Search

A spindle-like Cu-based framework (Cu-Trp, Trp = L-Tryptophan) nanocrystal with ammonia-responsiveness was fabricated via simple aqueous solution approach, and it was subsequently explored as a functional compatibilizer of carboxymethyl starch/polyvinyl alcohol (CMS/PVA) blend toward constructing high-performance intelligent packaging films. The results showed that incorporation of Cu-Trp nanocrystal into CMS/PVA blend resulted in significant promotions regarding to the compatibility, mechanical strength (42.92 MPa), UV-blocking (with UV transmittance of only 2.4%), and water vapor barrier effectiveness of the blend film. Besides, the constructed CMS/PVA/Cu-Trp nanocomposite film exhibited superb long-term color stability, favorable antibacterial capacity (over 98.0%) toward both E. coli and S. aureus bacteria, as well as color change ability under ammonia environment. Importantly, the application trial confirmed that the CMS/PVA/Cu-Trp nanocomposite film is capable of visually monitoring shrimp spoilage during storage. These results implied that the CMS/PVA/Cu-Trp nanocomposite film holds tremendous potential as an intelligent active packaging material. • Novel Cu-Trp compatibilized CMS/PVA-based smart active films were created. • The films presented higher mechanical, water barrier, and UV-blocking properties. • The films had outstanding antibacterial and ammonia-sensitive function. • These smart films were successfully applied for shrimp freshness monitoring. [ABSTRACT FROM AUTHOR]

Background & Aims Pancreatic ductal adenocarcinomas (PDACs) produce higher levels of truncated O-glycan structures (such as Tn and sTn) than normal pancreata. Dysregulated activity of core 1 synthase glycoprotein-N-acetylgalactosamine 3-β-galactosyltransferase 1 (C1GALT1) leads to increased expression of these truncated O-glycans. We investigated whether and how truncated O-glycans contributes to the development and progression of PDAC using mice with disruption of C1galt1. Methods We crossed C1galt1 floxed mice (C1galt1 loxP/loxP ) with Kras G12D/+ ; Trp53 R172H/+ ; Pdx1-Cre (KPC) mice to create KPCC mice. Growth and progression of pancreatic tumors were compared between KPC and KPCC mice; pancreatic tissues were collected and analyzed by immunohistochemistry; immunofluorescence; and Sirius red, alcian blue, and lectin staining. We used the CRISPR/Cas9 system to disrupt C1GALT1 in human PDAC cells (T3M4 and CD18/HPAF) and levels of O-glycans were analyzed by lectin blotting, mass spectrometry, and lectin pulldown assay. Orthotopic studies and RNA sequencing analyses were performed with control and C1GALT1 knockout PDAC cells. C1GALT1 expression was analyzed in well-differentiated (n = 36) and poorly differentiated (n = 23) PDAC samples by immunohistochemistry. Results KPCC mice had significantly shorter survival times (median 102 days) than KPC mice (median 200 days) and developed early pancreatic intraepithelial neoplasias at 3 weeks, PDAC at 5 weeks, and metastasis at 10 weeks compared with KPC mice. Pancreatic tumors that developed in KPCC mice were more aggressive (more invasive and metastases) than those in KPC mice, had a decreased amount of stroma, and had increased production of Tn. Poorly differentiated PDAC specimens had significantly lower levels of C1GALT1 than well-differentiated PDACs. Human PDAC cells with knockout of C1GALT1 had aberrant glycosylation of MUC16 compared with control cells and increased expression of genes that regulate tumorigenesis and metastasis. Conclusions In studies of KPC mice with disruption of C1galt1 , we found that loss of C1galt1 promotes development of aggressive PDACs and increased metastasis. Knockout of C1galt1 leads to increased tumorigenicity and truncation of O-glycosylation on MUC16, which could contribute to increased aggressiveness. Graphical abstract [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we consider a plant disease model with latent period and nonautonomous phenomenon. We investigate the long-time behavior of the epidemic model. By constructing auxiliary functions, the weaker integral form conditions for permanence and extinction of the model are obtained. Numerical simulations which support our theoretical analysis are also given. [Copyright &y& Elsevier]

