201 results on '"Das O"'
Search Results
52. Developmental regulation of glycoprotein biosynthesis in dictyostelium.
- Author
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Ivatt, Raymond J., Das, O. Prem, Henderson, Ellen J., and Robbins, Phillips W.
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- 1981
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53. Allelic Variation and Differential Expression at the 27-Kilodalton Zein Locus in Maize
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Das, O P and Messing, J W
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Transcription, Genetic ,Zein ,DNA, Recombinant ,Nucleic Acid Hybridization ,Plant Development ,DNA ,DNA Restriction Enzymes ,Cell Biology ,Plants ,Zea mays ,Gene Expression Regulation ,DNA Transposable Elements ,RNA ,Electrophoresis, Polyacrylamide Gel ,Molecular Biology ,Alleles ,Research Article - Abstract
Allelic variation between inbred lines at the 27-kilodalton zein gene locus in maize has been used to study gene expression in developing endosperm. The inbred lines W22 and W23 contain two genes for this protein within two tandem repeats; the individual genes are virtually identical, with 99.9% homology in the 5'-flanking regions. Using gene-specific oligonucleotide probes, we have shown that transcripts of the downstream gene are found at a 2.5-fold-higher level than those of the upstream gene. Another inbred line, BSSS53, has one copy of the gene which is a recombinant of the duplicated genes at the 3'-flanking region. This line has been used in reciprocal crosses to demonstrate dosage effects for the overexpression of the downstream gene and to show that the overexpression of mRNA is reflected in a corresponding increase in the protein level. The accumulation of the protein through development does not, however, always correspond to the difference in mRNA levels.
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- 1987
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54. Evaluating layered distributed software systems with fault-tolerant features
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Das, O. and Woodside, C. Murray
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- 2001
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55. Working of Markfed in Andhra Pradesh - A Case Study
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Das, O. Ghanashyam, Reddy, M. Prabhakar, and Sithambar, G.
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- 1985
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56. A new radioactive cross-linking reagent for studying the interactions of proteins.
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Schwartz, M A, Das, O P, and Hynes, R O
- Abstract
We have developed a photoactivable, heterobifunctional, reversible, radioactively labeled, chemical cross-linking reagent, 3-[(2-nitro-4-azidophenyl)-2-aminoethyldithio]-N-succinimidyl propionate, for studying the interactions of proteins in situ. When reacted in the dark with a purified protein, it forms a covalent derivative which can be purified and reconstituted into biological systems. This derivative will form cross-links to neighboring macromolecules only upon photolysis; reduction cleaves the cross-link and transfers the radiolabel to the second molecule, which can then be identified by standard techniques. We have tested the cross-linker using the binding of gelatin to fibronectin. The cross-linker gives the proper chemical behavior under biological conditions, reacts with high yield and with a very low level of nonspecific cross-linking, and can be used to identify protein-protein and other interactions at the cell surface and elsewhere. The advantages, limitations and possible uses for this reagent are discussed.
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- 1982
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57. Developmental regulation of Dictyostelium discoideum plasma membrane proteins.
- Author
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Prem Das, O and Henderson, E J
- Abstract
Developmental changes in the plasma membrane proteins of Dictyostelium discoideum have been studied using metabolic labeling with [35S]methionine and two-dimensional electrophoresis. Pulse labeling for 1 h at the early interphase, late interphase, aggregation, and tip formation stages of development showed that the profile of newly synthesized plasma membrane proteins changed dramatically over this interval. Only 14% of the polypeptide species were synthesized at all four stages at detectable levels; 86% of the species changed over this developmental interval according to the criterion that they were synthesized at some but not all of the four stages tested. Long-term labeling during vegetative growth followed by initiation of development showed that the "steady-state" levels of the plasma membrane proteins changed very little over the same period. The only changes were in minor species (33% overall change). Similar analyses of whole cell proteins showed 27 and 20% change, respectively. Cell surface radioiodination revealed 52 external proteins in the plasma membrane. Comparison with the uniform methionine labeling results showed that these proteins were, with one notable exception, minor membrane components. In these external proteins, also, developmental changes were limited and were observed in the less abundant species. These results demonstrate the existence of two general classes of plasma membrane proteins. The first is a population of high-abundance proteins that are present in vegetative cells and are largely conserved through development. These possibly serve "housekeeping" functions common to all stages. The second class consists of low-abundance species that are expressed in a highly stage-specific manner and which presumably participate in developmentally important functions.
- Published
- 1983
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58. Correlation between early- and later-age performance indices of early frost-damaged concrete
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Liu, D., Chao Wang, Gonzalez-Libreros, J., Mensah, R. A., Försth, M., Das, O., Sas, G., Elfgren, L., and Tu, Y.
- Abstract
Freeze‐thaw cycles can lead to serious damage of early‐age concrete and influence its behaviour at later ages. In this study, the later‐age compressive strength, resistance to chloride penetration and resistance to freeze‐thaw of early frost‐damaged concrete were experimentally studied and the relationship between its early‐ (i.e., strength and resistivity) and later‐age (i.e., strength, chloride ion electric flux and freeze‐thaw durability factor) performance indices were analysed. Results show that the later‐age performance of the concrete subjected to freeze‐thaw cycles at early age was generally worse than that of the control samples, which had not undergone early frost damage. This was especially significant for the concrete subjected to freeze‐thaw cycles before the age of 24 h. The compressive strength after early frost action had a higher linear correlation with the later‐age indices of the concrete than the compressive strength before early frost action. Results also showed that the early‐age resistivity is a good indicator for the later‐age performance of early frost‐damaged concrete if the pre‐curing time before frosting is at least 24 h.
59. Region-specific cis- and trans-acting factors contribute to genetic variability in meiotic recombination in maize
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Timmermans, Marja C. P., Prem Das, O., James Bradeen, and Joachim Messing
60. Influence of large-scale asperities on the stability of concrete dams
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Ulfberg, A., Gonzalez-Libreros, J., Das, O., Sas, G., Andersson, E., Bista, D., Bård Arntsen, and Seger, A.
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VDP::Teknologi: 500 ,Scale model tests / Scale model tests ,Scale model tests ,Technology: 500 [VDP] ,VDP::Technology: 500 ,Concrete dams / Concrete dams ,Digital image correlation ,Finite element analysis ,Digital image correlation / Digital image correlation ,Finite element analysis / Finite element analysis ,Concrete dams ,Teknologi: 500 [VDP] - Abstract
For concrete dams founded on rock, there are only a few options in the common analysis methods to account for large‐scale asperities. However, previous research alludes that they have a significant impact on the behaviour of interfaces under shear. This study investigates the behaviour of concrete dam scale models with varying interface geometries, under a realistic set of eccentric loads. The outcome of the scale model tests shows that not only the capacity of the scale models was significantly impacted by the asperities, but also the type of failure in the scale models. Influence of large-scale asperities on the stability of concrete dams
61. Evolution of aluminide coating microstructure on nickel-base cast superalloy CM-247 in a single-step high-activity aluminizing process
- Author
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Das, O. K., Vakil Singh, and Joshi, S. V.
