403 research outputs found
Novel silica filled deep eutectic solvent based nanofluids for energy transportation
Liquid range of nanofluids is a crucial parameter as it intensively determines their application temperature scope. Meanwhile, improved thermal conductivity and stability are of great significances and comprise the main fundamental research topics of nanofluids. In this work, 2- butoxy-3,4-dihydropyran (DP), produced from a convenient one-pot three-component reaction in water, was employed as dual lipophilic brusher and metal nanoparticle anchor. It was found that DP was able to enhance the dispersing ability and thermal conductivity of SiO2 nanoparticle filled deep eutectic solvent (DES) based nanofluids simultaneously. The key to the success of this protocol mainly relies on the electrophilic property and acetylacetonate moiety of DP, which ensures the formation of DP surficial modified and copper nanoparticle coated silica. Molecular dynamics simulation revealed that the hydrogen bonding effect between base solvent and alkane chain of nanoparticle was responsible for the enhanced affinity, which thus resulted in an improved stability. Viscosities of the nanofluids dropped within a certain range owing to the ruin of hydrogen bonding association among solvent molecules resulted by the hydrogen bonding effect between nanoparticle and solvent. Thermal conductivity of the copper modified silica filled DES nanofluids exhibits a maximum 13.6% enhancement, which demonstrated the advantages of this chemical covalent protocol. Additionally, study upon viscosity and convective heat transfer coefficient of the nanofluids with varies types of silica nanoparticle and DES base solvents indicated that a 24.9% heat transfer coefficient enhancement was gained that further revealed the superiority of this protocol
In vivo consequences of deleting EGF repeats 8–12 including the ligand binding domain of mouse Notch1
<p>Abstract</p> <p>Background</p> <p>Notch signaling is highly conserved in the metazoa and is critical for many cell fate decisions. Notch activation occurs following ligand binding to Notch extracellular domain. <it>In vitro </it>binding assays have identified epidermal growth factor (EGF) repeats 11 and 12 as the ligand binding domain of Drosophila Notch. Here we show that an internal deletion in mouse Notch1 of EGF repeats 8–12, including the putative ligand binding domain (lbd), is an inactivating mutation <it>in vivo</it>. We also show that maternal and zygotic <it>Notch1</it><sup><it>lbd</it>/<it>lbd </it></sup>mutant embryos develop through gastrulation to mid-gestation.</p> <p>Results</p> <p><it>Notch1</it><sup><it>lbd</it>/<it>lbd </it></sup>embryos died at mid-gestation with a phenotype indistinguishable from <it>Notch1 </it>null mutants. In embryonic stem (ES) cells, Notch1<sup>lbd </sup>was expressed on the cell surface at levels equivalent to wild type Notch1, but Delta1 binding was reduced to the same level as in <it>Notch1 </it>null cells. In an ES cell co-culture assay, Notch signaling induced by Jagged1 or Delta1 was reduced to a similar level in <it>Notch1</it><sup><it>lbd</it><it/></sup>and <it>Notch1 </it>null cells. However, the <it>Notch1</it><sup><it>lbd</it>/<it>lbd </it></sup>allele was expressed similarly to wild type Notch1 in <it>Notch1</it><sup><it>lbd</it>/<it>lbd </it></sup>ES cells and embryos at E8.75, indicating that Notch1 signaling is not essential for the <it>Notch1 </it>gene to be expressed. In addition, maternal and zygotic <it>Notch1 </it>mutant blastocysts developed through gastrulation.</p> <p>Conclusion</p> <p>Mouse Notch1 lacking the ligand binding domain is expressed at the cell surface but does not signal in response to the canonical Notch ligands Delta1 and Jagged1. Homozygous <it>Notch1</it><sup><it>lbd</it>/<it>lbd </it></sup>mutant embryos die at ~E10 similar to <it>Notch1 </it>null embryos. While Notch1 is expressed in oocytes and blastocysts, Notch1 signaling via canonical ligands is dispensable during oogenesis, blastogenesis, implantation and gastrulation.</p
Novel Silica Filled Deep Eutectic Solvent Based Nanofluids for Energy Transportation
