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  1. Article ; Online: Ab-initio study on the covalent nature of hydrogen bonding in cellobiose

    Mittal, Sumit / Prasad, Saurav / Payal, Rajdeep Singh / Ravi, Satyam

    Cellulose. 2023 Jan., v. 30, no. 2 p.689-704

    2023  

    Abstract: In this paper, a detailed ab-initio study on molecular interactions of cellobiose is presented by employing density functional theory (DFT) at the M06-2X-D3/6-31+G(d) level of theory. It is well known that hydrogen bonding plays a vital and dominating ... ...

    Abstract In this paper, a detailed ab-initio study on molecular interactions of cellobiose is presented by employing density functional theory (DFT) at the M06-2X-D3/6-31+G(d) level of theory. It is well known that hydrogen bonding plays a vital and dominating role in the dissolution of cellobiose. To understand the nature of H-bonding at the molecular level, we have considered the following solvents: water, methanol, acetate ([[Formula: see text]][Formula: see text]), propanoate ([[Formula: see text]][Formula: see text]), thioglycolate ([[Formula: see text]][Formula: see text] and alaninate ([Ala][Formula: see text]). The interaction energy, quantum theory of atom in molecules (QTAIM) analysis, natural bond orbital (NBO) and symmetry-adapted petrubation theory (SAPT0) were performed on the cellobiose-solvent complexes to get insights into the nature of H-bonding in cellobiose. It is shown that the [[Formula: see text]][Formula: see text] ion breaks the existing intra-molecular interactions in cellobiose and forms new inter-molecular interactions with it. The computed interaction energy for [cellobiose-solvent] complexes is in the following order: [[Formula: see text]][Formula: see text] > [[Formula: see text]][Formula: see text] > [[Formula: see text]][Formula: see text] > [Ala][Formula: see text] > methanol > water, which is in agreement with the experimental solubility observations. The QTAIM topological parameters indicate the polar covalent character of the [Cellobiose - acetate][Formula: see text] complex, which is further confirmed by the calculated hydrogen bond energy. Furthermore, the energy components from SAPT0 calculations display that while the interaction energy is primarily dominated by the electrostatic interactions, induction force also plays a significant role, reconfirming the covalent character of the associated H-bonds. Overall, these results have profound implications on the understanding of H-bonding and dissolution of cellobiose at the molecular level.
    Keywords acetates ; cellobiose ; cellulose ; density functional theory ; energy ; hydrogen ; hydrogen bonding ; methanol ; quantum mechanics ; solubility ; topology
    Language English
    Dates of publication 2023-01
    Size p. 689-704.
    Publishing place Springer Netherlands
    Document type Article ; Online
    ZDB-ID 1496831-9
    ISSN 1572-882X ; 0969-0239
    ISSN (online) 1572-882X
    ISSN 0969-0239
    DOI 10.1007/s10570-022-04939-2
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Tuning the tetrahedrality of the hydrogen-bonded network of water: Comparison of the effects of pressure and added salts.

    Prasad, Saurav / Chakravarty, Charusita

    The Journal of chemical physics

    2016  Volume 144, Issue 23, Page(s) 234509

    Abstract: Experiments and simulations demonstrate some intriguing equivalences in the effect of pressure and electrolytes on the hydrogen-bonded network of water. Here, we examine the extent and nature of equivalence effects between pressure and salt concentration ...

