| 44551. |
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| 44552. |
- Srivastava, K., et al.
(author)
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Molecular structure and hydrogen bond interactions of a paracetamol-4,4′-bipyridine cocrystal studied using a vibrational spectroscopic and quantum chemical approach
- 2018
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In: CrystEngComm. - : Royal Society of Chemistry. - 1466-8033. ; 20:2, s. 213-222
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Journal article (peer-reviewed)abstract
- The purpose of the current study is to perform the structural and spectroscopic characterization of paracetamol-4,4′-bipyridine (PRA-BPY) cocrystal using infrared, Raman spectroscopy and density functional theory (DFT) calculations. To reveal the interactions between PRA and BPY, two models (monomer and dimer + PRA) of a cocrystal are designed and optimized using DFT with a 6-311G (d, p) basis set. An atoms in molecule study shows that the non-covalent interactions in particular hydrogen bonds involved in forming the cocrystal are moderate in nature. Natural bond orbital analysis of the second order perturbation theory of the Fock matrix suggests that interactions LP (1) N13 → π∗(C15-O16) and LP (1) N56 → σ∗(N13-H14) are responsible for the stabilization of the molecule.
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| 44553. |
- Srivastava, Karnica, et al.
(author)
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Molecular structure, spectroscopic signature and reactivity analyses of paracetamol hydrochloride monohydrate salt using density functional theory calculations
- 2019
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In: CrystEngComm. - : Royal Society of Medicine Press. - 1466-8033. ; 21:5, s. 857-865
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Journal article (peer-reviewed)abstract
- The aim of this study was to understand the role of the intermolecular hydrogen bond interactions present in paracetamol hydrochloride monohydrated salt. Paracetamol hydrochloride monohydrate salt (PRA-HCl) and paracetamol (form I) were investigated via vibrational (FT-IR and FT-Raman) spectroscopy and density functional theory (DFT) to gain insight into the hydrogen bond patterns present in these crystalline materials. Two different density functionals, wB97X-D and M062X, were used for the comparison of the results. The geometrical parameters of PRA-HCl and form I obtained using these functional were compared with the crystallographic data, which proved the existence of intra-molecular and intermolecular hydrogen bonds. The C10O2 group of form I forms an intramolecular hydrogen bond, while the O1–H18 group of PRA-HCl forms an intermolecular hydrogen bond with a chloride ion (Cl−), resulting in the elongation of the bond length and shift to a lower wavenumber for the O1–H18 group. To examine the potency of hydrogen bonding, quantum theory of atoms in molecules (QTAIM) calculations were performed and the results suggested that O1–H18⋯Cl22 is a strong intermolecular hydrogen bond. The chemical reactivity parameters reveal that the PRA-HCl and PRA-OXA cocrystals are more reactive and softer (low HOMO–LUMO energy gap) in comparison to paracetamol (form I).
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| 44554. |
- Srivastava, Karnica, et al.
(author)
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Vibrational analysis and chemical activity of paracetamol-oxalic acid cocrystal based on monomer and dimer calculations : DFT and AIM approach
- 2016
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:12, s. 10024-10037
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Journal article (peer-reviewed)abstract
- The study of structural and spectral characteristics of a paracetamol-oxalic acid (PRA-OXA) cocrystal has been carried out using two models (monomer and dimer), with the aim to understand the supramolecular structure and intramolecular interactions within the cocrystal. The cocrystal has been characterized by infrared and Raman spectroscopy combined with quantum chemical calculations molecular electrostatic potential surface (MEPS), frontier orbital analysis and electronic reactivity descriptors were used to understand the role of interactions involved in affecting the chemical reactivity of individual molecules in the cocrystal. It is observed that the C=O, N-H and O-H groups of paracetamol are involved in hydrogen bonds to form cocrystals. NBO analysis suggests that the two types of interactions LP(1)(N8) -> pi*(C9-O10) and LP(2)(O10) -> sigma*(O25-H28) are responsible for the stability of the molecule. AIM analysis suggested that the non-covalent interactions are moderate in nature. The calculated HOMO-LUMO energies reveal that the charge transfer occurs within the cocrystal. Chemical reactivity parameters show that the cocrystal is more active than paracetamol.
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| 44555. |
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| 44556. |
- Srivastava, Vaibhav, et al.
(author)
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Alternative splicing studies of the reactive oxygen species gene network in Populus reveal two isoforms of high-isoelectric-point superoxide dismutase
- 2009
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In: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 149:4, s. 1848-1859
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Journal article (peer-reviewed)abstract
- Recent evidence has shown that alternative splicing (AS) is widely involved in the regulation of gene expression, substantially extending the diversity of numerous proteins. In this study, a subset of expressed sequence tags representing members of the reactive oxygen species gene network was selected from the PopulusDB database to investigate AS mechanisms in Populus. Examples of all known types of AS were detected, but intron retention was the most common. Interestingly, the closest Arabidopsis (Arabidopsis thaliana) homologs of half of the AS genes identified in Populus are not reportedly alternatively spliced. Two genes encoding the protein of most interest in our study (high-isoelectric-point superoxide dismutase [hipI-SOD]) have been found in black cottonwood (Populus trichocarpa), designated PthipI-SODC1 and PthipI-SODC2. Analysis of the expressed sequence tag libraries has indicated the presence of two transcripts of PthipI-SODC1 (hipI-SODC1b and hipI-SODC1s). Alignment of these sequences with the PthipI-SODC1 gene showed that hipI-SODC1b was 69 bp longer than hipI-SODC1s due to an AS event involving the use of an alternative donor splice site in the sixth intron. Transcript analysis showed that the splice variant hipI-SODC1b was differentially expressed, being clearly expressed in cambial and xylem, but not phloem, regions. In addition, immunolocalization and mass spectrometric data confirmed the presence of hipI-SOD proteins in vascular tissue. The functionalities of the spliced gene products were assessed by expressing recombinant hipI-SOD proteins and in vitro SOD activity assays.
