graphical and tabular presentations to clearly demonstrate the findings. Results: Yunnan Province reported 14,098 cases of dengue fever during the period from 2010 to 2021. Of these, 11,513 cases were caused by local transmission, 2,566 were imported internationally, and 19 were inter-provincial imports. Seasonal trends emerged, revealing a surge in incidences during the summer and autumn months. The sex ratio of male to female cases was 1:0.88, with a significant majority of 82.00% of cases involving individuals belonging to the age group of 15-60. Commercial service workers constituted the most impacted occupational group, forming 20.96% of total cases. A spatio-temporal scan identified significant clustering of dengue fever cases across space and time, with the most pronounced cluster observed in southern Yunnan, primarily between 2015 and 2019. Conclusions: Dengue fever in Yunnan Province manifests as biennial outbreaks, underscoring the necessity for increased surveillance, particularly in counties bordering other regions.

6.
Zhen Ci Yan Jiu ; 49(2): 155-163, 2024 Feb 25.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-38413036

RESUMO

OBJECTIVES: To investigate the mechanism of electroacupuncture (EA) at "Neiguan" (PC6) in impro-ving myocardial electrical remodeling in rats with acute myocardial infarction (AMI) by enhancing transient outward potassium current. METHODS: A total of 30 male SD rats were randomly divided into control, model and EA groups, with 10 rats in each group. The AMI model was established by subcutaneous injection with isoprenaline (ISO, 85 mg/kg). EA was applied to left PC6 for 20 min, once daily for 5 days. Electrocardiogram (ECG) was recorded after treatment. TTC staining was used to observe myocardial necrosis. HE staining was used to observe the pathological morphology of myocardial tissue and measure the cross-sectional area of myocardium. Potassium ion-related genes in myocardial tissue were detected by RNA sequencing. The mRNA and protein expressions of Kchip2 and Kv4.2 in myocardial tissue were detected by real-time fluorescence quantitative PCR and Western blot, respectively. RESULTS: Compared with the control group, cardiomyocyte cross-sectional area in the model group was significantly increased (P<0.01), the ST segment was significantly elevated (P<0.01), and QT, QTc, QTd and QTcd were all significantly increased (P<0.05, P<0.01). After EA treatment, cardiomyocyte cross-sectional area was significantly decreased (P<0.01), the ST segment was significantly reduced (P<0.01), and the QT, QTc, QTcd and QTd were significantly decreased (P<0.01, P<0.05). RNA sequencing results showed that a total of 20 potassium ion-related genes co-expressed by the 3 groups were identified. Among them, Kchip2 expression was up-regulated most notablely in the EA group. Compared with the control group, the mRNA and protein expressions of Kchip2 and Kv4.2 in the myocardial tissue of the model group were significantly decreased (P<0.01, P<0.05), while those were increased in the EA group (P<0.01, P<0.05). CONCLUSIONS: EA may improve myocardial electrical remodeling in rats with myocardial infarction, which may be related to its functions in up-regulating the expressions of Kchip2 and Kv4.2.


Assuntos
Remodelamento Atrial , Eletroacupuntura , Infarto do Miocárdio , Isquemia Miocárdica , Ratos , Masculino , Animais , Isquemia Miocárdica/terapia , Ratos Sprague-Dawley , Pontos de Acupuntura , Miocárdio/metabolismo , Infarto do Miocárdio/genética , Infarto do Miocárdio/terapia , Potássio/metabolismo , RNA Mensageiro/metabolismo
7.
EClinicalMedicine ; 67: 102391, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38274117