    Abstract Experiments and simulations demonstrate some intriguing equivalences in the effect of pressure and electrolytes on the hydrogen-bonded network of water. Here, we examine the extent and nature of equivalence effects between pressure and salt concentration using relationships between structure, entropy, and transport properties based on two key ideas: first, the approximation of the excess entropy of the fluid by the contribution due to the atom-atom pair correlation functions and second, Rosenfeld-type excess entropy scaling relations for transport properties. We perform molecular dynamics simulations of LiCl-H2O and bulk SPC/E water spanning the concentration range 0.025-0.300 molefraction of LiCl at 1 atm and pressure range from 0 to 7 GPa, respectively. The temperature range considered was from 225 to 350 K for both the systems. To establish that the time-temperature-transformation behaviour of electrolyte solutions and water is equivalent, we use the additional observation based on our simulations that the pair entropy behaves as a near-linear function of pressure in bulk water and of composition in LiCl-H2O. This allows for the alignment of pair entropy isotherms and allows for a simple mapping of pressure onto composition. Rosenfeld-scaling implies that pair entropy is semiquantitatively related to the transport properties. At a given temperature, equivalent state points in bulk H2O and LiCl-H2O (at 1 atm) are defined as those for which the pair entropy, diffusivity, and viscosity are nearly identical. The microscopic basis for this equivalence lies in the ability of both pressure and ions to convert the liquid phase into a pair-dominated fluid, as demonstrated by the O-O-O angular distribution within the first coordination shell of a water molecule. There are, however, sharp differences in local order and mechanisms for the breakdown of tetrahedral order by pressure and electrolytes. Increasing pressure increases orientational disorder within the first neighbour shell while addition of ions shifts local orientational order from tetrahedral to close-packed as water molecules get incorporated in ionic hydration shells. The variations in local order within the first hydration shell may underlie ion-specific effects, such as the Hofmeister series.
    Language English
    Publishing date 2016-06-21
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/1.4953796
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Onset of simple liquid behaviour in modified water models.

    Prasad, Saurav / Chakravarty, Charusita

    The Journal of chemical physics

    2014  Volume 140, Issue 16, Page(s) 164501

    Abstract: The transition to simple liquid behaviour is studied in a set of modified hybrid water models where the potential energy contribution of the Lennard-Jones dispersion-repulsion contribution is progressively enhanced relative to the electrostatic ... ...

    Abstract The transition to simple liquid behaviour is studied in a set of modified hybrid water models where the potential energy contribution of the Lennard-Jones dispersion-repulsion contribution is progressively enhanced relative to the electrostatic contribution. Characteristics of simple liquid behaviour that indicate the extent to which a given system can be mapped onto an inverse power law fluid are examined, including configurational energy-virial correlations, functional form of temperature dependence of the excess entropy along isochores, and thermodynamic and excess entropy scaling of diffusivities. As the Lennard-Jones contribution to the potential energy function increases, the strength of the configurational energy-virial correlations increases. The Rosenfeld-Tarazona temperature dependence of the excess entropy is found to hold for the range of state points studied here for all the hybrid models, regardless of the degree of correlating character. Thermodynamic scaling is found to hold for weakly polar fluids with a moderate degree of energy-virial correlations. Rosenfeld-scaling of transport properties is found not to be necessarily linked with the strength of energy-virial correlations but may hold for systems with poor thermodynamic scaling if diffusivities and excess entropies show correlated departures from the isomorph-invariant behaviour characteristic of approximate inverse power law fluids. The state-point dependence of the configurational energy-virial correlation coefficient and the implications for thermodynamic and excess entropy scalings are considered.
    Language English
    Publishing date 2014-04-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/1.4870823
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Conductance Switching in Liquid Crystal-Inspired Self-Assembled Monolayer Junctions

    Dlugosch, Julian M. / Seim, Henning / Bora, Achyut / Kamiyama, Takuya / Lieberman, Itai / May, Falk / Müller-Plathe, Florian / Nefedov, Alexei / Prasad, Saurav / Resch, Sebastian / Saller, Kai / Seim, Christian / Speckbacher, Maximilian / Voges, Frank / Tornow, Marc / Kirsch, Peer

    ACS applied materials & interfaces. 2022 July 01, v. 14, no. 27

    2022  

    Abstract: We present the prototype of a ferroelectric tunnel junction (FTJ), which is based on a self-assembled monolayer (SAM) of small, functional molecules. These molecules have a structure similar to those of liquid crystals, and they are embedded between two ... ...