62. Guanidine hydrochloride-induced shedding of a Dictyostelium discoideum plasma membrane fraction enriched in the cyclic adenosine 3′,5′-monophosphate receptor
- Author
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Henderson, Ellen J., primary, Ugol, Harry B., additional, and Prem Das, O., additional
- Published
- 1982
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63. Glycoprotein biosynthesis in Dictyostelium discoideum: Developmental regulation of the protein-linked glycans
- Author
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Ivatt, Raymond L., primary, Prem Das, O., additional, Henderson, Ellen J., additional, and Robbins, Phillips W., additional
- Published
- 1984
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64. A novel technique for gentle lysis of eucaryotic cells Isolation of plasma membranes from Dictyostelium discoideum
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Prem Das, O., primary and Henderson, Ellen J., additional
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- 1983
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65. The fault-tolerant layered queueing network model for performability of distributed systems
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Das, O., primary and Murray Woodside, C., additional
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66. Modeling the coverage and effectiveness of fault-management architectures in layered distributed systems
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Das, O., primary and Woodside, C.M., additional
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67. Dependable LQNS: a performability modeling tool for layered systems.
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Das, O. and Woodside, C.M.
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- 2003
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68. Hexanuclear copper(ii) cage with {Cu3O⋯H⋯OCu3} core supported by a dicompartmental oxime ligand with m-xylyl spacer: synthesis, molecular structure and magnetic studies
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Subhamoy Ghosh, Sibasree Karmakar, Tapan Kanti Paine, Sumit Khanra, Ennio Zangrando, Thomas Weyhermüller, Mara Johann, Oindrila Das, Eva Rentschler, Karmakar, S., Das, O., Ghosh, S., Zangrando, Ennio, Johann, M., Rentschler, E., Weyhermüller, T., Khanra, S., and Paine, T. K.
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crystal structure ,Hydrogen bond ,Ligand ,Exchange interaction ,Hexanuclear copper complex ,chemistry.chemical_element ,Crystallography, X-Ray ,Ligands ,Oxime ,oxime ,Copper ,Inorganic Chemistry ,Magnetics ,chemistry.chemical_compound ,Crystallography ,chemistry ,Unpaired electron ,Oximes ,Organometallic Compounds ,Molecule ,Single crystal - Abstract
A new dicompartmental dioxime ligand (H(2)L) with m-xylyl spacer between the donor sites has been synthesised by Schiff-base condensation of α,α'-diamino-m-xylene and diacetyl monooxime. The ligand reacts with copper(ii) salts giving rise to hexanuclear tricationic copper(II) cage complexes [Cu(II)(6)(μ(3)-O···H···O-μ(3))L(3)(H(2)O)(6)]X(3) (X = BF(4), 1a; X = ClO(4), 1b). The complexes have been characterised by different analytical and spectroscopic techniques and confirmed the hexanuclear structure even in solution. Single crystal X-ray diffraction studies of both the complexes revealed a very similar core structure with three dicompartmental ligands supporting two triangular Cu(3)O cores that share a proton, located on their common threefold axis and involved in a strong hydrogen bond interaction (O···O distance of 2.517(2) Å). Two Cu(3)O units do not superimpose but are staggered and disposed with the formation of a helicate structure. However both the enantiomers are present in the centrosymmetric space group. The facing Cu(3)-planes in 1a are separated at a distance of 3.476 Å. The temperature dependence of the magnetic behaviour of the hexanuclear complex 1a clearly indicates an overall antiferromagnetic exchange interaction between the spin carriers in the cage having two Cu(3)O subunits and leaves a single unpaired electron in each triangular unit. The unpaired electrons in the two Cu(3)O units interact antiferromagnetically through hydrogen bonding giving rise to an overall singlet-spin ground state.
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- 2010
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69. Pitfalls in Cytological Diagnosis of Extra Adrenal Paraganglioma and Pheochromocytoma: Experience From a Tertiary Care Center.
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Mukherjee R, Dey S, Khatun F, Sk FW, Das O, Sarkar D, Maiti K, and Chatterjee U
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- Humans, Adult, Male, Female, Middle Aged, Adolescent, Child, Retrospective Studies, Paraganglioma, Extra-Adrenal pathology, Paraganglioma, Extra-Adrenal diagnosis, Young Adult, Cytodiagnosis methods, Diagnosis, Differential, Diagnostic Errors, Pheochromocytoma pathology, Pheochromocytoma diagnosis, Tertiary Care Centers, Adrenal Gland Neoplasms pathology, Adrenal Gland Neoplasms diagnosis
- Abstract
Background: Pheochromocytoma and extra-adrenal paragangliomas increasingly coming into light nowadays because of improved imaging techniques and biochemical investigations. There is sparse literature available regarding cytological findings of adrenal and extra-adrenal paragangliomas., Material and Methods: We studied 16 cytological specimens retrospectively over a period of 3 years, where subsequent histological diagnosis of phaeochromocytoma or paraganglioma was available., Results: A total of 16 cytology specimens were studied. Nine patients had adrenal SOLs and seven patients had extra-adrenal lesions. Age range was 12 to 60 years Majority of the cytology smears were cellular (87.5%). The smears were composed of small clusters as well as dispersed plasmacytoid cells with eccentric nuclei containing salt and pepper chromatin and moderate to abundant granular cytoplasm. Large cellular clusters mimicking the Zellballen pattern was present in one case. Anisonucleosis was mild to moderate, except in three cases where marked anisonucleosis posed diagnostic challenges. The background was hemorrhagic in all cases, however, two cases in addition had necroinflammatory background. All cases lacked mitotic activity and cytoplasm was delicate with indistinct cell borders. Bare oval nuclei were a frequent finding. Nuclear grooves or cytoplasmic vacuoles were absent. In 12 out of 16 cases, the initial cytological diagnosis correlated with final histological diagnosis, with an overall diagnostic accuracy of 75%. Four misdiagnosed cases had some atypical cytological features like marked anisonucleosis, necroinflammatory background, and presence of prominent nucleoli., Conclusion: Here we have highlighted some of the distinguishing cytological features that can help in cytological diagnosis of paragangliomas. Hemorrhagic background with plasmacytoid morphology, granular cytoplasm, naked nuclei, and absence of mitosis are useful clues., (© 2024 Wiley Periodicals LLC.)
- Published
- 2024
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70. Onyx dilution reduces time to resolution of chronic subdural hematomas after middle meningeal artery embolization.
