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2. Rapid detection of Pb2+ heavy metal ions using paper-based green synthesized silver nanoparticles colorimetric assays.
- Author
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Wicaksono, Wiyogo Prio, Khoirunisa, Zahra, Hasna Azizah, Audita, Rahmania, and Fadillah, Ganjar
- Subjects
- *
SILVER nanoparticles , *SILVER , *HEAVY metals , *METAL ions , *MANGOSTEEN , *CRYSTAL structure , *X-ray diffraction , *RAMAN scattering - Abstract
Herein we report the facile synthesis of silver nanoparticles (AgNPs) via the green synthesis method using mangosteen (Garcinia Mangostana L.) peels waste extract (MPE) as the bioreducing agent. The synthesized AgNPs were employed as the probe in the paper-based colorimetric detection of Pb2+. Initially, the MPE was prepared using a reflux system for a 3 h reaction, followed by mixing the AgNO3 precursor and the prepared MPE, then left undisturbed for a 6 h reaction until a dark brown solution of AgNPs was obtained. The AgNPs showed a strong visible absorbance peak at 415 nm that indicated the AgNPs were successfully formed, whereas there was no peak observed at 415 m for the MPE. Further investigation, the IR spectra revealed that the OH-groups of flavonoids derivative in the MPE have a main role in the AgNPs formation, while the XRD pattern confirmed the prepared AgNPs have face center cubic structure with the crystalline size of 11.38 nm as well as the SEM characterization showed a spherical to triangle morphology of AgNPs. The paper-based-colorimetric performance evaluation showed a wide linearity range from 8 ppb to 100 ppm with a limit of detection (LOD) less than 12.50 ppm and high selectivity toward Pb2+ instead of Zn2+, Mg2+, Na+, and K+ at 30 min reaction, indicating the green synthesized AgNPs have the potential for probe in colorimetric sensing. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Effect of Dissolution Time on the Development of All-Cellulose Composites Using the NaOH/Urea Solvent System.
- Author
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Delgado, Juan Francisco, Salvay, Andrés Gerardo, Arroyo, Silvana, Bernal, Celina Raquel, and Foresti, María Laura
- Subjects
- *
UREA , *FILTER paper , *HOT pressing , *CRYSTAL structure , *SODIUM hydroxide , *DISTILLED water - Abstract
Innovative and sustainable all-cellulose composites (ACCs) can be obtained by partial dissolution of cellulosic fibers and regeneration of the dissolved fraction. Among cellulose solvents, sodium hydroxide/urea solutions are recognized as promising low-environmental impact systems. In this work, filter paper (FP) was dissolved with a 7 wt% NaOH/12 wt% urea aqueous solution, kept at −18 °C for different time intervals, regenerated with distilled water and finally dried under different conditions. The developed films were characterized in terms of morphology, porosity, optical properties, crystalline structure, hydration and mechanical properties. The porosity of the composites decreased with dissolution time due to the progressive filling of voids as the cellulosic fibers' surface skin layer was dissolved and regenerated. Samples treated for 4 h showed the minimum values of porosity and opacity, high hydration and a substantial change from cellulose I to cellulose II. Hot pressing during drying led to relevant improvements in ACCs stiffness and strength values. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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4. H2O2 modified-hydrochar derived from paper waste sludge for enriched surface functional groups and promoted adsorption to ammonium
- Author
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Lan Huong Nguyen, Xuan Hoan Nguyen, Ngoc Dang Khoa Nguyen, Huu Tap Van, Van Nam Thai, Hoang Nghiem Le, Van Dat Pham, Ngoc Anh Nguyen, Tan Phong Nguyen, and The Hung Nguyen
- Subjects
Work (thermodynamics) ,Contact time ,General Chemical Engineering ,Kinetics ,Langmuir adsorption model ,General Chemistry ,Crystal structure ,Endothermic process ,chemistry.chemical_compound ,symbols.namesake ,Adsorption ,chemistry ,Chemical engineering ,symbols ,Ammonium - Abstract
Background This work investigated adsorption behaviors of NH4+ onto H2O2 modified paper waste sludge-derived hydrochar (HPSH). Methods Effect of various operational parameters, including modification ratio, solution pH, adsorbent dosage, initial NH4+ concentration and contact time on NH4+ adsorption was studied. Besides, the NH4+ adsorption isotherms, kinetics and thermodynamics at different operational temperatures were systematically investigated. The textural, morphology, crystalline structure and surface chemistry characteristics of hydrochars were analyzed. Specially, NH4+ adsorption mechanisms controlled by enriched oxygen-containing surface functional groups by treatment of H2O2 onto hydrochars were deeply discussed. Significant findings The results showed that the optimal treatment ratio between H2O2 and PPSH was 40. Characterization data indicated H2O2 modification increased the oxygen-containing functional groups on the hydrochar surface. The maximum adsorption capacity of HPSH-40 was 7.941 mg/g which was higher that of PPSH about double. NH4+ adsorption onto hydrochars was well described by the pseudo-second-order model and Langmuir isotherm. The thermodynamic studies showed NH4+ adsorption onto hydrochars was endothermic in nature. The mechanisms of NH4+ adsorption onto hydrochars included π-cation interaction, cation exchange, surface complexation and electrostatic attraction which were attributed to the vital role of enriched oxygen-containing surface functional groups on hydrochar's surface.
- Published
- 2021
5. Crystal Structure and Photochromic Properties of Two Complexes based on 1‐(4‐carboxybenzyl)‐4,4′‐bipyridinium Ligand.
- Author
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Yang, Fengyi, Liu, Na, Chen, Jiali, and Liu, Jinjian
- Subjects
CRYSTAL structure ,LIGANDS (Chemistry) ,CHARGE exchange ,FILTER paper ,METAL ions ,ETHANOL - Abstract
Selecting different metal ions, two novel complexes {[Zn(BCbpy)(m‐BDC)(H2O)] ⋅ 2H2O}n (1) and [Co(H2O)6]0.5[Co0.5(BCbpy)(H2O)2](m‐BDC) ⋅ 3H2O ⋅ DMF (2) have been prepared and structurally characterized in the presence of the viologen ligand 1‐(4‐carboxybenzyl)‐4,4′‐bipyridinium (BCbpy) and 1,3‐benzenedicarboxylic acid (m‐H2BDC). The crystal structures and photochromic properties of two complexes have been investigated in this article. 1 possesses a two‐dimensional (2D) layered structure, while the structure of 2 is zero‐dimensional (0D). As expected, 1 and 2 were discovered to be photochromic accompanying electron transfer (ET). Interestingly, 1 can be dissolved in ethanol solution and deposited on filter paper, applied to a printing medium without ink. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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6. Engineering of GH11 Xylanases for Optimal pH Shifting for Industrial Applications.
- Author
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Kim, In Jung, Kim, Soo Rin, Bornscheuer, Uwe T., and Nam, Ki Hyun
- Subjects
XYLANASES ,INDUSTRIAL applications ,PAPER pulp ,ENGINEERING ,PROTEIN engineering ,METHODS engineering ,BACTERIAL leaching ,CRYSTAL structure - Abstract
Endo-1,4-β-xylanases belonging to the glycoside hydrolase (GH) 11 family hydrolyze the β-1,4-glycosidic linkages in the xylan backbone to convert polymeric xylan into xylooligosaccharides. GH11 xylanases play an essential role in sugar metabolism and are one of the most widely used enzymes in various industries, such as pulp and paper, food and feed, biorefinery, textile, and pharmaceutical industries. pH is a crucial factor influencing the biochemical properties of GH11 xylanase and its application in bioprocessing. For the optimal pH shifting of GH11 xylanase in industrial applications, various protein engineering studies using directed evolution, rational engineering, and in silico approaches have been adopted. Here, we review the functions, structures, and engineering methods developed for the optimal pH shifting of GH11 xylanases. The various GH11 engineering techniques and key residues involved in pH shifting are discussed based on their crystal and modeled structure. This review provides an overview of recent advancements in the characterization and engineering of GH11 xylanases, providing a guide for future research in this field. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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7. Comments on the paper on the properties of BaFe0.5Nb0.5O3:Ca by R. Chakravarty et al., and published in Vacuum 216, 112415 (2023).
- Author
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Tomaszewski, Paweł E.
- Subjects
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UNIT cell , *DIFFRACTION patterns , *CRYSTAL structure , *CRYSTAL symmetry , *DOPING agents (Chemistry) - Abstract
My comments concern the errors in the crystallographic part of the commented paper. The diffraction patterns are erroneously analysed. The crystal structure was not presented in the commented paper. • Correction of erroneous analysis of diffraction patterns. • Comparison of unit cells relation to the content of Ca dopant. • The crystal structure was not given in the commented paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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8. Crystal structure optimization approach to problem solving in mechanical engineering design
- Author
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Talatahari, Babak, Azizi, Mahdi, Talatahari, Siamak, Tolouei, Mohamad, and Sareh, Pooya
- Published
- 2022
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9. 镀陶纸陶瓷颜料的制备及其 抑菌性能研究.
- Author
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宁语苹, 郭瑞, 宋阳, 李剑, and 刘文波
- Subjects
ESCHERICHIA coli ,SINTERING ,POROSITY ,ADSORPTION capacity ,CERAMIC industries ,CRYSTAL structure ,GAS storage - Abstract
Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
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10. Structural and mechanical properties of a-axis AlN thin films growth using reactive RF magnetron sputtering plasma
- Author
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Bakri, Anis Suhaili, Nayan, Nafarizal, Soon, Chin Fhong, Ahmad, Mohd Khairul, Abu Bakar, Ahmad Shuhaimi, Abd Majid, Wan Haliza, and Raship, Nur Amaliyana
- Published
- 2021
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11. An easily processable silver nanowires-dual-cellulose conductive paper for versatile flexible pressure sensors.
