Edge effect removal in Fourier ptychographic microscopy via perfect Fourier transformation (PFT)

Edge effect may degrade the imaging precision and is caused by the aperiodic image extension of fast Fourier transform (FFT). In this letter, a perfect Fourier transform algorithm termed PFT was reported to remove the artifacts with comparable efficiency to FFT. Although we demonstrated the performance of PFT in Fourier ptychographic microscopy (FPM) only, it can be expanded in any occasion where the conventional FFT is used.Comment: 4 pages, 6 figure

Value of single or combined measurement of serum PCT, peripheral WBC, and WBC/PCT for early diagnosis of bacterial infection in patients with liver cirrhosis

ObjectiveTo investigate the early diagnostic value of single or combined measurement of serum procalcitonin (PCT), peripheral white blood cells (WBC), and ratio of WBC to platelets (PLT) (WBC/PLT) for spontaneous bacterial peritonitis (SBP) in patients with liver cirrhosis. MethodsThe clinical data of 129 patients with liver cirrhosis who were admitted to our hospital from January 2011 to June 2013 were retrospectively analyzed. One hundred and twelve patients who died of liver cirrhosis were divided into infection group, in which the cause of death was complicated infection (n=94, including 61 SBP cases), and non-infection group (n=18). Seventeen patients with compensated cirrhosis were assigned to control group. Before treatment with antibiotics, routine bacterial culture was made, and serum PCT, WBC, and WBC/PLT were measured. Mean comparison was made by t test and chi-square analysis. Ratio comparison was made by Pearson χ2 test. The receiver operating characteristic (ROC) curve was plotted to calculate the sensitivity and specificity. ResultsThere were 66 patients in the infection group whose bacterial culture was positive, and the positive rates for cultures from blood, ascites and other exudates were 25.8%, 30.3%, and 43.9%, respectively. In the infection group, lung infection, SBP, and unknown focus of infection accounted for 8.5%, 64.9%, and 26.6% of total cases, respectively. The level of serum PCT in the infection group was significantly higher than those in the non-infection group and the control group (F=10.98, P<0.05), but showed no significant difference in patients with different sites of infection. When PCT was ≥0.5 ng/ml, the sensitivity and specificity for diagnosis of complicated infection were 92.5% and 77.1%, respectively, and the area under the ROC curve was 0.89. When PCT was ≥2 ng/ml, the sensitivity was 62.7% and the specificity was 94.2%. When the peripheral WBC count was ≥10×109/L and the WBC/PLT was ≥0.25, the sensitivity was 47.8% and 396%, respectively, and the specificity was 100%. When PCT was combined with WBC/PLT for diagnosis of complicated infection, the sensitivity was 76.8% and the specificity was 94.2%. For patients with SBP, the levels of PCT and WBC and WBC/PLT showed no significant differences between positive and negative ascites cultures. When PCT was combined with WBC/PLT for diagnosis of SBP, the sensitivity was 83.6% and the specificity was 94.2%. ConclusionPCT and WBC/PLT can be used as early diagnostic indicators for complicated infection in cirrhotic patients. PCT combined with WBC/PLT has a significant value for early diagnosis of SBP in cirrhotic patients

Non-Destructive Analysis of Degradation Mechanisms in Cycle-Aged Graphite/LiCoO2 Batteries

Non-destructive analysis of degradation mechanisms can be very beneficial for the prognostics and health management (PHM) study of lithium-ion batteries. In this paper, a type of graphite/LiCoO2 battery was cycle aged at high ambient temperature, then 25 parameters of the multi-physics model were identified. Nine key parameters degraded with the cycle life, and they were treated as indicators of battery degradation. Accordingly, the degradation mechanism was discussed by using the multi-physics model and key parameters, and the reasons for capacity fade and the internal resistance increase were analyzed in detail. All evidence indicates that the formation reaction of the solid electrolyte interface (SEI) film is the main cause of battery degradation at high ambient temperature