- Author
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Hung A, Yang W, Das O, Wang X, Ran K, Ejimogu E, Abdulrahim M, Nakamura R, Hui F, Yedavalli V, Jackson CM, Huang J, Tamargo RJ, Caplan JM, Gonzalez LF, and Xu R
- Abstract
Background: The benefit of distal embolite penetration for middle meningeal artery (MMA) embolization in chronic subdural hematomas (cSDH) remains controversial., Objective: To compare the use of diluted Onyx with undiluted Onyx in the management of cSDH., Methods: This is a retrospective study of patients with cSDH who underwent MMA embolization using Onyx 18 at our institution. The study population was divided into two subgroups based on whether the Onyx used was diluted or not. Baseline characteristics and technical aspects were compared. Primary outcome was cSDH resolution at follow-up. Secondary outcomes included time to resolution and duration of procedure. Univariate statistical analysis was performed., Results: Of the 111 MMA embolizations performed at our institution, 99 were performed using Onyx 18 only. Within this cohort, 53 (53.5%) cases used standard Onyx and 46 (46.5%) cases used diluted Onyx. The diluted Onyx group had significantly greater volume of embolic agent used measured radiographically (P<0.001). There was no significant difference in duration of procedure. The percentage of cSDH resolution at last follow-up was similar between the two groups (P=0.98), but the time to resolution was significantly shorter in the diluted Onyx group (P=0.02)., Conclusion: The use of diluted Onyx for MMA embolization is associated with greater embolization volume achieved under similar procedural times. While the percentage of patients who achieved cSDH resolution with diluted Onyx is similar to that for standard Onyx, the time to cSDH resolution is significantly shorter. Adoption of Onyx dilution can be considered in MMA embolization for cSDH., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)
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- 2024
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71. Transradial approach for middle meningeal artery embolization is a safe alternative to transfemoral approach in patients with chronic subdural hematoma: A single-center retrospective comparative study.
- Author
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Hung A, Ran K, Das O, Ejimogu E, Yang W, Caplan J, Gonzalez F, and Xu R
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- Humans, Male, Female, Aged, Retrospective Studies, Middle Aged, Aged, 80 and over, Treatment Outcome, Femoral Artery, Embolization, Therapeutic methods, Hematoma, Subdural, Chronic therapy, Hematoma, Subdural, Chronic surgery, Meningeal Arteries surgery, Radial Artery
- Abstract
Background: Transradial approach (TRA) has been increasingly utilized in various neuroendovascular interventions as a safe alternative to the transfemoral approach (TFA). As middle meningeal artery (MMA) embolization emerges as an effective therapy for treating chronic subdural hematomas (cSDH), some studies have explored using TRA. In this study, we compared procedural times and post-operative outcomes between those with TRA and TFA., Methods: This is a single-institution retrospective study of patients undergoing MMA embolization for cSDH. The cohort was divided into the TRA and TFA subgroups. Baseline characteristics, procedural times, and immediate outcomes were compared. Univariate analysis was performed., Results: We performed 62 MMA embolizations for treatment of cSDH, of which 37 (59.7 %) were performed transradial and 25 (40.3 %) were performed transfemoral. Those who underwent TRA were significantly younger than those who had TFA (p = 0.02). For patients who underwent unilateral MMA embolization, those with TRA had significantly shorter duration of procedure compared to the TRF group (p = 0.01). This difference was not observed in the bilateral MMA embolization subgroup. Only three patients had access site complications, and all were in the TFA group. There was no significant difference in length of hospital stay., Conclusion: As MMA embolization for cSDH becomes more prevalent, efforts to optimize the safety and efficacy of the technical aspects become critical. In this study we demonstrate that TRA is a safe and efficient alternative to traditional TFA in those undergoing unilateral MMA embolization., (Copyright © 2024 Elsevier B.V. All rights reserved.)
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- 2024
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72. Cost Savings on Inpatient Hospitalization for Middle Meningeal Artery Embolization in the Setting of Increased Case Volume and Low Complications Rate.
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Hung A, Das O, Kalluri A, Wang X, Ran K, Ejimogu E, Yang W, Caplan J, Gonzalez F, and Xu R
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- Humans, Male, Female, Aged, Retrospective Studies, Middle Aged, Aged, 80 and over, Length of Stay economics, Postoperative Complications economics, Postoperative Complications epidemiology, Embolization, Therapeutic economics, Embolization, Therapeutic methods, Embolization, Therapeutic adverse effects, Meningeal Arteries, Cost Savings, Hematoma, Subdural, Chronic economics, Hematoma, Subdural, Chronic therapy, Hospitalization economics
- Abstract
Background: Middle meningeal artery (MMA) embolization for the treatment of chronic subdural hematomas (cSDHs) is becoming increasingly prevalent. It is essential to optimize the safety and cost effectiveness of the postprocedural management. In this study, we examined our cases over time to determine the most appropriate postprocedural destination., Methods: This is a retrospective study of patients who underwent MMA embolization for cSDH at our institution. The study cohort was divided into 2 groups based on the year of embolization. Baseline characteristics, postprocedural complications, and length of stay were compared. Patients with shorter intensive care unit (ICU) stay were also compared to those with longer stay. Univariate statistical analysis was performed., Results: 92 MMA embolizations for cSDH have been performed at our institution, of which 36 (39.1%) were done between 2019 and 2022 and 56 (60.9%) after 2023. No patients experienced stroke, cranial nerve palsy, or intraparenchymal hemorrhage after embolization. All but 5 patients were admitted to the ICU postembolization, of which 59 (64.1%) were downgraded after one day. Factors associated with a longer ICU stay included preoperative location (P = 0.002) and need for surgery (P = 0.02). Of those who came from home or nonmonitored bed, 82% were downgraded from the ICU in less than 2 days. The average cost of one night in the ICU, intermediate care, and nonmonitored unit was $3671.75, $2605.22, and $2303.81 respectively., Conclusions: MMA embolization for cSDH is a safe procedure with low rate of procedure-related complications. In carefully selected patients, the necessity ICU admission postoperatively should be weighed against better hospital resource utilization., (Copyright © 2024 Elsevier Inc. All rights reserved.)
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- 2024
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73. Phosphorylated and carbamylated Kraft lignin for improving fire- and biological-resistance of Scots pine wood.
- Author
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Lin CF, Karlsson O, Myronycheva O, Das O, Mensah RA, Mantanis GI, Jones D, Antzutkin ON, Försth M, and Sandberg D
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- Phosphorylation drug effects, Fires, Magnetic Resonance Spectroscopy, Lignin chemistry, Lignin pharmacology, Wood chemistry, Pinus sylvestris chemistry
- Abstract
In this study, Kraft lignin was modified by ammonium dihydrogen phosphate (ADP) and urea for achieving phosphorylation and carbamylation, aiming to protect wood against biological and fire attack. Scots pine (Pinus sylvestris L.) sapwood was impregnated with a water solution containing Kraft lignin, ADP, and urea, followed by heat treatment at 150 °C, resulting in changes in the properties of the Kraft lignin as well as the wood matrix. Infrared spectroscopy,
13 C cross-polarisation magic-angle-spinning (MAS) nuclear magnetic resonance (NMR), and direct excitation single-pulse31 P MAS NMR analyses suggested the grafting reaction of phosphate and carbamylate groups onto the hydroxyl groups of Kraft lignin. Scanning electron microscopy with energy dispersive X-ray spectroscopy indicated that the condensed Kraft lignin filled the lumen as well as partially penetrating the wood cell wall. The modified Kraft lignin imparted fire-retardancy and increased char residue to the wood at elevated temperature, as confirmed by limiting oxygen index, microscale combustion calorimetry, and thermogravimetric analysis. The modified wood exhibited superior resistance against mold and decay fungi attack under laboratory conditions. The modified wood had a similar modulus of elasticity to the unmodified wood, while experiencing a reduction in the modulus of rupture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)- Published
- 2024
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74. The functional antagonist of sphingosine-1-phosphate, FTY720, impairs gut barrier function.
