733 research outputs found
A multi-continuum model for simulating in-situ conversion process in low-medium maturity shale oil reservoir
In-situ conversion is proposed applicable for low-medium maturity shale oil reservoir. However, parallel chemical kinetic reactions and evolution of shale pores during in-situ conversion make the numerical simulation a challenging problem. Although shale is typical multiscale and heterogeneous media, few models in previous studies take the difference between organic and inorganic system into consideration, which cannot simulate fluid flow accurately. In this paper, a multi-continuum model, considering coupled thermal-reactive compositional flow, is developed to simulate in-situ conversion process in low-medium maturity shale oil reservoir. The reaction of kerogen and hydrocarbon is quantified using kinetic reaction model. The evolution of fluid composition and shale properties are also incorporated. The accuracy of multiple-interacting-continua model and compositional model are demonstrated by comparing with commercial software and analytical solution. Then, the typical hexagon vertical well heating pattern is simulated and the feasibility is evaluated from an economic aspect. Finally, a series of case studies are conducted to investigate the impact of operation parameters on shale oil production.Cited as: Wang, Z., Yao, J., Sun, H, Yan, X., Yang, Y. A multi-continuum model for simulating in-situ conversion process in low-medium maturity shale oil reservoir. Advances in Geo-Energy Research, 2021, 5(4): 456-464, doi: 10.46690/ager.2021.04.1
Studies on some active components and antimicrobial activities of the fermentation broth of endophytic fungi DZY16 Isolated from Eucommia ulmoides Oliv.
Research into plant-derived endophytic fungi has grown in recent decades. Endophytic fungi still have enormous potential to inspire and influence modern agriculture. In this study, the endophytic fungi DZY16 isolated from Eucommia ulmoides Oliv. was tested for its bioactive components and antimicrobial activities using phenol-sulfuric acid method, high performance liquid chromatography method and growth inhibition measurements. The results show that variation trend of extracellular polysaccharide content at different growth stages of the strain DZY16 and the maximum content of extracellular polysaccharide was 2.02 g/L at the sixth day. Moreover, the fermentation broth of the DZY16 contained guanosine, uridine and adenosine; the contents were 1.54 mg/g, 1.07 mg/g and 1.36 mg/g respectively. On the other hand, the strongest antimicrobial activity was exhibited by the acetylacetate extract of strain DZY16 against Rhizoctonia solani and Gibberella zeae, showing 59.84 and 70.86% respectively. The strain DZY16 was identified by internal transcribed spacer (ITS) sequence as belonging to Nigrospora. The results indicate that the endophytic fungi DZY16 of the plant E. ulmoides Oliv. is a promising source of novel bioactive compounds.Keywords: Eucommia ulmoides Oliv., endophytic fungi, extracellular polysaccharide, nucleotides, antimicrobial activityAfrican Journal of Biotechnology Vol. 12(15), pp. 1862-186
Recent advances and current issues in single-cell sequencing of tumors
AbstractIntratumoral heterogeneity is a recently recognized but important feature of cancer that underlies the various biocharacteristics of cancer tissues. The advent of next-generation sequencing technologies has facilitated large scale capture of genomic data, while the recent development of single-cell sequencing has allowed for more in-depth studies into the complex molecular mechanisms of intratumoral heterogeneity. In this review, the recent advances and current challenges in single-cell sequencing methodologies are discussed, highlighting the potential power of these data to provide insights into oncological processes, from tumorigenesis through progression to metastasis and therapy resistance
A comparative study of nemertean complete mitochondrial genomes, including two new ones for Nectonemertes cf. mirabilis and Zygeupolia rubens, may elucidate the fundamental pattern for the phylum Nemertea
<p>Abstract</p> <p>Background</p> <p>The mitochondrial genome is important for studying genome evolution as well as reconstructing the phylogeny of organisms. Complete mitochondrial genome sequences have been reported for more than 2200 metazoans, mainly vertebrates and arthropods. To date, from a total of about 1275 described nemertean species, only three complete and two partial mitochondrial DNA sequences from nemerteans have been published. Here, we report the entire mitochondrial genomes for two more nemertean species: <it>Nectonemertes </it>cf. <it>mirabilis </it>and <it>Zygeupolia rubens</it>.</p> <p>Results</p> <p>The sizes of the entire mitochondrial genomes are 15365 bp for <it>N</it>. cf. <it>mirabilis </it>and 15513 bp for <it>Z. rubens</it>. Each circular genome contains 37 genes and an AT-rich non-coding region, and overall nucleotide composition is AT-rich. In both species, there is significant strand asymmetry in the distribution of nucleotides, with the coding strand being richer in T than A and in G than C. The AT-rich non-coding regions of the two genomes have some repeat sequences and stem-loop structures, both of which may be associated with the initiation of replication or transcription. The 22 tRNAs show variable substitution patterns in nemerteans, with higher sequence conservation in genes located on the H strand. Gene arrangement of <it>N</it>. cf. <it>mirabilis </it>is identical to that of <it>Paranemertes </it>cf. <it>peregrina</it>, both of which are Hoplonemertea, while that of <it>Z. rubens </it>is the same as in <it>Lineus viridis</it>, both of which are Heteronemertea. Comparison of the gene arrangements and phylogenomic analysis based on concatenated nucleotide sequences of the 12 mitochondrial protein-coding genes revealed that species with closer relationships share more identical gene blocks.</p> <p>Conclusion</p> <p>The two new mitochondrial genomes share many features, including gene contents, with other known nemertean mitochondrial genomes. The tRNA families display a composite substitution pathway. Gene order comparison to the proposed ground pattern of Bilateria and some lophotrochozoans suggests that the nemertean ancestral mitochondrial gene order most closely resembles the heteronemertean type. Phylogenetic analysis proposes a sister-group relationship between Hetero- and Hoplonemertea, which supports one of two recent alternative hypotheses of nemertean phylogeny.</p
1,3-Bis[(4-nitrobenzylidene)aminooxy]propane
The complete molecule of title compound, C17H16N4O6, is generated by a crystallographic twofold axis. Within the molecule, the two benzene units are approximately perpendicular, making a dihedral angle of 85.91 (4)°. In the crystal, molecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds and short O⋯O and N⋯O interactions, with distances of 2.998 (2) and 2.968 (3) Å, respectively
A comprehensive review on the ferroelectric orthochromates: Synthesis, property, and application
Multiferroics represent a class of advanced materials for promising
applications and stand at the forefront of modern science for the special
feature possessing both charge polar and magnetic order. Previous studies
indicate that the family of RECrO3 (RE = rare earth) compounds is likely
another rare candidate system holding both ferroelectricity and magnetism.
