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  1. Article: Coherence in Polycrystalline Thin Films of Twisted Molecular Crystals.

    Yang, Yongfan / Shtukenberg, Alexander G / Zhou, Hengyu / Ruzie, Christian / Geerts, Yves Henri / Lee, Stephanie S / Kahr, Bart

    Chemistry of materials : a publication of the American Chemical Society

    2024  Volume 36, Issue 2, Page(s) 881–891

    Abstract: Helicoidal crystallites in rhythmically banded spherulites manifest spectacular optical patterns in small molecules and polymers. It is shown that concentric optical bands indicating crystallographic orientations typically lose coherence (in-phase ... ...

    Abstract Helicoidal crystallites in rhythmically banded spherulites manifest spectacular optical patterns in small molecules and polymers. It is shown that concentric optical bands indicating crystallographic orientations typically lose coherence (in-phase twisting) with growth from the center of nucleation. Here, coherence is shown to increase as the twist period decreases for seven molecular crystals grown from the melt. This dependence was correlated to crystallite fiber thickness and length, as well as crystallite branching frequency, a parameter that was extracted from scanning electron micrographs, and supported by numerical simulations. Hole mobilities for 2,5-didodecyl-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP-C12) measured by using organic field-effect transistors demonstrated that more incoherent boundaries between optical bands in spherulites lead to higher charge transport for films with the same twist period. This was rationalized by combining our growth model with electrodynamic simulations. This work illustrates the emergence of complexity in crystallization processes (spherulite formation) that arises in the extra variable of helicoidal radial twisting. The details of the patterns analyzed here link the added complexity in crystal growth to the electronic and optical properties of the thin films.
    Language English
    Publishing date 2024-01-04
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1500399-1
    ISSN 1520-5002 ; 0897-4756
    ISSN (online) 1520-5002
    ISSN 0897-4756
    DOI 10.1021/acs.chemmater.3c02740
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Synthesis and application of novel silver magnetic amino silicone adhesive particles for preparation of high purity α-linolenic acid from tree peony seed oil under applied magnetic field

    Chen, Fengli / Yang, Xinyu / Ma, Yibo / Wang, Xiaoxia / Luo, Duqiang / Yang, Lei / Yang, Yongfan

    Journal of chromatography. 2020 Jan. 11, v. 1610

    2020  

    Abstract: Silver magnetic amino silicone adhesive (Fe₃O₄@SiO₂@NH₂@Ag) particles were prepared for the purification of α-linolenic acid from tree peony seed oil under applied magnetic field. First, Fe₃O₄@SiO₂@NH₂@Ag particles were prepared and physicochemically ... ...

    Abstract Silver magnetic amino silicone adhesive (Fe₃O₄@SiO₂@NH₂@Ag) particles were prepared for the purification of α-linolenic acid from tree peony seed oil under applied magnetic field. First, Fe₃O₄@SiO₂@NH₂@Ag particles were prepared and physicochemically characterized, including XRD, TG, FTIR, SEM, magnetic hysteresis curves and elemental analysis. The static process for the purification of α-linolenic acid using Fe₃O₄@SiO₂@NH₂@Ag particles was investigated, including adsorption curve, desorption curve, elution solvent composition and adsorption isotherm. The result indicated that 0-1–4% acetone-n-hexane elution solvent was selected for the gradient elution process, 2 h and 60 min were the time required to reach adsorption and desorption equilibrium, 20 °C was selected as the adsorption temperature, Langmuir model was suitable to fit and explain the equilibrium data, and the adsorption process was spontaneous and exothermic. Under applied magnetic field, the dynamic process for the purification of α-linolenic acid using Fe₃O₄@SiO₂@NH₂@Ag particles was investigated, and the optimum conditions were 20:1 µL/g loading amount, 0.5 mL/min flow rate and 51.73 Oe magnetic field intensity. After purification, the purity and recovery ratio of α-linolenic acid were calculated to be 94% and 74%, respectively. Furthermore, the recycled Fe₃O₄@SiO₂@NH₂@Ag particles still achieved better purification result. Therefore, the developed method shows a good application prospect in the field of separation and purification of α-linolenic acid.
    Keywords Fourier transform infrared spectroscopy ; Paeonia suffruticosa ; X-ray diffraction ; adsorption ; alpha-linolenic acid ; chromatography ; desorption ; heat production ; hysteresis ; iron oxides ; magnetic fields ; scanning electron microscopy ; seed oils ; silica ; silicone ; silver ; solvents ; sorption isotherms ; temperature ; thermogravimetry
    Language English
    Dates of publication 2020-0111
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 218139-3
    ISSN 0021-9673 ; 0378-4355 ; 0376-737X
    ISSN 0021-9673 ; 0378-4355 ; 0376-737X
    DOI 10.1016/j.chroma.2019.460540
    Database NAL-Catalogue (AGRICOLA)

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  3. Article: Self-Patterning Tetrathiafulvalene Crystalline Films.