RESUMO

Background: Clinical appearance and high-frequency ultrasound (HFUS) are indispensable for diagnosing skin diseases by providing internal and external information. However, their complex combination brings challenges for primary care physicians and dermatologists. Thus, we developed a deep multimodal fusion network (DMFN) model combining analysis of clinical close-up and HFUS images for binary and multiclass classification in skin diseases. Methods: Between Jan 10, 2017, and Dec 31, 2020, the DMFN model was trained and validated using 1269 close-ups and 11,852 HFUS images from 1351 skin lesions. The monomodal convolutional neural network (CNN) model was trained and validated with the same close-up images for comparison. Subsequently, we did a prospective and multicenter study in China. Both CNN models were tested prospectively on 422 cases from 4 hospitals and compared with the results from human raters (general practitioners, general dermatologists, and dermatologists specialized in HFUS). The performance of binary classification (benign vs. malignant) and multiclass classification (the specific diagnoses of 17 types of skin diseases) measured by the area under the receiver operating characteristic curve (AUC) were evaluated. This study is registered with www.chictr.org.cn (ChiCTR2300074765). Findings: The performance of the DMFN model (AUC, 0.876) was superior to that of the monomodal CNN model (AUC, 0.697) in the binary classification (P = 0.0063), which was also better than that of the general practitioner (AUC, 0.651, P = 0.0025) and general dermatologists (AUC, 0.838; P = 0.0038). By integrating close-up and HFUS images, the DMFN model attained an almost identical performance in comparison to dermatologists (AUC, 0.876 vs. AUC, 0.891; P = 0.0080). For the multiclass classification, the DMFN model (AUC, 0.707) exhibited superior prediction performance compared with general dermatologists (AUC, 0.514; P = 0.0043) and dermatologists specialized in HFUS (AUC, 0.640; P = 0.0083), respectively. Compared to dermatologists specialized in HFUS, the DMFN model showed better or comparable performance in diagnosing 9 of the 17 skin diseases. Interpretation: The DMFN model combining analysis of clinical close-up and HFUS images exhibited satisfactory performance in the binary and multiclass classification compared with the dermatologists. It may be a valuable tool for general dermatologists and primary care providers. Funding: This work was supported in part by the National Natural Science Foundation of China and the Clinical research project of Shanghai Skin Disease Hospital.

8.
J Tradit Complement Med ; 13(3): 236-244, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37128199

RESUMO

Background and aim: Propagated sensation along meridians (PSM) is an important basis for the formation of the meridian theory, but its mechanism is still unclear. The study explored the mechanism of PSM from the perspective of gene expression. Procedures: PSM induced by moxibustion was determined and classified according to the Modern Study of Meridians of Chinese Medicine. Seven subjects with obvious PSM (obvious PSM group) and five subjects with unobvious PSM (unobvious PSM group) were selected from 33 healthy volunteers according to the scores in their infrared radiant track along meridians (IRRTM) and the degree of subjective transduction. Agilent Human 4 × 44 K Gene Expression Microarrays V2 were used to detect the whole genome expression profile of subjects in the two groups. KEGG and GO were applied to analyze differentially expressed genes. Results: Compared with the unobvious PSM group, 120 genes were differentially expressed in the obvious PSM group, including 76 up-regulated and 44 down-regulated genes. The differentially expressed genes were enriched in dopaminergic synapse, 5-hydroxychrominable synapse, glutamatergic synapse, calcium release channel, gap junction, and adherens junction pathways. Conclusions: The study provides a comprehensive set of gene expression data of subjects with obvious PSM, which indicates that the molecular basis of PSM may be closely related to neurotransmitters, calcium ions and cell junction pathways. This study combines the holistic concept of traditional Chinese medicine with modern molecular biology technology to explore the molecular mechanism of PSM from the perspective of genomics, which may shed new insights into the molecular mechanism of PSM.

