36 research outputs found
MRI in the differential diagnosis of primary architectural distortion detected by mammography
PURPOSEWe aimed to evaluate the diagnostic accuracy of a combination of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and apparent diffusion coefficient (ADC) values in lesions that manifest with architectural distortion (AD) on mammography.METHODSAll full-field digital mammography (FFDM) images obtained between August 2010 and January 2013 were reviewed retrospectively, and 57 lesions showing AD were included in the study. Two independent radiologists reviewed all mammograms and MRI data and recorded lesion characteristics according to the BI-RADS lexicon. The gold standard was histopathologic results from biopsies or surgical excisions and results of the two-year follow-up. Receiver operating characteristic curve analysis was carried out to define the most effective threshold ADC value to differentiate malignant from benign breast lesions. We investigated the sensitivity and specificity of FFDM, DCE-MRI, FFDM+DCE-MRI, and DCE-MRI+ADC.RESULTSOf the 57 lesions analyzed, 28 were malignant and 29 were benign. The most effective threshold for the normalized ADC (nADC) was 0.61 with 93.1% sensitivity and 75.0% specificity. The sensitivity and specificity of DCE-MRI combined with nADC was 92.9% and 79.3%, respectively. DCE-MRI combined with nADC showed the highest specificity and equal sensitivity compared with other modalities, independent of the presentation of calcification.CONCLUSIONDCE-MRI combined with nADC values was more reliable than mammography in differentiating the nature of disease manifesting as primary AD on mammography
Distribution, degradation and dynamics of dissolved organic carbon and its major compound classes in the Pearl River estuary, China
We investigated the distribution, degradation and dynamics of organic carbon and its major compound classes, carbohydrates and amino acids, based upon a cruise in the Pearl River estuary in April 2007. Dissolved oxygen (DO), nutrients, particulate organic carbon (POC), chlorophyll a (Chl a), dissolved organic carbon (DOC), total dissolved carbohydrates (TCHO, including monosaccharides, MCHO, and polysaccharides, PCHO) as well as total dissolved amino acids (TAA, both dissolved free, DFAA, and combined components. DCAA) were measured along a salinity gradient. Community respiration and biodegradable DOC were also determined via both short term (within 3 days) and long term (lasting 30 days) incubation. DOC, MCHO, TCHO, DFAA and TAA concentrations were high in the upper reach of the Pearl River estuary and decreased rapidly downstream. Anthropogenic sewage input appeared to be an important source of the DOC pool in the upper estuary. DOC distribution was non-conservative during the estuarine mixing, showing a net consumption of DOC in the upper reach and in the low salinity (S<20) region of the Pearl River estuary. Changes in the relative compositions of carbohydrates (MCHO vs. PCHO) and amino acids (DFAA vs. DCAA) along the salinity gradient further indicated that different processes (biodegradation, flocculation, and phytoplankton production) had different influences on distributions of organic compound classes in this estuarine system. Our one-month incubation experiment further revealed that a substantial portion (15-45%) of DOC from the estuary was biodegradable. Bacterial respiration rates were much higher (0.12-5.8 mu mol O-2 L-1 h(-1)) than the DOC consumption rates, suggesting that there were other oxygen consumption processes, such as nitrification besides the aerobic respiration of organic matter in the Pearl River estuary, as inferred by the distribution of NH4+ and NO3-. We estimated that 5.3 x 10(8) g C d(-1) of DOC can be exported out from the Lingdingyang Bay (a major subestuary of the Pearl River estuary) to the continental shelf of the South China Sea during this low flow season. (C) 2009 Elsevier B.V. All rights reserved.Natural Science Foundation of China [40576036, 90711005, 40821063
Characterization of miRNAs in Response to Short-Term Waterlogging in Three Inbred Lines of Zea mays