Abstract: Air sparging is now a standard approach to reduce concentration polarization and fouling of membrane modules in membrane bioreactors (MBRs). The hydrodynamic shear stresses, bubble-induced turbulence and cross flows scour the membrane surfaces and help reduce the deposit of foulants onto the membrane surface. However, the detailed quantitative knowledge on the effect of air sparging remains lacking in the literature due to the complex hydrodynamics generated by the gas–liquid flows. To date, there is no valid model that describes the relationship between the membrane fouling performance and the flow hydrodynamics. The present study aims to examine the impact of hydrodynamics induced by air sparging on the membrane fouling mitigation in a quantitative manner. A modelled hollow fiber module was placed in a cylindrical bubble column reactor at different axial heights with the trans-membrane pressure (TMP) monitored under constant flux conditions. The configuration of bubble column without the membrane module immersed was identical to that studied by Gan et al. (2011) using Phase Doppler Anemometry (PDA), to ensure a good quantitative understanding of turbulent flow conditions along the column height. The experimental results showed that the meandering flow regime which exhibits high flow instability at the 0.3 m is more beneficial to fouling alleviation compared with the steady flow circulation regime at the 0.6 m. The filtration tests also confirmed the existence of an optimal superficial air velocity beyond which a further increase is of no significant benefit on the membrane fouling reduction. In addition, the alternate aeration provided by two air stones mounted at the opposite end of the diameter of the bubble column was also studied to investigate the associated flow dynamics and its influence on the membrane filtration performance. It was found that with a proper switching interval and membrane module orientation, the membrane fouling can be effectively controlled with even smaller superficial air velocity than the optimal value provided by a single air stone. Finally, the testing results with both inorganic and organic feeds showed that the solid particle composition and particle size distribution all contribute to the cake formation in a membrane filtration system. [Copyright &y& Elsevier]

Abstract: Earthworms are important engineering species of many terrestrial ecosystems as they play a significant role in regulating C turnover. The effects of earthworms on moderating C decomposition processes differ across species and with interactions between species, which is not fully understood. We carried out an experiment to study the interactions of Lumbricus rubellus and Octolasion lacteum, and their effects on soil respiration. Laboratory mesocosms were set up using tulip poplar (Liriodendron tulipifera) leaf litter and varying densities of earthworms in single and combined species treatments. CO2 efflux rate was used as an indicator of C decomposition rates, and measured with CO2 sensors every five days over one month. L. rubellus induced higher leaf consumption rate and higher CO2 efflux than O. lacteum; meanwhile O. lacteum grew more than L. rubellus. Both litter consumption rate and growth rate of earthworms decreased with increasing earthworm density. Soil CO2 efflux increased with increasing earthworm density (from ∼1–2 μg CO2 g−1 hr−1 with no earthworms to ∼ 4 μg CO2 g−1 hr−1 with 8 earthworms). Combining the two species had a synergistic effect on leaf litter consumption, and neutralizing effects on soil respiration. The data suggest that the strength of intra- and inter-specific interactions among earthworm ecological groups varies at different absolute and relative densities, leading to altered leaf litter decomposition and C cycling. [Copyright &y& Elsevier]

Leukocyte recruitment to the arterial vessel wall is the first step in the development of atherosclerotic lesions. Leukocyte homing in this event proceeds through a well-defined adhesion cascade, which includes tethering, rolling, adhesion, and transmigration. Selectins, including the P-, E-, and L-selectins, and their ligands mediate the initial tethering and rolling. Interactions between selectins and their ligands serve as a braking system to decelerate fast-flowing leukocytes from the central blood stream and enable them to adhere to and transmigrate underneath the activated endothelium. The best characterized ligand for selectins is P-selectin glycoprotein ligand-1, an extended homodimeric mucin on leukocytes that binds to all three selectins. Recent studies show that differential expression or glycosylation of P-selectin glycoprotein ligand-1 in different leukocytes mediates selective recruitment of different subsets of monocytes or lymphocytes to atherosclerotic arteries. [Copyright &y& Elsevier]

Abstract: To assess the feasibility of using animal excrement to biomonitor the extent of heavy metal contamination in the marine environment, concentrations of mercury (Hg), lead (Pb), copper (Cu) and zinc (Zn) in the fresh excrement of seabirds and marine mammals, along with other biomaterials, from the Arctic, Antarctica (West and East), and Xisha Archipelago of the South China Sea were determined. Results show that the excrement of marine animals at higher trophic levels generally contained high levels of Hg, demonstrating the biomagnification of Hg through food chains in different remote regions. Significant variations in metal accumulation in the excrements were observed among the distinctive geographical areas, with the highest Hg concentration in Xisha Archipelago and the highest Pb concentration in the Arctic, which reflects different levels of air metal pollution at various sampling locations. Concentrations of Cu in the excrements primarily correlate to the geochemical background levels in the regions. High Cu concentrations were found near the Great Wall Station in West Antarctica where a copper mineralized belt exists. No clear spatial variation pattern was found for Zn accumulation in the excrement. This study shows that animal excrement can be used as bioindicators for the level of metal contamination in the marine environment, with the advantages of easy sampling, accurate detection (i.e., with high levels of metal accumulation), and reconstructing historical metal contamination trends by long-term monitoring of sedimentary excrements. [Copyright &y& Elsevier]