- Author
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Fu, Danning, Wang, Ruibin, Wang, Yang, Sun, Qianyu, Cheng, Chen, Guo, Xiaohui, and Yang, Rendang
- Subjects
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PRESSURE sensors , *SILVER , *ELECTRIC conductivity , *TENSILE strength , *THERMAL stability , *CRYSTAL structure - Abstract
To date, flexible pressure sensors built on silver nanowires (AgNWs) have attracted tremendous attention, owing to their versatile applications in wearable, human-interactive, health-monitoring devices. Cellulose and its derivatives, which show great promise in serving flexible pressure sensors as the desired substrate due to their natural abundance, biocompatibility, easy processibility, and low costs. Herein, we reported a rational strategy to design a silver nanowires-dual-cellulose conductive paper. Its morphology, chemical and crystal structures, thermal stability, mechanical performances, and electrical properties were carefully studied. The results suggested that good tensile properties (tensile strength ≤8.10 MPa), high electrical conductivity (≤ 1.74 × 104 S·m−1) with long-term stability, and good adhesion stability (bending cycles over 500) were obtained. Furthermore, the use of such conductive paper as substrate for versatile flexible pressure sensors was demonstrated, which exhibited fast response (~ 0.48 s) and high sensitivity, in response to finger motion, voice recognition, and human pulse, etc. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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12. One amino-functionalized luminescence sensor demonstrating high sensitivity and selectivity for detecting Al3+ and Cu2+ as well as its luminescent mixed matrix membranes and test papers.
- Author
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Wan, Xiaoyu, Zhang, Yifan, Wang, Huaiwei, Lu, Jing, Li, Dacheng, Dou, Jianmin, Li, Yunwu, and Wang, Suna
- Subjects
- *
COORDINATION polymers , *LUMINESCENCE , *METHYL methacrylate , *LUMINESCENCE measurement , *INTERMOLECULAR interactions , *CARBOXYLIC acids - Abstract
A novel 3D Zn-based coordination polymer (NH 2 -LCU-110 , LCU names Liaocheng University) with the formula [Zn(L1)(bpea) n (H 2 L1 = 2-aminoterephthalic acid, bpea = 1,2-bis(4-pyridyl)ethane), was hydrothermally synthesized from a flexible nitrogen-containing carboxylic acid ligand with various coordination modes as main ligands and nitrogen-containing auxiliary ligand with different structures. NH 2 -LCU-110 demonstrates an interesting 5-fold interpenetrating diamond structure. Luminescence measurements reveal that this complex has obvious emission enhancement and quenching towards Al3+ and Cu2+, respectively. The mixed matrix membranes (MMMs) incorporating NH 2 -LCU-110 and poly(methyl methacrylate) (PMMA) as well as simple test papers were both prepared for potential application. The MMMs can quickly detect Al3+ and Cu2+ and the original emission could be regenerated by lifting from the analytical solutions, demonstrating its fast response and good selectivity. The sensing mechanism was investigated in details by various measurements and compared with isostructural complex LCU-110 without –NH 2 groups. All observations indicate that introduction of Lewis basic –NH 2 groups can enhance the intermolecular interactions between the frameworks of coordination polymers and sensing analytes (Al3+ and Cu2+). An amino-functionalized coordination polymer NH 2 -LCU-110 exhibits luminescence turn-on/off toward Al3+/Cu2+, and its mixed matrix membranes and test papers were prepared. [Display omitted] • An amino-functionalized coordination polymer was employed as a multiresponsive luminescence sensor. • NH 2 -LCU-110 exhibits luminescence turn-on and turn-off behavior toward Al3+ and Cu2+, respectively. • Mixed matrix membranes (MMMs) and test papers made the detection more simple and convenient. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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13. Comments on the paper "Synthesis and third order optical nonlinearity studies of toluidine tartrate single crystal supported by photophysical characterization and vibrational spectral analysis".
- Author
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Srinivasan, Bikshandarkoil R.
- Subjects
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SINGLE crystals , *TOLUIDINE , *CRYSTAL surfaces , *SPECTRAL imaging , *SURFACES (Technology) , *CRYSTAL structure , *ONLINE comments - Abstract
The brown coloration of the crystal is due to surface degradation. [Display omitted] • Growth of toluidine tartrate (TT) crystal is critiqued. • Brown colour of TT is due to surfacial degradation. • Experimental data in the title paper contradict literature report. The authors of the title paper (J Photochem & Photobio A:Chem 393 (2020) 112413) claim to have synthesized a toluidine tartrate (TT) crystal and examined its nonlinear optical (NLO) behavior by experimental and theoretical studies. In this critique, it is shown that the so-called TT crystal is a surface degraded material and the experimental and theoretical data contradict literature reports on the 1:1 salt of p -toluidine and l -tartaric acid. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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14. Comments on the paper "Influence of ethylenediaminetetraacetic acid on the performance of ferrous sulphate heptahydrate nonlinear optical single crystal".
- Author
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Srinivasan, Bikshandarkoil R. and Shet Verenkar, Vidhyadatta M.
- Subjects
- *
FERROUS sulfate , *ETHYLENEDIAMINETETRAACETIC acid , *SINGLE crystals , *CRYSTAL growth , *AQUEOUS solutions , *SPACE groups - Abstract
Slow evaporation of an aqueous solution containing FeSO 4 ·7H 2 O and ethylenediaminetetraacetic acid (H 4 -EDTA) first results in the fractional crystallization of the less soluble H 4 -EDTA. [Display omitted] • Crystal growth of FeEDTA (I) is critiqued. • Ethylenediaminetetraacetic acid does not contain any –NH 2 group. • FeSO 4 ·7H 2 O crystallizes in the centrosymmetric P 2 1 / c space group. The authors of the title paper (Mater. Lett. 161 (2015) 224–226) claimed to have grown ethylenediaminetetraacetic acid doped ferrous sulfate heptahydrate (FeEDTA) crystal by slow evaporation method. In this letter, many points of criticism concerning the growth of the so-called FeEDTA crystal are described to prove that it is in fact surface degraded FeSO 4 ·7H 2 O crystal. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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15. Comments on the paper "Insight on the growth and property studies of inorganic hydrated borate (Na6[B4O5(OH)4]3·8H2O) single crystal ̶ An effective third order nonlinear optical (NLO) material for optical limiting application".
- Author
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Srinivasan, Bikshandarkoil R.
- Subjects
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OPTICAL limiting , *OPTICAL materials , *SINGLE crystals , *BORATES , *CRYSTAL growth , *ALKALI metal ions - Abstract
The authors of the title paper (Mater. Chem. Phy. 205 (2018) 138–146) claimed to have grown for the first time a new alkali metal borate with formula Na 6 [B 4 O 5 (OH) 4 ] 3 ·8H 2 O (I) by slow evaporation of an aqueous solution containing NaOH, H 3 BO 3 and C 3 H 4 O 4 in 3:1:1 mol ratio. In this letter to the Editor, many points of criticism concerning the crystal growth, structure characterization and interpretation of the spectral and thermal data of I are described to prove that it is improperly characterized. The most intense line in the powder pattern of tincalconite is the (303) reflection. [Display omitted] • Crystal growth of Na 6 [B 4 O 5 (OH) 4 ] 3 ·8H 2 O (I) is critiqued. • Experimental data of I are inconsistent with the proposed formula. • I is an improperly characterized material. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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16. A new ternary Eu(III) β‐diketonate complex with diimine ligand and its application as fluorescent probe for highly sensitive and selective ammonia sensor.
- Author
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Wang, You‐Yu, Song, Li, Wang, Jian‐Teng, Zhou, Yi‐Ming, Dai, Ze‐Qi, Liu, Wei, Guo, Jia‐Yu, Shen, Hang‐Yan, and Chai, Wen‐Xiang
- Subjects
FLUORESCENT probes ,AMMONIA ,DETECTORS ,ENVIRONMENTAL monitoring ,THIN films ,ELEMENTAL analysis - Abstract
The rapid and accurate detection of ammonia is very important for manufacture and environmental monitoring, which needs to be developed urgently. Herein, a thin film‐based fluorescence sensor is fabricated by using a ternary europium (III) complex probe for ammonia. The new complex Eu(TPM)3(2‐PBO) (1) was designed and synthesized by utilizing a trifluoromethyl substituted β‐diketone ligand TPM and a diimine ligand 2‐PBO (TPM = 1,1,1‐trifluoro‐5,5‐dimethyl‐2,4‐hexanedione, 2‐PBO = 2‐(2′‐pyridyl)‐benzoxazole). This complex probe was synthetically characterized by elemental analysis, crystallographic and spectroscopic analysis, and photoluminescence (PL) study. The crystallographic analysis revealed complex 1 as a neutral complex structure with the Eu(III) center in a distorted square antiprism EuO6N2 coordination polyhedron. Based on this complex probe, a thin film fluorescence sensor with highly sensitive and selective response to ammonia was developed by polymethyl methacrylate (PMMA): complex composite and cellulose paper support. When the paper‐based sensor was exposed to ammonia, its PL emission showed a sensing behavior of rapid quenching. Surprisingly, this new method can achieve excellent limit of detection as low as 2.740 × 10−6 ppm. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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17. Mineralogical Crystallography Volume III.
- Author
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Gurzhiy, Vladislav V.
- Subjects
CRYSTALLOGRAPHY ,SULFATE minerals ,CARBONATE minerals ,MINERALS ,TRACE elements - Abstract
The text discusses the importance of mineralogy and crystallography in modern human life and highlights the significance of the International Year of Crystallography and the Year of Mineralogy. The third volume of the Special Issue "Mineralogical Crystallography" focuses on crystal chemistry and properties of minerals and their synthetic analogs, gemology, and crystal growth techniques and cultural heritage. The papers in this volume cover a range of topics, including the crystal chemistry of uranyl molybdate compounds, the discovery of the mercury sulphohalide mineral hanauerite, the crystal structures of synthetic analogs of transition metals, and the crystal structure of layered double-hydroxide quintinite. Other topics include the crystal structure of the sulfate mineral alunogen, the synthesis of pyrochlore minerals, the synthesis of novel analogs of the vesuvianite mineral, and the study of Jedi spinel and jade weathering rinds. The text also discusses the examination of painted stone carvings, the effect of ions on carbonate mineral phases, and the evaluation of cooling behavior in metamorphic rocks. The authors express their hope that this collection of papers will inspire readers to pursue their own research. [Extracted from the article]
- Published
- 2024
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18. Hydrogen-bonded assemblies of iron(II) spin crossover complexes.