    Whittaker, St John / McDowell, Merritt / Bendesky, Justin / An, Zhihua / Yang, Yongfan / Zhou, Hengyu / Zhang, Yuze / Shtukenberg, Alexander G / Kalyon, Dilhan M / Kahr, Bart / Lee, Stephanie S

    Chemistry of materials : a publication of the American Chemical Society

    2023  Volume 35, Issue 20, Page(s) 8599–8606

    Abstract: Tetrathiafulvalene (TTF) crystals grown from the melt are organized as spherulites in which helicoidal fibrils growing radially from the nucleation center twist in concert with one another. Alternating bright and dark concentric bands are apparent when ... ...

    Abstract Tetrathiafulvalene (TTF) crystals grown from the melt are organized as spherulites in which helicoidal fibrils growing radially from the nucleation center twist in concert with one another. Alternating bright and dark concentric bands are apparent when films are viewed between crossed polarizers, indicating an alternating pattern of crystallographic faces exposed at the film surface. Band-dependent reorganization of the TTF crystals was observed during exposure to methanol vapor. Crystalline growth appears on bright bands at the expense of the dark bands. After a 24 h period of exposure to methanol vapor, the original spherulites were completely restructured, and the films comprise isolated, concentric circles of crystallites whose orientations are determined by the initial TTF crystal fibril orientation. While the surface of these outgrowths appears faceted and smooth, cross-sectional SEM images revealed a semiporous inner structure, suggesting solvent-vapor-induced recrystallization. Collectively, these results show that crystal twisting can be used to rhythmically redistribute material. Crystal twisting is a common and often controllable phenomenon independent of molecular or crystal structure and therefore offers a generalizable path to spontaneous pattern formation in a wide range of materials.
    Language English
    Publishing date 2023-10-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1500399-1
    ISSN 1520-5002 ; 0897-4756
    ISSN (online) 1520-5002
    ISSN 0897-4756
    DOI 10.1021/acs.chemmater.3c01604
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Leveling up Organic Semiconductors with Crystal Twisting.

    Whittaker, St John / Zhou, Hengyu / Spencer, Rochelle B / Yang, Yongfan / Tiwari, Akash / Bendesky, Justin / McDowell, Merritt / Sundaram, Pallavi / Lozano, Idalys / Kim, Shin / An, Zhihua / Shtukenberg, Alexander G / Kahr, Bart / Lee, Stephanie S

    Crystal growth & design

    2023  Volume 24, Issue 2, Page(s) 613–626

    Abstract: The performance of crystalline organic semiconductors depends on the solid-state structure, especially the orientation of the conjugated components with respect to device platforms. Often, crystals can be engineered by modifying chromophore substituents ... ...

    Abstract The performance of crystalline organic semiconductors depends on the solid-state structure, especially the orientation of the conjugated components with respect to device platforms. Often, crystals can be engineered by modifying chromophore substituents through synthesis. Meanwhile, dissymetry is necessary for high-tech applications like chiral sensing, optical telecommunications, and data storage. The synthesis of dissymmetric molecules is a labor-intensive exercise that might be undermined because common processing methods offer little control over orientation. Crystal twisting has emerged as a generalizable method for processing organic semiconductors and offers unique advantages, such as patterning of physical and chemical properties and chirality that arises from mesoscale twisting. The precession of crystal orientations can enrich performance because achiral molecules in achiral space groups suddenly become candidates for the aforementioned technologies that require dissymetry.
    Language English
    Publishing date 2023-11-14
    Publishing country United States
    Document type Journal Article ; Review
    ISSN 1528-7483
    ISSN 1528-7483
    DOI 10.1021/acs.cgd.3c01072
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Collimating the growth of twisted crystals of achiral compounds.

