scholarly journals Unidirectional crystallization and 3D structure of ternary four-component eutectic of B4C-NbB2-SiC system

2021 ◽  
pp. 6-13
Author(s):  
V. Mazur ◽  
Yu. Bogomol ◽  
N. Upatov
Keyword(s):  
Structural Model ◽  
3D Structure ◽  
Eutectic Phase ◽  
Eutectic Cell ◽  
Directional Crystallization ◽  
Small Crystals ◽  
Three Phase ◽  
Ternary Eutectics ◽  
First Time ◽  
Kinetics Of

Purpose. To investigate the laws of crystallization and formation of 3D morphology of ternary eutectics in system B4C-NbB2-SiC. Research methods. SEM (SE, BSE), РСМА (EDS, WDS), XRD. Results. The micro- and macro-morphology of eutectic colonies in alloys of the system NbB2-SiC-В4С formed during directional crystallization have been investigated. The obtained patterns are embodied in a 3D structural model of (B4C+NbB2+SiC) eutectic cell and from these result, a microscopic kinetics of crystallization of this cell was proposed. The continuity of eutectic phase dendrites from nucleation to the end of growth and inadequacy of ideas about eutectic as a mechanical mixture of small crystals of eutectic phases were shown. Scientific novelty. For the first time a 3D model of a three-phase 4-component eutectic cell of eutectic colony was built. For the first time the possibility of combined microscopic crystallization kinetics of a three-phase eutectics was revealed, including both paired cooperative microscopic kinetics of (SіC+ NbB2) growth and the kinetics of autonomous growth of the third eutectic phase B4C. Practical value. Revealing the pattern of micro and macrostructure formation of a three-phase eutectics, which was formed in the course of directional crystallization, opens up technological prospects for purposeful control of the structure and properties of eutectic alloy due to the change of micro and macro morphological constituents, including the method of modification.

scholarly journals Reactive Infiltration and Microstructural Characteristics of Sn-V Active Solder Alloys on Porous Graphite

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1532 ◽  
Author(s):  
Yubin Zhang ◽  
Xinjiang Liao ◽  
Qiaoli Lin ◽  
Dekui Mu ◽  
Jing Lu ◽  
...  
Keyword(s):  
Microstructural Characterization ◽  
Contact Angles ◽  
Carbide Formation ◽  
Quasi Equilibrium ◽  
Reactive Infiltration ◽  
Porous Graphite ◽  
Three Phase ◽  
Vanadium Carbides ◽  
First Time ◽  
Kinetics Of

In this work, the reactive wetting and infiltration behaviors of a newly designed Sn-V binary alloy were comprehensively explored on porous graphite for the first time. It was discovered that 0.5 wt.% addition of V can obviously improve the wettability of liquid Sn on porous graphite and the nominal V contents in Sn-V binary alloys has minor effects on the apparent contact angles wetted at 950 °C. Moreover, the V-containing Sn-V alloys were initiated to spread on porous graphite at ~650 °C and reached a quasi-equilibrium state at ~900 °C. Spreading kinetics of Sn-3V alloy on porous graphite well fitted in the classic product reaction controlled (PRC) model. However, our microstructural characterization demonstrated that, besides vanadium carbide formation, the adsorption of V element at the wetting three-phase contact line spontaneously contributed to the reactive spreading and infiltrating of Sn-V alloys on porous graphite. Meanwhile, the formation of continuous vanadium carbides could completely block the infiltration of Sn-V active solder alloy in porous graphite. Affected by the growth kinetics of vanadium carbides, the infiltration depth of Sn-V alloys in porous graphite decreased at increased isothermal wetting temperatures. This work is believed to provide implicative notions on the fabrication of graphite related materials and devices using novel V-containing bonding alloys.

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

scholarly journals A Novel Pseudomonas geniculata AGE Family Epimerase/Isomerase and Its Application in d-Mannose Synthesis

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1809
Author(s):  
Zhanzhi Liu ◽  
Ying Li ◽  
Jing Wu ◽  
Sheng Chen
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Optimal Temperature ◽  
Reaction Conditions ◽  
Enzymatic Production ◽  
Physiological Properties ◽  
Potential Applications ◽  
Kinetics Of ◽  
Optimal Reaction ◽  
Gene Age

d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s−1, and 9.7 ± 0.5 s−1·mM−1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L−1 under optimal reaction conditions of 200 g·L−1d-fructose and 2.5 U·mL−1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.

scholarly journals Rapid systemic surge of IL-33 after severe human trauma: a prospective observational study