A 3D WebGIS-Enhanced Representation Method Fusing Surveillance Video Information

In Internet applications, there are more and more demands for geographic information expression technology that integrates video surveillance information, but there are generally problems such as camera position, direction, field of view and other parameters that are difficult to calculate accurately, texture occlusion, etc., which seriously affect the fusion expression of 3D scenes and video information Effect. To address the above problems, in this study, movable objects and trees are removed from the model surface, and an enhanced representation framework is designed for the fusion of video and 3D WebGIS under weak constraints. At the same time, the proposed method is verified and analyzed from three aspects: feature point matching, line coincidence degree and occlusion effect. The experimental results show the following. 1) In terms of the feature point matching ability, the feature point matching ability of the proposed method is 22.22&#x0025; higher than that under strong constraints. 2) In terms of the occlusion effect, the proposed method achieves a 74.12&#x0025; reduction in the area of the occlusion area, which is 1.63&#x0025; higher than the occlusion area reduction rate after video projection under strong constraints. 3) In terms of the straight line coincidence, the experimental results of the proposed method are significantly better than those obtained using the strong constraints method. Both the length difference of the straight line with the same name and the relative offset angle are smaller than the result of the method using the strong constraint conditions. Also, the FPS is stabilized at about 30f/s during system operation with high rendering efficiency, which further proves the feasibility and stability of this system. Experiments show that using the proposed method can reflect real geospatial information, better enhance geographic information expression and be easy to implement, providing a valuable reference for the construction of applications such as real-world 3D models and smart cities

A Study on the Vulnerability of the Gross Primary Production of Rubber Plantations to Regional Short-Term Flash Drought over Hainan Island

Rapidly developing droughts, including flash droughts, have occurred frequently in recent years, causing significant damage to agroforestry ecosystems, and they are expected to increase in the future due to global warming. The artificial forest area in China is the largest in the world, and its carbon budget is crucial to the global carbon sink. As the most prominent plantation plant in the tropics, the rubber (Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg.) ecosystem not only has important economic significance, but also has the potential to be a major natural carbon sink in hot areas. Frequent drought events have a significant impact on rubber ecosystem productivity, yet there have been few reports on the vulnerability of rubber productivity to drought. The objective of this study is to evaluate the vulnerability of rubber ecosystem gross primary production (GPP) to short-term flash drought (STFD) in Hainan Island, utilizing the localized EC-LUE model (eddy covariance–light use efficiency) validated by flux tower observations as the research tool to conduct the scenario simulations which defined by standard relative humidity index (SRHI), in a total of 96 scenarios (timing × intensity). The results show that, in terms of time, the rubber ecosystem in Hainan Island has the highest vulnerability to STFD during the early rainy season and the lowest at the end of the rainy season. From the dry season to the rainy season, the impact of STFD gradually extends to the northeast. Spatially, the vulnerability of the northern island is higher than that of the southern island and that of the western part is higher than that of eastern Hainan Island. With the increase in STFD intensity, the spatial distribution center of the vulnerability of rubber ecosystem GPP in Hainan Island gradually moves southward. The spatiotemporal pattern of the vulnerability of the rubber ecosystem GPP to STFD over Hainan Island plotted by this study is expected to provide decision makers with more accurate information on the prevention and control of drought disaster risk in rubber ecosystems

The endoscopic ultrasound probe findings in prediction of esophageal variceal recurrence after endoscopic variceal eradication therapies in cirrhotic patients: a cohort prospective study

Abstract Background The recurrence of esophageal varices remains high in patients with hepatic portal hypertension after the endoscopic esophageal variceal eradication therapies, including endoscopic variceal band ligation (EVL), injection sclerotherapy (EIS) or EVL plus EIS. The aim of this study was to evaluate the endoscopic ultrasound probe examinations (EUP) findings in the prediction of recurrence following esophageal variceal eradication in a prospective cohort. Methods A total of 206 cirrhotic portal hypertension patients with esophageal variceal eradication, who underwent endoscopic variceal therapy (EVL or EIS or EVL plus EIS) were initially enrolled. All patients were scheduled for a follow-up every 6 months for up to 3 years. EUP was performed to evaluate peri-esophageal collateral veins (peri-ECVs), perforating veins (PFV) and para-esophageal collateral veins (para-ECVs). In addition, computed tomography (CT) were conducted to detect portal vein diameter, portal vein embolus, and major portosystemic collateral shunts. The relationship between esophageal variceal recurrence and EUP findings were analyzed. Results We found that as high as 93.5% of patients developed esophageal variceal recurrence in the 3-year follow-up. The time of esophageal variceal recurrence after variceal eradication was 13.4 months (13.4 ± 9.2 months). Furthermore, the median time of recurrence in patients who were undertaken EVL,EIS and EVL plus EIS was 10, 13 and 12 months, respectively. We identified that the risk factors, including EVL (OR 0.23, 95% CI 0.08–0.71, p < 0.01), Child-Pugh score (OR 3.32,95% CI 1.31–35.35, p < 0.05), large peri-ECVs (OR 4.56, 95% CI 2.17–9.58, p < 0.0001), and existence of PFV (OR 2.14, 95% CI 1.44–3.16, p < 0.001), were significantly associated with the recurrence of esophageal varices. The peri-ECVs and PFV showed better ability to predict esophageal variceal recurrence. When cut-off value of peri-ECVs diameter was 3.5 mm, the specificity of prediction 1-year variceal recurrence was 86% and the sensitivity was 45%. Conclusions The EUP appears to be very effective, convenient and economical examinations to predict esophageal varices recurrence after variceal eradication by endoscopic therapies. The high Child-pugh score, large peri-ECVs, and PFV are independent risk factors related to esophageal varices recurrence