    Lozano, Idalys / Whittaker, St John / Yang, Yongfan / Tiwari, Akash / Zhou, Hengyu / Kim, Shin / Mendoza, Magaly / Sow, Maryam / Shtukenberg, Alexander G / Kahr, Bart / An, Zhihua / Lee, Stephanie S

    Chirality

    2023  Volume 35, Issue 7, Page(s) 418–426

    Abstract: A great proportion of molecular crystals can be made to grow as twisted fibrils. Typically, this requires high crystallization driving forces that lead to spherulitic textures. Here, it is shown how micron size channels fabricated from poly( ... ...

    Abstract A great proportion of molecular crystals can be made to grow as twisted fibrils. Typically, this requires high crystallization driving forces that lead to spherulitic textures. Here, it is shown how micron size channels fabricated from poly(dimethylsiloxane) (PDMS) serve to collimate the circular polycrystalline growth fronts of optically banded spherulites of twisted crystals of three compounds, coumarin, 2,5-bis(3-dodecyl-2-thienyl)-thiazolo[5,4-d]thiazole, and tetrathiafulvalene. The relationships between helicoidal pitch, growth front coherence, and channel width are measured. As channels spill into open spaces, collimated crystals "diffract" via small angle branching. On the other hand, crystals grown together from separate channels whose bands are out of phase ultimately become a single in-phase bundle of fibrils by a cooperative mechanism yet unknown. The isolation of a single twist sense in individual channels is described. We forecast that such chiral molecular crystalline channels may function as chiral optical wave guides.
    Language English
    Publishing date 2023-03-18
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1011639-4
    ISSN 1520-636X ; 0899-0042
    ISSN (online) 1520-636X
    ISSN 0899-0042
    DOI 10.1002/chir.23558
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Magnetically stabilized bed packed with synthesized magnetic silicone loaded with ionic liquid particles for efficient enrichment of flavonoids from tree peony petals

    Chen, Fengli / Xiao, Yao / Zhang, Bingwen / Chang, Ruigang / Luo, Duqiang / Yang, Lei / Yang, Yongfan / Liu, Dongmei

    Journal of chromatography. 2020 Feb. 22, v. 1613

    2020  

    Abstract: In this work, synthesized magnetic silicone loaded with ionic liquid (Fe3O4@SiO2@IL) particles combined with gas-liquid-solid magnetically stabilized bed (GLS-MSB) were applied to enrich flavonoids from tree peony petal extraction solution. The magnetic ... ...

    Abstract In this work, synthesized magnetic silicone loaded with ionic liquid (Fe3O4@SiO2@IL) particles combined with gas-liquid-solid magnetically stabilized bed (GLS-MSB) were applied to enrich flavonoids from tree peony petal extraction solution. The magnetic core (Fe3O4) encased in silica was conducive to its rapid and efficient separation, and the modification of silica with ionic liquids (ILs) could provide the functional groups for selective adsorption of flavonoids. Furthermore, the magnetic materials were evenly dispersed in the GLS-MSB system, realizing the adequate contact and causing the positive influence on the result. After physicochemical characterization, the prepared Fe3O4@SiO2@IL (IL=VBimBr) particles were validated in the enrichment performance of flavonoids, including the type of ionic liquid loaded, desorption solution, adsorption and desorption kinetics. The adsorption kinetics obeyed the pseudo-second-order model, the adsorption isotherms were consistent with the Langmuir equation, and the adsorption process was spontaneous and exothermic. Additionally, the dynamic processes using GLS-MSB packed with Fe3O4@SiO2@IL particles were evaluated systematically, deriving the optimum conditions (5 mL/min liquid flow rate, 130 mL Loading amount and 42.55 Oe magnetic field intensity) and improving the purity of flavonoids. After enrichment, the Fe3O4@SiO2@IL particles were successfully recycled and reused. Overall, the developed method offers a great potential for the enrichment of flavonoids from natural materials.
    Keywords Paeonia suffruticosa ; adsorption ; chromatography ; corolla ; desorption ; flavonoids ; heat production ; ionic liquids ; iron oxides ; liquids ; magnetic fields ; magnetic materials ; models ; moieties ; silica ; silicone ; sorption isotherms
    Language English
    Dates of publication 2020-0222
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 218139-3
    ISSN 0021-9673 ; 0378-4355 ; 0376-737X
    ISSN 0021-9673 ; 0378-4355 ; 0376-737X
    DOI 10.1016/j.chroma.2019.460671
    Database NAL-Catalogue (AGRICOLA)

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  7. Article ; Online: Synthesis and application of novel silver magnetic amino silicone adhesive particles for preparation of high purity α-linolenic acid from tree peony seed oil under applied magnetic field.