- Author
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Jornet-Mollá, Verónica, Rodríguez-Tarrazó, Marina I., Dolz-Lozano, Miquel J., Giménez-Saiz, Carlos, and Romero, Francisco M.
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IRON ,MAGNETIC properties ,THERMAL properties ,LOW temperatures ,CRYSTAL structure ,SPIN crossover ,ANIONS - Abstract
The paper reports on the synthesis, crystal structure, thermal and magnetic properties of spin crossover (SCO) salts containing the [Fe(bpp)
2 ]2+ cation (bpp = 2,6-bis(pyrazol-3-yl)pyridine) and different rigid polycarboxylate anions, such as anthracene-9,10-dicarboxylate (ADC), benzene-1,3,5-tricarboxylate (BTC) and biphenyl-4,4′-dicarboxylate (BPDC). Compound [Fe(bpp)2 ](ADC)·9H2 O (1) shows a porous hydrogen-bonded structure with water molecules sitting in the channels. It contains low-spin (LS) Fe2+ cations that undergo crossover to the high-spin (HS) state upon dehydration. Anhydrous 1 remains HS on cooling at low temperatures. A similar magnetic behaviour is obtained for the partially protonated BTC salt [Fe(bpp)2 ](HBTC)·5H2 O (2), showing a spin change concomitant with dehydration to a HS phase that undergoes gradual and partial SCO on cooling, affecting 25% of the Fe2+ cations. Instead, the BPDC salt [Fe(bpp)2 ](BPDC)·5H2 O (3) has a ground HS state in its fully hydrated form. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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19. Introduction of new guest molecules into BEDTTTF radical-cation salts with tris(oxalato)ferrate.
- Author
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Blundell, Toby J., Rusbridge, Elizabeth K., Pemberton, Rebecca E., Brannan, Michael J., Morritt, Alexander L., Ogar, Joseph O., Wallis, John D., Hiroki Akutsu, Yasuhiro Nakazawa, Shusaku Imajo, and Martin, Lee
- Subjects
SUPERCONDUCTING transitions ,SALTS ,MOLECULES ,BENZONITRILE ,CRYSTAL structure ,ETHANOL ,BENZALDEHYDE - Abstract
Radical-cation salts of formula β?-(BEDT-TTF)
4 [(H3 O)Fe(C2 O4 )3 ]·guest have produced a large number of superconductors and provided a route to introduce magnetism and chirality into the same multifunctional material. A relationship has been found in these salts between the length of the b axis and the superconducting Tc. Increasing the b axis length by introducing larger guest molecules, such as benzonitrile and nitrobenzene, gives the highest superconducting Tcs in this family of salts. Smaller guests such as pyridine show no superconducting transition, whilst asymmetrical guests which are larger than nitrobenzene have given a different bilayered structure. Other potential guest molecules have been limited by their ability to be used as the solvent in which the crystals are grown via electrocrystallisation. This paper reports a method which introduces guest molecules into the crystal which are a solid or liquid additive within the crystal-growing solvent 1,2,4-trichlorobenzene:ethanol. We present the crystal structures of five new BEDT-TTF radical-cation salts with tris(oxalato)ferrate anions using guest molecules toluene, phenol, benzaldehyde, 4-bromobenzaldehyde, and kojic acid. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
20. Comprehensive understanding of the crystal structure of perovskite-type Ba3Y4O9 with Zr substitution: a theoretical and experimental study.
- Author
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Ueno, Katsuhiro, Hashimoto, Atsunori, Toyoura, Kazuaki, Hatada, Naoyuki, Sato, Shigeo, and Uda, Tetsuya
- Subjects
EXTENDED X-ray absorption fine structure ,CRYSTAL structure ,BODY centered cubic structure ,X-ray powder diffraction ,UNIT cell - Abstract
We previously reported that Zr substitution improves the chemical stability of Ba
3 Y4 O9 and nominally 20 mol% Zr-substituted Ba3 Y4 O9 is an oxide-ion conductor at intermediate temperatures (500–700 °C). However, the influence of Zr substitution on the structural properties of Ba3 Y4 O9 was poorly understood. This paper aims to comprehensively understand the crystal structure of Ba3 Y4 O9 with Zr substitution by powder X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements, and first-principles calculations. From the results, firstly we found that the hexagonal unit cell of Ba3 Y4 O9 reported in the database should be revised as doubled along the c-axis in terms of the periodicity of oxide-ion positions. The revised unit cell of Ba3 Y4 O9 consists of 18 layers of BaO3 and 24 layers of Y which periodically stack along the c-axis. In this work, we focused on the cationic lattice and noticed that the periodical stacking of Ba and Y layers comprises a similar sequence to that in the body-centered cubic (BCC) structure. There are two regions in the Ba3 Y4 O9 structure: one is a hetero-stacking region of Ba and Y layers (Ba–Y–Ba–Y–Ba) and the other is a homo-stacking region (Ba–Y–Y–Ba). It is noteworthy that the former region is similar to a cubic perovskite. In Zr-substituted Ba3 Y4 O9 , Zr ions preferentially substitute for Y ions in the hetero-stacking region, and therefore the local environment of Zr ions in Ba3 Y4 O9 is quite similar to that in BaZrO3 . Besides, the Zr substitution for Y in Ba3 Y4 O9 increases the fraction of the cubic-perovskite-like region in the stacking sequences. The structural change in the long-range order strongly affects the other material properties such as chemical stability and the ionic-conduction mechanism. Our adopted description of perovskite-related compounds based on the stacking sequence of the BCC structure should help in understanding the complex structure and developing new perovskite-related materials. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
21. Simulation of XRD data of Ba(NdxTi(1-2x)Nbx)O3 ceramics with cubic crystal structure and (Na0.5Bi0.5)(NdyTi(1-2y)Nby)O3 ceramics with rhombohedral crystal structure by modified Arrhenius and Lorentz equations
- Author
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Mahboob, Syed and Rizwana
- Subjects
X-ray diffraction ,CRYSTAL structure ,CERAMICS ,ARRHENIUS equation ,X-ray scattering - Abstract
Ba(Nd
x Ti(1-2x) Nbx )O3 (x=0.025, 0.05, 0.1 & 0.2) and (Na0.5 Bi0.5 )(Ndy Ti(1-2y) Nby)O3 (y=0.0125, 0.025 & 0.05) ceramics were prepared through solid state sintering route. In the present paper X-ray diffraction (XRD) data was obtained using (Philips X-pert Pro Pan Analytical: Model PW3040/60). The XRD data was simulated using modified Arrhenius and Lorentz equation using ORIGIN 6.1 software which was proposed by us earlier. In the case of Ba(Ndx Ti(1-2x) Nbx )O3 ceramics the values of lattice parameter obtained using modified Arrhenius and Lorentz equations are 3.9597Ao, 4.2534Ao, 5.2364Ao & 5.2690Ao for x=0.025, 0.05, 0.1 & 0.2 respectively. The average values of activation energy for x-ray scattering are 74.47 meV, 85.21 meV, 90.20 meV & 95.79 meV for x=0.025, 0.05, 0.1 & 0.2 respectively. Similar simulation studies were also carried on (Na0.5 Bi0.5 )(Ndy Ti(1-2y) Nby)O3 ceramics and the results are presented in this paper. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
22. Enhanced dissolution of cellulose in CO2 switchable system by solvent with low Henry's constants as CO2 absorbent.
- Author
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Zhang, Jinyang, Mi, Shu, Liu, Fei, Qiao, Qian, Na, Haining, and Zhu, Jin
- Subjects
CELLULOSE ,PROPYLENE carbonate ,ORGANIC solvents ,CRYSTAL structure ,CHEMICAL structure ,CELLULOSE chemistry ,SOLVENTS ,DISSOLUTION (Chemistry) - Abstract
Organic solvents with low Henry's constants, such as propylene carbonate (PC) and sulfolane, were proposed to be used as CO
2 absorbents to increase CO2 absorption capacity in the CO2 switchable solvent, so that the dissolution of cellulose can be effectively enhanced. With the addition of PC, the maximum concentration achieved for the dissolution of paper cellulose can be largely increased from 1.0 to 5.0 wt%, while those for microcrystalline cellulose and corncob cellulose were increased from 5.0 to 10.0 and 7.0 wt%, respectively. Moreover, the chemical and crystalline structure of the regenerated cellulose was not affected by the addition of CO2 absorbents. This study illustrated a simple and effective way to modify the CO2 switchable solvent, which would be helpful for the application of the complex solvent system for the enhanced dissolution, derivatization, and processing of cellulose in the future. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
23. Potassium Ion Conductivity in the Cubic Labyrinth of a Piezoelectric, Antiferromagnetic Oxoferrate(III) Tellurate(VI)
- Author
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Michael Ruck, Markus Hoelzel, Ralf Albrecht, Henrik Beccard, Thomas Doert, Michael Rüsing, and Lukas M. Eng
- Subjects
hydroflux ,Full Paper ,Potassium ,Organic Chemistry ,Neutron diffraction ,chemistry.chemical_element ,General Chemistry ,Crystal structure ,Conductivity ,Full Papers ,Tellurate ,Catalysis ,chemistry.chemical_compound ,Magnetization ,Crystallography ,crystal structures ,chemistry ,Octahedron ,piezoelectric materials ,Antiferromagnetism ,ion conductivity ,oxoferrates - Abstract
Orange‐colored crystals of the oxoferrate tellurate K12+6x Fe6Te4−x O27 [x=0.222(4)] were synthesized in a potassium hydroxide hydroflux with a molar water–base ratio n(H2O)/n(KOH) of 1.5 starting from Fe(NO3)3 ⋅ 9H2O, TeO2 and H2O2 at about 200 °C. By using (NH4)2TeO4 instead of TeO2, a fine powder consisting of microcrystalline spheres of K12+6x Fe6Te4−x O27 was obtained. K12+6x Fe6Te4−x O27 crystallizes in the acentric cubic space group I 4‾ 3d. [FeIIIO5] pyramids share their apical atoms in [Fe2O9] groups and two of their edges with [TeVIO6] octahedra to form an open framework that consists of two loosely connected, but not interpenetrating, chiral networks. The flexibility of the hinged oxometalate network manifests in a piezoelectric response similar to that of LiNbO3.The potassium cations are mobile in channels that run along the directions and cross in cavities acting as nodes. The ion conductivity of cold‐pressed pellets of ball‐milled K12+6x Fe6Te4−x O27 is 2.3×10−4 S ⋅ cm−1 at room temperature. Magnetization measurements and neutron diffraction indicate antiferromagnetic coupling in the [Fe2O9] groups., K(nockout) response: K12+6x Fe6Te4−x O27 was synthesized under hydroflux conditions. The acentric cubic crystal structure comprises two non‐interpenetrating chiral oxometalate networks formed by edge‐ or corner‐sharing [TeVIO6] and [FeIIIO5] polyhedra. The potassium ions are mobile in the labyrinth between the networks. The magnetic moments of the iron cations are pairwise antiparallel, and the compound exhibits a strong piezoelectric response.