9.
J Vis Exp ; (194)2023 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-37154577

RESUMO

In recent years, the incidence of thyroid cancer has been increasing. Thyroid nodule detection is critical for both the detection and treatment of thyroid cancer. Convolutional neural networks (CNNs) have achieved good results in thyroid ultrasound image analysis tasks. However, due to the limited valid receptive field of convolutional layers, CNNs fail to capture long-range contextual dependencies, which are important for identifying thyroid nodules in ultrasound images. Transformer networks are effective in capturing long-range contextual information. Inspired by this, we propose a novel thyroid nodule detection method that combines the Swin Transformer backbone and Faster R-CNN. Specifically, an ultrasound image is first projected into a 1D sequence of embeddings, which are then fed into a hierarchical Swin Transformer. The Swin Transformer backbone extracts features at five different scales by utilizing shifted windows for the computation of self-attention. Subsequently, a feature pyramid network (FPN) is used to fuse the features from different scales. Finally, a detection head is used to predict bounding boxes and the corresponding confidence scores. Data collected from 2,680 patients were used to conduct the experiments, and the results showed that this method achieved the best mAP score of 44.8%, outperforming CNN-based baselines. In addition, we gained better sensitivity (90.5%) than the competitors. This indicates that context modeling in this model is effective for thyroid nodule detection.


Assuntos
Neoplasias da Glândula Tireoide , Nódulo da Glândula Tireoide , Humanos , Nódulo da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Ultrassonografia , Fontes de Energia Elétrica , Processamento de Imagem Assistida por Computador
10.
Appl Radiat Isot ; 191: 110528, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36379133

RESUMO

Research on unmanned online monitoring equipment for marine radioactivity surrounding nuclear power plants is of great significance. In this work, a small radioactivity monitoring system based on buoy was designed and manufactured for the emergency situation of nuclear accidents. The core of the radioactivity monitoring system is the underwater gamma spectrometer. The spectrometer can respond to gamma rays from 60 keV to 3 MeV, and can identify the nuclides whose characteristic rays belong to this energy range. The detection efficiency curve was calculated through Monte Carlo simulation and verified in a standard liquid source. A data acquisition processor was also designed to coordinate the detectors in the system and wirelessly transmit online monitoring data. Three experiments were carried out in the seawater around the Tianwan Nuclear Power Plant in Lianyungang, China using this online marine radioactivity monitoring system based on buoys. The stability and radioactivity monitoring capabilities of the system have been verified.


Assuntos
Monitoramento de Radiação , Radioatividade , Espectrometria gama/métodos , Raios gama , Monitoramento de Radiação/métodos , Método de Monte Carlo
11.
J Integr Med ; 21(1): 89-98, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36424268

RESUMO

OBJECTIVE: The study explores the effects of electroacupuncture (EA) at the governing vessel (GV) on proteomic changes in the hippocampus of rats with cognitive impairment. METHODS: Healthy male rats were randomly divided into 3 groups: sham, model and EA. Cognitive impairment was induced by left middle cerebral artery occlusion in the model and EA groups. Rats in the EA group were treated with EA at Shenting (GV24) and Baihui (GV20) for 7 d. Neurological deficit was scored using the Longa scale, the learning and memory ability was detected using the Morris water maze (MWM) test, and the proteomic profiling in the hippocampus was analyzed using protein-labeling technology based on the isobaric tag for relative and absolute quantitation (iTRAQ). The Western blot (WB) analysis was used to detect the proteins and validate the results of iTRAQ. RESULTS: Compared with the model group, the neurological deficit score was significantly reduced, and the escape latency in the MWM test was significantly shortened, while the number of platform crossings increased in the EA group. A total of 2872 proteins were identified by iTRAQ. Differentially expressed proteins (DEPs) were identified between different groups: 92 proteins were upregulated and 103 were downregulated in the model group compared with the sham group, while 142 proteins were upregulated and 126 were downregulated in the EA group compared with the model group. Most of the DEPs were involved in oxidative phosphorylation, glycolipid metabolism and synaptic transmission. Furthermore, we also verified 4 DEPs using WB technology. Although the WB results were not exactly the same as the iTRAQ results, the expression trends of the DEPs were consistent. The upregulation of heat-shock protein ß1 (Hspb1) was the highest in the EA group compared to the model group. CONCLUSION: EA can effect proteomic changes in the hippocampus of rats with cognitive impairment. Hspb1 may be involved in the molecular mechanism by which acupuncture improves cognitive impairment.


