The Kinetics of the Three-Dimensional Photopolymerization: Some Di(methyi)Acrylates of the Microheterogeneous Model

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.

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When rDNA transcription is arrested during mitosis, UBF is still associated with non-condensed rDNA

Journal of Cell Science ◽

10.1242/jcs.110.19.2429 ◽

1997 ◽

Vol 110 (19) ◽

pp. 2429-2440 ◽

Cited By ~ 4

Author(s):

J. Gebrane-Younes ◽

N. Fomproix ◽

D. Hernandez-Verdun

Keyword(s):

Secondary Constriction ◽

Three Dimensional ◽

Ribosomal Gene ◽

Rdna Transcription ◽

Transcription Machinery ◽

Late Anaphase ◽

Early Anaphase ◽

Dimensional Distribution ◽

Open Question ◽

Kinetics Of

The mechanisms that control inactivation of ribosomal gene (rDNA) transcription during mitosis is still an open question. To investigate this fundamental question, the precise timing of mitotic arrest was established. In PtK1 cells, rDNA transcription was still active in prophase, stopped in prometaphase until early anaphase, and activated in late anaphase. Because rDNA transcription can still occur in prophase and late anaphase chromosomes, the kinetics of rDNA condensation during mitosis was questioned. The conformation of the rDNA was analyzed by electron microscopy from the G2/M transition to late anaphase in the secondary constriction, the chromosome regions where the rDNAs are clustered. Whether at transcribing or non-transcribing stages, non-condensed rDNA was observed in addition to axial condensed rDNA. Thus, the persistence of this non-condensed rDNA during inactive transcription argues in favor of the fact that mitotic inactivation is not the consequence of rDNA condensation. Analysis of the three-dimensional distribution of the rDNA transcription factor, UBF, revealed that it was similar at each stage of mitosis in the secondary constriction. In addition, the colocalization of UBF with non-condensed rDNA was demonstrated. This is the first visual evidence of the association of UBF with non-condensed rDNA. As we previously reported that the rDNA transcription machinery remained assembled during mitosis, the colocalization of rDNA fibers with UBF argues in favor of the association of the transcription machinery with certain rDNA copies even in the absence of transcription. If this hypothesis is correct, it can be assumed that condensation of rDNA as well as dissociation of the transcription machinery from rDNA cannot explain the arrest of rDNA transcription during mitosis. It is proposed that modifications of the transcription machinery occurring in prometaphase could explain the arrest of transcription, while reverse modifications in late anaphase could explain activation.

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Thermal Properties and Non-Isothermal Crystallization Kinetics of Poly (δ-Valerolactone) and Poly (δ-Valerolactone)/Titanium Dioxide Nanocomposites

Crystals ◽

10.3390/cryst8120452 ◽

2018 ◽

Vol 8 (12) ◽

pp. 452 ◽

Cited By ~ 3

Author(s):

Waseem Saeed ◽

Abdel-Basit Al-Odayni ◽

Abdulaziz Alghamdi ◽

Ali Alrahlah ◽

Taieb Aouak

Keyword(s):

Titanium Dioxide ◽

Crystallization Kinetics ◽

Isothermal Crystallization ◽

Three Dimensional ◽

Degree Of Crystallinity ◽

Simultaneous Occurrence ◽

Scanning Calorimetry ◽

Isothermal Crystallization Kinetics ◽

The Stability ◽

Kinetics Of

New poly (δ-valerolactone)/titanium dioxide (PDVL/TiO2) nanocomposites with different TiO2 nanoparticle loadings were prepared by the solvent-casting method and characterized by Fourier transform infra-red, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy, and thermogravimetry analyses. The results obtained reveal good dispersion of TiO2 nanoparticles in the polymer matrix and non-formation of new crystalline structures indicating the stability of the crystallinity of TiO2 in the composite. A significant increase in the degree of crystallinity was observed with increasing TiO2 content. The non-isothermal crystallization kinetics of the PDVL/TiO2 system indicate that the crystallization process involves the simultaneous occurrence of two- and three-dimensional spherulitic growths. The thermal degradation analysis of this nanocomposite reveals a significant improvement in the thermal stability with increasing TiO2 loading.