Waterlogging of plants leads to low oxygen levels (hypoxia) in the roots and causes a metabolic switch from aerobic respiration to anaerobic fermentation that results in rapid changes in gene transcription and protein synthesis. Our research seeks to characterize the microRNA-mediated gene regulatory networks associated with short-term waterlogging. MicroRNAs (miRNAs) are small non-coding RNAs that regulate many genes involved in growth, development and various biotic and abiotic stress responses. To characterize the involvement of miRNAs and their targets in response to short-term hypoxia conditions, a quantitative real time PCR (qRT-PCR) assay was used to quantify the expression of the 24 candidate mature miRNA signatures (22 known and 2 novel mature miRNAs, representing 66 miRNA loci) and their 92 predicted targets in three inbred Zea mays lines (waterlogging tolerant Hz32, mid-tolerant B73, and sensitive Mo17). Based on our studies, miR159, miR164, miR167, miR393, miR408 and miR528, which are mainly involved in root development and stress responses, were found to be key regulators in the post-transcriptional regulatory mechanisms under short-term waterlogging conditions in three inbred lines. Further, computational approaches were used to predict the stress and development related cis-regulatory elements on the promoters of these miRNAs; and a probable miRNA-mediated gene regulatory network in response to short-term waterlogging stress was constructed. The differential expression patterns of miRNAs and their targets in these three inbred lines suggest that the miRNAs are active participants in the signal transduction at the early stage of hypoxia conditions via a gene regulatory network; and crosstalk occurs between different biochemical pathways
Effects of Xylanase Pretreatment on the Quality of Refiner Mechanical Mulberry Branch Fibers
We performed xylanase pretreatment prior to mechanical refining in the production of mulberry branch fibers, with the objective of saving energy and studying the effects of such pretreatment on the quality of the fibers. To determine the effects of the enzyme action, we analyzed the energy required for refining, related yield, and the dimension, deformation, and morphology of the fibers. We found that, with the xylanase pretreatment, the refining energy was reduced by 4%, with the yield of fibers being maintained at >85%. In addition, the fiber bundles were defibered further, resulting in reduced average length of the fiber. Furthermore, the fiber widths increased because of the improved swelling effect of the xylanase pretreatment. However, in some instances, the fine elements were reduced. With a low enzyme dosage, the fiber coarseness decreased remarkably and, because of the swelling and softening effects of the xylanase pretreatment on the mulberry branches, the fiber kink ratios and curl were reduced. Additionally, the mulberry branch tissue was loosened, facilitating fiber separation. In view of these findings, the biomechanical process could be a potentially green and efficient process for the manufacturing of mulberry branch fibers
Combined application of organic fertilizer and chemical fertilizer alleviates the kernel position effect in summer maize by promoting post-silking nitrogen uptake and dry matter accumulation
Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields. In order to clarify whether the combined application of organic fertilizer and chemical fertilizer (CAOFCF) can alleviate the kernel position effect of summer maize, field experiments were conducted during the 2019 and 2020 growing seasons, and five treatments were assessed: CF, 100% chemical fertilizer; OFCF1, 15% organic fertilizer+85% chemical fertilizer; OFCF2, 30% organic fertilizer+70% chemical fertilizer; OFCF3, 45% organic fertilizer+55% chemical fertilizer; and OFCF4, 60% organic fertilizer+40% chemical fertilizer. Compared with the CF treatment, the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels. These effects were largely due to the improved filling and starch accumulation of inferior kernels. However, there were no obvious differences in the kernel position effect among plants treated with CF, OFCF3, or OFCF4 in most cases. Leaf area indexes, post-silking photosynthetic rates, and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF, reflecting an enhanced photosynthetic capacity and improved post-silking dry matter accumulation (DMA) in the plants treated with OFCF1 or OFCF2. Compared with the CF treatment, the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%, respectively, which was the major factor driving post-silking photosynthetic capacity and DMA. Moreover, the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence, which is associated with an increased post-silking N uptake. Analyses showed that post-silking N uptake, DMA, and grain yield in summer maize were negatively correlated with the kernel position effect. In conclusion, the combined application of 15β30% organic fertilizer and 70β85% chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA. These results provide new insights into how CAOFCF can be used to improve maize productivity