Background & Aims Core 1– and core 3–derived mucin-type O -linked oligosaccharides ( O -glycans) are major components of the colonic mucus layer. Defective forms of colonic O -glycans, such as the Thomsen-nouveau (Tn) antigen, frequently are observed in patients with ulcerative colitis and colorectal cancer, but it is not clear if they contribute to their pathogenesis. We investigated whether and how impaired O -glycosylation contributes to the development of colitis-associated colorectal cancer using mice lacking intestinal core 1– and core 3–derived O -glycans. Methods We generated mice that lack core 1– and core 3–derived intestinal O -glycans (DKO mice) and analyzed them, along with mice that singly lack intestinal epithelial core 1 O -glycans (IEC C1galt1 - /- mice) or core 3 O -glycans (C3 Gnt -/- mice). Intestinal tissues were collected at different time points and analyzed for levels of mucin and Tn antigen, development of colitis, and tumor formation using imaging, quantitative polymerase chain reaction, immunoblot, and enzyme-linked immunosorbent assay techniques. We also used cellular and genetic approaches, as well as intestinal microbiota depletion, to identify inflammatory mediators and pathways that contribute to disease in DKO and wild-type littermates (controls). Results Intestinal tissues from DKO mice contained higher levels of Tn antigen and had more severe spontaneous chronic colitis than tissues from IEC C1galt1 - /- mice, whereas spontaneous colitis was absent in C3GnT - /- and control mice. IEC C1galt1 - /- mice and DKO mice developed spontaneous colorectal tumors, although the onset of tumors in the DKO mice occurred earlier (age, 8–9 months) than that in IEC C1galt1 -/- mice (15 months old). Antibiotic depletion of the microbiota did not cause loss of Tn antigen but did reduce the development of colitis and cancer formation in DKO mice. Colon tissues from DKO mice, but not control mice, contained active forms of caspase 1 and increased caspase 11, which were reduced after antibiotic administration. Supernatants from colon tissues of DKO mice contained increased levels of interleukin-1β and interleukin-18, compared with those from control mice. Disruption of the caspase 1 and caspase 11 genes in DKO mice (DKO/ Casp 1/11 - /- mice) decreased the development of colitis and cancer, characterized by reduced colonic thickening, hyperplasia, inflammatory infiltrate, and tumors compared with DKO mice. Conclusions Impaired expression of O -glycans causes colonic mucus barrier breach and subsequent microbiota-mediated activation of caspase 1–dependent inflammasomes in colonic epithelial cells of mice. These processes could contribute to colitis-associated colon cancer in humans. [ABSTRACT FROM AUTHOR]

A strain FDN-01 was isolated from the sequencing batch biofilm reactor (SBBR) which was seeded with wasted activated sludge from a municipal wastewater treatment plant in Shanghai. Bacterium FDN-01 was identified as Thauera sp., and Genbank Sequence_ID was KY393097. By comparing inorganic total nitrogen (TN) removal efficiency by strain FDN-01 under different conditions, the optimal initial pH, carbon source and the ratio of carbon to nitrogen were 7.5, sodium succinate and 4.0, respectively. Inorganic TN removal efficiency was 93% within 3 d while the concentration of nitrate was 100 mg/L, and the type of substrates affected extracellular polymeric substances (EPS) production and the ratio of protein to polysaccharide in the EPS. Further investigation for the application of strain FDN-01 in the SBBRs showed that anoxic ammonia oxidation occurred at room temperature, and the removal efficiencies of inorganic TN were noticeably enhanced by the augmentation of bacterium FDN-01 back into the SBBR. This study provided a promising method of TN removal requiring less carbon source in the wastewater. Unlabelled Image • A newly strain FDN-01 was isolated from the sequencing batch biofilm reactor. • FDN-01 was identified as Thauera sp., and Genbank Sequence_ID was KY393097. • The removal efficiency of inorganic TN by augmentation of strain FDN-01 back into SBBRs was evidently increased. • The type of substrates affected EPS production and the ratio of protein to polysaccharide in the EPS. • A promising method of nitrogen removal from domestic sewage with lower C/N was provided. [ABSTRACT FROM AUTHOR]

