The nitrogen conversions in relation to NH3 and HCN were investigated during microwave pyrolysis of sewage sludge. The nitrogen distributions and evolution of nitrogen functionalities in the char, ...tar, and gas fractions were conducted. The results suggested that the thermal cracking of protein in sludge produced three important intermediate compounds, including the amine-N, heterocyclic-N, and nitrile-N compounds. The deamination of amine-N compounds resulted from labile proteins cracking led to the formation of NH3 (about 7.5% of SS-N) between 300 and 500 °C. The cracking of nitrile-N and heterocyclic-N compounds in the tars from the dehydrogenation and polymerization of amine-N generated HCN (6.6%) from 500 to 800 °C, respectively. Moreover, the ring-opening of heterocyclic-N in the char and tar contributed to the release of NH3 accounting for about 18.3% of SS-N with the temperature increasing from 500 to 800 °C. Specifically, the thermal cracking of amine-N, heterocyclic-N and nitrile-N compounds contributed to above 80% of the total (HCN+NH3) productions. Consequently, it might be able to reduce the HCN and NH3 emissions through controlling the three intermediates production at the temperature of 500–800 °C.
► A novel Microwave Heating Reactor was designed to introduce microwave heating in the pyrolysis. ► The evolution of nitrogenated compounds in the char, tar and gas fractions were investigated. ► ...Three key intermediate compounds was identified in the pyrolysis tars during the pyrolysis. ► The gas products were formed with comparable activation energies from the same reactive species. ► The nitrogen transformation pathways in relation to NH3 and HCN formation were proposed.
The nitrogen transformations with attention to NH3 and HCN were investigated at temperatures of 300–800°C during microwave pyrolysis of a protein model compound. The evolution of nitrogenated compounds in the char, tar and gas products were conducted. The amine-N, heterocyclic-N and nitrile-N compounds were identified as three important intermediates during the pyrolysis. NH3 and HCN were formed with comparable activation energies competed to consume the same reactive substances at temperatures of 300–800°C. The deamination and dehydrogenation of amine-N compounds from protein cracking contributed to the formation of NH3 (about 8.9% of Soy-N) and HCN (6.6%) from 300 to 500°C. The cracking of nitrile-N and heterocyclic-N compounds from the dehydrogenation and polymerization of amine-N generated HCN (13.4%) and NH3 (31.3%) between 500 and 800°C. It might be able to reduce the HCN and NH3 emissions through controlling the intermediates production at temperatures of 500–800°C.
Distribution variation of a metabolic uncoupler, 2,6-dichlorophenol (2,6-DCP), in long-term sludge culture was studied, and the effects on sludge reduction and biological inhibition of this chemical ...during the 90-day operation were established. The extracellular polymeric substance (EPS) matrix functioned as a protective barrier for the bacteria inside sludge flocs to 2,6-DCP, resulting in the transfer of 2,6-DCP from the liquid phase to the activated sludge fraction. Significant sludge reduction (about 40%) was observed after the addition of 2,6-DCP in the first 40 days, while the ineffective function of 2,6-DCP in sludge reduction (days 70–90) might be correlated to the EPS protection mechanism. The inhibitory effect of 2,6-DCP on the COD removal was extremely lower than on the nitrification performance due to the fact that 2,6-DCP was much more toxic to autotrophic microorganisms than heterotrophic microorganisms. Moreover, both of them recovered to a higher level again with the transfer potential of 2,6-DCP to sludge. Thus, the application of metabolic uncoupler for excess sludge reduction should be cautious.
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► Sludge reduction and biological inhibition of 2,6-DCP are widely linked to its transformation behavior. ► EPS functions as protective barrier for sludge bacteria to 2,6-DCP to transfer from liquid to sludge. ► Significant sludge reduction (about 40%) was observed in the first addition of 2,6-DCP for 40 days. ► The ineffective function of 2,6-DCP in sludge reduction was found in long-term operation. ► 2,6-DCP was much more toxic to autotrophic microorganisms than heterotrophic microorganisms.
Several approaches to expand human hematopoietic stem cells (HSCs) have been reported, but the ability of these methods to expand long-term hematopoietic stem cells (LT-HSCs) remains to be improved, ...which limits the application of HSCs-based therapies.
CD34+ cells were purified from umbilical cord blood using MacsCD34 beads, and then cultured for 12 d in a serum-free medium. Flow cytometry was used to detect phenotype, cell cycle distribution, and apoptosis of the cultured cells. Colony-forming cell (CFC) assays can evaluate multi-lineage differentiation potential of HSCs. Real-time polymerase chain reaction was employed to detect the expression of genes related to self-renewal programs and antioxidant activity. DCFH-DA probes were used to evaluate intracellular production of reactive oxygen species (ROS). Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead array.