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Sikdar S, Mitra D, Das O, Bhaumik M, and Dutta S
- Abstract
FTY720 or fingolimod is a known functional antagonist of sphingosine-1-phosphate (S1P), and it is effective in treating multiple sclerosis and preventing inflammatory bowel disease (IBD). Evidence shows that its use in mice can increase the susceptibility to mucosal infections. Despite the significant contribution of S1P to barrier function, the effect of the administration of FTY720 on the mucosal barrier has never been investigated. In this study, we looked into how FTY720 therapy affected the function of the gut barrier susceptibility. Administration of FTY720 to C57BL/6 mice enhances the claudin-2 expression and reduces the expression of claudin-4 and occludin, as studied by qPCR, Western blot, and immunofluorescence. FTY720 inhibits the Akt-mTOR pathway to decrease occludin and claudin-4 expression and increase claudin-2 expression. FTY720 treatment induced increased colonic inflammation, with notably greater immune cell infiltration, colon histopathology, and increased production of TNF-α, IFN-γ, CXCL-1, and CXCL-2 than that in control mice. Taking into account the close association of "the leaky gut" and gut dysbiosis among the major diseases, we therefore can infer that the vigilance of gut pathology should be maintained, where FTY720 is used as a treatment option., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Sikdar, Mitra, Das, Bhaumik and Dutta.)
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- 2024
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75. Nerve-Targeted Surgical Treatments for Spasticity: A Narrative Review.
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Ran KR, Das O, Johnston DT, Vutakuri N, Ranganathan S, Broachwala M, Chopra H, Long Azad C, Azad TD, Robinson S, Belzberg AJ, Tuffaha SH, and Lubelski D
- Subjects
- Humans, Neurosurgical Procedures methods, Nerve Transfer methods, Muscle Spasticity surgery, Rhizotomy methods
- Abstract
Spasticity is a potentially debilitating symptom of various acquired and congenital neurologic pathologies that, without adequate treatment, may lead to long-term disability, compromise functional independence, and negatively impact mental health. Several conservative as well as non-nerve targeted surgical strategies have been developed for the treatment of spasticity, but these may be associated with significant drawbacks, such as adverse side effects to medication, device dependence on intrathecal baclofen pumps, and inadequate relief with tendon-based procedures. In these circumstances, patients may benefit from nerve-targeted surgical interventions such as (i) selective dorsal rhizotomy, (ii) hyperselective neurectomy, and (iii) nerve transfer. When selecting the appropriate surgical approach, preoperative patient characteristics, as well as the risks and benefits of nerve-targeted surgical intervention, must be carefully evaluated. Here, we review the current evidence on the efficacy of these nerve-targeted surgical approaches for treating spasticity across various congenital and acquired neurologic pathologies., (Copyright © 2024 Elsevier Inc. All rights reserved.)
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- 2024
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76. Antiepileptic drug-loaded and multifunctional iron oxide@silica@gelatin nanoparticles for acid-triggered drug delivery.
- Author
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Ghane N, Khalili S, Khorasani SN, Das O, Ramakrishna S, and Neisiany RE
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- Hydrogen-Ion Concentration, Humans, Ferric Compounds chemistry, Drug Liberation, Drug Carriers chemistry, Magnetic Iron Oxide Nanoparticles chemistry, Magnetite Nanoparticles chemistry, Nanoparticles chemistry, Particle Size, Gelatin chemistry, Anticonvulsants chemistry, Anticonvulsants administration & dosage, Silicon Dioxide chemistry, Phenytoin chemistry, Phenytoin administration & dosage, Drug Delivery Systems methods
- Abstract
The current study developed an innovative design for the production of smart multifunctional core-double shell superparamagnetic nanoparticles (NPs) with a focus on the development of a pH-responsive drug delivery system tailored for the controlled release of Phenytoin, accompanied by real-time monitoring capabilities. In this regard, the ultra-small superparamagnetic iron oxide@silica NPs (IO@Si MNPs) were synthesized and then coated with a layer of gelatin containing Phenytoin as an antiepileptic drug. The precise saturation magnetization value for the resultant NPs was established at 26 emu g
-1 . The polymeric shell showed a pH-sensitive behavior with the capacity to regulate the release of encapsulated drug under neutral pH conditions, simultaneously, releasing more amount of the drug in a simulated tumorous-epileptic acidic condition. The NPs showed an average size of 41.04 nm, which is in the desired size range facilitating entry through the blood-brain barrier. The values of drug loading and encapsulation efficiency were determined to be 2.01 and 10.05%, respectively. Moreover, kinetic studies revealed a Fickian diffusion process of Phenytoin release, and diffusional exponent values based on the Korsmeyer-Peppas equation were achieved at pH 7.4 and pH 6.3. The synthesized NPs did not show any cytotoxicity. Consequently, this new design offers a faster release of PHT at the site of a tumor in response to a change in pH, which is essential to prevent epileptic attacks., (© 2024. The Author(s).)- Published
- 2024
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77. Machine Learning Identifies Variation in Timing of Palliative Care Consultations Among Traumatic Brain Injury Patients.
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Aude CA, Vattipally VN, Das O, Ran KR, Giwa GA, Rincon-Torroella J, Xu R, Byrne JP, Muehlschlegel S, Suarez JI, Mukherjee D, Huang J, Azad TD, and Bettegowda C
- Abstract
Background and Objective Timely palliative care involvement offers demonstrable benefits for traumatic brain injury (TBI) patients; however, palliative care consultations (PCCs) are used inconsistently during TBI management. This study aimed to employ advanced machine learning techniques to elucidate the primary drivers of PCC timing variability for TBI patients. Methods Data on admission, hospital course, and outcomes were collected for a cohort of 232 TBI patients who received both PCCs and neurosurgical consultations during the same hospitalization. Principal Component Analysis (PCA) and K-means clustering were used to identify patient phenotypes, which were then compared using Kaplan-Meier analysis. An extreme gradient boosting model (XGBoost) was employed to determine drivers of PCC timing, with model interpretation performed using SHapley Additive exPlanations (SHAP). Results Cluster A (n = 86) consisted mainly of older (median [IQR] = 87 [78, 94] years), White females with mild TBIs and demonstrated the shortest time-to-PCC (2.5 [1.0, 7.0] days). Cluster B (n = 108) also sustained mild TBIs but comprised moderately younger (81 [75, 86] years) married White males with later PCC (5.0 [3.0, 10.8] days). Cluster C (n = 38) represented much younger (46.5 [29.5, 59.8] years), more severely injured, non-White patients with the latest PCC initiation (9.0 [4.2, 17.0] days). The clusters did not differ by discharge disposition (p = 0.4) or frequency inpatient mortality (p > 0.9); however, Kaplan-Meier analysis revealed a significant difference in the time from admission to PCC (p < 0.001), despite no differences in time from admission to mortality (p = 0.18). SHAP analysis of the XGBoost model identified age, sex, and race as the most influential drivers of PCC timing. Conclusions This study highlights crucial disparities in PCC timing for TBI patients and underscores the need for targeted strategies to ensure timely and equitable palliative care integration for this vulnerable population., Competing Interests: Declarations Other Competing Interests: The authors have no other competing interest to disclose.