Assuntos
Disfunção Cognitiva , Eletroacupuntura , Ratos , Masculino , Animais , Ratos Sprague-Dawley , Proteômica , Disfunção Cognitiva/terapia , Hipocampo
12.
EClinicalMedicine ; 60: 102027, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37333662

RESUMO

Background: Identifying patients with clinically significant prostate cancer (csPCa) before biopsy helps reduce unnecessary biopsies and improve patient prognosis. The diagnostic performance of traditional transrectal ultrasound (TRUS) for csPCa is relatively limited. This study was aimed to develop a high-performance convolutional neural network (CNN) model (P-Net) based on a TRUS video of the entire prostate and investigate its efficacy in identifying csPCa. Methods: Between January 2021 and December 2022, this study prospectively evaluated 832 patients from four centres who underwent prostate biopsy and/or radical prostatectomy. All patients had a standardised TRUS video of the whole prostate. A two-dimensional CNN (2D P-Net) and three-dimensional CNN (3D P-Net) were constructed using the training cohort (559 patients) and tested on the internal validation cohort (140 patients) as well as on the external validation cohort (133 patients). The performance of 2D P-Net and 3D P-Net in predicting csPCa was assessed in terms of the area under the receiver operating characteristic curve (AUC), biopsy rate, and unnecessary biopsy rate, and compared with the TRUS 5-point Likert score system as well as multiparametric magnetic resonance imaging (mp-MRI) prostate imaging reporting and data system (PI-RADS) v2.1. Decision curve analyses (DCAs) were used to determine the net benefits associated with their use. The study is registered at https://www.chictr.org.cn with the unique identifier ChiCTR2200064545. Findings: The diagnostic performance of 3D P-Net (AUC: 0.85-0.89) was superior to TRUS 5-point Likert score system (AUC: 0.71-0.78, P = 0.003-0.040), and similar to mp-MRI PI-RADS v2.1 score system interpreted by experienced radiologists (AUC: 0.83-0.86, P = 0.460-0.732) and 2D P-Net (AUC: 0.79-0.86, P = 0.066-0.678) in the internal and external validation cohorts. The biopsy rate decreased from 40.3% (TRUS 5-point Likert score system) and 47.6% (mp-MRI PI-RADS v2.1 score system) to 35.5% (2D P-Net) and 34.0% (3D P-Net). The unnecessary biopsy rate decreased from 38.1% (TRUS 5-point Likert score system) and 35.2% (mp-MRI PI-RADS v2.1 score system) to 32.0% (2D P-Net) and 25.8% (3D P-Net). 3D P-Net yielded the highest net benefit according to the DCAs. Interpretation: 3D P-Net based on a prostate grayscale TRUS video achieved satisfactory performance in identifying csPCa and potentially reducing unnecessary biopsies. More studies to determine how AI models better integrate into routine practice and randomized controlled trials to show the values of these models in real clinical applications are warranted. Funding: The National Natural Science Foundation of China (Grants 82202174 and 82202153), the Science and Technology Commission of Shanghai Municipality (Grants 18441905500 and 19DZ2251100), Shanghai Municipal Health Commission (Grants 2019LJ21 and SHSLCZDZK03502), Shanghai Science and Technology Innovation Action Plan (21Y11911200), and Fundamental Research Funds for the Central Universities (ZD-11-202151), Scientific Research and Development Fund of Zhongshan Hospital of Fudan University (Grant 2022ZSQD07).

13.
ACS Appl Mater Interfaces ; 14(46): 52253-52261, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36346779

RESUMO

To date, measuring the carrier mobility in semiconductor films, especially for the amorphous organic small-molecule films, is still a big challenge. Here, we demonstrate that transient electroluminescence (TrEL) spectroscopy with quantum-dot light-emitting diodes as the platform is a feasible and reliable method to evaluate the carrier mobility of such amorphous films. The position of the exciton formation zone is precisely determined and controlled by employing a quantum dot monolayer as the emissive layer. The electrical field intensity across the organic layer is evaluated through the charge density at the electrode calculated by the transient current. Then, the charge carrier mobility is obtained by combining the electroluminescence (EL) delay time and the thickness of the organic layer. Additionally, we demonstrate that the large roughness of the organic layer leads to serious charge accumulation and, hence, a high localized electrical field, which provides preferred charge injection paths, reducing the EL delay time and underestimating the EL delay time. Therefore, a thick organic film is the prerequisite for a reliable measurement of charge carrier mobility, which can circumvent the negative effect of film roughness.