Here, we show a combination, Nicotinamide (NAM) combined with pyrimidoindole derivative UM171, can massively expand LT-HSCs ex vivo, and the expanded cells maintained the capability of self-renewal and multilineage differentiation. Additionally, our data indicated that UM171 promoted self-renewal of HSCs by inducing HSCs entry into the cell cycle and activating Notch and Wnt pathways, but the infinite occurrence of this process may lead to mitochondrial metabolism disorder and differentiation of HSCs. NAM kept HSCs in their primitive and dormant states by reducing intracellular ROS levels and upregulating the expression of stemness related genes, so we believed that NAM can act as a brake to control the above process.
The discovery of the synergistic effect of NAM and UM171 for expanding LT-HSCs provides a new strategy in solving the clinical issue of limited numbers of HSCs.
•NAM and UM171 have a synergistic effect on expanding LT-HSCs.•NAM maintains HSCs in dormant states by reducing intracellular ROS and upregulating the expression of stemness related genes.•UM171 promotes self-renewal of HSCs by inducing HSCs entry into the cell cycle and activating Notch and Wnt pathways.•NAM can act as a brake to control the effects of UM171, ensuring precise regulation of self-renewal.
A crucial aim in neuroscience is to understand how the human brain adapts to varying cognitive demands. This study investigates network reconfiguration during controlled semantic retrieval in ...differing contexts. We analyze brain responses to two semantic tasks of varying difficulty – global association and feature matching judgments – which are contrasted with non-semantic tasks on the cortical surface and within a whole-brain state space. Demanding semantic association tasks elicit activation in anterior prefrontal and temporal regions, while challenging semantic feature matching and non-semantic tasks predominantly activate posterior regions. Task difficulty also modulates activation along different dimensions of functional organization, suggesting different mechanisms of cognitive control. More demanding semantic association judgments engage cognitive control and default mode networks together, while feature matching and non-semantic tasks are skewed towards cognitive control networks. These findings highlight the brain’s dynamic ability to tailor its networks to support diverse neurocognitive states, enriching our understanding of controlled cognition.An fMRI study on healthy participants suggests that two distinct brain states support controlled semantic cognition: one state facilitates the controlled retrieval of semantic associations, while the other state supports goal-driven control.
Monitoring living plankton status has greatly developed owing to machine vision technology. One of these developments is the automatic video acquisition system, which can capture high-resolution ...information and record considerable details of a scene. However, existing optical sensors cannot usually obtain a whole image, in which all details of plankton are fully clear, due to the influence of many factors, such as depth-of-field limitation of lenses, movement of plankton, and large difference in plankton scale. The captured video also needs to be filtered to eliminate the redundancy before using for the sparsity of the sample. This procedure is time-consuming and costly. Therefore, in this article, we develop an end-to-end plankton database collection system that can directly generate complete, clear plankton images from video. First, the regions of interest of the plankton are extracted. Then, the same plankton which appears in successive frames is identified to reconstruct the clearest morphological and structure features through their detailed information. Experimental results indicate that the proposed system can effectively compress the original data. The proposed fusion method also outperforms the state-of-the-art methods, especially for images with anisotropic blur. Furthermore, this system can monitor the abundance and distribution of marine plankton with the help of an embedded computing platform.
Haematopoietic stem cell transplantation (HSCT) is considered an effective treatment for some haematopoietic malignancies, haematopoietic failure and immunodeficiency. Compared with bone marrow and ...mobilized peripheral blood, cord blood has the advantages of easy access, being harmless to donors and low requirement for HLA matching. In addition, umbilical cord blood transplantation (UCBT) has achieved remarkable clinical success in the past 30 years due to the low recurrence rate of malignancies treated by UCBT, mild degree of chronic graft-versus-host disease (GVHD) and good quality of life for patients after transplantation. However, the number of cells in a single cord blood is too small for rapid bone marrow implantation. We summarize the various factors involved that need to be considered in the expansion of haematopoietic stem cells (HSCs) in vitro, which all avoid complex operations, such as vector construction and virus transfection. We also found it necessary to identify a new molecule as the carrier of HSCs cultured in vitro, which not only would provide a three-dimensional structure conducive to the self-renewal of HSCs but also prevent their differentiation.