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| 44557. |
- Srivastava, Vaibhav, et al.
(author)
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OnPLS integration of transcriptomic, proteomic and metabolomic data shows multi-level oxidative stress responses in the cambium of transgenic hipI- superoxide dismutase Populus plants
- 2013
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In: BMC Genomics. - : BioMed Central. - 1471-2164. ; 14
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Journal article (peer-reviewed)abstract
- BACKGROUND: Reactive oxygen species (ROS) are involved in the regulation of diverse physiological processes in plants, including various biotic and abiotic stress responses. Thus, oxidative stress tolerance mechanisms in plants are complex, and diverse responses at multiple levels need to be characterized in order to understand them. Here we present system responses to oxidative stress in Populus by integrating data from analyses of the cambial region of wild-type controls and plants expressing high-isoelectric-point superoxide dismutase (hipI-SOD) transcripts in antisense orientation showing a higher production of superoxide. The cambium, a thin cell layer, generates cells that differentiate to form either phloem or xylem and is hypothesized to be a major reason for phenotypic perturbations in the transgenic plants. Data from multiple platforms including transcriptomics (microarray analysis), proteomics (UPLC/QTOF-MS), and metabolomics (GC-TOF/MS, UPLC/MS, and UHPLC-LTQ/MS) were integrated using the most recent development of orthogonal projections to latent structures called OnPLS. OnPLS is a symmetrical multi-block method that does not depend on the order of analysis when more than two blocks are analysed. Significantly affected genes, proteins and metabolites were then visualized in painted pathway diagrams.RESULTS: The main categories that appear to be significantly influenced in the transgenic plants were pathways related to redox regulation, carbon metabolism and protein degradation, e.g. the glycolysis and pentose phosphate pathways (PPP). The results provide system-level information on ROS metabolism and responses to oxidative stress, and indicate that some initial responses to oxidative stress may share common pathways.CONCLUSION: The proposed data evaluation strategy shows an efficient way of compiling complex, multi-platform datasets to obtain significant biological information.
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| 44558. |
- Srivatsan, B, et al.
(author)
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Fault diagnosis of air compressors using transfer learning: A comparative study of pre-trained networks and hyperparameter optimization
- 2024
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In: Journal of Low Frequency Noise, Vibration and Active Control. - 1461-3484 .- 2048-4046.
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Journal article (peer-reviewed)abstract
- Air compressors are critical components in many industries whose catastrophic failure results in huge financial losses anddowntime leading to accidents. Hence, real time fault diagnosis of air compressor is essential to predict the health conditionof air compressor and plan scheduled maintenance thereby reducing financial losses and accidents. Fault diagnosis usingtransfer learning aids in real time fault detection. In the present study, five air compressor conditions were considerednamely, check valve fault, inlet and outlet reed valve fluttering fault, inlet reed valve fluttering fault, outlet reed valvefluttering fault, and good condition. The raw vibration data was converted to radar plot images that were pre-processed andclassified using four pre-trained networks (ResNet-50, GoogLeNet, AlexNet, and VGG-16). The hyperparameters likeepochs, batch size, optimizer, train-test split ratio, and learning rate were varied to find out the best network for aircompressor fault diagnosis. ResNet-50 among all other pre-trained networks produced the maximum classificationaccuracy (average of five trials) of 98.72%.
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| 44559. |
- Sroka, Paweł, et al.
(author)
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Policy-Based Traffic Steering and Load Balancing in O-RAN-Based Vehicle-to-Network Communications
- 2024
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In: IEEE Transactions on Vehicular Technology. - : IEEE. - 0018-9545 .- 1939-9359. ; 73:7, s. 9356-9369
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Journal article (peer-reviewed)abstract
- Vehicular communication (V2X) is one of the challenging use cases in the context of 5G and beyond networks due to its temporal and spatial dynamics. It is very specific and demanding from the perspective of a mobile network, especially since it covers a wide range of services with different requirements. On the other end, one of the key ideas behind the Open Radio Access Network (O-RAN) concept is to embed intelligence into the RAN to allow network and resource optimization through tailored applications. This is possible due to the introduction of the RAN Intelligent Controller (RIC), along with xApps and rApps. In this paper, we bring both of these worlds together and propose the use of Traffic Management and Traffic Steering applications in V2X scenarios. We also emphasize the usage of enrichment information (EI), enabled by O-RAN, specific to vehicular services (e.g., car platoon geolocation, or emergency situation notifications) which allows for optimal policy control. The numerical results for multiple V2X use cases show that the flexibility, provided by the O-RAN architecture enables optimized handling of the resources through policy control when dynamic changes occur on the road. Thus, we conclude that O-RAN is fit for purpose for the V2X scenarios.
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| 44560. |
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