14.
PeerJ ; 9: e12029, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34707922

RESUMO

In the past two decades, Amazon rainforest countries (Brazil, Bolivia, Colombia, Ecuador, Guyana, Peru and Venezuela) have experienced a substantial increase in fire frequency due to the changes in the patterns of different anthropogenic and climatic drivers. This study examines how both fire dynamics and bioclimatic factors varied based on the season (wet season and dry season) El Niño years across the different countries and ecosystems within the Amazon rainforest. Data from publicly available databases on forest fires (Global Fire Atlas) and bioclimatic, topographic and anthropogenic variables were employed in the analysis. Linear mixed-effect models discovered that year type (El Niño vs. non-El Niño), seasonality (dry vs. wet), land cover and forest strata (in terms of canopy cover and intactness) and their interactions varied across the Amazonian countries (and the different ecosystems) under consideration. A machine learning model, Multivariate Adaptive Regression Spline (MARS), was utilized to determine the relative importance of climatic, topographic, forest structure and human modification variables on fire dynamics across wet and dry seasons, both in El Niño and non-El Niño years. The findings of this study make clear that declining precipitation and increased temperatures have strong impact on fire dynamics (size, duration, expansion and speed) for El Niño years. El Niño years also saw greater fire sizes and speeds as compared to non-El Niño years. Dense and relatively undisturbed forests were found to have the lowest fire activity and increased human impact on a landscape was associated with exacerbated fire dynamics, especially in the El Niño years. Additionally, the presence of grass-dominated ecosystems such as grasslands also acted as a driver of fire in both El Niño and non-El Niño years. Hence, from a conservation perspective, increased interventions during the El Niño periods should be considered.

15.
Appl Radiat Isot ; 176: 109848, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34237552

RESUMO

The radiation-monitoring systems of miniaturized unmanned aerial vehicles (UAVs) have wide-ranging applications. However, the load capacity and flight time of radiation-monitoring systems of UAVs are limited. Thus, a lightweight and low-power radiation monitoring load is significant to develop. Herein, a lightweight CeBr3 gamma-ray spectrometer based on Silicon photomultiplier (SiPM) was developed for small-UAV radiation-monitoring systems. Experiments were conducted to test the performance of the spectrometer. Excellent linearity and high energy resolution were achieved. Compared with the traditional CeBr3 scintillator gamma-ray spectrometer, the volume, mass, and power consumption of the spectrometer decreased by 73%, 55%, and 38%, respectively. Carrying the spectrometer developed in this paper can increase the compactness and flight time of small-UAV radiation-monitoring systems.

16.
Biotechnol Prog ; 36(5): e2993, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32185869

RESUMO

Ultrafiltration and diafiltration (UF/DF) unit operations are widely used for the manufacture of therapeutic antibodies to control drug substance protein concentration, pH, and excipient properties. During UF/DF, molecular interactions and volume exclusion effects often lead to substantial differences in pH and excipient concentrations between the diafiltration buffer and final UF/DF pool. These differences complicate the design process beyond simply specifying a buffer with the desired drug substance pH and excipient conditions. This article describes a UF/DF process model which dynamically and accurately simulates UF/DF retentate pool pH and excipient conditions throughout the UF/DF process. This multiscale model accounts for microscopic descriptions of ion-protein charge interactions using the Poisson-Boltzmann equation as well as macroscopic descriptions of volume exclusion and mass transfer. Model predictions of the final UF/DF pool properties were experimentally verified through comparisons to design of experiment (DoE) data from four monoclonal antibody (mAb) processes, each with differing formulations and UF/DF operating conditions. Additionally, model simulations of the retentate pool properties throughout the UF/DF process were verified for two mAb processes through comparisons to experimental data collected at intermediate process points. Model results were qualified, using statistical equivalence tests, against the outputs from large-scale GMP runs which confirmed that the model accurately captures large-scale process performance. Finally, the model was applied toward the simulation of process scenarios beyond those examined experimentally. These in-silico experiments demonstrate the model's capability as a tool for augmented process design and it is potential to reduce the extent of UF/DF laboratory experiments.