Umbilical cord blood (UCB) is a valuable source of hematopoietic stem cells (HSCs) used for transplantation; the number of cells in a single UCB is too small to quickly establish bone marrow (BM) ...implantation, and ex vivo expansion of HSCs has the potential to overcome this limitation. The purpose of this study is to explore the culture conditions conducive to the maintenance and expansion of hematopoietic stem and progenitor cells (HSPCs) and long‐term hematopoietic stem cells (LT‐HSCs) derived from human umbilical cord blood, compare the different effects of albumin (HSA) and polyvinyl alcohol (PVA), optimize the culture system using UM171 and investigate the molecular mechanism of PVA and UM171 promoting the expansion of primitive hematopoietic stem cells. CD34+ cells were purified from UCB using MacsCD34 beads, and then cultured in serum‐free medium supplemented with cytokines for 12 days, with PVA or UM171 added according to experimental requirements; the relative percentage of different HSCs subsets after culture were detected by flow cytometry; CFU Assay Setup for detecting the multilineage differentiation potential of HSCs; RT‐PCR detection of gene expression levels; reactive oxygen detection assessment of intracellular ROS levels. (1) The conditions of 20 ng/mlSCF, 100 ng/mlTPO, and 5% oxygen concentration are conducive to the maintenance of LT‐HSCs. (2) Compared with HSA, PVA significantly increased the proportion of HSPCs and LT‐HSCs, as well as dramatically promoted the expression of antioxidant enzymes and reduced the production of reactive oxygen species (ROS). (3) After adding UM171 to PVA‐based medium, the proportion of HSPCs and LT‐HSCs further increased, and downstream genes of Notch and Wnt pathways were selectively activated. (1) PVA may inhibit ROS production by upregulating the expression of antioxidant enzymes, which is beneficial for maintaining stemness and inhibiting differentiation of HSCs. (2) The antioxidant properties of PVA can delay differentiation, while UM171 can promote self‐renewal by regulating the stem cell pathway, and the combination of them is beneficial for the maintenance and expansion of HSCs in vitro.
Plankton is the base of the ocean ecosystem and is very sensitive to changes in their environment. Thus, monitoring the status of plankton
in-situ
has incredible importance for environmental study. ...Hologram is one of the most effective methods to record the plankton’s living status underwater. However, the reconstruction of holograms, conventionally achieved by numerical calculation, costs high both in computation and memory. Moreover, the plankton holograms are heavily noised, and useful information is sparsely distributed. To obtain high-speed visual image reconstruction from plankton holograms with good performance, in this paper, an efficient, low-redundant, and multi-object reconstruction network for plankton holograms, that is Holo-Net, is proposed. The Holo-Net includes a plankton detection unit and a reconstruction unit. It can first detect the plankton region and then map it to a visual image. A plankton hologram dataset is produced to verify the efficiency of the proposed method. Experiments show that the Holo-Net achieves PSNR and SSIM up to 20.61 and 0.65, respectively. More important, the Holo-Net is faster than the numerical method at least 100 times. We believe this work will facilitate the development of a compact
in-situ
plankton holographic monitoring system and help the research of the marine biosystem.
Japonica rice (Oryza sativa, L.), Fangxin 4 was cultured under ambient night temperature (ANT) and high night temperature (HNT) in greenhouse. The average HNTs were 4.7 °C and 8.6 °C greater than ...ANTs in 2009 and 2010, respectively. The effects of HNT on formation of amyloplast, crystalline structure, thermal properties, and molecular structure were investigated during grain filling stage of 10–35 d after anthesis. Results indicated that amylose contents were gradually formed along with the maturing of rice amyloplast. Moreover, amylose content of HNT treatment decreased by 7.13%–15.44% compared with that of ANT at 35 d after anthesis. TO, TP, TC and ΔHgel for HNT were higher than those of ANT. From 10 to 35 d, relative crystallinity presented an increase–decrease–increase pattern, and the relative crystallinity of HNT was 4.06%–14.51% higher than that of ANT at 35 d after anthesis. Amylopectin under ANT had a higher percentage of degree of polymerization (DP) 6–11, while amylopectin under HNT had a higher percentage of DP 12–23. HNT stress had an influence on the formation of amylose content and amylopectin structure, and then changed the crystalline and thermal properties of rice starch.
•Amylose content of Fangxin 4 decreased by 7.13%–15.44% under high night temperature.•Relative crystallinity of starch presented an increase–decrease–increase pattern.•TO, TP, TC and ΔHgel of starch for high night temperature were higher than control.•Amylopectin under high night temperature had a higher percentage of DP 12–23.
