Acceleration of Histogram-Based Contrast Enhancement via Selective Downsampling

In this paper, we propose a general framework to accelerate the universal histogram-based image contrast enhancement (CE) algorithms. Both spatial and gray-level selective down- sampling of digital images are adopted to decrease computational cost, while the visual quality of enhanced images is still preserved and without apparent degradation. Mapping function calibration is novelly proposed to reconstruct the pixel mapping on the gray levels missed by downsampling. As two case studies, accelerations of histogram equalization (HE) and the state-of-the-art global CE algorithm, i.e., spatial mutual information and PageRank (SMIRANK), are presented detailedly. Both quantitative and qualitative assessment results have verified the effectiveness of our proposed CE acceleration framework. In typical tests, computational efficiencies of HE and SMIRANK have been speeded up by about 3.9 and 13.5 times, respectively.Comment: accepted by IET Image Processin

Contrast Enhancement of Brightness-Distorted Images by Improved Adaptive Gamma Correction

As an efficient image contrast enhancement (CE) tool, adaptive gamma correction (AGC) was previously proposed by relating gamma parameter with cumulative distribution function (CDF) of the pixel gray levels within an image. ACG deals well with most dimmed images, but fails for globally bright images and the dimmed images with local bright regions. Such two categories of brightness-distorted images are universal in real scenarios, such as improper exposure and white object regions. In order to attenuate such deficiencies, here we propose an improved AGC algorithm. The novel strategy of negative images is used to realize CE of the bright images, and the gamma correction modulated by truncated CDF is employed to enhance the dimmed ones. As such, local over-enhancement and structure distortion can be alleviated. Both qualitative and quantitative experimental results show that our proposed method yields consistently good CE results

Chrysophanol exerts protective effect against atherosclerosis via NFκB-mediated signaling in LDLR-/- mice model

Purpose: To study the therapeutic effect of chrysophanol (CHR) on diet-induced atherogenesis in LDLR-/- mice.Methods: Mice were fed atherogenic diet for 12 weeks after which some lipid profile markers such as total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c) and triglyceride (TG) were measured. The mRNA expression levels of lipid synthesis genes and lipid overload-related inflammatory indicator molecules were assayed with quantitative real time polymerase chain reaction (qRT-PCR), while the corresponding protein expressions were determined with western blotting assay. The therapeutic effect of CHR on atherogenesis was confirmed using H & E and Oil red O stainings of mice aortic sections.Results: CHR administration significantly reduced levels of TC, LDL-c, HDL-c and TG (p ≤ 0.05), and restored the mRNA and protein expressions of genes involved in lipid and glucose homeostasis, namely, AdipoR1, PPAR-Ƴ and HMco-A (p < 0.05). Moreover, CHR potentially alleviated diet-induced inflammation, as is evident in reduced levels of molecular inflammatory signaling factors NF-κB and TLR-4, and significant down-regulations of the proinflammatory cytokines, TNF-α, IL-6 and IL-1β (p < 0.05). Furthermore, aorta histology revealed that CHR significantly reduced lipid storage in the arteries of mice fed atherogenic diet (p < 0.05).Conclusion: These results indicate that CHR reduces diet-induced lipid storage in LDLR-/- mice and also controlled inflammation-associated lipid overload. These findings may provide a molecular basis for potential application of chrysophanol in the treatment of atherosclerosis

Comparing efficacy and safety of plasmapheresis versus atorvastatin in pathological progression of atherosclerosis in a rodent model

Purpose: To evaluate the effect of plasmapheresis versus atorvastatin in pathological progression of atherosclerosis in a rodent model.Method: A total of 90 male adult rats of up to 300 g were randomly distributed in three groups (n = 30): group 1 (plasmapheresis up to 1.5 ml daily); group 2 (atorvastatin 0.1 mg/kg per day), and group 3 (hypercholesteremic rats). The following variables were assessed for 24 weeks: plasma and hepatic lipid and anti-oxidant profiles; atherosclerotic abrasions/lesions; coronary atherosclerosis/coronary stenosis score (CSS), composition of atherosclerotic lesions, incidence of xanthoma, arch and thoracic surface involvement including arch and thoracic area occupied by lesion; and thoracic aorta (I/M) ratio.Results: Compared to rats administered with atorvastatin, the rats treated with plasmapheresis had significantly greater improvement in levels of triglycerides (132 vs 124 mg/dl, p < 0.05), total cholesterol (201 vs 189 mg/dl, p < 0.05)), low-density lipoproteins (134 vs 123 mg/dl, p < 0.05)), very-low-density lipoprotein (11 vs 9 mg/dl, p < 0.05)) and high-density lipoprotein (36 vs 39 mg/dl, p < 0.05) levels. Plasmapheresis after 24 weeks of treatment improve CSS in all coronary arteries than atorvastatin (22 vs 24 respectively; p < 0.05. Furthermore, lesioned composition, I/M ratio and xanthoma incidence were significantly lower in plasmapheresis group than in atorvastatin group (p < 0.05).Conclusion: Plasmapheresis is a better alternative than atorvastatin in preventing pathological progression of atherosclerosis

Dioscorea deltoidei (Dioscoreaceae) leaf extract exerts anti-atherosclerotic effect in rats via down-regulation of phosphorylated JAK/STAT