Assuntos
Anticorpos Monoclonais , Excipientes , Anticorpos Monoclonais/análise , Anticorpos Monoclonais/química , Simulação por Computador , Composição de Medicamentos , Excipientes/análise , Excipientes/química , Concentração de Íons de Hidrogênio , Ultrafiltração
17.
PLoS One ; 15(9): e0239823, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32986773

RESUMO

Houttuynia cordata (Saururaceae), an ancient and relic species, has been used as an important medicinal and edible plant in most parts of Asia. However, because of the lack of genome information and reliable molecular markers, studies on its population structure, or phylogenetic relationships with other related species are still rare. Here, we de novo assembled the complete chloroplast (cp) genome of H. cordata using the integration of the long PacBio and short Illumina reads. The cp genome of H. cordata showed a typical quadripartite cycle of 160,226 bp. This included a pair of inverted repeats (IRa and IRb) of 26,853 bp, separated by a large single-copy (LSC) region of 88,180 bp and a small single-copy (SSC) region of 18,340 bp. A total of 112 unique genes, including 79 protein-coding genes, 29 tRNA genes, and four rRNA genes, were identified in this cp genome. Eighty-one genes were located on the LSC region, 13 genes were located on the SSC region, and 17 two-copy genes were located on the IR region. Additionally, 48 repeat sequences and 86 SSR loci, which can be used as genomic markers for population structure analysis, were also detected. Phylogenetic analysis using 21 cp genomes of the Piperales family demonstrated that H. cordata had a close relationship with the species within the Aristolochia genus. Moreover, the results of mVISTA analysis and comparisons of IR regions demonstrated that the cp genome of H. cordata was conserved with that of the Aristolochia species. Our results provide valuable information for analyzing the genetic diversity and population structure of H. cordata, which can contribute to further its genetic improvement and breeding.


Assuntos
Cloroplastos/genética , Genoma de Cloroplastos , Houttuynia/genética , Plantas Comestíveis/genética , Aristolochia/genética , Evolução Molecular , Genes de Plantas , Genes de RNAr , Loci Gênicos , Variação Genética , Genoma de Planta , Sequências Repetidas Invertidas , Filogenia , Plantas Medicinais/genética , RNA de Transferência/genética
18.
J Hazard Mater ; 162(2-3): 1542-50, 2009 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-18650001

RESUMO

The batch removal of hexavalent chromium (Cr(VI)) from aqueous solution by using oxidized multiwalled carbon nanotubes (MWCNTs) was studied under ambient conditions. The effect of pH, initial concentration of Cr(VI), MWCNT content, contact time and ionic strength on the removal of Cr(VI) was also investigated. The removal was favored at low pH with maximum removal at pH <2. The adsorption kinetics was modeled by first-order reversible kinetics, pseudo-first-order kinetics, pseudo-second-order kinetics, and intraparticle diffusion models, respectively. The rate constants for all these kinetic models were calculated, and the results indicate that pseudo-second-order kinetics model was well suitable to model the kinetic adsorption of Cr(VI). The removal of chromium mainly depends on the occurrence of redox reaction of adsorbed Cr(VI) on the surface of oxidized MWCNTs to the formation of Cr(III), and subsequent the sorption of Cr(III) on MWCNTs appears as the leading mechanism for chromium uptake to MWCNTs. The presence of Cr(III) and Cr(VI) on oxidized MWCNTs was confirmed by the X-ray photoelectron spectroscopic analysis. The application of Langmuir and Freundlich isotherms are applied to fit the adsorption data of Cr(VI). Equilibrium data were well described by the typical Langmuir adsorption isotherm. Overall, the study demonstrated that MWCNTs can effectively remove Cr(VI) from aqueous solution under a wide range of experimental conditions, without significant Cr(III) release.


