Snow water equivalent (SWE) is a key parameter in the Earth's energy budget and water cycle. It has been demonstrated that SWE can be retrieved using active microwave remote sensing from space. This necessitates the development of forward models that are capable of simulating the interactions of microwaves and the snow medium. Several proposed models have described snow as a collection of sphere-or ellipsoid-shaped ice particles embedded in air, while the microstructure of snow is, in reality, more complex. Natural snow usually forms a sintered structure following mechanical and thermal metamorphism processes. In this research, the bi-continuous vector radiative transfer (bi-continuous-VRT) model, which firstly constructs snow microstructure more similar to real snow and then simulates the snow backscattering signal, is used as the forward model for SWE estimation. Based on this forward model, a parameterization scheme of snow volume backscattering is proposed. A relationship between snow optical thickness and single scattering albedo at X and Ku bands is established by analyzing the database generated from the bi-continuous-VRT model. A cost function with constraints is used to solve effective albedo and optical thickness, while the absorption part of optical thickness is obtained from these two parameters. SWE is estimated after a correction for physical temperature. The estimated SWE is correlated with the measured SWE with an acceptable accuracy. Validation against two-year measurements, using the SnowScat instrument from the Nordic Snow Radar Experiment (NoSREx), shows that the estimated SWE using the presented algorithm has a root mean square error (RMSE) of 16.59 mm for the winter of 2009
The development of colorectal cancer is a complex and multistep process mediated by a variety of factors including the dysregulation of genetic and epigenetic under the influence of microenvironment. It is evident that epigenetics that affects gene activity and expression has been recognized as a critical role in the carcinogenesis. Aside from DNA methylation, miRNA level, and genomic imprinting, histone modification is increasingly recognized as an essential mechanism underlying the occurrence and development of colorectal cancer. Aberrant regulation of histone modification like acetylation, methylation and phosphorylation levels on specific residues is implicated in a wide spectrum of cancers, including colorectal cancer. In addition, as this process is reversible and accompanied by a plethora of deregulated enzymes, inhibiting those histone-modifying enzymes activity and regulating its level has been thought of as a potential path for tumor therapy. This review provides insight into the basic information of histone modification and its application in the colorectal cancer treatment, thereby offering new potential targets for treatment of colorectal cancer.
As the major component of the tumor matrix, collagen greatly influences tumor invasion and prognosis. The present study compared the remodeling of collagen and collagenase in 56 patients with colorectal cancer (CRC) using Sirius red stain and immunohistochemistry, exploring the relationship between collagen remodeling and the prognosis of CRC. Weak or strong changes in collagen fiber arrangement in birefringence were observed. With the exception of a higher density, weak changes equated to a similar arrangement in normal collagen, while strong changes facilitated cross-linking into bundles. Compared with normal tissues, collagen I (COL I) and III (COL III) deposition was significantly increased in CRC tissues, and was positively correlated with the metastasis status. In tissues without distant metastasis, collagen IV (COL IV) levels were higher than that in normal tissues, while in tissues with distant metastasis, collagen IV expression was significantly lower. Furthermore, the expression of matrix metalloproteinase (MMP)-1, MMP-2, MMP-7, MMP-9 and lysyl oxidase-like 2 (LOXL2) was found to be elevated in the cancer stroma, which contributed to the hyperactive remodeling of collagen. The association between collagen-related genes and the occurrence and prognosis of CRC were analyzed using biometric databases. The results indicated that patients with upregulated expression of a combination of coding genes for collagen and collagenase exhibited poorer overall survival times. The coding genes COL1A1-2, COL3A1, COL4A3, COL4A6 and MMP2 may therefore be used as biomarkers to predict the prognosis of patients with CRC. Furthermore, the results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggest that collagen may promote tumor development by activating platelets. Collectively, the abnormal collagen remodeling, including associated protein and coding genes is associated with the tumorigenesis and metastasis, affecting the prognosis of patients with CRC.
China's socioeconomic transitions have dramatically accelerated its economic growth in last three decades, but also companioned with continuous environmental degradation. This study will advance the knowledge of heavy metal water pollution in China from a spatial-temporal perspective. Specifically, this study addressed the following: (1) spatial patterns of heavy metal water pollution levels were analyzed using data of prefecture-level cities from 2004 to 2011; and (2) spatial statistical methods were used to examine the underlying socioeconomic and physical factors behind water pollution including socioeconomic transitions (industrialization, urbanization, globalization and economic development), and environmental characteristic (natural resources, hydrology and vegetation coverage). The results show that only Cr pollution levels increased over the years. The individual pollution levels of the other four heavy metals, As, Cd, Hg, and Pb, declined. High heavy metal water pollution levels are closely associated with both anthropogenic activities and physical environments, in particular abundant mineral resources and industrialization prosperity. On the other hand, economic development and urbanization play important roles in controlling water pollution problems. The analytical findings will provide valuable information for OPEN ACCESSSustainability 2015, 7 9068 policy-makers to initiate and adjust protocols and strategies for protecting water sources and controlling water pollution; thus improving the quality of living environments.
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