Liquid range of nanofluids is a crucial parameter as it intensively determines their application temperature scope. Meanwhile, improved thermal conductivity and stability are of great significances and comprise the main fundamental research topics of nanofluids. In this work, 2-butoxy-3,4-dihydropyran (DP), produced from a convenient one-pot three-component reaction in water, was employed as dual lipophilic brusher and metal nanoparticle anchor. It was found that DP was able to enhance the dispersing ability and thermal conductivity of SiO2 nanoparticle filled deep eutectic solvent (DES) based nanofluids simultaneously. The key to the success of this protocol mainly relies on the electrophilic property and acetylacetonate moiety of DP, which ensures the formation of DP surficial modified and copper nanoparticle coated silica. Molecular dynamics simulation revealed that the hydrogen bonding effect between base solvent and alkane chain of nanoparticle was responsible for the enhanced affinity, which thus resulted in an improved stability. Viscosities of the nanofluids dropped within a certain range owing to the ruin of hydrogen bonding association among solvent molecules resulted by the hydrogen bonding effect between nanoparticle and solvent. Thermal conductivity of the copper modified silica filled DES nanofluids exhibits a maximum 13.6% enhancement, which demonstrated the advantages of this chemical covalent protocol. Additionally, study upon viscosity and convective heat transfer coefficient of the nanofluids with varies types of silica nanoparticle and DES base solvents indicated that a 24.9% heat transfer coefficient enhancement was gained that further revealed the superiority of this protocol
Role of the PADI family in inflammatory autoimmune diseases and cancers: A systematic review
The peptidyl arginine deiminase (PADI) family is a calcium ion-dependent group of isozymes with sequence similarity that catalyze the citrullination of proteins. Histones can serve as the target substrate of PADI family isozymes, and therefore, the PADI family is involved in NETosis and the secretion of inflammatory cytokines. Thus, the PADI family is associated with the development of inflammatory autoimmune diseases and cancer, reproductive development, and other related diseases. In this review, we systematically discuss the role of the PADI family in the pathogenesis of various diseases based on studies from the past decade to provide a reference for future research
A New Guide Lifter for the Transceiver of USBL
A new guide lifter has been put forward for the transceiver of Ultra Short Base Line (USBL) with a worm gear reducer applied as self-locking of the lifter and a chain structure applied to drive the sliding shaft moving up and down. The new device is 7500 mm long and connected to the end of the transceiver. Linear motion products are introduced to ensure the shaft unable to rotate and the position measurements are provided by position sensors. A heavy self-sealing sliding bearing, which is 800 mm in length, keeps the shaft running reliably. Then the three-dimensional model is built and the structure parameters of the lifter are calculated. Later, the working process of the lifter is simulated to guarantee the movement parameters meet the request of USBL. Finally, the experiment on the intensity and stiffness of the lifter is carried out via the finite element model of the lifter built in ANSYS with the maximum load conditions and the result has been experimentally verified. This device provides a reliable approach of operating USBL which plays a vitally important role in ocean exploration and the research results are successfully applied to the scientific research vessels of Dayang No. 1 as well as Xiangyanghong No. 9
Nitrogen addition mediates the response of foliar stoichiometry to phosphorus addition: a meta-analysis
Background Changes in foliar nitrogen (N) and phosphorus (P) stoichiometry play important roles in predicting the effects of global change on ecosystem structure and function. However, there is substantial debate on the effects of P addition on foliar N and P stoichiometry, particularly under different levels of N addition. Thus, we conducted a global meta-analysis to investigate how N addition alters the effects of P addition on foliar N and P stoichiometry across different rates and durations of P addition and plant growth types based on more than 1150 observations. Results We found that P addition without N addition increased foliar N concentrations, whereas P addition with N addition had no effect. The positive effects of P addition on foliar P concentrations were greater without N addition than with N addition. Additionally, the effects of P addition on foliar N, P and N:P ratios varied with the rate and duration of P addition. In particular, short-term or low-dose P addition with and without N addition increased foliar N concentration, and the positive effects of short-term or low-dose P addition on foliar P concentrations were greater without N addition than with N addition. The responses of foliar N and P stoichiometry of evergreen plants to P addition were greater without N addition than with N addition. Moreover, regardless of N addition, soil P availability was more effective than P resorption efficiency in predicting the changes in foliar N and P stoichiometry in response to P addition. Conclusions Our results highlight that increasing N deposition might alter the response of foliar N and P stoichiometry to P addition and demonstrate the important effect of the experimental environment on the results. These results advance our understanding of the response of plant nutrient use efficiency to P addition with increasing N deposition