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Olav Sundnes ◽  
William Ottestad ◽  
Camilla Schjalm ◽  
Peter Lundbäck ◽  
Lars la Cour Poulsen ◽  
...  
Keyword(s):  
High Resolution ◽  
Prospective Observational Study ◽  
Tissue Injury ◽  
Trauma Patients ◽  
Decoy Receptor ◽  
Interleukin 33 ◽  
Injured Patients ◽  
First Time ◽  
Kinetics Of ◽  
Insight Into

Abstract Background Alarmins are considered proximal mediators of the immune response after tissue injury. Understanding their biology could pave the way for development of new therapeutic targets and biomarkers in human disease, including multiple trauma. In this study we explored high-resolution concentration kinetics of the alarmin interleukin-33 (IL-33) early after human trauma. Methods Plasma samples were serially collected from 136 trauma patients immediately after hospital admission, 2, 4, 6, and 8 h thereafter, and every morning in the ICU. Levels of IL-33 and its decoy receptor sST2 were measured by immunoassays. Results We observed a rapid and transient surge of IL-33 in a subset of critically injured patients. These patients had more widespread tissue injuries and a greater degree of early coagulopathy. IL-33 half-life (t1/2) was 1.4 h (95% CI 1.2–1.6). sST2 displayed a distinctly different pattern with low initial levels but massive increase at later time points. Conclusions We describe for the first time early high-resolution IL-33 concentration kinetics in individual patients after trauma and correlate systemic IL-33 release to clinical data. These findings provide insight into a potentially important axis of danger signaling in humans.

scholarly journals Modeling and Molecular Dynamics of the 3D Structure of the HPV16 E7 Protein and Its Variants

2021 ◽  
Vol 22 (3) ◽  
pp. 1400
Author(s):  
Ciresthel Bello-Rios ◽  
Sarita Montaño ◽  
Olga Lilia Garibay-Cerdenares ◽  
Lilian Esmeralda Araujo-Arcos ◽  
Marco Antonio Leyva-Vázquez ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
3D Structure ◽  
Epidemiological Studies ◽  
Dynamics Simulation ◽  
Structural Refinement ◽  
Oncogenic Potential ◽  
Structural Differences ◽  
Reference Protein ◽  
E6 And E7 ◽  
First Time

The oncogenic potential of high-risk human papillomavirus (HPV) is predicated on the production of the E6 and E7 oncoproteins, which are responsible for disrupting the control of the cell cycle. Epidemiological studies have proposed that the presence of the N29S and H51N variants of the HPV16 E7 protein is significantly associated with cervical cancer. It has been suggested that changes in the amino acid sequence of E7 variants may affect the oncoprotein 3D structure; however, this remains uncertain. An analysis of the structural differences of the HPV16 E7 protein and its variants (N29S and H51N) was performed through homology modeling and structural refinement by molecular dynamics simulation. We propose, for the first time, a 3D structure of the E7 reference protein and two of Its variants (N29S and H51N), and conclude that the mutations induced by the variants in N29S and H51N have a significant influence on the 3D structure of the E7 protein of HPV16, which could be related to the oncogenic capacity of this protein.

The kinetics of the decarboxylation of β-resorcylic acid in catechol

1976 ◽  
Vol 29 (2) ◽  
pp. 443 ◽  
Author(s):  
MA Haleem ◽  
MA Hakeem
Keyword(s):  
Rate Equation ◽  
Kinetic Data ◽  
Reaction Rate ◽  
Complex Mechanism ◽  
First Order ◽  
Absolute Reaction Rate ◽  
First Time ◽  
Kinetics Of ◽  
Absolute Reaction ◽  
Reaction Rate Equation

Kinetic data are reported for the decarboxylation of β-resorcylic acid in resorcinol and catechol for the first time. The reaction is first order. The observation supports the view that the decomposition proceeds through an intermediate complex mechanism. The parameters of the absolute reaction rate equation are calculated.