    Chen, Fengli / Yang, Xinyu / Ma, Yibo / Wang, Xiaoxia / Luo, Duqiang / Yang, Lei / Yang, Yongfan

    Journal of chromatography. A

    2019  Volume 1610, Page(s) 460540

    Abstract: Silver magnetic amino silicone adhesive ( ... ...

    Abstract Silver magnetic amino silicone adhesive (Fe
    MeSH term(s) Adhesives ; Magnetic Fields ; Magnetite Nanoparticles/chemistry ; Paeonia/chemistry ; Plant Oils/chemistry ; Seeds/chemistry ; Silicones/chemistry ; Silver/chemistry ; alpha-Linolenic Acid/analysis ; alpha-Linolenic Acid/chemistry ; alpha-Linolenic Acid/isolation & purification ; alpha-Linolenic Acid/metabolism
    Chemical Substances Adhesives ; Magnetite Nanoparticles ; Plant Oils ; Silicones ; alpha-Linolenic Acid (0RBV727H71) ; Silver (3M4G523W1G)
    Language English
    Publishing date 2019-09-14
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 1171488-8
    ISSN 1873-3778 ; 0021-9673
    ISSN (online) 1873-3778
    ISSN 0021-9673
    DOI 10.1016/j.chroma.2019.460540
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Imidacloprid Crystal Polymorphs for Disease Vector Control and Pollinator Protection

    Zhu, Xiaolong / Hu, Chunhua T. / Erriah, Bryan / Vogt-Maranto, Leslie / Yang, Jingxiang / Yang, Yongfan / Qiu, Mengdi / Fellah, Noalle / Tuckerman, Mark E. / Ward, Michael D. / Kahr, Bart

    Journal of the American Chemical Society. 2021 Oct. 12, v. 143, no. 41

    2021  

    Abstract: Imidacloprid, the world’s leading insecticide, has been approved recently for controlling infectious disease vectors; yet, in agricultural settings, it has been implicated in the frightening decline of pollinators. This argues for strategies that sharply ...

    Abstract Imidacloprid, the world’s leading insecticide, has been approved recently for controlling infectious disease vectors; yet, in agricultural settings, it has been implicated in the frightening decline of pollinators. This argues for strategies that sharply reduce the environmental impact of imidacloprid. When used as a contact insecticide, the effectiveness of imidacloprid relies on physical contact between its crystal surfaces and insect tarsi. Herein, seven new imidacloprid crystal polymorphs are reported, adding to two known forms. Anticipating that insect uptake of imidacloprid molecules would depend on the respective free energies of crystal polymorph surfaces, measurements of insect knockdown times for the metastable crystal forms were as much as nine times faster acting than the commercial form against Aedes, Anopheles, and Culex mosquitoes as well as Drosophila (fruit flies). These results suggest that replacement of commercially available imidacloprid crystals (a.k.a. Form I) in space-spraying with any one of three new polymorphs, Forms IV, VI, IX, would suppress vector-borne disease transmission while reducing environmental exposure and harm to nontarget organisms.
    Keywords Aedes ; Anopheles ; Culex ; Drosophila ; disease transmission ; disease vectors ; environmental exposure ; environmental impact ; fruits ; imidacloprid ; infectious diseases ; pollinators ; vector control ; vector-borne diseases
    Language English
    Dates of publication 2021-1012
    Size p. 17144-17152.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.1c07610
    Database NAL-Catalogue (AGRICOLA)

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  9. Article ; Online: Charge Transport in Twisted Organic Semiconductor Crystals of Modulated Pitch.

    Yang, Yongfan / Silva de Moraes, Lygia / Ruzié, Christian / Schweicher, Guillaume / Geerts, Yves Henri / Kennedy, Alan R / Zhou, Hengyu / Whittaker, St John / Lee, Stephanie S / Kahr, Bart / Shtukenberg, Alexander G

    Advanced materials (Deerfield Beach, Fla.)