Assuntos
Cromo/química , Nanotubos de Carbono , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Oxirredução , Soluções , Análise Espectral/métodos , Água/química , Raios X
19.
Appl Radiat Isot ; 150: 1-13, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31108333

RESUMO

Locating lost radioactive sources quickly, precisely, and safely is very important in emergency responses of lost radioactive source accidents. This paper describes a source localization approach using an independently developed unmanned aerial vehicle (UAV) radiation monitoring system, which uses a specialized source localization algorithm. Once a radiation anomaly spot is found on the ground, an L×L (m2) square area around the anomaly spot defined as suspicious region is selected to perform an accurate source localization. Then, the UAV radiation monitoring instrument is dispatched to hover at some scheduled detection positions within the suspicious region for radiation measurements. After the last hover finished, the actual source position is calculated by the source localization algorithm program in real time. The source localization algorithm was developed on the basis of the inverse-square law and statistical methods. Five critical factors of the algorithm that may lead to errors in localization such as the meshing number in calculations, the size of the suspicious region, the number of the detection positions, the distribution of the detection positions, and the coverage range of the detection positions were studied by using measurement data from Monte Carlo simulations. Subsequently, the approach was experimentally verified for a 3.7 × 107 Bq 131I source localization. Three experimental scenes were applied such as the source on the grass, next to a tree, and in a puddle. Different distributions of the detection positions and different numbers of the detection positions were studied. The best localization distance error was 30 cm within a 10 × 10 m2 suspicious region, and the calculation time was not more than 0.1 s after a total survey flight of 5 min.

20.
Zhongguo Zhen Jiu ; 39(6): 615-8, 2019 Jun 12.
Artigo em Chinês | MEDLINE | ID: mdl-31190498

RESUMO

OBJECTIVE: To explore the specificity of the relevant points along the governor vessel in chronic gastritis through the synchronous observation of the tenderness reaction and tenderness threshold on the back along the governor vessel in the volunteers with chronic gastritis and make the comparison with healthy volunteers. METHODS: A chronic gastritis group and a healthy volunteer group were prepared, 30 cases in each one. Using synchronous comparison, the tenderness reaction at the point inferior to each of the spinous processes from T1 to L3 along the governor vessel was observed. The mechanical pressure pain threshold was determined. RESULTS: Regarding the tenderness reaction at the point inferior to each spinous process on the back along the governor vessel, the occurrence rate was different significantly between the chronic gastritis group and the healthy volunteer group (P<0.01). The tenderness threshold at the point inferior to each spinous process from T1 to L3 along the governor vessel in the chronic gastritis group was lower than the healthy volunteer group, the tenderness thresholds from T4 to T9 and T12 were different significantly between the two groups (P<0.01, P<0.05). The tenderness reaction at the point inferior to each spinous process on the back along the governor vessel presented the significant negative correlation with the tenderness threshold in the chronic gastritis group (P<0.01), and the correlation was not displayed in the healthy volunteer group (P>0.05). CONCLUSION: The point inferior to the spoinous process of T4 on the governor vessel, Shendao (GV 11, T5) and Lingtai (GV 10, T6) are the points with the high specificity in chronic gastritis, which provides the reference to clinical treatment with acupuncture and moxibustion. The occurrence rate of high tenderness reaction and the low tenderness threshold may be the important manifestation of the point specificity on the back along the governor vessel in chronic gastritis.


Assuntos
Terapia por Acupuntura , Gastrite , Moxibustão , Pontos de Acupuntura , Gastrite/terapia , Humanos , Pressão , Sensibilidade e Especificidade
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