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- 2021
24. Distances in the face‐centered cubic crystalline structure applying operational research.
- Author
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Stomfai, Gergely, Kovács, Gergely, Nagy, Benedek, Turgay, Neşet Deniz, and Vizvári, Béla
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FACE centered cubic structure ,OPERATIONS research ,MINERALS ,CRYSTAL structure ,SIMPLEX algorithm - Abstract
The f.c.c. (face‐centered cubic) grid is the structure of many crystals and minerals. It consists of four cubic lattices. It is supposed that there are two types of steps between two grid points. It is possible to step to one of the nearest neighbors of the same cubic lattice (type 1) or to step to one of the nearest neighbors of another cubic lattice (type 2). Steps belonging to the same type have the same length (weight). However, the two types have different lengths and thus may have different weights. This paper discusses the minimal path between any two points of the f.c.c. grid. The minimal paths are explicitly given, i.e. to obtain a minimal path one is required to perform only O(1) computations. The mathematical problem can be the model of different spreading phenomena in crystals having the f.c.c. structure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. Crystal structures and stimuli-responsive properties for three novel D–A type salicylhydrazide–viologen compounds with free radical properties under ambient conditions.
- Author
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Xu, Yu-Ru, Zheng, Wen-Hui, Fang, Zong-Bin, Huang, Jian-Cai, and Wu, Shu-Ting
- Subjects
CRYSTAL structure ,OPTICAL spectroscopy ,ULTRAVIOLET radiation ,SINGLE crystals ,BIPYRIDINE ,FREE radicals - Abstract
Viologen is capable of generating radicals in response to an applied stimulus, giving it an abundance of stimuli responsive properties. However, the radical state of viologen is often unstable, which hinders further studies on the radical properties of viologen. In this paper, the salicylhydrazide group was chosen as a donor group to bond with mono-substituted bipyridyl groups to obtain three novel D–A type viologen compounds. The compounds were harvested and characterized by X-ray single crystal diffraction, optical spectroscopy, EPR and DFT calculation, etc. The results show that compounds 1–3 adopt certain free radical states at room temperature under ambient light, which may be attributed to the electron-donating properties of the salicylhydrazide group and the degree of system conjugation. In addition, compound 1 has a hydrochromic property and compounds 2 and 3 have photocurrent effects under UV radiation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Porous materials: Covalent Organic Frameworks (COFs) as game-changers in practical applications, a review.
- Author
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Shahbaz, Amsal, Ahmad, Khalil, Qureshi, Khizar, Majeed, Hammad, Arshad, Ifzan, Tabinda, Tabinda, Iftikhar, Tehreema, Kashaf-ul Khair, Ashfaq, Muhammad, Rehman Shah, Habib Ur, Ahmad, Muhammad Zubair, and Lee, Shern-long
- Subjects
POROUS materials ,CRYSTAL structure ,SEPARATION of gases ,SURFACE area ,GAS storage - Abstract
Covalent Organic Frameworks (COFs) represents a class of remarkable porous materials composed of organic building blocks that are covalently linked in a periodic manner to form crystalline structures. High surface area, high porosity, tunable pore size, and high stability are their exceptional properties, which make them attractive candidates for various applications in the fields of catalysis, energy storage devices, biomedical applications, gas separation and storage applications. In fact, the great interest shown in COFs gave us a stimulus to review the output of the recent substantial efforts in this area. Meanwhile, the development of portable and sophisticated systems based on these particles is believed to create deeper insights for the scientists to embark on new investigations to pave the way for discovering new fundamental characteristics of COFs, modifications. Furthermore, the effect of modifications/fractionalizations on the performance of COFs will be thoroughly explained and challenging problems are mentioned. Moreover, the paper covers an inclusive collection of referenced recent research articles, providing readers with a comprehensive understanding of the subject matter and an extensive bibliography for further exploration. Through this comprehensive overview, the paper alleviates the noteworthy contributions of COFs in driving innovation and progress in a range of key scientific disciplines. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Advancements in Photovoltaic Cell Materials: Silicon, Organic, and Perovskite Solar Cells.
- Author
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Machín, Abniel and Márquez, Francisco
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PHOTOVOLTAIC cells ,SOLAR cells ,PHOTOVOLTAIC power systems ,PEROVSKITE ,CRYSTAL structure ,CELLULAR evolution - Abstract
The evolution of photovoltaic cells is intrinsically linked to advancements in the materials from which they are fabricated. This review paper provides an in-depth analysis of the latest developments in silicon-based, organic, and perovskite solar cells, which are at the forefront of photovoltaic research. We scrutinize the unique characteristics, advantages, and limitations of each material class, emphasizing their contributions to efficiency, stability, and commercial viability. Silicon-based cells are explored for their enduring relevance and recent innovations in crystalline structures. Organic photovoltaic cells are examined for their flexibility and potential for low-cost production, while perovskites are highlighted for their remarkable efficiency gains and ease of fabrication. The paper also addresses the challenges of material stability, scalability, and environmental impact, offering a balanced perspective on the current state and future potential of these material technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Hydrogen solubility of stishovite provides insights into water transportation to the deep Earth.
- Author
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Chen, Mengdan, Yin, Changxin, Chen, Danling, Tian, Long, Liu, Liang, and Kang, Lei
- Subjects
MARITIME shipping ,SOLUBILITY ,LITERATURE reviews ,HYDROGEN ,CRYSTAL structure - Abstract
Water dissolved in nominally anhydrous minerals (NAMs) can be transported to deep regions of the Earth through subducting slabs, thereby significantly influencing the physicochemical properties of deep-Earth materials and impacting dynamic processes in the deep Earth. Stishovite, a prominent mineral present in subducting slabs, remains stable at mantle pressures of 9–50 GPa and can incorporate various amounts of water (H + , OH - , and H 2 O) in its crystal structure. Consequently, stishovite can play a crucial role in transporting water into the deep Earth through subducting slabs. This paper provides a comprehensive review of the research process concerning water (hydrogen) solubility in stishovite. The key factors that govern water solubility in stishovite are summarized as temperature, pressure, water fugacity, and aluminum content. Combined with published results on the dependence of water solubility on the aforementioned parameters, this paper proposes a new equation to describe the solubility of water in Al-bearing stishovite. Calculation results based on this equation suggest that stishovite may effectively accommodate water released from processes such as hydrous mineral breakdown, which could ultimately contribute to the presence of a water-rich transition zone. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Study on Thermodynamic Properties and Elastic Deformation of Full-Heusler Alloys Co2TaGa and Co2VGa by Statistical Moment Method.
- Author
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Hoc, Nguyen Quang, Quang, Nguyen Duc, Hanh, Nguyen Thi Hong, Linh, Nguyen Thi Bao, Huyen, Nguyen Thi Thanh, Hung, Doan Manh, Thanh, Pham Duy, and Dao, Doan Nhan
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HEUSLER alloys ,THERMODYNAMICS ,ELASTIC deformation ,ELASTIC modulus ,AB initio quantum chemistry methods ,CRYSTAL structure - Abstract
Heusler alloy is a ferromagnetic alloy based on the Heusler phase. It is an intermetallic alloy between metallic and non-metallic elements that can be non-ferromagnetic and has a BCC crystal structure. This paper presents the theory of thermodynamics and elastic deformation of full-Heusler A
2 BC alloy with BCC structure built on the basis of statistical moment method (SMM). The paper presents numerical results for the temperature and pressure dependence of the mean nearest neighbor distance between two atoms, the density, the volume, the thermal expansion coefficient, the isotherm and adiabatic compressibilities, the isothermal elastic modulus, the heat capacities at constant volume and pressure, Young's modulus, the bulk modulus, longitudinal and transverse wave velocities of alloys Co2 TaGa and Co2 VGa when using the coordination sphere method and the Mie–Lennard-Jones pair interaction potential. Some SMM calculation results agree well with available ab initio calculation results. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
30. Two different kinds of interaction modes of deaminase <scp>APOBEC3A</scp> with single‐stranded <scp>DNA</scp> in solution detected by nuclear magnetic resonance
- Author
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Wenxian Lan, Yaping Liu, Chunxi Wang, and Chunyang Cao
- Subjects
Magnetic Resonance Spectroscopy ,Stereochemistry ,Full‐Length Papers ,DNA, Single-Stranded ,Proteins ,Crystal structure ,Biochemistry ,Solution structure ,Crystal ,chemistry.chemical_compound ,chemistry ,Cytidine Deaminase ,Humans ,APOBEC3A ,Molecular Biology ,Conformational isomerism ,Zinc ion binding ,Heteronuclear single quantum coherence spectroscopy ,DNA - Abstract
APOBEC3A (A3A) deaminates deoxycytidine in target motif TC in a single-stranded DNA (we termed it as TC DNA), which mortally mutates viral pathogens and immunoglobulins, and leads to the diversification and lethality of cancers. The crystal structure of A3A-DNA revealed a unique U-shaped recognition mode of target base dC0 . However, when TC DNA was titrated into 15 N-labeled A3A solution, we observed two sets of 1 H-15 N cross-peaks of A3A in HSQC spectra, and two sets of 1 H-1 H cross-peaks of DNA in two-dimensional 13 C,15 N- filtered TOCSY spectra, indicating two different kinds of conformers of either A3A or TC DNA existing in solution. Here, mainly by NMR, we demonstrated that one DNA conformer interacted with one A3A conformer, forming a specific complex A3AS -DNAS in a way almost similar to that observed in the reported crystal A3A-DNA structure, where dC0 inserted into zinc ion binding center. While the other DNA conformer bound with another A3A conformer, but dC0 did not extend into the zinc-binding pocket, forming a non-specific A3ANS -DNANS complex. The NMR solution structure implied three sites Asn61 , His182 and Arg189 were necessary to DNA recognition. These observations indicate a distinctive way from that reported in X-ray crystal structure, suggesting an unexpected mode of deaminase APOBEC3A to identify target motif TC in DNA in solution. This article is protected by copyright. All rights reserved.