    2022  Volume 34, Issue 38, Page(s) e2203842

    Abstract: Many molecular crystals (approximately one third) grow as twisted, helicoidal ribbons from the melt, and this preponderance is even higher in restricted classes of materials, for instance, charge-transfer complexes. Previously, twisted crystallites of ... ...

    Abstract Many molecular crystals (approximately one third) grow as twisted, helicoidal ribbons from the melt, and this preponderance is even higher in restricted classes of materials, for instance, charge-transfer complexes. Previously, twisted crystallites of such complexes present an increase in carrier mobilities. Here, the effect of twisting on charge mobility is better analyzed for a monocomponent organic semiconductor, 2,5-bis(3-dodecyl-2-thienyl)-thiazolo[5,4-d]thiazole (BDT), that forms twisted crystals with varied helicoidal pitches and makes possible a correlation of twist strength with carrier mobility. Films are analyzed by X-ray scattering and Mueller matrix polarimetry to characterize the microscale organization of the polycrystalline ensembles. Carrier mobilities of organic field-effect transistors are five times higher when the crystals are grown with the smallest pitches (most twisted), compared to those with the largest pitches, along the fiber elongation direction. A tenfold increase is observed along the perpendicular direction. Simulation of electrical potential based on scanning electron microscopy images and density functional theory suggests that the twisting-enhanced mobility is mainly controlled by the fiber organization in the film. A greater number of tightly packed twisted fibers separated by numerous smaller gaps permit better charge transport over the film surface compared to fewer big crystallites separated by larger gaps.
    Language English
    Publishing date 2022-08-19
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1474949-X
    ISSN 1521-4095 ; 0935-9648
    ISSN (online) 1521-4095
    ISSN 0935-9648
    DOI 10.1002/adma.202203842
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Natural antioxidant of rosemary extract used as an additive in the ultrasound-assisted extraction of anthocyanins from lingonberry (Vaccinium vitis-idaea L.) pomace

    Jin, Yusong / Liu, Zaizhi / Liu, Dongmei / Shi, Guangyu / Liu, Dewen / Yang, Yongfan / Gu, Huiyan / Yang, Lei / Zhou, Zhiqiang

    Industrial crops and products. 2019 Oct. 05, v. 138

    2019  

    Abstract: The effects of natural antioxidant rosemary extracts with different carnosic acid concentrations (30%, 60%, and 90%) and of three synthetic antioxidants in the extraction of anthocyanins from lingonberry (Vaccinium vitis-idaea L.) pomace under ultrasound ...

    Abstract The effects of natural antioxidant rosemary extracts with different carnosic acid concentrations (30%, 60%, and 90%) and of three synthetic antioxidants in the extraction of anthocyanins from lingonberry (Vaccinium vitis-idaea L.) pomace under ultrasound irradiation conditions were compared. The optimum extraction conditions were selected: antioxidant rosemary extract with carnosic acid of 30% (purity), 0.02% (carnosic acid to lingonberry pomace sample mass ratio); ethanol volume fraction, 40%; pH 1.5; liquid–solid ratio, 20 mL/g; ultrasound frequency, 80 kHz; ultrasound irradiation power, 170 W; reaction temperature, 55 °C; and ultrasound irradiation time, 35 min. Compared with traditional extraction techniques (no addition of rosemary extract), we obtained satisfactory yields of anthocyanins of 4.12 ± 0.18 mg/g (cyanidin-3-galactoside yield of 3.36 ± 0.14 mg/g, cyanidin-3-glucoside yield of 0.15 ± 0.01 mg/g and cyanidin-3-arabinoside yield of 0.61 ± 0.03 mg/g). The supplement of natural antioxidant rosemary extract was first added to inhibit the oxidation of anthocyanins, and the proposed natural antioxidant rosemary extract exhibited potential to replace synthetic antioxidants with greater security.
    Keywords Vaccinium vitis-idaea ; anthocyanins ; antioxidants ; ethanol ; oxidation ; pH ; pomace ; rosemary ; temperature ; ultrasonic treatment ; ultrasonics
    Language English
    Dates of publication 2019-1005
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1132158-1
    ISSN 1872-633X ; 0926-6690
    ISSN (online) 1872-633X
    ISSN 0926-6690
    DOI 10.1016/j.indcrop.2019.05.074
    Database NAL-Catalogue (AGRICOLA)

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