We previously demonstrated that the survival time of BALB/c mice challenged with Toxoplasma gondii RH strain was prolonged by immunising the mice with a eukaryotic vector expressing the protein ROP16 of T. gondii . Building upon previous findings, we are exploring improved vaccination strategies to enhance protection. In this work, a novel recombinant canine adenovirus type 2 expressing ROP16 (CAV-2-ROP16) of T. gondii was constructed and identified to express ROP16 in Madin-Darby canine kidney cells (MDCK) cells by western blot (WB) and indirect immunofluorescence (IFA) assays. Intramuscular immunisation of BALB/c mice with CAV-2-ROP16 was performed to evaluate the humoral and cellular immune responses. This vaccination triggered significant humoral and cellular responses, including ROP16-stimulated lymphoproliferation ( P < 0.05). Compared to control groups, the CAV-2-ROP16 immunised mice had high production of IFN-γ, IL-2 and IL-12 ( P < 0.05), with a predominance of IgG2a production, but not IL-10 ( P > 0.05), revealing that a predominant Th1-type response had developed. The cell-mediated cytotoxic activity with high levels of IFN-γ and TNF-α was significantly increased in both CD4 + and CD8 + T-cell compartments in the mice immunised with CAV-2-ROP16 ( P < 0.05), compared to three control groups. In addition, when immunised mice were challenged with the RH strain of T. gondii , they showed a significantly increased survival rate (25%) 80 days post infection compared with control mice that all died within seven days ( P < 0.05). The 25% protection rate elicited by the recombinant virus CAV-2-ROP16 has not been achieved in the field of anti- T. gondii vaccination until now. Our work presents the successful use of recombinant virus CAV-2-ROP16 in vaccination protocols to protect against intraperitoneal challenge with the virulent RH strain of T. gondii . This system was shown to be extremely efficient in eliciting humoral and cellular immune responses that led to a significant improvement in survival time in mice. [ABSTRACT FROM AUTHOR]

Flow behavior and particle distribution in an inverted U-shape A356/SiCp composite casting produced by conventional investment casting were investigated experimentally and numerically. The mold filling process was directly observed by real-time X-ray radiography and the SiCp contents in casting different parts were quantitatively measured and analyzed. Based on the Euler and Lagrangian methods, the flow behavior of composite slurry and the particle distribution were simulated. During mold filling process, eddy flow occurred at gravity part and back flow formed at horizontal part after the gravity part had filled. The predicted results of particle trajectories showed that the flow characteristic of particles were turbulence, laminar, and large eddy flow at anti-gravity, horizontal, and gravity part, respectively. For the particle distribution, the measured and predicted results showed that more particles concentrate in the central section, while fewer particles were present near the surface section along the thickness. Moreover, the particle fractions generally decreased with the increasing distance to the ingate. The simulate results were reasonably suited with experimental data. [ABSTRACT FROM AUTHOR]

Abstract: Earthworms influence the biotic and abiotic characteristics of soils, but studying these effects in situ is challenging. Secondary forests in the Mid-Atlantic have abundant earthworm communities. To investigate the interaction of earthworms with the below- and aboveground part of the ecosystem, we manipulated earthworm densities in 1m2 enclosures located at 12 study sites within four different-aged forest stands at the Smithsonian Environmental Research Center (SERC) in Maryland, USA. The treatment plots were created by trenching around the perimeter and lining the trenches with fiberglass mesh before backfilling. Two types of untrenched plots served as control and leaf litter treatment plots. Enclosures were electroshocked between four and nine times over a two-year period to remove earthworms and to compare densities among treatment and untrenched plots. Earthworms were weighed and identified to determine whether removal by electroshocking varied depending on body size or ecological grouping. Earthworm abundances were 30–50% lower in reduced-density enclosures than in high density enclosures; however, the efficiency of the exclusion treatments varied by earthworm size and ecological group. Manipulating earthworm populations in temperate forests to assess their influence on ecological functions is feasible using electroshocking, but careful planning is essential given the amount of effort required to set up and maintain the desired experimental conditions. [Copyright &y& Elsevier]