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- 2024
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78. Facile encapsulation of cyanoacrylate-based bioadhesive by electrospray method and investigation of the process parameters.
- Author
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Aminoroaya A, Khorasani SN, Bagheri R, Talebi Z, Malekkhouyan R, Das O, and Neisiany RE
- Abstract
Polymer microcapsules containing cyanoacrylates have represented a promising option to develop self-healing biomaterials. This study aims to develop an electrospray method for the preparation of capsules using poly(methyl methacrylate) (PMMA) as the encapsulant and ethyl 2-cyanoacrylate (EC) as the encapsulate. It also aims to study the effect of the electrospray process parameters on the size and morphology of the capsules. The capsules were characterized using Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). Moreover, the effects of electrospray process parameters on the size were investigated by Taguchi experimental design. FTIR and TGA approved the presence of both PMMA and EC without further reaction. FE-SEM micrograph demonstrated that an appropriate choice of solvents, utilizing an appropriate PMMA:EC ratio and sufficient PMMA concentration are critical factors to produce capsules dominantly with an intact and spherical morphology. Utilizing various flow rates (0.3-0.5 ml/h) and applied voltage (18-26 kV), capsules were obtained with a 600-1000 nm size range. At constantly applied voltages, the increase in flow rate increased the capsule size up to 40% (ANOVA, p ≤ 0.05), while at constant flow rates, the increase in applied voltage reduced the average capsule size by 3.4-26% (ANOVA, p ≤ 0.05). The results from the Taguchi design represented the significance of solution flow rate, applied voltage, and solution concentration. It was shown that the most effective parameter on the size of capsules is flow rate. This research demonstrated that electrospray can be utilized as a convenient method for the preparation of sub-micron PMMA capsules containing EC. Furthermore, the morphology of the capsules is dominated by solvents, PMMA concentration, and PMMA:EC ratio, while the average size of the capsules can be altered by adjusting the flow rate and applied voltage of the electrospray process., (© 2024. The Author(s).)
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- 2024
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79. Testicular Mixed Teratoma and Yolk Sac Tumor, Prepubertal Type: A Case Report with Summary of Prior Published Cases.
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Mohin M, Dey S, Ray R, Wasim Sk F, Das O, and Chatterjee U
- Subjects
- Male, Infant, Newborn, Humans, Infant, Endodermal Sinus Tumor diagnosis, Endodermal Sinus Tumor pathology, Teratoma diagnosis, Teratoma pathology, Testicular Neoplasms diagnosis, Testicular Neoplasms pathology, Neoplasms, Germ Cell and Embryonal
- Abstract
Background: Testicular mixed germ cell tumor is common in the post-pubertal age, less so in prepuberty. There are only 3 reports of prepubertal mixed teratoma and yolk sac tumor. Two of these cases had immature teratoma component and were in the neonatal age group. The third case in a toddler had a mature teratoma component., Case Report: An 18-month-old boy presented with a testicular mass. Serum AFP was elevated (2200 ng/ml). The orchidectomy specimen contained a yolk-sac tumor and a small epidermoid cyst, indicating a mature teratomatous component., Conclusion: We report a testicular mixed teratoma and yolk sac tumor, prepubertal type along with summary of prior published cases. There is only one report describing this combination of mature teratoma with yolk sac tumor in the prepubertal testis.
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- 2024
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80. Effect of Low to High Pressure on the Structural, Mechanical, Electrical, and Optical Properties of Inorganic Material Ca 3 AsBr 3 : An Ab Initio Investigation.
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Ul Islam MA, Das O, Khadka DB, Islam MR, Rahman MF, Kato S, and Soga T
- Abstract
Inorganic metal halide solar cells made from perovskite stand out for having outstanding efficiency, cheap cost, and simple production processes and recently have generated attention as a potential rival in photovoltaic technology. Particularly, lead-free Ca
3 AsBr3 inorganic materials have a lot of potential in the renewable industry due to their excellent qualities, including thermal, electric, optoelectronic, and elastic features. In this work, we thoroughly analyzed the stress-driven structural, mechanical, electrical, and optical properties of Ca3 AsBr3 utilizing first-principles theory. The unstressed planar Ca3 AsBr3 compound's bandgap results in 1.63 eV, confirming a direct bandgap. The bandgap within this compound could have changed by applying hydrostatic stress; consequently, a semiconductor-to-metallic transition transpired at 50 GPa. Simulated X-ray diffraction further demonstrated that it maintained its initial cubic form, even after external disruption. Additionally, it has been shown that an increase in compressive stress causes a change of the absorption spectra and the dielectric function with a red shift of photon energy at the lower energy region. Because of the material's mechanical durability and increased degree of ductility, demonstrated by its stress-triggered mechanical characteristics, the Ca3 AsBr3 material may be suitable for solar energy applications. The mechanical and optoelectronic properties of Ca3 AsBr3 , which are pressure sensitive, could potentially be advantageous for future applications in optical devices and photovoltaic cell architecture., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)- Published
- 2024
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81. Cytological findings of phosphaturic mesenchymal tumor: Report of a case with summary of prior published cases.
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Das O, Mohin M, Dey S, Kar A, Singhania P, Adhikari S, Chowdhury S, and Chatterjee U
- Subjects
- Female, Humans, Middle Aged, Biopsy, Fine-Needle adverse effects, Soft Tissue Neoplasms pathology, Mesenchymoma pathology, Paraneoplastic Syndromes complications, Paraneoplastic Syndromes diagnosis, Osteomalacia etiology
- Abstract
Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm causing tumor-induced osteomalacia (TIO) and is characterized by secretion of FGF23, renal phosphate wasting and hypophosphataemia. It can be completely cured by resection and therefore its diagnosis is of utmost importance. Although the histology is well described, there is sparse literature on cytology of PMT and only three cases have been described so far. A 45-year-old lady presented with a non-tender mass in hard palate for 2 years from which fine-needle aspiration was done. The smears were paucicellular and showed bland spindle cells embedded in osteoid-like stromal matrix in a hemorrhagic background. Here we take the opportunity to describe the cytological findings of PMT along with its cytological differentials and a summary of prior published cases., (© 2023 Wiley Periodicals LLC.)