However, many issues remain unsolved, casting hot disputes about whether RECrO3
is multiferroic or not. For example, an incompatibility exists between reported
structural models and observed ferroelectric behaviors, and it is not easy to
determine the spin canting degree. To address these questions, one key step is
to grow single crystals because they can provide more reliable information than
other forms of matter do. In this review, the parent and doped ferroelectric
YCrO3 compounds are comprehensively reviewed based on scientific and patent
literatures from 1954 to 2022. The materials syntheses with different methods,
including poly-, nano-, and single-crystalline samples and thin films, are
summarized. The structural, magnetic, ferroelectric and dielectric, optical,
and chemical-pressure (on Y and Cr sites by doping) dependent chemical and
physical properties and the corresponding phase diagrams, are discussed.
Diverse (potential) applications, including anti-corrosion, magnetohydrodynamic
electrode, catalyst, negative-temperature-coefficient thermistor, magnetic
refrigeration, protective coating, and solid oxide fuel cell, are present. To
conclude, we summarize general results, reached consensuses, and existing
controversies of the past nearly 69 years of intensive studies and highlight
future research opportunities and emerging challenges to address existing
issues.Comment: 69 pages, 35 figures, accepted by Coordination Chemistry Review
Microwave assisted synthesis, antifungal activity, DFT and SAR study of 1,2,4-triazolo[4,3-a]pyridine derivatives containing hydrazone moieties
Temperature-dependent structure of an intermetallic ErPdSi single crystal: A combined synchrotron and in-house X-ray diffraction study
We have grown intermetallic ErPdSi single crystals employing
laser-diodes with the floating-zone method. The temperature-dependent
crystallography was determined using synchrotron and in-house X-ray powder
diffraction measurements from 20 to 500 K. The diffraction patterns fit well
with the tetragonal 4/ space group (No. 139) with two chemical formulas
within one unit cell. Our synchrotron X-ray powder diffraction study shows that
the refined lattice constants are = 4.10320(2) {\AA}, = 9.88393(5)
{\AA} at 298 K and = 4.11737(2) {\AA}, = 9.88143(5) {\AA} at 500 K,
resulting in the unit-cell volume = 166.408(1) {\AA} (298 K) and
167.517(2) {\AA} (500 K). In the whole studied temperature range, we did
not find any structural phase transition. Upon cooling, the lattice constants a
and c are shortened and elongated, respectively.Comment: 5 Figures, 4 Table
Sexual Interference Behaviors in Male Adult and Subadult Tibetan Macaques (\u3ci\u3eMacaca thibetana\u3c/i\u3e)
Male nonhuman primate sexual interference, which includes copulation interruption and copulation harassment, has been related to reproductive success, but its significance has been challenging to test. Copulation interruption results in the termination of a copulation before ejaculation, whereas copulation harassment does not. We conducted this study using the all-occurrence behavior sampling method on sexual interference behaviors of seven adult and four subadult male Tibetan macaques (Macaca thibetana) in mating and non-mating seasons at Mt. Huangshan, China, from August 2016 to May 2017. Our results showed that males’ individual proportion of copulation interruption and harassment was higher during the mating season than during the non-mating season. In addition, dominant males more often performed interruption, whereas subordinate males more often performed harassment. We found no difference in the individual proportion of copulation interruption or harassment between adult and subadult males. Adult and subadult males both directed copulation interruption and harassment more often toward the mating male than toward the mating female. Lastly, the post-ejaculation phase of copulation was shorter when copulation harassment occurred than when it did not. Our results suggest that sexual interference may be an important mating tactic that adult and subadult males use in male–male sexual competition
Characterization of adipocyte differentiation from human mesenchymal stem cells in bone marrow
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