Effect of Sheet Properties of Cellulosic Polyglycidyl Methacrylate-Grafted Fibers in a Cationic Polyacrylamide/SiO<sub>2</sub>/Anionic Polyacrylamide Retention Aid System
As increasing fiber hydrophobicity can significantly improve the paper dewatering process, we found that replacing SBKP and HBKP with 0.5% superhydrophobic CPGMA can significantly improve the dewatering of paper sheets. Therefore, it can be concluded that if CPGMA has little effect on paper properties, it will have potential industrial value in the papermaking industry. Consequently, it is necessary to further study the effect of the CPGMAs@CPAM/SiO2/APAM system on paper properties. To evaluate the application potential of the system in the papermaking industry, we investigated the effects of CPGMAs, which replaced the fibers in the stocks, on the paper properties in the CPAM/SiO2/APAM system. The findings demonstrate that as the CPGMA replacement increased, the paperβs tensile strength, bursting strength, tear resistance, and folding endurance all declined. The trend can be segmented into two phases: a rapid decrease for substitution amounts below 0.5% and a gradual decline for substitution amounts exceeding 0.5%. When replaced with a small amount of CPGMAs, there was a negligible effect on these properties. Second, the paper air permeability increased with the CPGMA substitution amount in the stock. Furthermore, the trend of paper air permeability can be divided into two stagesβa rapid stage with a substitution amount of 0.5%. A small amount of CPGMAs could distinctly improve the paperβs air permeability. Third, CPGMAs, which replaced fibers in the stock, minutely affected the paper formation. A small amount of CPGMAs substantially boosted the efficacy of the process of paper manufacture and certain characteristics of the paper, and it had a negligible impact on the strength of paper. The CPGMAs@CPAM/SiO2/APAM technology has the potential to improve the retention and filtration performance of CPAM/SiO2/APAM
Mutations in the Type II Protein Arginine Methyltransferase AtPRMT5 Result in Pleiotropic Developmental Defects in Arabidopsis1[C][OA]
Human PROTEIN ARGININE METHYLTRANSFERASE5 (PRMT5) encodes a type II protein arginine (Arg) methyltransferase and its homologs in animals and yeast (Saccharomyces cerevisiae and Schizosaccharomyces pombe) are known to regulate RNA processing, signal transduction, and gene expression. However, PRMT5 homologs in higher plants have not yet been reported and the biological roles of these proteins in plant development remain elusive. Here, using conventional biochemical approaches, we purified a plant histone Arg methyltransferase from cauliflower (Brassica oleracea) that was nearly identical to AtPRMT5, an Arabidopsis (Arabidopsis thaliana) homolog of human PRMT5. AtPRMT5 methylated histone H4, H2A, and myelin basic protein in vitro. Western blot using symmetric dimethyl histone H4 Arg 3-specific antibody and thin-layer chromatography analysis demonstrated that AtPRMT5 is a type II enzyme. Mutations in AtPRMT5 caused pleiotropic developmental defects, including growth retardation, dark green and curled leaves, and FlOWERING LOCUS C (FLC)-dependent delayed flowering. Therefore, the type II protein Arg methyltransferase AtPRMT5 is involved in promotion of vegetative growth and FLC-dependent flowering time regulation in Arabidopsis
Kinetics and Size Effects on Adsorption of Cu(II), Cr(III), and Pb(II) Onto Polyethylene, Polypropylene, and Polyethylene Terephthalate Microplastic Particles
Due to its small size, large specific surface area and hydrophobicity, microplastics, and the adsorbed contaminants may together cause potential negative effects on ecosystems and human beings. In this study, kinetics and size effects on adsorption of Cu(II), Cr(III), and Pb(II) onto PE, PP and PET microplastic particles were explored. Results indicated that the PE and PET microplastics have the higher adsorption capacity for Cu(II), Cr(III), and Pb(II) than that for PP microplastic. The adsorption capacity was affected by microplastic types and metal species. Among the three metals, Pb(II) had the largest adsorption amount on microplastic particles, especially on PET particles. Moreover, the adsorption capacities of microplastics increase with the decrease of particle size. The metal adsorption capacity of &lt;0.9 mm microplastics is greater than that of 0.9β2 mm and 2β5 mm microplastics. The size effect on metal adsorption was largest for PE microplastic. More attention should be paid in case of the coexistence of heavy metals and tiny PE and PET microplastics in the environment