- Published
- 2024
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82. Surface coated ZnO powder as flame retardant for wood: A short communication.
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Öhrn O, Sykam K, Gawusu S, Mensah RA, Försth M, Shanmugam V, Karthik Babu NB, Sas G, Jiang L, Xu Q, Restás Á, and Das O
- Abstract
In the present study, the ability of a coating of zinc oxide (ZnO) powder to improve the fire-safety of wood exposed to radiative heat flux was examined, focusing on the ignition time of the wood. To test ZnO's efficiency on the wood substrate, two different amounts of ZnO (0.5 and 1 g ZnO per dm
2 ) were applied to the wood surface and exposed to radiative heat from a cone calorimeter wherein a pristine piece of wood with no ZnO treatment was taken as control. The experiments were conducted at three different irradiation levels i.e., 20, 35, and 50 kWm-2 . The results showed that applying ZnO on the surface of the wood significantly increased the ignition time (TTI). For the three different heat fluxes, using 0.5 g ZnO per dm2 coating on the wood surface increased the TTI by 26-33 %. Furthermore, the application of 1 g of ZnO per dm2 generated a TTI increment of 37-40 %. All three irradiation levels showed similar trends in TTI. The micrographs taken before and after combustion showed no significant disparity in the morphology of ZnO. The agglomerated ZnO particles on the wood surface remained intact after combustion. This study demonstrates a facile method of using ZnO to delay the ignition of wood. This could potentially impart fire-safety to wooden structures/façades in wildland-urban interfaces and elsewhere by reducing flame spread., Competing Interests: Declaration of competing interest All authors declare no financial/commercial conflicts of interest, with any parties., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)- Published
- 2023
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83. Pyrolysis of Automotive Shredder Residue (ASR): Thermogravimetry, In-Situ Synchrotron IR and Gas-Phase IR of Polymeric Components.
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Kohli I, Srivatsa SC, Das O, Devasahayam S, Singh Raman RK, and Bhattacharya S
- Abstract
This article reports the characterisation of pyrolysis of automotive shredder residue using in situ synchrotron IR, gas-phase IR, and thermal analyses to explore if the automotive shredder residue can be converted into value-added products. When heating to ~600 °C at different heating rates, thermal analyses suggested one- to two-stage pyrolysis. Transformations in the first stage, at lower temperatures, were attributed to the degradation of carbonyl, hydroxyl, or carboxyl functional stabilisers (aldehyde and ether impurities, additives, and stabilisers in the ASR). The second stage transformations, at higher temperatures, were attributed to the thermal degradation of the polymer char. Simultaneous thermal analyses and gas-phase IR spectroscopy confirmed the evolution of the gases (alkanes (CH
4 ), CO2 , and moisture). The synchrotron IR data have demonstrated that a high heating rate (such as 150 °C/min) results in an incomplete conversion of ASRs unless sufficient time is provided. The thermogravimetry data fit the linearised multistage kinetic model at different heating rates. The activation energy of reactions varied between 24.98 and 124.94 kJ/mol, indicating a surface-controlled reaction exhibiting high activation energy during the initial stages and a diffusion and mass transfer control showing lower activation energy at the final stages. The corresponding frequency factors were in the range of 3.34 × 1013 -5.68 × 101 mg-1 /min for different pyrolysis stages. The evolution of the functional groups decreased with an increase in the heating rate.- Published
- 2023
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84. PP2Ac Deficiency Enhances Tumor Immunogenicity by Activating STING-Type I Interferon Signaling in Glioblastoma.
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Mondal I, Das O, Sun R, Gao J, Yu B, Diaz A, Behnan J, Dubey A, Meng Z, Eskandar E, Xu B, Lu RO, and Ho WS
- Subjects
- Humans, Immunity, Innate, Nucleotidyltransferases genetics, Tumor Microenvironment, Glioblastoma, Glioma, Interferon Type I metabolism
- Abstract
Glioblastoma (GBM) is an immunologically "cold" tumor that does not respond to current immunotherapy. Here, we demonstrate a fundamental role for the α-isoform of the catalytic subunit of protein phosphatase-2A (PP2Ac) in regulating glioma immunogenicity. Genetic ablation of PP2Ac in glioma cells enhanced double-stranded DNA (dsDNA) production and cGAS-type I IFN signaling, MHC-I expression, and tumor mutational burden. In coculture experiments, PP2Ac deficiency in glioma cells promoted dendritic cell (DC) cross-presentation and clonal expansion of CD8+ T cells. In vivo, PP2Ac depletion sensitized tumors to immune-checkpoint blockade and radiotherapy treatment. Single-cell analysis demonstrated that PP2Ac deficiency increased CD8+ T-cell, natural killer cell, and DC accumulation and reduced immunosuppressive tumor-associated macrophages. Furthermore, loss of PP2Ac increased IFN signaling in myeloid and tumor cells and reduced expression of a tumor gene signature associated with worse patient survival in The Cancer Genome Atlas. Collectively, this study establishes a novel role for PP2Ac in inhibiting dsDNA-cGAS-STING signaling to suppress antitumor immunity in glioma., Significance: PP2Ac deficiency promotes cGAS-STING signaling in glioma to induce a tumor-suppressive immune microenvironment, highlighting PP2Ac as a potential therapeutic target to enhance tumor immunogenicity and improve response to immunotherapy., (©2023 American Association for Cancer Research.)
- Published
- 2023
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85. Machine learning for fault analysis in rotating machinery: A comprehensive review.
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Das O, Bagci Das D, and Birant D
- Abstract
As the concept of Industry 4.0 is introduced, artificial intelligence-based fault analysis is attracted the corresponding community to develop effective intelligent fault diagnosis and prognosis (IFDP) models for rotating machinery. Hence, various challenges arise regarding model assessment, suitability for real-world applications, fault-specific model development, compound fault existence, domain adaptability, data source, data acquisition, data fusion, algorithm selection, and optimization. It is essential to resolve those challenges for each component of the rotating machinery since each issue of each part has a unique impact on the vital indicators of a machine. Based on these major obstacles, this study proposes a comprehensive review regarding IFDP procedures of rotating machinery by minding all the challenges given above for the first time. In this study, the developed IFDP approaches are reviewed regarding the pursued fault analysis strategies, considered data sources, data types, data fusion techniques, machine learning techniques within the frame of the fault type, and compound faults that occurred in components such as bearings, gear, rotor, stator, shaft, and other parts. The challenges and future directions are presented from the perspective of recent literature and the necessities concerning the IFDP of rotating machinery., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)
- Published
- 2023
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86. First-Principles Calculations to Investigate the Stability and Thermodynamic Properties of a Newly Exposed Lithium-Gallium-Iridium-Based Full-Heusler Compound.