Nighttime luminosity transitions are tightly spatiotemporally correlated with land use changes: A pixelwise case study in Beijing, China

Nighttime light data and land use data derived from remote sensing satellites are commonly used to monitor human activities on the Earth. A thorough understanding of the spatiotemporal interactions between these data enables better characterization and reconstruction of urbanization processes. In this work, a pixelwise fusion analysis using nighttime light data and land use data was performed to explore the spatiotemporal correlation between urban nighttime light luminosity transitions and land use changes. We found that the nighttime luminosity transitions are tightly related to the corresponding land use change types at the pixel level. A significant spatial correlation was identified between the nighttime light luminosity transitions and urban lands with intensive human activity. Relevant policies enacted in Beijing have greatly influenced the local light luminosity and land use type transitions. Pixels with change values in light luminosity in the same range have the same types of land use changes, the reasons for the changes in light luminosity are similar, and the spatial distribution characteristics are the same. This study provides a theoretical basis for quickly assessing changes in urban land use types through transitions in nighttime light luminosity. Simultaneously, the data in our study after integrating nighttime light luminosity and land use information perform well in urban development research and can provide valuable datasets and decision-making references for adjusting and optimizing urban sustainable development policies

Dynamic model for an oxygen-staged slagging entrained flow gasifier

A dynamic gasifier model including slag flow behavior simulation was established to simulate a new type of oxygen-staged gasifier recently developed in China. A reactor network model (RNM) is used to simulate the internal gas-solid reaction zone of the gasifier, in which the reactor is divided into several zones based on the understanding of the flow characteristics in the gasifier, with each zone represented by either a plug-flow reactor or a well-stirred reactor. This space division concept can provide a more reasonable temperature distribution prediction than one-dimensional models, without costing too much computational expense. In addition, a widely accepted slag layer model is used to simulate the time-varying slag accumulation and flow on the wall and the heat transfer process through the wall. Using the developed model, two kinds of oxygen-staged gasifiers were simulated: the refractory wall gasifier and the membrane wall gasifier. The RNM predictions were compared with industrial data and computational fluid dynamics (CFD) model results, and good agreement has been observed. The temperature distribution simulation results also showed that staged oxygen feeding can reduce the temperature near the main burner significantly, therefore extending the lifetime of the burner compared with that of without staged oxygen feed. Dynamic simulation results suggest that the dynamic response of the refractory wall gasifier is much slower than that of the membrane wall gasifier. In the membrane wall gasifier, the dynamic response of the syngas temperature and composition is rather fast compared to that of the wall temperature. However, for the refractory wall gasifier, the dynamic response of syngas temperature is as slow as that of the wall temperature indicating that different control strategies should be taken into account for better slag flow and syngas temperature control for these two kinds of gasifier

The intra- and inter-annual responses of soil respiration to climate extremes in a semiarid grassland

Increasing frequency and magnitude of climate extremes could fundamentally affect terrestrial carbon (C) cycling. However, as the second-largest terrestrial C flux, soil respiration (SR) responses to climate extremes are not well understood. Here, we investigated the effects of drought, heat wave and drought plus heat wave on SR in a semiarid grassland during the growing season over 3 years. The results indicated that drought consistently reduced the growing-season mean SR, especially during the period of drought treatment, while heat wave, alone or when combined with drought, had little effect on SR. The decreased SR under drought at the intra-annual timescale could be primarily attributable to restriction of low soil moisture to microbial biomass, as there were no consistent changes in plant community (aboveground biomass, richness and abundance). In contrast, the inter-annual variation in SR was positively related to plant community abundance, richness and aboveground biomass in additional to soil water availability, but was not significantly affected by microbial biomass. Our study highlighted that incorporating microbial biomass in C cycling models can improve simulation of seasonal dynamics of soil respiration while incorporating plant community characteristics can benefit prediction of variation in SR across multiple years in semiarid grasslands