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Kinetics of formation of unitary three-dimensional structural elements: numerical experiment

Polymer Bulletin ◽

10.1007/s00289-010-0427-2 ◽

2011 ◽

Vol 66 (4) ◽

pp. 571-581

Author(s):

Yu. M. Sivergin ◽

S. M. Usmanov

Keyword(s):

Numerical Experiment ◽

Three Dimensional ◽

Structural Elements ◽

Kinetics Of Formation ◽

Kinetics Of

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Synthesis and characterization of a new conjugated polymer containing bithiazole group and its thermal decomposition kinetics

Macedonian Journal of Chemistry and Chemical Engineering ◽

10.20450/mjcce.2020.2025 ◽

2020 ◽

Vol 39 (2) ◽

pp. 227

Author(s):

Adnan Kurt ◽

Hacer Andan ◽

Murat Koca

Keyword(s):

Thermal Decomposition ◽

Heating Rate ◽

Conjugated Polymer ◽

Three Dimensional ◽

Heating Rates ◽

Diffusion Type ◽

Optimum Heating ◽

Rate Loss ◽

Kinetics Of

A new conjugated polymer containing a bithiazole group is prepared by the polycondensation of 2,2'-diamino-4,4'-bithiazole and terephthaldialdehyde in the presence of glacial acetic acid. The kinetics of thermal degradation of the new polymer are investigated by thermogravimetric analysis at different heating rates. The temperature corresponding to the maximum rate loss shifts to higher temperatures with increasing heating rate. The thermal decomposition activation energies of the conjugated polymer in a conversion range of 3–15 % are 288.4 and 281.1 kJ/mol by the Flynn–Wall–Ozawa and Kissinger methods, respectively. The Horowitz–Metzger method shows that the thermodegradation mechanism of the conjugated polymer proceeds over a three-dimensional diffusion type deceleration D3 mechanism. The optimum heating rate is 20 ºC/min.

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Spatial organization of transcript elongation and splicing kinetics

10.1101/2021.01.28.428713 ◽

2021 ◽

Author(s):

Alyssa D. Casill ◽

Adam J. Haimowitz ◽

Brian Kosmyna ◽

Charles C. Query ◽

Kenny Ye ◽

...

Keyword(s):

Alternative Splicing ◽

Spatial Organization ◽

Dimensional Space ◽

Three Dimensional ◽

Regulatory Elements ◽

Multiple Control ◽

Pol Ii ◽

Topologically Associated Domains ◽

Transcript Elongation ◽

Kinetics Of

SummaryThe organization of the genome in three-dimensional space has been shown to play an important role in gene expression. Specifically, facets of genomic interaction such as topologically associated domains (TADs) have been shown to regulate transcription by bringing regulatory elements into close proximity1. mRNA production is an intricate process with multiple control points including regulation of Pol II elongation and the removal of non-coding sequences via pre-mRNA splicing2. The connection between genomic compartments and the kinetics of RNA biogenesis and processing has been largely unexplored. Here, we measure Pol II elongation and splicing kinetics genome-wide using a novel technique that couples nascent RNA-seq with a mathematical model of transcription and co-transcriptional RNA processing. We uncovered multiple layers of spatial organization of these rates: the rate of splicing is coordinated across introns within individual genes, and both elongation and splicing rates are coordinated within TADs, as are alternative splicing outcomes. Overall, our work establishes that the kinetics of transcription and splicing are coordinated by the spatial organization of the genome and suggests that TADs are a major platform for coordination of alternative splicing.

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Three-Dimensional Observation and Growth Kinetics of Proeutectoid Ferrite Formed at Austenite Grain Boundary in a Low Carbon Microalloyed Steel

THERMEC 2006 - Materials Science Forum ◽

10.4028/0-87849-428-6.4578 ◽

2007 ◽

pp. 4578-4583

Author(s):

Kai Ming Wu ◽

A.M. Guo ◽

Lin Cheng

Keyword(s):

Grain Boundary ◽

Growth Kinetics ◽

Microalloyed Steel ◽

Three Dimensional ◽

Low Carbon ◽

Austenite Grain ◽

Proeutectoid Ferrite ◽

Carbon Microalloyed ◽

Austenite Grain Boundary ◽

Kinetics Of

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The Effect of Acidity Coefficient on Crystallization Behavior of Blast Furnace Slag Fibers

High Temperature Materials and Processes ◽

10.1515/htmp-2015-0280 ◽

2018 ◽

Vol 37 (1) ◽

pp. 33-37

Author(s):

Tie-Lei Tian ◽

Yu-Zhu Zhang ◽

Hong-wei Xing ◽

Jie Li ◽

Zun-Qian Zhang

Keyword(s):

Thermal Stability ◽

Crystallization Kinetics ◽

Blast Furnace Slag ◽

Chemical Structure ◽

Crystallization Behavior ◽

Three Dimensional ◽

Mineral Wool ◽

Mineral Wool Fiber ◽

Kinetics Of ◽

Furnace Slag

AbstractThe chemical structure of mineral wool fiber was investigated by using Fourier Transform Infrared Spectroscopy (FTIR). Next, the glass transition temperature and the crystallization temperature of the fibers were studied. Finally, the crystallization kinetics of fiber was studied. The results show that the chemical bond structure of fibers gets more random with the increase of acidity coefficient. The crystallization phases of the fibers are mainly melilites, and also a few anorthites and diopsides. The growth mechanism of the crystals is three dimensional. The fibers with acidity coefficient of 1.2 exhibit the best thermal stability and is hard to crystallize as it has the maximum aviation energy of crystallization kinetics.

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