- Author
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Islam MAU, Islam MR, das O, Kato S, Kishi N, and Soga T
- Abstract
The structural, optical, electrical, thermodynamic, superconducting, and mechanical characteristics of LiGa
2 Ir full-Heusler alloys with the MnCu2 Al configuration were comprehensively examined in this work using the first-principles computation approach premised upon density functional analysis. This theoretical approach is the first to investigate the influence of pressure on the mechanical and optical characteristics of LiGa2 Ir. The structural and chemical bonding analysis shows that hydrostatic pressure caused a decrease in the lattice constant, volume, and bond length of each cell. According to the mechanical property calculations, the LiGa2 Ir cubic Heusler alloy exhibits mechanical stability. It also has ductility and anisotropic behavior. This metallic substance shows no band gap throughout the applied pressure range. The physical characteristics of the LiGa2 Ir full-Heusler alloy are analyzed in the operating pressure range of 0-10 GPa. The quasi-harmonic Debye model is employed to analyze thermodynamic properties. The Debye temperature (291.31 K at 0 Pa) increases with hydrostatic pressure. A newly invented structure attracted a lot of attention around the globe for its superior superconductivity ( Tc ∼ 2.95 K). Optical functions have also been improved after applying stress to utilize it in optoelectronic/nanoelectric devices. The optical function analysis is supported strongly by the electronic properties. Due to these reasons, LiGa2 Ir imposed an essential guiding principle for relevant future research and could be a credible candidate substance for industrial settings., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)- Published
- 2023
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87. Butyrate driven raft disruption trots off enteric pathogen invasion: possible mechanism of colonization resistance.
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Das O, Masid A, Chakraborty M, Gope A, Dutta S, and Bhaumik M
- Abstract
The gut microbiome derived short chain fatty acids perform multitude of functions to maintain gut homeostasis. Here we studied how butyrate stymie enteric bacterial invasion in cell using a simplistic binary model. The surface of the mammalian cells is enriched with microdomains rich in cholesterol that are known as rafts and act as entry points for pathogens. We showed that sodium butyrate treated RAW264.7 cells displayed reduced membrane cholesterol and less cholera-toxin B binding coupled with increased membrane fluidity compared to untreated cells indicating that reduced membrane cholesterol caused disruption of lipid rafts. The implication of such cellular biophysical changes on the invasion of enteric pathogenic bacteria was assessed. Our study showed, in comparison to untreated cells, butyrate-treated cells significantly reduced the invasion of Shigella and Salmonella, and these effects were found to be reversed by liposomal cholesterol treatment, increasing the likelihood that the rafts' function against bacterial invasion. The credence of ex vivo studies found to be in concordance in butyrate fed mouse model as evident from the significant drift towards a protective phenotype against virulent enteric pathogen invasion as compared to untreated mice. To produce a cytokine balance towards anti-inflammation, butyrate-treated mice produced more of the gut tissue anti-inflammatory cytokine IL-10 and less of the pro-inflammatory cytokines TNF-α, IL-6, and IFN-γ. In histological studies of Shigella infected gut revealed a startling observation where number of neutrophils infiltration was noted which was correlated with the pathology and was essentially reversed by butyrate treatment. Our results ratchet up a new dimension of our understanding how butyrate imparts resistance to pathogen invasion in the gut., (© 2023. The Author(s).)
- Published
- 2023
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88. Extralobar Pulmonary Sequestration in Adrenal Mimicking Neuroblastoma: A Case Report.
- Author
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Mukherjee R, Das O, Chakravorty S, Mohanty S, and Chatterjee U
- Subjects
- Infant, Newborn, Female, Humans, Lung, Bronchopulmonary Sequestration diagnosis, Bronchopulmonary Sequestration pathology, Bronchopulmonary Sequestration surgery, Adrenal Gland Neoplasms diagnosis, Cystic Adenomatoid Malformation of Lung, Congenital pathology, Neuroblastoma diagnosis, Neuroblastoma pathology
- Abstract
Background: Extralobar pulmonary sequestration (ELS) is a malformation composed of bronchopulmonary tissue outside the lungs that is discontinuous from the main tracheobronchial tree. ELS can present as a suprarenal space occupying lesion. Case Report: A 1-day old girl presented with a right supra-adrenal mass, first detected in-utero at 34 weeks. The differential included congenital neuroblastoma, but the urinary VMA was normal. At resection, there was lung tissue composed of dilated and tortuous bronchioles lined by columnar epithelium present in a back- to- back arrangement along with thick-walled vessels, features of an ELS with congenital pulmonary airway malformation type II. Conclusion: ELS enters the differential diagnosis of neonatal suprarenal masses with normal urinary catecholamines, and can have the morphology of a type II congenital pulmonary airway malformation.
- Published
- 2023
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89. PP2Ac/STRN4 negatively regulates STING-type I IFN signaling in tumor-associated macrophages.
- Author
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Ho WS, Mondal I, Xu B, Das O, Sun R, Chiou P, Cai X, Tahmasebinia F, McFadden E, Wu CY, Wu Z, Matsui W, Lim M, Meng Z, and Lu RO
- Subjects
- Animals, Humans, Mice, Calmodulin-Binding Proteins, Macrophages, Protein Processing, Post-Translational, Signal Transduction, Tumor Microenvironment, Interferon Type I metabolism, Glioblastoma, Tumor-Associated Macrophages
- Abstract
Stimulator of IFN genes type I (STING-Type I) IFN signaling in myeloid cells plays a critical role in effective antitumor immune responses, but STING agonists as monotherapy have shown limited efficacy in clinical trials. The mechanisms that downregulate STING signaling are not fully understood. Here, we report that protein phosphatase 2A (PP2A), with its specific B regulatory subunit Striatin 4 (STRN4), negatively regulated STING-Type I IFN in macrophages. Mice with macrophage PP2A deficiency exhibited reduced tumor progression. The tumor microenvironment showed decreased immunosuppressive and increased IFN-activated macrophages and CD8+ T cells. Mechanistically, we demonstrated that Hippo kinase MST1/2 was required for STING activation. STING agonists induced dissociation of PP2A from MST1/2 in normal macrophages, but not in tumor conditioned macrophages. Furthermore, our data showed that STRN4 mediated PP2A binding to and dephosphorylation of Hippo kinase MST1/2, resulting in stabilization of YAP/TAZ to antagonize STING activation. In human patients with glioblastoma (GBM), YAP/TAZ was highly expressed in tumor-associated macrophages but not in nontumor macrophages. We also demonstrated that PP2A/STRN4 deficiency in macrophages reduced YAP/TAZ expression and sensitized tumor-conditioned macrophages to STING stimulation. In summary, we demonstrated that PP2A/STRN4-YAP/TAZ has, in our opinion, been an unappreciated mechanism that mediates immunosuppression in tumor-associated macrophages, and targeting the PP2A/STRN4-YAP/TAZ axis can sensitize tumors to immunotherapy.