- Published
- 2021
31. Naphthalene-based bis-N-salicylidene aniline dyes: Crystal structures, Hirshfeld surface analysis, computational study and molecular docking with the SARS-CoV-2 proteins
- Author
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Maria G. Babashkina, Damir A. Safin, Tatyana M. Burkhanova, Tugba Taskin-Tok, and Artem V. Sharov
- Subjects
SARS-CoV-2 proteins ,Original Paper ,Chemistry ,Hydrogen bond ,N-salicylidene aniline dye ,Crystal structure ,Intermolecular force ,Binding energy ,Supramolecular chemistry ,General Chemistry ,SARS-COV-2 PROTEINS ,Tautomer ,CRYSTAL STRUCTURE ,Crystallography ,Intramolecular force ,Molecular docking ,MOLECULAR DOCKING ,Hirshfeld surface analysis ,Molecule ,N-SALICYLIDENE ANILINE DYE ,HIRSHFELD SURFACE ANALYSIS - Abstract
In this work, we report structural and computational studies of a series of naphthalene-based bis-N-salicylidene aniline dyes, namely N,N′-bis-salicylidene-1,5-diaminonaphthalene (1), N,N′-bis(3-hydroxysalicylidene)-1,5-diaminonaphthalene (2) and N,N′-bis(3-methoxysalicylidene)-1,5-diaminonaphthalene (3). For 3, two polymorphs are known, namely 3red and 3yellow. Both polymorphs of 3 were analyzed and discussed. All the molecules adopt an enol-imine tautomer, stabilized by two intramolecular O–H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯N hydrogen bonds. The structure of 2 is further stabilized by a couple of additional O–H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯O hydrogen bonds and by intermolecular O–H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯O interactions, yielding a 1D zig-zag supramolecular chain. Molecules of 2, 3red and 3yellow are interlinked through intermolecular C–H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯π interactions, while the crystal packing of 1 and 2 is also described by intermolecular π\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯π interactions. More than 90% of the total Hirshfeld surface area for all the discussed molecules is occupied by H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯H, H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯C, H\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯O and C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdots$$\end{document}⋯C contacts. The polymorphs 3red and 3yellow, despite being chemically the same, differ geometrically, thus yielding remarkably different Hirshfeld surfaces. The Hirshfeld surface of 3yellow is very similar to that of 2. All structures are mainly characterized by the dispersion energy framework followed by the less significant electrostatic energy framework contribution. Molecular docking studies were employed to inspect the effect of 1–3 on the SARS-CoV-2 protein targets. The docking analysis revealed that the dye 2 showed the best binding energies toward Papain-like protease (PLpro, –10.40 kcal/mol), nonstructural protein 14 (nsp14 (N7-MTase), –10.10 kcal/mol), RdRp-RTP (–9.70 kcal/mol) and nonstructural protein 3 (nsp3_range 207-379-MES, –9.30 kcal/mol). The obtained results can give an insight into chemical and biological activities of the studied molecules that could aid in designing of potent reagents SARS-CoV-2. Supplementary Information The online version contains supplementary material available at 10.1007/s13738-021-02438-y.
- Published
- 2021
32. A previously unknown cyclic alkanolamine and molecular ranking using the pair distribution function
- Author
-
Martin Etter, Igor L. Moudrakovski, Robert E. Dinnebier, Tatjana Huber, Bernd Hinrichsen, Martin Ernst, Gianpiero Gallo, and Maxwell W. Terban
- Subjects
Chemistry ,Metals and Alloys ,Ab initio ,Infrared spectroscopy ,Pair distribution function ,Crystal structure ,Research Papers ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Crystallography ,chemistry.chemical_compound ,X-ray powder diffraction ,structure solution ,co-refinement ,pair distribution function ,Materials Chemistry ,Molecule ,ddc:530 ,Orthorhombic crystal system ,Alkanolamine ,Powder diffraction ,heterocycle - Abstract
Acta crystallographica / B 77(6), 986 - 995 (2021). doi:10.1107/S2052520621010088, A new six-membered cyclic alkanolamine with chemical formula C$_6$H$_{15}$N$_3$O$_3$ was synthesized by the reaction of glycolaldehyde with gaseous ammonia. The molecular structure, characterized by a hexagonal ring of alternating carbon and nitro��gen atoms with three hy��droxy��methyl groups attached to the carbon atoms, could not be unambiguously determined by elemental analysis and $^1$H/$^{13}$C/$^{15}$N NMR. The molecular structure and conformation were further determined using a combination of vibrational spectroscopy (IR and Raman) and real-space pair distribution function (PDF) analysis. The crystal structure was determined ab initio from laboratory X-ray powder diffraction (XRPD) with orthorhombic space group Ama2 (No. 40) and unit-cell parameters a = 12.1054 (2) ��, b = 13.5537 (2) �� and c = 5.20741 (8) ��. Consistent structure models could be obtained by symmetry-independent PDF and PDF-Rietveld co-refinements. Independent local structure refinements indicate that the most likely deviations from the average structure consist of small tilting and translational distortions of hydrogen-bonded molecular stacks. Thermal analysis (TG/DTA) and temperature-dependent XRPD measurements were also performed to determine the thermal behavior., Published by Wiley-Blackwell, Oxford [u.a.]
- Published
- 2021
33. Helical filament structure of the DREP3 CIDE domain reveals a unified mechanism of CIDE-domain assembly
- Author
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So Yeon Lee, Sunghark Kwon, Hyun Ho Park, Hyun Ji Ha, and Sung Hoon Lee
- Subjects
chemistry.chemical_classification ,crystal structure ,DREP3 ,Protein Conformation ,Effector ,Apoptotic DNA fragmentation ,Lipid metabolism ,apoptotic DNA fragmentation ,Crystallography, X-Ray ,higher-order structure ,Research Papers ,Amino acid ,Protein filament ,Turn (biochemistry) ,Biopolymers ,Drosophila melanogaster ,Protein Domains ,chemistry ,CIDE family ,Structural Biology ,Biophysics ,Animals ,Drosophila Proteins ,DNA fragmentation ,Function (biology) - Abstract
The CIDE domain was initially identified in apoptotic nucleases and now forms a highly conserved family with diverse functions ranging from cell death to lipid metabolism. Based on structural determination of the DREP3 domain, it is suggested that the head-to-tail helical filament structure might be a unified mechanism of CIDE-domain assembly and represents a critical higher-order scaffolding structure that is important for the function of CIDE-domain-containing proteins in DNA fragmentation and lipid-droplet fusion., The cell-death-inducing DFF45-like effector (CIDE) domain is a protein-interaction module comprising ∼80 amino acids and was initially identified in several apoptotic nucleases and their regulators. CIDE-domain-containing proteins were subsequently identified among proteins involved in lipid metabolism. Given the involvement of CIDE-domain-containing proteins in cell death and lipid homeostasis, their structure and function have been intensively studied. Here, the head-to-tail helical filament structure of the CIDE domain of DNA fragmentation factor-related protein 3 (DREP3) is presented. The helical filament structure was formed by opposing positively and negatively charged interfaces of the domain and was assembled depending on protein and salt concentrations. Although conserved filament structures are observed in CIDE family members, the structure elucidated in this study and its comparison with previous structures indicated that the size and the number of molecules used in one turn vary. These findings suggest that this charged-surface-based head-to-tail helical filament structure represents a unified mechanism of CIDE-domain assembly and provides insight into the function of various forms of the filament structure of the CIDE domain in higher-order assembly for apoptotic DNA fragmentation and control of lipid-droplet size.
- Published
- 2021
34. Michaelis-like complex of SARS-CoV-2 main protease visualized by room-temperature X-ray crystallography
- Author
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Leighton Coates, Daniel W. Kneller, Qiu Zhang, Andrey Kovalevsky, and John M. Louis
- Subjects
Stereochemistry ,medicine.medical_treatment ,In silico ,Crystal structure ,catalytic mechanism ,medicine.disease_cause ,Biochemistry ,c145a mutant ,3cl protease ,medicine ,General Materials Science ,Enzyme substrate complex ,Mutation ,Protease ,Crystallography ,Chemistry ,enzyme–substrate complex ,room-temperature x-ray crystallography ,Substrate (chemistry) ,General Chemistry ,Condensed Matter Physics ,Cysteine protease ,Research Papers ,sars-cov-2 ,main protease ,QD901-999 ,X-ray crystallography - Abstract
Understanding the catalytic mechanism of SARS-CoV-2 main protease (Mpro) can help in guiding drug design of specific small-molecule antivirals. A 2.0 Å resolution room-temperature X-ray crystal structure of inactive C145A mutant Mpro in complex with the octapeptide Ac-SAVLQSGF-CONH2 that resembles a Michaelis complex is reported., SARS-CoV-2 emerged at the end of 2019 to cause an unprecedented pandemic of the deadly respiratory disease COVID-19 that continues to date. The viral main protease (Mpro) is essential for SARS-CoV-2 replication and is therefore an important drug target. Understanding the catalytic mechanism of Mpro, a cysteine protease with a catalytic site comprising the noncanonical Cys145–His41 dyad, can help in guiding drug design. Here, a 2.0 Å resolution room-temperature X-ray crystal structure is reported of a Michaelis-like complex of Mpro harboring a single inactivating mutation C145A bound to the octapeptide Ac-SAVLQSGF-CONH2 corresponding to the nsp4/nsp5 autocleavage site. The peptide substrate is unambiguously defined in subsites S5 to S3′ by strong electron density. Superposition of the Michaelis-like complex with the neutron structure of substrate-free Mpro demonstrates that the catalytic site is inherently pre-organized for catalysis prior to substrate binding. Induced fit to the substrate is driven by P1 Gln binding in the predetermined subsite S1 and rearrangement of subsite S2 to accommodate P2 Leu. The Michaelis-like complex structure is ideal for in silico modeling of the SARS-CoV-2 Mpro catalytic mechanism.