Numerical analysis on the centralization effect of improved horizontal well casing centralizer
Horizontal well technology is a promising method for oil and gas development. During cementing operations in horizontal wells, it was found that conventional casing centralizers could not meet the requirements for casing cementing in expanded wellbores. Therefore, a new type of casing centralizer needs to be designed for horizontal well sections that have undergone enlargement. By analyzing the most common materials currently used, 45 steel was selected for the spring leaf of the novel casing centralizer. To evaluate the centralization effect of the horizontal well casing centralizer, a casing centralization degree evaluation function was established, and a wellbore-centralizer mechanical model was proposed using the finite element method to simulate the working conditions of the centralizer spring leaf in ϕ215.9 and ϕ311.2 mm well sections. On this basis, a wellbore-centralizer-casing coupling model that does not consider the effect of wellbore fluid on the casing was established to simulate the centralization characteristics of the new casing centralizer and traditional centralizer under different wellbore sizes. Simulation results show that the average casing centralization degree of the new centralizer is 85.53%, while that of the traditional centralizer is 55.58%. That is, the horizontal well casing centralizer can maintain a good centralization effect on the casing string
Contrasting Soil Bacterial Community, Diversity, and Function in Two Forests in China
Bacteria are the highest abundant microorganisms in the soil. To investigate bacteria community structures, diversity, and functions, contrasting them in four different seasons all the year round with/within two different forest type soils of China. We analyzed soil bacterial community based on 16S rRNA gene sequencing via Illumina HiSeq platform at a temperate deciduous broad-leaved forest (Baotianman, BTM) and a tropical rainforest (Jianfengling, JFL). We obtained 51,137 operational taxonomic units (OTUs) and classified them into 44 phyla and 556 known genera, 18.2% of which had a relative abundance >1%. The composition in each phylum was similar between the two forest sites. Proteobacteria and Acidobacteria were the most abundant phyla in the soil samples between the two forest sites. The Shannon index did not significantly differ among the four seasons at BTM or JFL and was higher at BTM than JFL in each season. The bacteria community at both BTM and JFL showed two significant (P < 0.05) predicted functions related to carbon cycle (anoxygenic photoautotrophy sulfur oxidizing and anoxygenic photoautotrophy) and three significant (P < 0.05) predicted functions related to nitrogen cycle (nitrous denitrificaton, nitrite denitrification, and nitrous oxide denitrification). We provide the basis on how changes in bacterial community composition and diversity leading to differences in carbon and nitrogen cycles at the two forests
Recent advances of nanofluids in micro/nano scale energy transportation
As the continuing integration and size deflation of component dimensions in electronic circuits and increase in the number of transistors in modern microprocessor chips, especially for heat dissipation of micro/nano scale devise, traditionally used single phase fluid cannot meet the requirements for highly efficient heat transfer, which thus frequently results in the damage of electrical devices. Consequently, thermal conductivity enhancement of working fluids is of great significance for advanced thermal energy conservation and conversion. Nanofluids, which possess a superior thermal conductive performance, are studied towards an alternative to the traditionally used working fluids, have attracted ample attention within the past decades. In this paper, firstly, we summarized the recent progress in the preparation of nanofluids, in particular for a method involving a covalent concerning reorganization or generation; subsequently, the utilization of nanofluids in hitherto unsummerized micro/nano scale heat and mass transfer fields, especially for some chemistry relating applications were discussed. All works demonstrated in this review are aiming at clarifying the fact that advanced material technologies are required in preparation of recent nanofluids on the premise of continuing harsh energy transfer situation; on the other hand, nanofluids were also able to offer insights for novel micro/nano scale energy transportation which has not yet been reviewed before
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