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The nonlocal Allen–Cahn equation with nonlocal diffusion operator is important for simulating a series of physical and biological phenomena involving long-distance interactions in space. As a generalization of the classical Allen–Cahn equation, the nonlocal Allen–Cahn equation also satisfies the energy dissipation law and maximum bound principle. In this paper, we construct first- and second-order (in time) accurate linear schemes for the nonlocal Allen–Cahn type model based on the stabilized exponential scalar auxiliary variable approach which preserve discrete maximum bound principle and unconditionally energy stability. On the one hand, we prove the discrete maximum bound principle, unconditional energy stability and error convergence analysis carefully and rigorously in the fully discrete levels. On the other hand, we adopt an efficient FFT-based fast solver to compute the nearly full coefficient matrix which generated from the spatial discretization, which improves the computational efficiency. Finally, typical numerical experiments are presented to demonstrate the performance of our proposed schemes. [ABSTRACT FROM AUTHOR]

Fenton conditioning processes have been recently employed to improve the dewaterability of sewage sludge. However, it remains unclear whether the conditioning with Fenton's reagent would simultaneously attenuate antibiotic resistance genes (ARGs) in sludge and improve sludge dewaterability. It was found in the present study that sludge pre-acidification played a pivotal role in simultaneously removing ARGs and improving sludge dewaterability by conditioning with Fenton's reagent. When the sewage sludge was pre-acidified to pH = 3.0 and was then conditioned using Fenton's reagent, the absolute abundances of the total ARGs and the total mobile genic elements (MGEs) in conditioned sludge were reduced by 1.85–2.10 and 2.84–3.12 log units, respectively. Additionally, sludge capillary suction time (CST) and specific resistance to filtration (SRF) were drastically reduced, and the moisture content (MC) in dewatered sludge cake was reduced to only 60.61–69.95%. Such effective attenuation of ARGs and MGEs in conditioned sludge led to their removal in both the dewatered sludge cakes and dewatering filtrate. However, only the improvement of sludge dewaterability was attained by sludge conditioning with Fenton's reagent but without sludge pre-acidification. During the conditioning treatment, the removal of loosely bound extracellular polymeric substance (EPS) and tightly bound EPS in conditioned sludge contributed to the improvement of sludge dewaterability, and the damage of sludge microbial cells was highly correlated with the attenuation of antibiotic resistance. Thus, sludge pre-acidification combined with conditioning using Fenton's reagent can be employed to simultaneously attenuate the antibiotic resistance in sewage sludge and improve sludge dewaterability. [ABSTRACT FROM AUTHOR]

Orchids (Phalaenopsis amabilis), renowned for their extraordinary floral diversity which implies the complex flower color development, are one of the most valuable research materials for molecular biology studies. However, the genetic mechanisms underlying flower color formation in this non-model plant remain unclear. Here, the biochemical and molecular basis of the flavonoid/anthocyanin biosynthesis between purple petal cultivar (PP) and white petal cultivar (WP) was investigated. The results revealed that 142 differential flavonoid-related metabolites were identified using LC–MS/MS method, and the primary anthocyanins were identified as cyanidin derivatives. Moreover, RNA-seq revealed a total of 9523 upregulated and 6941 downregulated genes were detected. GO and KEGG analysis of DEGs indicated metabolic pathways were preferentially upregulated in PP. The expression of most known genes encoding the enzymes in anthocyanin and related derivative biosynthesis was significantly higher in PP than in WP, especially the downstream ones. We hypothesized that altered flavanone and flavone accumulation may lead to pigment elimination in WP, and the limited flux in cyanidin biosynthesis pathway seems to be the most likely reason for the colorless petal. Besides, 115 differentially expressed regulatory genes relating to anthocyanin biosynthesis were also detected, including MYB, bHLH, WD40, WRKY, MADS and bZIP. Subsequently, high consistency was observed between the results of qRT-PCR and those of RNA-seq. collectively, this study provides a comprehensive metabolic and transcriptional dataset for Phalaenopsis, the informative list of candidate structural and regulatory genes associated with purple trait offer a valuable opportunity to unravel the genetic mechanism underlying flower color formation in Phalaenopsis. [ABSTRACT FROM AUTHOR]