- Published
- 2021
35. Insights into molecular recognition from the crystal structures of p-tert-butylcalix[6]arene complexed with different solvents
- Author
-
Maura Malinska
- Subjects
calixarenes ,Crystallography ,intermolecular interactions ,Hydrogen bond ,Methyl acetate ,General Chemistry ,Crystal structure ,macromolecular substances ,Condensed Matter Physics ,Anisole ,hydrogen bonding ,Biochemistry ,Research Papers ,law.invention ,chemistry.chemical_compound ,Molecular recognition ,chemistry ,law ,QD901-999 ,Calixarene ,Molecule ,General Materials Science ,molecular recognition ,Crystallization - Abstract
With a view to establishing molecular recognition rules, the host p-tert-butylcalix[6]arene was crystallized with different guest molecules. The ratio between the apolar surface area and the volume was used to predict the formation of inclusion versus exclusion complexes, with inclusion complexes observed at ratios, Calixarenes are host molecules that can form complexes with one or more guest molecules, and molecular recognition in calixarenes can be affected by many factors. With a view to establishing molecular recognition rules, the host p-tert-butylcalix[6]arene (TBC6) was crystallized with different guest molecules (cyclohexane, anisole, heptane, toluene, benzene, methyl acetate, ethyl acetate, dichloromethane, tetrahydrofuran and pyridine) and the obtained structures were characterized by X-ray diffraction. With most solvents, 1:1 and/or 1:3 host–guest complexes were formed, although other stoichiometries were also observed with small guest molecules, and crystallization from ethyl acetate produced the unsolvated form. The calculated fill percentage of the TBC6 cavity was ∼55% for apolar guests and significantly lower for polar solvents, indicating that polar molecules can bind to apolar cavities with significantly lower packing coefficients. The most stable crystals were formed by 1:1 host–guest inclusion complexes. The ratio between the apolar surface area and the volume was used to predict the formation of inclusion versus exclusion complexes, with inclusion complexes observed at ratios
- Published
- 2021
36. Co(NCS)2(abpt)2 and Ni(NCS)2(abpt)2 [abpt is 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole]: structural characterization of polymorphs A and B
- Author
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Helen E. Mason, Judith A. K. Howard, and Hazel A. Sparkes
- Subjects
crystal structure ,Chemistry ,Hydrogen bond ,Stacking ,1,2,4-Triazole ,chemistry.chemical_element ,Crystal structure ,Condensed Matter Physics ,Research Papers ,polymorphism ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,Nickel ,abpt ,Spin crossover ,4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole ,Materials Chemistry ,Physical and Theoretical Chemistry ,Isostructural ,Cobalt - Abstract
The synthesis and structures of two polymorphs, A and B, of Co(NCS)2(abpt)2 and Ni(NCS)2(abpt)2 are reported. The polymorph structures of A with CoII or NiII were found to be isostructural, as were the corresponding pair of polymorph B structures with the different metals., The synthesis and structures of bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ2 N 2,N 3]bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C12H10N6)2] or Co(NCS)2(abpt)2, and bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ2 N 2,N 3]bis(thiocyanato-κN)nickel(II), [Ni(NCS)2(C12H10N6)2] or Ni(NCS)2(abpt)2, are reported. In both cases, two polymorphs, A and B, were identified and structurally characterized. For both polymorphs, the structures obtained with the different metals, i.e. CoII or NiII, were found to be isostructural. All of the structures contained an intramolecular N—H⋯N hydrogen bond, C—H⋯N interactions and π–π stacking interactions. No structural evidence was observed for a thermal spin crossover for either of the Co(NCS)2(abpt)2 polymorphs between 300 (2) and 120 (2) K.
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- 2021
37. Location‐Dependent Lanthanide Selectivity Engineered into Structurally Characterized Designed Coiled Coils
- Author
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Hannah Campbell, Scott A. White, Anna F. A. Peacock, Oliver J Daubney, and Louise N. Slope
- Subjects
Models, Molecular ,Protein Conformation, alpha-Helical ,Lanthanide ,Protein design ,Sequence (biology) ,Peptide ,Crystal structure ,Lanthanoid Series Elements ,Catalysis ,bioinorganic chemistry ,lanthanides ,Amino Acid Sequence ,Binding site ,protein design ,Ions ,Coiled coil ,chemistry.chemical_classification ,Binding Sites ,Chemistry ,Communication ,General Medicine ,General Chemistry ,Communications ,Bioinorganic Chemistry | Hot Paper ,coiled coils ,Crystallography ,peptides ,Selectivity - Abstract
Herein we report unprecedented location‐dependent, size‐selective binding to designed lanthanide (Ln3+) sites within miniature protein coiled coil scaffolds. Not only do these engineered sites display unusual Ln3+ selectivity for moderately large Ln3+ ions (Nd to Tb), for the first time we demonstrate that selectivity can be location‐dependent and can be programmed into the sequence. A 1 nm linear translation of the binding site towards the N‐terminus can convert a selective site into a highly promiscuous one. An X‐ray crystal structure, the first of a lanthanide binding site within a coiled coil to be reported, coupled with CD studies, reveal the existence of an optimal radius that likely stems from the structural constraints of the coiled coil scaffold. To the best of our knowledge this is the first report of location‐dependent metal selectivity within a coiled coil scaffold, as well as the first report of location‐dependent Ln3+ selectivity within a protein., Location‐dependent size selectivity can be programmed into designed metallo coiled coils, allowing for the generation of near‐identical selective and promiscuous metal‐ion sites. The first crystal structure of a lanthanide bound within a coiled coil reveals that the existence of an optimal radius stems from the structural constraints of the peptide scaffold. Therefore, a selective site can in principle be designed de novo for any given Ln3+ ion.
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- 2021
38. Conductance stability and Na+ interaction with Shab K+ channels under low K+ conditions
- Author
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Froylan Gómez-Lagunas, Carolina Barriga-Montoya, and Elisa Carrillo
- Subjects
Ions ,Chemistry ,Cell Membrane ,Sodium ,Biophysics ,KcsA potassium channel ,selectivity ,Conductance ,Crystal structure ,Permeation ,Hydrogen-Ion Concentration ,Biochemistry ,Potassium channel ,Ion ,Potassium channels ,Crystallography ,Permeability (electromagnetism) ,hypokalemia ,Potassium ,Selectivity ,TEA blockage ,Research Article ,Research Paper ,conductance stability ,Na blockage - Abstract
K+ ions exert a structural effect that brings stability to K+ selective pores. Thus, upon bathing Shab channels in 0 K+ solutions the ion conductance, GK, irreversibly collapses. Related to this, studies with isolated KcsA channels have suggested that there is a transition [K+] around which the pore takes one of two conformations, either the low (non-conducting) or high K+ (conducting) crystal structures. We examined this premise by looking at the K+-dependency of GK stability of Shab channels within the cell membrane environment. We found that: K+ effect on GK stability is highly asymmetrical, and that as internal K+ is replaced by Na+ GK drops in a way that suggests a transition internal [K+]. Additionally, we found that external permeant ions inhibit GK drop with a potency that differs from the global selectivity-sequence of K+ pores; the non-permeant TEA inhibited GK drop in a K+-dependent manner. Upon lowering internal [K+] we observed an influx of Na+ at negative potentials. Na+ influx was halted by physiological external [K+], which also restored GK stability. Hyperpolarized potentials afforded GK stability but, as expected, do not restore GK selectivity. For completeness, Na+ interaction with Shab was also assessed at depolarized potentials by looking at Na block followed by permeation (pore unblock) at positive potentials, in solutions approaching the 0 K+ limit. The stabilizing effect of negative potentials along with the non-parallel variation of Na+ permeability and conductance-stability herein reported, show that pore stability and selectivity, although related, are not strictly coupled.
- Published
- 2021
39. Structural basis for SdgB- and SdgA-mediated glycosylation of staphylococcal adhesive proteins
- Author
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Jin Young Kim, Se Won Suh, Geul Bang, Inwha Baek, Dong-Gyun Kim, Byung Woo Han, Yeon Kyu Lee, Hyerry Kim, Hyoun S. Kim, Hye-Jin Yoon, and Sunghwan Kim
- Subjects
Models, Molecular ,crystal structure ,Staphylococcus aureus ,Glycosylation ,Protein Conformation ,Virulence Factors ,serine–aspartate repeats ,Staphylococcal infections ,medicine.disease_cause ,SdgB ,Crystallography, X-Ray ,SdgA ,Epitope ,Virulence factor ,Substrate Specificity ,chemistry.chemical_compound ,Structural Biology ,Glycosyltransferase ,glycosyltransferases ,medicine ,Humans ,Innate immune system ,Transition (genetics) ,biology ,Chemistry ,Staphylococcal Infections ,medicine.disease ,Research Papers ,carbohydrates (lipids) ,Biochemistry ,biology.protein ,lipids (amino acids, peptides, and proteins) ,staphylococcal adhesion - Abstract
The crystal structures of SdgB and SdgA from Staphylococcus aureus provide functional and structural insights into the glycosylation mechanism in staphylococcal adhesion., The initiation of infection of host tissues by Staphylococcus aureus requires a family of staphylococcal adhesive proteins containing serine–aspartate repeat (SDR) domains, such as ClfA. The O-linked glycosylation of the long-chain SDR domain mediated by SdgB and SdgA is a key virulence factor that protects the adhesive SDR proteins against host proteolytic attack in order to promote successful tissue colonization, and has also been implicated in staphylococcal agglutination, which leads to sepsis and an immunodominant epitope for a strong antibody response. Despite the biological significance of these two glycosyltransferases involved in pathogenicity and avoidance of the host innate immune response, their structures and the molecular basis of their activity have not been investigated. This study reports the crystal structures of SdgB and SdgA from S. aureus as well as multiple structures of SdgB in complex with its substrates (for example UDP, N-acetylglucosamine or SDR peptides), products (glycosylated SDR peptides) or phosphate ions. Together with biophysical and biochemical analyses, this structural work uncovered the novel mechanism by which SdgB and SdgA carry out the glycosyl-transfer process to the long SDR region in SDR proteins. SdgB undergoes dynamic changes in its structure such as a transition from an open to a closed conformation upon ligand binding and takes diverse forms, both as a homodimer and as a heterodimer with SdgA. Overall, these findings not only elucidate the putative role of the three domains of SdgB in recognizing donor and acceptor substrates, but also provide new mechanistic insights into glycosylation of the SDR domain, which can serve as a starting point for the development of antibacterial drugs against staphylococcal infections.