Purpose: To investigate the effect of leaf extract of Dioscorea deltoidea (Dioscoreaceae) leaf (DDE) on atherosclerosis-induced aorta wall damage in a rat model, and the underlying mechanism of action.Methods: Rats were fed high-fat diet containing vitamin D2 for 16 weeks to induce atherosclerosis. Histopathological changes in the aorta were examined using hematoxylin and eosin (H & E) staining, while ELISA kits were used to measure cytokine levels.Results: Treatment with DDE significantly (p < 0.05) alleviated atherosclerosis-induced increase in mean lesion area in the rat aorta. The mean lesion area in atherosclerotic rats was decreased to 51.5, 21.2 and 2.3 mm2, on treatment with DDE at doses of 2.5, 5 and 10 mg/kg, respectively. Furthermore, DDE significantly suppressed atherosclerosis-induced elevation in IL-1β and IL-6 levels in the rat aorta (p < 0.05). The levels of MCP-1 and TNF-α decreased in the artherosclerotic rats on treatment with DDE. In DDE-treated rats, the atherosclerosis-induced increase in the levels of Ang II, AT1, AT2, p-STAT3, p-p65 and p-p38 were significantly decreased, relative to the model group (p < 0.05). However, DDE treatment did not alter the levels of total STAT3, p65 and p38 in the rat aorta tissues.Conclusion: These results indicate that DDE inhibits inflammatory response and atherosclerosisinduced damage to aorta wall. Moreover, RAAS expression, inflammatory cytokines and JAK/STAT signalling pathway were down-regulated in atherosclerotic rats on treatment with DDE. Thus, DDE may be a potential source of drug for the management of atherosclerosis

Mapping and Assessment of the Urban Heat Island in Zhengzhou City

The rapid urbanization of Chinese cities has resulted in significant effects to the urban environment and to urban ecological networks. Zhengzhou city, the capital city of Henan province in central China, is characterized by a warm climate and four distinctive seasons, with a dry spring, and a hot and rainy summer. Based on satellite images, we analyzed land surface temperature (LST) and prepared a further assessment. Using LST data, we analyzed the urban heat island (UHI) and its relationship to green space, in order to make suggestions for future urban planning. The results show that urban heat island exists in Zhengzhou city Central Urban area. The mean land surface temperature (MLST) difference between urban and non-urban is significant. In addition, the urban green space reveals a negative relationship with LST. To conclude, we discuss the role of green space in mitigating urban heat island and propose some greenway related strategies for urban landscape planning in Zhengzhou city

City in the park,” Greenway Network Concept of High-Density Cities: Adaptation of Singapore Park Connector Network in Chinese Cities

This paper uses the “Park Connector Network” (PCN) as a model, to analyze Singapore’s experience and to cope with the dramatic increase in population and urbanization, and then to apply this experience to Chinese high-density cities. The research goal is to provide guidance for the adaptation of “City in the Park” in China and the construction of high-density urban green space systems. The concept of “City in the Park” that was born in 2018 in China can be related directly to the “Park Connector Network” model

Discovery of two new hypervelocity stars from the LAMOST spectroscopic surveys

We report the discovery of two new unbound hypervelocity stars (HVSs) from the LAMOST spectroscopic surveys. They are respectively a B2V type star of ~ 7 M$_{\rm \odot}$ with a Galactic rest-frame radial velocity of 502 km/s at a Galactocentric radius of ~ 21 kpc and a B7V type star of ~ 4 M$_{\rm \odot}$ with a Galactic rest-frame radial velocity of 408 km/s at a Galactocentric radius of ~ 30 kpc. The origins of the two HVSs are not clear given their currently poorly measured proper motions. However, the future data releases of Gaia should provide proper motion measurements accurate enough to solve this problem. The ongoing LAMOST spectroscopic surveys are expected to yield more HVSs to form a statistical sample, providing vital constraint on understanding the nature of HVSs and their ejection mechanisms.Comment: 5 pages, 3 figures, 1 table, accepted for publication in ApJ

An Enhanced Drought-Tolerant Method Using SA-Loaded PAMPS Polymer Materials Applied on Tobacco Pelleted Seeds

Drought is one of the most important stress factors limiting the seed industry and crop production. Present study was undertaken to create novel drought-resistant pelleted seeds using the combined materials with superabsorbent polymer, poly(2-acrylamide-2-methyl propane sulfonic acid) (PAMPS) hydrogel, and drought resistance agent, salicylic acid (SA). The optimized PAMPS hydrogel was obtained as the molar ratio of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) to potassium peroxydisulfate (KPS) and N, N′-methylene-bis-acrylamide (MBA) was 1 : 0.00046 : 0.00134. The hydrogel weight after swelling in deionized water for 24 h reached 4306 times its own dry weight. The water retention ratio (RR) of PAMPS was significantly higher as compared with the control. It could keep as high as 85.3% of original weight after 30 min at 110°C; even at 25°C for 40 d, the PAMPS still kept RR at 33.67%. PAMPS disintegration ratio increased gradually and reached around 30% after embedding in soil or activated sludge for 60 d. In addition, there were better seed germination performance and seedling growth in the pelleted treatments with SA-loaded PAMPS hydrogel under drought stress than control. It suggested that SA-loaded PAMPS hydrogel, a nontoxic superabsorbent polymer, could be used as an effective drought resistance material applied to tobacco pelleted seeds