    Abstract We present the prototype of a ferroelectric tunnel junction (FTJ), which is based on a self-assembled monolayer (SAM) of small, functional molecules. These molecules have a structure similar to those of liquid crystals, and they are embedded between two solid-state electrodes. The SAM, which is deposited through a short sequence of simple fabrication steps, is extremely thin (3.4 ± 0.5 nm) and highly uniform. The functionality of the FTJ is ingrained in the chemical structure of the SAM components: a conformationally flexible dipole that can be reversibly reoriented in an electrical field. Thus, the SAM acts as an electrically switchable tunnel barrier. Fabricated stacks of Al/Al₂O₃/SAM/Pb/Ag with such a polar SAM show pronounced hysteretic, reversible conductance switching at voltages in the range of ±2–3 V, with a conductance ratio of the low and the high resistive states of up to 100. The switching mechanism is analyzed using a combination of quantum chemical, molecular dynamics, and tunneling resistance calculation methods. In contrast to more common, inorganic material-based FTJs, our approach using SAMs of small organic molecules allows for a high degree of functional complexity and diversity to be integrated by synthetic standard methods, while keeping the actual device fabrication process robust and simple. We expect that this technology can be further developed toward a level that would then allow its application in the field of information storage and processing, in particular for in-memory and neuromorphic computing architectures.
    Keywords chemical structure ; electric field ; information storage ; molecular dynamics ; prototypes ; quantum mechanics
    Language English
    Dates of publication 2022-0701
    Size p. 31044-31053.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1944-8252
    DOI 10.1021/acsami.2c05264
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Conductance Switching in Liquid Crystal-Inspired Self-Assembled Monolayer Junctions.

    Dlugosch, Julian M / Seim, Henning / Bora, Achyut / Kamiyama, Takuya / Lieberman, Itai / May, Falk / Müller-Plathe, Florian / Nefedov, Alexei / Prasad, Saurav / Resch, Sebastian / Saller, Kai / Seim, Christian / Speckbacher, Maximilian / Voges, Frank / Tornow, Marc / Kirsch, Peer

    ACS applied materials & interfaces

    2022  Volume 14, Issue 27, Page(s) 31044–31053

    Abstract: We present the prototype of a ferroelectric tunnel junction (FTJ), which is based on a self-assembled monolayer (SAM) of small, functional molecules. These molecules have a structure similar to those of liquid crystals, and they are embedded between two ... ...

    Abstract We present the prototype of a ferroelectric tunnel junction (FTJ), which is based on a self-assembled monolayer (SAM) of small, functional molecules. These molecules have a structure similar to those of liquid crystals, and they are embedded between two solid-state electrodes. The SAM, which is deposited through a short sequence of simple fabrication steps, is extremely thin (3.4 ± 0.5 nm) and highly uniform. The functionality of the FTJ is ingrained in the chemical structure of the SAM components: a conformationally flexible dipole that can be reversibly reoriented in an electrical field. Thus, the SAM acts as an electrically switchable tunnel barrier. Fabricated stacks of Al/Al
    Language English
    Publishing date 2022-07-01
    Publishing country United States
    Document type Journal Article
    ISSN 1944-8252
    ISSN (online) 1944-8252
    DOI 10.1021/acsami.2c05264
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Homo-fermentative production of D-lactic acid by Lactobacillus sp. employing casein whey permeate as a raw feed-stock.

    Prasad, Saurav / Srikanth, Katla / Limaye, Anil M / Sivaprakasam, Senthilkumar

    Biotechnology letters

    2014  Volume 36, Issue 6, Page(s) 1303–1307

    Abstract: Casein whey permeate (CWP), a lactose-enriched dairy waste effluent, is a viable feed stock for the production of value-added products. Two lactic acid bacteria were cultivated in a synthetic casein whey permeate medium with or without pH control. ... ...