The spliceosome assembly pathway in mammalian extracts

1992 ◽  
Vol 12 (10) ◽  
pp. 4279-4287 ◽  
Author(s):  
S F Jamison ◽  
A Crow ◽  
M A Garcia-Blanco
Keyword(s):  
Spliceosome Assembly ◽  
Protein Factor ◽  
Small Nuclear Ribonucleoprotein ◽  
U2 Snrnp ◽  
U1 Snrnp ◽  
U2 Auxiliary Factor ◽  
Nuclear Ribonucleoprotein ◽  
Auxiliary Factor ◽  
First Time ◽  
Kinetics Of

A mammalian splicing commitment complex was functionally defined by using a template commitment assay. This complex was partially purified and shown to be a required intermediate for complex A formation. The productive formation of this commitment complex required both splice sites and the polypyrimidine tract. U1 small nuclear ribonucleoprotein (snRNP) was the only spliceosomal U snRNP required for this formation. A protein factor, very likely U2AF, is probably involved in the formation of the splicing commitment complex. From the kinetics of appearance of complex A and complex B, it was previously postulated that complex A represents a functional intermediate in spliceosome assembly. Complex A was partially purified and shown to be a required intermediate for complex B (spliceosome) formation. Thus, a spliceosome pathway is for the first time supported by direct biochemical evidence: RNA+U1 snRNP+?U2 auxiliary factor+?Y----CC+U2 snRNP+Z----A+U4/6,5 snRNPs+ beta----B.

scholarly journals IMMUNE RESPONSES IN VITRO

1971 ◽  
Vol 134 (2) ◽  
pp. 395-416 ◽  
Author(s):  
Carl W. Pierce ◽  
Barbara M. Johnson ◽  
Harriet E. Gershon ◽  
Richard Asofsky
Keyword(s):  
Culture Conditions ◽  
Antibody Concentration ◽  
Spleen Cells ◽  
Immunoglobulin Class ◽  
Cell Densities ◽  
Erythrocyte Antigen ◽  
First Time ◽  
Kinetics Of

We have demonstrated for the first time that mouse spleen cells stimulated in vitro with heterologous erythrocytes developed immunoglobulin class-specific γM, γ1, γ2a+2b, and γA plaque-forming cell (PFC) responses. A modification of the hemolytic plaque technique, the addition of goat anti-mouse µ-chain antibody to the assay preparation, specifically prevented development of all γM PFC and enabled accurate and reproducible enumeration of immunoglobulin class-specific PFC after treatment with appropriate monospecific anti-globulins and complement. Culture conditions, with regard to medium, atmosphere, agitation, and spleen cell densities, were similar to those previously shown to support only γM PFC responses. Evaluation of the kinetics of appearance of PFC showed that γM PFC reached maximum numbers on days 4–5; the magnitude of this response was 3–10 times greater than γ1 γ2a+2b, or γA PFC which reached maximum numbers on days 5–6. Optimal erythrocyte antigen dose for γM PFC responses was 107/culture, whereas a dose of 106 erythrocytes/culture consistently stimulated optimal γ1 γ2a+2b, or γA PFC responses. Investigations of the effects of anti-erythrocyte antibody on γM and γG PFC responses indicated that antibody suppressed these responses by neutralizing the effective antigenic stimulus at the macrophage-dependent phase of the response. At the same antibody concentration, γG PFC responses were more effectively suppressed than γM PFC responses. Further, γG responses could be almost completely suppressed by antibody as long as 48 hr after initiation of cultures, whereas γM PFC responses could only be completely suppressed during the first 24 hr. These results were discusssed in terms of the role of antigen in the stimulation γM and γG antibody.

Study on 3D Fine Structural Modeling of Typical Block in Sanan Oilfield, Daqing

2014 ◽  
Vol 628 ◽  
pp. 348-353
Author(s):  
Tao Li ◽  
Zian Li ◽  
Jiang Wang
Keyword(s):  
Structural Model ◽  
3D Structure ◽  
High Water ◽  
Oil Distribution ◽  
Remaining Oil ◽  
Modeling Software ◽  
Remaining Oil Distribution ◽  
High Water Cut ◽  
Reservoir Description ◽  
Water Cut

Sanan oilfield has entered late stage of high water cut development. It urgently needs accurate prediction of remaining oil distribution. But previous studies on 3D structure were far could not meet the requirements of fine reservoir description. This paper applied RMS, a piece of excellent geological modeling software establishing the 3D fine structural model of typical block in Sanan oilfield on the bases of 3D fine seismic structural interpretation data. It included the 28 faults’ model, 11 horizons’ model and the structural model. And then measured and analyzed the faults elements data. Based on abundant geologic data, well data and seismic data of the block, this structural model reproduced the fine seismic interpretation results accurately. It was really fine enough to meet the requirements of the fine reservoir description. This research solved the problem that traditional modeling techniques could not handle complex cutting relationship of faults’ model. It laid a solid foundation for reservoir numerical simulation and remaining oil distribution prediction.

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