Sweet potato [ Ipomoea batatas (L.) Lam.] is a vegetable crop with significant economic value that is utilized both as a staple food and as an industrial raw material. Sweet potato possesses a variety of healthful beneficial secondary metabolites, which also contribute towards its adaptation to the environment and capacity to withstand stresses. Cinnamate 4-hydroxylase constitutes a primary enzyme in the phenylpropanoid pathway that is involved in the biosynthesis of numerous secondary metabolites. Elucidating the molecular and expressional characteristics of C4H is essential for understanding the functional genetic diversity of sweet potato germplasms. Based on the transcriptome analysis of five sweet potato genotypes with different anthocyanin contents, a cinnamate 4-hydroxylase ( C4H) gene, termed IbC4H, was isolated from a purple sweet potato cv. 'Xuzishu 3'. The cDNA sequence of IbC4H contained a 1518-bp ORF encoding a 505 amino acid protein with a molecular weight of 58.15 kDa. Genomic DNA analysis revealed that the IbC4H gene possessed three exons and two introns. The IbC4H protein shared 86.34-97.82% sequence identity with that reported for other plants. A significant positive correlation between the expression of IbC4H and phenolic acid content suggested that IbC4H might be integral to the regulation of phenolic biosynthesis in sweet potato. Furthermore, IbC4H was significantly upregulated in the young leaves and roots of cv. 'Xuzishu 3' and was strongly induced when subjected to drought stress. Drought stress tolerance in transgenic tobacco plants was significantly improved by the heterologous expression of the transgene IbC4H, which was simultaneously associated with the increased expression of stress-related genes, higher superoxide dismutase (SOD) activity, and proline (Pro) content, along with lower malondialdehyde (MDA) production. Collectively, these results highlight the important role of IbC4H in the phenylpropanoid pathway and support the protective function of polyphenols in the improved scavenging of reactive oxygen species of plants under stress. [ABSTRACT FROM AUTHOR]

White light colonoscopy is widely used to detect colorectal polyps, but flat and depressed lesions are often missed. Here, we report a molecular imaging strategy to potentially improve diagnostic performance by developing a fluorescently-labeled peptide specific for cMet. This 7mer is conjugated to Cy5.5, a near-infrared (NIR) cyanine dye. Specific binding to cMet was confirmed by cell staining, knockdown, and competition assays. The probe showed high binding affinity (kd = 57 nM) and fast onset (k = 1.6 min) to support topical administration in vivo. A mouse model (CPC;Apc) that develops spontaneous adenomas that overexpress cMet was used to demonstrate feasibility for real time in vivo imaging. This targeting ligand showed significantly higher target-to-background (T/B) ratio for polypoid and non-polypoid lesions by comparison with a scrambled control peptide. Immunofluorescence staining on human colon specimens show significantly greater binding to tubular and sessile serrated adenomas versus hyperplastic polyps and normal mucosa. These results demonstrate a peptide specific for cMet that is promising for endoscopic detection of pre-malignant lesions and guiding of tissue biopsy. [ABSTRACT FROM AUTHOR]

DEAD-box RNA helicases play pivotal roles in almost all processes in RNA metabolisms, associated with various cellular functions including plant development and the response to abiotic stress. Previously, although DEAD-box genes were identified in tomato genome, specific molecular characterizations regarding development- and/or stress-related tomato DEAD-box genes are still rudimentary. In this study, a systematic expression analysis and function evaluation of 42 DEAD-box RNA helicase genes was conducted in the growth development and stress response of tomato using qRT-PCR. The results revealed that these SlDEAD genes showed discrepant tissue-/organ-specific (such as leaf, flower and fruit) expression levels, indicating that they might play important and different roles in tomato development. Variant expression profiles of many SlDEAD genes were observed when treated with different hormones including ABA, ACC, GA3, IAA, and SA. Moreover, the transcription of multiple tomato SlDEAD genes was also upregulated by multiple abiotic stresses, such as salinity, dehydration, and heat and cold stresses. Cumulatively, the data will be valuable to comprehensive functional characterization of SlDEAD genes, and to support the thesis that DEAD-box RNA helicases may represent one of the main components that mediate hormone signaling and stress responses in tomato. [ABSTRACT FROM AUTHOR]

The catalytic activity of palladium (Pd) nanostructures highly relies on their size and morphology, especially enclosed with high-index facets, which provide more active sites so as to enhance their catalytic performance comparing with their low-index facet counterparts. Herein, Pd concave nanocubes enclosed with {730} facets by a one-pot scalable liquid method, with various high-index facets are synthesized via tuning reduction kinetics. Due to their high-index facets, the Pd concave nanocubes exhibit much higher electrocatalytic activity and stability for methanol oxidation than the Pd nanocubes enclosed by {100} facets and commercial Pd/C. Furthermore, we scale up synthesis of Pd concave nanocubes by expanding the volume of all species to fifty times with high-yield production. [ABSTRACT FROM AUTHOR]