Prediction of Depth Distribution Curve of Dissolution Rates Based on the Undulating Features of Rock Surfaces

In karst regions, the drilling into the rock layer is restricted, if the construction site has a thick overburden and a small upper load. The evaluation of karst development features beneath the site becomes a common technical difficulty in building foundation engineering. Drawing on our previous research into the depth distribution features of dissolution rate, this paper collects 1000 plus data on typical karst regions across China, and selects 65 data for detailed analysis. Specifically, the rock surface dissolution features were analyzed on the top and bottom of the strong dissolution zone, and used to set up the control conditions for the top and bottom predictions of the strong dissolution zone. On this basis, the authors provided a prediction method for the depth distribution curve of dissolution rates. The results show that the elevation of 75% dissolution rate can be regarded as the top elevation of the strong dissolution zone at the site, which controls the prediction error within 0.5 m. If the pores and fissures are not so developed at the karst site, the elevation of 15% dissolution rate can be regarded as the bottom elevation of the strong dissolution zone at the site. According to the top and bottom elevations, the authors derived the predicted curve of the depth distribution function for the dissolution rates at each site. The predicted curve basically overlapped the curve and scatterplot of the dissolution rates measured at the site, a sign of reliable prediction. The proposed prediction method for the depth distribution curve of the dissolution rates at karst construction sites mainly applies to the sites with undeveloped to moderately developed pores and fissures. Further research is needed to verify its effectiveness in sites with strongly developed pores and fissures

Postoperative Ratio of C-Reactive Protein to Albumin as a Predictive Marker in Patients with Crohn’s Disease Undergoing Bowel Resection

Background. The ratio of C-reactive protein (CRP) to albumin (CAR) has a significant correlation with postoperative complications and acts as a predictor in patients with pancreatic cancer and colorectal cancer. However, whether the CAR can be used to predict complications in Crohn’s disease (CD) patients after surgery has not yet been reported. Methods. A total of 534 CD patients undergoing surgery between 2016 and 2020 were enrolled. The risk factors of postoperative complications were assessed by univariate and multivariate analyses. The cutoff values and the accuracy of diagnosis for the CAR and postoperative CRP levels were examined with receiver operating characteristic (ROC) curves. Results. The rate of postoperative complications was 32.2%. The postoperative CAR (OR 13.200; 95% CI 6.501-26.803; P<0.001) was a significant independent risk factor for complications. Compared with the CRP level on postoperative day 3, the CAR more accurately indicated postoperative complications in CD patients (AUC: 0.699 vs. 0.771; Youden index: 0.361 vs. 0.599). ROC curves showed that the cutoff value for the CAR was 3.25. Patients with a CAR≥3.25 had more complications (P<0.001), a longer postoperative stay (15.5±0.6 d vs. 9.0±0.2 d, P<0.001), and more surgical site infections (48.2% vs. 5.7%, P<0.001) than those with a CAR<3.25. Conclusions. Compared to the CRP level, the CAR can more accurately predict postoperative complications and can act as a predictive marker in CD patients after surgery

Seasonal and Particle Size-Dependent Variations of Hexabromocyclododecanes in Settled Dust: Implications for Sampling

Particle size is a significant parameter which determines the environmental fate and the behavior of dust particles and, implicitly, the exposure risk of humans to particle-bound contaminants. Currently, the influence of dust particle size on the occurrence and seasonal variation of hexabromocyclododecanes (HBCDs) remains unclear. While HBCDs are now restricted by the Stockholm Convention, information regarding HBCD contamination in indoor dust in China is still limited. We analyzed composite dust samples from offices (<i>n</i> = 22), hotels (<i>n</i> = 3), kindergartens (<i>n</i> = 2), dormitories (<i>n</i> = 40), and main roads (<i>n</i> = 10). Each composite dust sample (one per type of microenvironment) was fractionated into 9 fractions (F1<i>–</i>F9: 2000<i>–</i>900, 900<i>–</i>500, 500<i>–</i>400, 400<i>–</i>300, 300<i>–</i>200, 200<i>–</i>100, 100<i>–</i>74, 74<i>–</i>50, and <50 μm). Total HBCD concentrations ranged from 5.3 (road dust, F4) to 2580 ng g^–1 (dormitory dust, F4) in the 45 size-segregated samples. The seasonality of HBCDs in indoor dust was investigated in 40 samples from two offices. A consistent seasonal trend of HBCD levels was evident with dust collected in the winter being more contaminated with HBCDs than dust from the summer. Particle size-selection strategy for dust analysis has been found to be influential on the HBCD concentrations, while overestimation or underestimation would occur with improper strategies

Single-base resolution maps of cultivated and wild rice methylomes and regulatory roles of DNA methylation in plant gene expression

<p>Abstract</p> <p>Background</p> <p>DNA methylation plays important biological roles in plants and animals. To examine the rice genomic methylation landscape and assess its functional significance, we generated single-base resolution DNA methylome maps for Asian cultivated rice <it>Oryza sativa</it> ssp<it>. japonica</it>, <it>indica</it> and their wild relatives, <it>Oryza rufipogon</it> and <it>Oryza nivara</it>.</p> <p>Results</p> <p>The overall methylation level of rice genomes is four times higher than that of <it>Arabidopsis</it>. Consistent with the results reported for <it>Arabidopsis</it>, methylation in promoters represses gene expression while gene-body methylation generally appears to be positively associated with gene expression<b>.</b> Interestingly, we discovered that methylation in gene transcriptional termination regions (TTRs) can significantly repress gene expression, and the effect is even stronger than that of promoter methylation. Through integrated analysis of genomic, DNA methylomic and transcriptomic differences between cultivated and wild rice, we found that primary DNA sequence divergence is the major determinant of methylational differences at the whole genome level, but DNA methylational difference alone can only account for limited gene expression variation between the cultivated and wild rice. Furthermore, we identified a number of genes with significant difference in methylation level between the wild and cultivated rice.</p> <p>Conclusions</p> <p>The single-base resolution methylomes of rice obtained in this study have not only broadened our understanding of the mechanism and function of DNA methylation in plant genomes, but also provided valuable data for future studies of rice epigenetics and the epigenetic differentiation between wild and cultivated rice.</p