- Published
- 2021
40. Solvent induced synthesis of fluorescence Zn(II)-based metal–organic frameworks with distinctive responsiveness to DMF stimuli.
- Author
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Zhang, Yan-Kai, Wang, Na, Wang, Fu-Tian, Zhou, Wen-Feng, Zhang, Yong-Zheng, Yang, Man, Li, Zhen, Geng, Longlong, Zhang, Da-Shuai, Zhuang, Shujuan, and Zhang, Xiuling
- Subjects
- *
METAL-organic frameworks , *LIGHT filters , *LUMINESCENCE , *FLUORESCENCE , *COORDINATION polymers , *SOLVENTS , *FILTER paper - Abstract
[Display omitted] Two novel luminescent MOFs, namely, {[Zn 2 (TCA)(BPPB)(DMA)(OH)]·2DMA} n (DZU-115) and [Zn(HTCA)(BPPB) 0.5 (DMA)] n (DZU-116), have been successfully synthesized. These MOFs were crafted using a combination of 4,4′,4″-tricarboxytriphenylamine (H 3 TCA) and 4,4′-(9,10-anthracenediyl)bis-pyridine (BPPB) as mixed ligands, with solvent modulation as the method of choice. Among them, DZU-115 stands out due to its captivating dual interpenetrating structure. This structure enables DZU-115 to exhibit a unique fluorescence response when stimulated by DMF, which can be visually observed as a change in fluorescence color on filter paper. Two new luminescent MOFs, namely, {[Zn 2 (TCA)(BPPB)(DMA)(OH)]·2DMA} n (DZU-115), [Zn(HTCA)(BPPB) 0.5 (DMA)] n (DZU-116. DZU, H 3 TCA, BPPB is short for Dezhou University, 4,4′,4″-tricarboxyltriphenylamine and 4,4′-(9,10-anthracenediyl)bis-Pyridine, respectively), were successfully synthesized by solvent adjustment and characterized by single crystal X-ray diffraction. DZU-115 shows a fascinating three dimensional (3D) framework derived from the interlocking of 2D coordination dual-layers, while DZU-116 displays a different 2D layer structure. Due to the interpenetrated structure of DZU-115 that is in favor of the formation of interaction between the host frameworks and DMF molecules, a luminescent color transition from yellow-green to light orange has been found in DZU-115 when exposing the MOF to DMF solvent. Moreover, the DZU-115-based filter paper was also prepared, which is capable of producing visual changes in fluorescent color to identify DMF vapor. Remarkably, the color variation is highly reversible and the light orange color could be further converted back into yellow-green by immersing the material in DMA solvent again. Such a reversible stimuli-response behavior with the apparent luminescence color change indicates the potential application of the MOF as a recognition platform for DMF molecules. This study provides valuable insight into optimizing the performance of MOF by tuning the framework structures, and offers a promising avenue for the development of vapor molecule recognition materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Preparation of high-entropy nitride ceramics (TiVCrNbZr1-x)Ny by introducing nitrogen vacancies.
- Author
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Wang, Peixun, Li, Jiuyang, Yang, Luyu, Mo, Peicheng, and Wu, Yi
- Subjects
STRENGTHENING mechanisms in solids ,SOLUTION strengthening ,VACANCIES in crystals ,NONSTOICHIOMETRIC compounds ,FLEXURAL strength - Abstract
High-entropy ceramics have emerged as a research hotspot in the field of ceramics due to their single-crystal structure and excellent physicochemical properties. In this paper, an innovative approach is adopted to synthesize high-entropy nitride ceramics (TiVCrNbZr
1-x )Ny . To achieve this, the non-stoichiometric compound TiN0.3 was introduced as a sintering additive and the Spark Plasma Sintering (SPS) technique was employed. By adding TiN0.3 , successfully preparing high-entropy nitride ceramics at 1500°C, which introduces vacancy defects that provide additional space for the diffusion and migration of atoms, allowing for more efficient migration and diffusion within the crystal structure, thereby accelerating the sintering process. The (TiVCrNbZr1-x )Ny - xZrO2 samples achieved outstanding mechanical properties when sintered at 1700°C, owing to the mechanisms of solid solution strengthening and second-phase diffusion toughening. Specifically, the samples exhibited a hardness of 25.42 ± 1.58 GPa, a flexural strength of 888 ± 32 MPa, and a fracture toughness of 6.23 ± 0.27 MPa·m1/2 . This innovative sintering route provides an efficient method for preparing high-entropy nitride ceramics at relatively low temperatures without sacrificing quality. This approach not only enhances production efficiency but also expands the potential practical applications of these ceramics. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Crystal structure and optoelectronic properties of Rb-based metal halide perovskites RbSiI3 and RbGeI3: GGA–PBE study.
- Author
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SAAD H-E, M MUSA, KHAIRY, ABEER M, SHIRGAWI, MOHAMED Y, ABDELRAHMAN, A H, ELHAG, A, and ALSOBHI, B O
- Subjects
METAL halides ,CRYSTAL structure ,BRILLOUIN zones ,PHOTOVOLTAIC cells ,LIGHT absorption ,RUBIDIUM compounds ,PEROVSKITE - Abstract
In this paper, the crystal structure, optical and electronic properties of two related rubidium iodide halide perovskites RbSiI
3 and RbGeI3 are investigated and discussed thoroughly. The calculations of these properties are performed using the generalized gradient approximation under Perdew–Burke–Ernzerhof functional (GGA–PBE). Also, the structural optimizations and accurate optoelectronic properties have been achieved by exploiting full-potential linearized augmented plane wave method (FP-LAPW). Analysis of optimization results exposed that the volume per unit cell and lattice parameter (a0 = 5.8348 Å (RbSiI3 )) and (a0 = 5.9631 Å (RbGeI3 )) are closely in agreement with the previous results. In addition, the calculated values of tolerance factor (TF ≈ 1.0) satisfy the creation criterion for perovskites, and the negative and small values of formation energy (ΔFE ) confirm the chemical stability of studied compounds. The results of density of states and band structures reveal that RbSiI3 and RbGeI3 are nonmagnetic semiconductors having a proper direct energy gap (Eg ) of 0.465 and 0.953 eV, respectively, along the M–M symmetry directions in the first Brillouin zone. The 2-D distributions of charge density confirm that the chemical bonding of Rb–I and Si/Ge–I bonds obey the covalent and ionic nature. Moreover, we have calculated and discussed the optoelectronic properties, real ε1 (ω) and imaginary ε2 (ω) functions, optical absorption α(ω), reflectivity R(ω) and refractivity n(ω). The results obtained in this study like structural stability, suitable Eg and highly accurate optical absorption α(ω) of visible light waves, indicate the possible exploitation of semiconductors RbSiI3 and RbGeI3 and make them candidate materials for optoelectronics, such as photovoltaic solar cells, photosensors, photodetectors and photodiodes devices. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
43. Probing the interaction between asphaltene-wax and its effects on the crystallization behavior of waxes in heavy oil via molecular dynamics simulation.
- Author
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Yong Hu, Xi Lu, Hai-Bo Wang, Ji-Chao Fang, Yi-Ning Wu, and JianFang Sun
- Subjects
MOLECULAR dynamics ,STERIC hindrance ,MOLECULAR weights ,WAXES ,CRYSTAL structure ,HEAVY oil - Abstract
High content of asphaltenes and waxes leads to the high pour point and the poor flowability of heavy oil, which is adverse to its efficient development and its transportation in pipe. Understanding the interaction mechanism between asphaltene-wax is crucial to solve these problems, but it is still unclear. In this paper, molecular dynamics simulation was used to investigate the interaction between asphaltenewax and its effects on the crystallization behavior of waxes in heavy oil. Results show that molecules in pure wax are arranged in a paralleled geometry. But wax molecules in heavy oil, which are close to the surface of asphaltene aggregates, are bent and arranged irregularly. When the mass fraction of asphaltenes in asphaltene-wax system (ω
asp ) is 0-25 wt%, the attraction among wax molecules decreases and the bend degree of wax molecules increases with the increase of ωasp . The ωasp increases from 0 to 25 wt %, and the attraction between asphaltene-wax is stronger than that among waxes. This causes that the wax precipitation point changes from 353 to 333 K. While the ωasp increases to 50 wt%, wax molecules are more dispersed owing to the steric hindrance of asphaltene aggregates, and the interaction among wax molecules transforms from attraction to repulsion. It causes that the ordered crystal structure of waxes can't be formed at normal temperature. Simultaneously, the asphaltene, with the higher molecular weight or the more hetero atoms, has more obvious inhibition to the formation of wax crystals. Besides, resins also have an obvious inhibition on the wax crystal due to the formation of asphalteneresin aggregates with a larger radius. Our results reveal the interaction mechanism between asphaltene-wax, and provide useful guidelines for the development of heavy oil. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
44. Investigation on the crystallinity of crosslinked polyethylene.
- Author
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Sun, Wu-Ji, Liu, Xiong-Jun, Yuan, Li-Juan, Xiao, Han, and Lu, Jian-Mei
- Subjects
CRYSTALLINITY ,POLYETHYLENE ,CRYSTAL structure ,STRUCTURAL health monitoring ,HIGH voltages ,ENERGY consumption - Abstract
High voltage AC/DC cables require thicker insulation to ensure excellent insulation performance. Selecting the appropriate crosslinker to design the crosslink and crystalline structure of XLPE is key to the insulating properties. Although the crystallinity of XLPE has been extensively studied by using X-ray diffraction and differential scanning calorimeters, few researchers have designed in situ experiments to observe its structure. In this paper, we have created an in situ observational experiment to monitor the structural changes of XLPE insulation. XLPE formed by DTAP crosslinker produces lower gas byproducts, which can effectively reduce the degassing time and energy consumption. The test results and COMSOL simulations indicate that the XLPE formed by straight-chain alkane crosslinkers has better mechanical, thermal and electrical insulating properties than cyclic alkane crosslinkers. Our work is of great significance for selecting suitable crosslinker to control the structure of XLPE and determining the production conditions for high-voltage cables. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Advances in Plasmonic Photonic Crystal Fiber Biosensors: Exploring Innovative Materials for Bioimaging and Environmental Monitoring.