    Abstract Casein whey permeate (CWP), a lactose-enriched dairy waste effluent, is a viable feed stock for the production of value-added products. Two lactic acid bacteria were cultivated in a synthetic casein whey permeate medium with or without pH control. Lactobacillus lactis ATCC 4797 produced D-lactic acid (DLA) at 12.5 g l(-1) in a bioreactor. The values of Leudking-Piret model parameters suggested that lactate was a growth-associated product. Batch fermentation was also performed employing CWP (35 g lactose l(-1)) with casein hydrolysate as a nitrogen supplement in a bioreactor. After 40 h, L. lactis produced 24.3 g lactic acid l(-1) with an optical purity >98 %. Thus CWP may be regarded as a potential feed-stock for DLA production.
    MeSH term(s) Bioreactors ; Culture Media/chemistry ; Fermentation ; Food Handling ; Industrial Waste ; Lactic Acid/metabolism ; Lactobacillus/growth & development ; Lactobacillus/metabolism
    Chemical Substances Culture Media ; Industrial Waste ; Lactic Acid (33X04XA5AT)
    Language English
    Publishing date 2014-06
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 423853-9
    ISSN 1573-6776 ; 0141-5492
    ISSN (online) 1573-6776
    ISSN 0141-5492
    DOI 10.1007/s10529-014-1482-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 4564: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
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  7. Article: Homo-fermentative production of D-lactic acid by Lactobacillus sp. employing casein whey permeate as a raw feed-stock

    Prasad, Saurav / Srikanth, Katla / Limaye, Anil M / Sivaprakasam, Senthilkumar

    Biotechnology letters. 2014 June, v. 36, no. 6

    2014  

    Abstract: Casein whey permeate (CWP), a lactose-enriched dairy waste effluent, is a viable feed stock for the production of value-added products. Two lactic acid bacteria were cultivated in a synthetic casein whey permeate medium with or without pH control. ... ...

    Abstract Casein whey permeate (CWP), a lactose-enriched dairy waste effluent, is a viable feed stock for the production of value-added products. Two lactic acid bacteria were cultivated in a synthetic casein whey permeate medium with or without pH control. Lactobacillus lactis ATCC 4797 produced D-lactic acid (DLA) at 12.5� g� l⁻¹ in a bioreactor. The values of Leudking–Piret model parameters suggested that lactate was a growth-associated product. Batch fermentation was also performed employing CWP (35� g lactose l⁻¹) with casein hydrolysate as a nitrogen supplement in a bioreactor. After 40� h, L. lactis produced 24.3� g lactic acid l⁻¹ with an optical purity >98� %. Thus CWP may be regarded as a potential feed-stock for DLA production.
    Keywords Lactobacillus delbrueckii subsp. lactis ; batch fermentation ; casein ; casein hydrolysates ; feedstocks ; lactic acid ; lactic acid bacteria ; value-added products ; whey
    Language English
    Dates of publication 2014-06
    Size p. 1303-1307.
    Publishing place Springer-Verlag
    Document type Article
    ZDB-ID 423853-9
    ISSN 1573-6776 ; 0141-5492
    ISSN (online) 1573-6776
    ISSN 0141-5492
    DOI 10.1007/s10529-014-1482-9
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 4564: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
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    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  8. Article: Homo-fermentative production of D-lactic acid by Lactobacillus sp. employing casein whey permeate as a raw feed-stock

    Prasad, Saurav / Srikanth, Katla / Limaye, Anil M. / Sivaprakasam, Senthilkumar

    Biotechnology letters

    Volume v. 36,, Issue no. 6

    Abstract: Casein whey permeate (CWP), a lactose-enriched dairy waste effluent, is a viable feed stock for the production of value-added products. Two lactic acid bacteria were cultivated in a synthetic casein whey permeate medium with or without pH control. ... ...

    Abstract Casein whey permeate (CWP), a lactose-enriched dairy waste effluent, is a viable feed stock for the production of value-added products. Two lactic acid bacteria were cultivated in a synthetic casein whey permeate medium with or without pH control. Lactobacillus lactis ATCC 4797 produced D-lactic acid (DLA) at 12.5� g� l⁻¹ in a bioreactor. The values of Leudking–Piret model parameters suggested that lactate was a growth-associated product. Batch fermentation was also performed employing CWP (35� g lactose l⁻¹) with casein hydrolysate as a nitrogen supplement in a bioreactor. After 40� h, L. lactis produced 24.3� g lactic acid l⁻¹ with an optical purity >98� %. Thus CWP may be regarded as a potential feed-stock for DLA production.
    Keywords casein hydrolysates ; casein ; lactic acid bacteria ; lactic acid ; feedstocks ; batch fermentation ; Lactobacillus delbrueckii subsp. lactis ; value-added products ; whey
    Language English
    Document type Article
    ISSN 0141-5492
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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