- Author
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Vatani, Sareh, Biney, Jeshurun, Faramarzi, Vahid, Jabbour, Ghassan, and Park, Jeongwon
- Subjects
- *
ENVIRONMENTAL monitoring , *BIOSENSORS , *RESEARCH personnel , *CRYSTAL structure , *FOOD safety , *OPTICAL fibers , *PHOTONIC crystal fibers - Abstract
This review paper comprehensively analyzes recent advancements in optical fiber‐based biosensors, focusing on conventional fiber and photonic crystal structures. This paper overviews the significant applications of optical fiber biosensors, including bioimaging, quality analysis, food safety, and field environment monitoring, setting the stage for subsequent discussions. The primary objective of the review is to systematically evaluate recent literature concerning optical fiber‐based biosensors, emphasizing their sensitivities and resolutions. The second section explores integrating plasmonic materials such as graphene, TDMC, germanium, black phosphorus, and silicon within optical fiber biosensors, elucidating their roles in enhancing sensitivity and resolution in biosensing applications. A detailed examination of photonic crystal fibers (PCF) follows, categorizing them into internally and externally metal film‐coated biosensors, highlighting their distinct advantages and limitations. Comparative analyses in two tables delineate the performance and sensitivity of optical fiber‐based biosensors, mainly focusing on different coating strategies. The final section of the review discusses emerging trends and applications in optical fiber biosensing technologies, underscoring their potential to transform biomedical and environmental monitoring fields. By synthesizing recent developments and challenges, this review aims to offer researchers and practitioners a comprehensive understanding of optical fiber‐based biosensors, facilitating informed decision‐making and driving further advancements in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Investigating Cross-Linking Parameters and Molecular Arrangement in Liquid Crystalline Epoxy Monomer with Aromatic Diamine: DSC-TOPEM ® and WAXS Analysis.
- Author
-
Zając, Weronika, Mossety-Leszczak, Beata, Kisiel, Maciej, Włodarska, Magdalena, and Szałański, Piotr
- Subjects
DIFFERENTIAL scanning calorimetry ,LIQUID crystals ,X-ray scattering ,TRANSITION temperature ,CRYSTAL structure - Abstract
This study presents the characterization of cross-linking parameters of a liquid crystalline epoxy monomer with an aromatic diamine as a curing agent. The mixture tested consisted of bis [4-(10,11-epoxyundecanoyloxy)benzoate] p-phenylene (LCEM) and 1,3-phenylenediamine (1,3-PDA). This paper focuses on the structural characterization of such systems using X-ray analysis. To investigate this, a comprehensive analysis was conducted using Differential Scanning Calorimetry (DSC) and Wide-Angle X-ray Scattering (WAXS). Through DSC analysis, the curing behavior and transition temperature of the liquid crystal epoxy system were established. To fully characterize the cross-linking of the system, a novel technique called DSC-TOPEM
® was employed. The use of this technique enabled real-time monitoring of the curing process and provided precise information on the cross-linking energy, which resulted in the finding that the mixture was cross-linking faster than expected. WAXS analysis was performed to assess the structural changes formed during the cross-linking. The results of this analysis confirm that lower cross-linking temperatures of the mixture cause better ordering of mesogens than higher ones. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
47. A database of high-pressure crystal structures from hydrogen to lanthanum.
- Author
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Giannessi, Federico, Di Cataldo, Simone, Saha, Santanu, and Boeri, Lilia
- Subjects
CRYSTAL structure ,DATABASES ,PERIODIC table of the elements ,LANTHANUM ,DENSITY functional theory - Abstract
This paper introduces the HEX (High-pressure Elemental Xstals) database, a complete database of the ground-state crystal structures of the first 57 elements of the periodic table, from H to La, at 0, 100, 200 and 300 GPa. HEX aims to provide a unified reference for high-pressure research, by compiling all available experimental information on elements at high pressure, and complementing it with the results of accurate evolutionary crystal structure prediction runs based on Density Functional Theory. Besides offering a much-needed reference, our work also serves as a benchmark of the accuracy of current ab-initio methods for crystal structure prediction. We find that, in 98% of the cases in which experimental information is available, ab-initio crystal structure prediction yields structures which either coincide or are degenerate in enthalpy to within 300 K with experimental ones. The main manuscript contains synthetic tables and figures, while the Crystallographic Information File (cif) for all structures can be downloaded from the related figshare online repository. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Prediction of molecular packing characteristics of two-component crystals.
- Author
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Perlovich, German L. and Surov, Artem O.
- Subjects
VAN der Waals clusters ,QUASIMOLECULES ,CRYSTALS ,CRYSTAL structure ,UNIT cell - Abstract
In this paper, we propose an approach based on parameter β, which equals the free volume in a unit cell normalized to the van der Waals volume of the molecules. The analysis was carried out within a cluster including two-component crystals [CF1 + CF2], in which one of the components remains constant (CF1) and the other varies (CF2). Linear correlation equations, such as β(CC) = C + D·β(CF2), linking the β(CC) parameter of the two-component crystals with the similar parameter β(CF2) of the single-component crystal for the strictly fixed temperatures were derived on the basis of the crystallographic experimental data. The coefficients of the correlation equations for different clusters were analyzed. A relationship was discovered between the correlation coefficient D and the HYBOT descriptor describing the donor and acceptor interactions with the other molecules. A graphic method was developed for analyzing the β(CC) parameter for the cocrystals belonging to the same cluster relative to the β parameter values of the individual compounds β(CF1) and β(CF2). The correlation equations derived in the study give an opportunity to evaluate the unit cell volume of a hypothetical cocrystal knowing only the crystal structure of a single-component crystal of one of the cocrystal components. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Crystal structures of a dodecameric multicopper oxidase from Marinithermus hydrothermalis
- Author
-
Craig M. Ogata, Millie M. Georgiadis, Joseph L. Paavola, and Umberto Battistin
- Subjects
Models, Molecular ,chemistry.chemical_classification ,Bacteria ,Protein Conformation ,Stereochemistry ,Protein subunit ,Laccase ,Substrate (chemistry) ,chemistry.chemical_element ,Crystal structure ,Crystallography, X-Ray ,Multicopper oxidase ,Research Papers ,Copper ,Electron transfer ,Dodecameric protein ,Enzyme ,chemistry ,Structural Biology ,Catalytic Domain ,Protein Multimerization ,Oxidoreductases - Abstract
Multicopper oxidases (MCOs) represent a diverse family of enzymes that catalyze the oxidation of either an organic or a metal substrate with concomitant reduction of dioxygen to water. These enzymes contain variable numbers of cupredoxin domains, two, three or six per subunit, and rely on four copper ions, a single type I copper and three additional copper ions organized in a trinuclear cluster (TNC), with one type II and two type III copper ions, to catalyze the reaction. Here, two crystal structures and the enzymatic characterization of Marinithermus hydrothermalis MCO, a two-domain enzyme, are reported. This enzyme decolorizes Congo Red dye at 70°C in the presence of high halide concentrations and may therefore be useful in the detoxification of industrial waste that contains dyes. In two distinct crystal structures, MhMCO forms the trimers seen in other two-domain MCOs, but differs from these enzymes in that four trimers interact to create a dodecamer. This dodecamer of MhMCO forms a closed ball-like structure and has implications for the sequestration of bound divalent metal ions as well as substrate accessibility. In each subunit of the dodecameric structures, a Trp residue, Trp351, located between the type I and TNC sites exists in two distinct conformations, consistent with a potential role in facilitating electron transfer in the enzyme.
- Published
- 2021
50. A trigonal coordination of Au(I) phosphane complexes stabilized by O–H⋯X (X = Cl–, Br–, I–) interactions
- Author
-
Petra Gründlinger, Uwe Monkowius, Cezarina Cela Mardare, and Thorsten Wagner
- Subjects
chemistry.chemical_classification ,Original Paper ,Hydrogen bond ,Crystal structure ,Carboxylic acid ,General Chemistry ,Trigonal crystal system ,Tri-coordinate gold(I) ,Hydrogen bonds ,chemistry.chemical_compound ,Crystallography ,chemistry ,Intramolecular force ,Atom ,Gold complexes ,Benzoic acid - Abstract
In this work, we show that intramolecular hydrogen bonding can be used to stabilize tri-coordinated phosphane-gold(I) complexes. Two molecular structures of 2-(diphenylphosphino)benzoic acid (L) coordinated to a gold(I) atom were determined by single-crystal X-ray diffraction. The linear L–Au–Br shows a standard linear coordination and dimerizes via hydrogen bonds of the carboxylic acid. Upon addition of two additional phosphane ligands the complex [L3Au]X is formed which is stabilized by three intramolecular –C(O)O–H…X hydrogen bonds as proven by the X-ray structure of the respective chlorido-complex. X-ray powder diffractograms suggest the same structure also for X– = Br– and I–. Graphic abstract
- Published
- 2021
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