- Published
- 2023
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90. High Leach-Resistant Fire-Retardant Modified Pine Wood ( Pinus sylvestris L. ) by In Situ Phosphorylation and Carbamylation.
- Author
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Lin CF, Karlsson O, Das O, Mensah RA, Mantanis GI, Jones D, Antzutkin ON, Försth M, and Sandberg D
- Abstract
The exterior application of fire-retardant (FR) timber necessitates it to have high durability because of the possibility to be exposed to rainfall. In this study, water-leaching resistance of FR wood has been imparted by grafting phosphate and carbamate groups of the water-soluble FR additives ammonium dihydrogen phosphate (ADP)/urea onto the hydroxyl groups of wood polymers via vacuum-pressure impregnation, followed by drying/heating in hot air. A darker and more reddish wood surface was observed after the modification. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, solid-state
13 C cross-polarization magic-angle-spinning nuclear magnetic resonance (13 C CP-MAS NMR), and direct-excitation31 P MAS NMR suggested the formation of C-O-P covalent bonds and urethane chemical bridges. Scanning electron microscopy/energy-dispersive X-ray spectrometry suggested the diffusion of ADP/urea into the cell wall. The gas evolution analyzed by thermogravimetric analysis coupled with quadrupole mass spectrometry revealed a potential grafting reaction mechanism starting with the thermal decomposition of urea. Thermal behavior showed that the FR-modified wood lowered the main decomposition temperature and promoted the formation of char residues at elevated temperatures. The FR activity was preserved even after an extensive water-leaching test, confirmed by the limiting oxygen index (LOI) and cone calorimetry. The reduction of fire hazards was achieved through the increase of the LOI to above 80%, reduction of 30% of the peak heat release rate (pHRR2 ), reduction of smoke production, and a longer ignition time. The modulus of elasticity of FR-modified wood increased by 40% without significantly decreasing the modulus of rupture., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)- Published
- 2023
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91. Prenatal arsenic exposure stymies gut butyrate production and enhances gut permeability in post natal life even in absence of arsenic deftly through miR122-Occludin pathway.
- Author
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Chakraborty M, Gautam A, Das O, Masid A, and Bhaumik M
- Subjects
- Animals, Mice, Butyric Acid metabolism, Drinking Water chemistry, Gastrointestinal Tract metabolism, Permeability, Arsenic adverse effects, Arsenic toxicity, Lower Gastrointestinal Tract metabolism, MicroRNAs genetics, MicroRNAs metabolism, Occludin genetics, Occludin metabolism, Prenatal Exposure Delayed Effects metabolism
- Abstract
This discourse attempts to capture a few important dimensions of gut physiology like microbial homeostasis, short chain fatty acid (SCFA) production, occludin expression, and gut permeability in post-natal life of mice those received arsenic only during pre-natal life. Adult Balb/c mice were fed with 4 ppm arsenic trioxide in drinking water during breeding and gestation. After the birth of the pups, the arsenic water was withdrawn and replaced with clean drinking water. The pups were allowed to grow for 28 days (pAs-mice) and age matched Balb/c mice which were never exposed to arsenic served as control The pAs-mice showed a striking reduction in Firmicutes to Bacteroidetes (F/B) ratio coupled with a decrease in tight junction protein, occludin resulting in an increase in gut permeability, increased infiltration of inflammatory cells in the colon and decrease in common SCFAs in which butyrate reduction was quite prominent in fecal samples as compared to normal control. The above phenotypes of pAs-mice were mostly reversed by supplementing 5% sodium butyrate (w/w) with food from 21st to 28th day. The ability of butyrate in enhancing occludin expression, in particular, was dissected further. As miR122 causes degradation of Occludin mRNA, we transiently overexpressed miR122 by injecting appropriate plasmids and showed reversal of butyrate effects in pAs-mice. Thus, pre-natal arsenic exposure orchestrates variety of effects by decreasing butyrate in pAs-mice leading to increased permeability due to reduced occludin expression. Our research adds a new dimension to our understanding that pre-natal arsenic exposure imprints in post-natal life while there was no further arsenic exposure., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2023
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92. Synthesis of TiO 2 nanogel composite for highly efficient self-healing epoxy coating.
- Author
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Rezvani Ghomi E, Nouri Khorasani S, Koochaki MS, Dinari M, Ataei S, Enayati MH, Das O, and Esmaeely Neisiany R
- Subjects
- Nanogels, Polymers, Epoxy Resins, Polyethylene Glycols
- Abstract
Introduction: Organic coatings are the most effective and facile methods of protecting steel against corrosion, which shields it from direct contact with oxygen and moisture. However, they are inherently defective and susceptible to damage, which allows the penetration of the corrosive media into the underlying substrates. Self-healing coatings were developed to address this shortcoming., Objective: The current research aims to develop a coating with superior self-healing ability via embedment of titanium dioxide (TiO
2 ) nanogel composite (NC) in a commercial epoxy., Methods: The TiO2 NC was prepared by efficient dispersion of TiO2 nanoparticles in copolymer gel of acrylamide (AAm) and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) with the help of 3-(trimethoxysilyl) propyl methacrylate (MPS). The chemical structure, morphology, and thermal properties of the modified and functionalized nanoparticles were assessed by infrared spectroscopy, electron microscopy, X-ray diffraction, and thermogravimetric analysis, respectively. In addition, TiO2 nanoparticles, nano-TiO2 functionalized monomer (NTFM), and NTFM/AAm/AMPS in different weight percentages were incorporated into epoxy resin to prepare a self-healing coating., Results: The results confirmed the successful fabrication of the NC. In addition, the incorporation of 1 wt% NTFM/AAm/AMPS led to homogenous dispersion, enhanced anti-corrosive and self-healing performance with the healing efficiencies of 100% and 98%, which were determined by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods, respectively., Conclusion: The prepared NC was sensitive towards salt concentration, pH, which aids the quick reaction of the TiO2 NC to corrosive ions, once the cracks occur. In addition, this is a unique feature compared to the other self-healing mechanisms, especially, the encapsulation of healing agents, which can be effective as long as the healing agent is present., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Production and hosting by Elsevier B.V.)- Published
- 2023
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93. AUF-1 knockdown in mice undermines gut microbial butyrate-driven hypocholesterolemia through AUF-1-Dicer-1-mir-122 hierarchy.
- Author
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Das O, Kundu J, Ghosh A, Gautam A, Ghosh S, Chakraborty M, Masid A, Gauri SS, Mitra D, Dutta M, Mukherjee B, Sinha S, and Bhaumik M
- Subjects
- Animals, Mice, Butyrates, Cholesterol, Heterogeneous Nuclear Ribonucleoprotein D0, Gastrointestinal Microbiome, MicroRNAs genetics, MicroRNAs metabolism
- Abstract
Introduction and Objective: Cholesterol homeostasis is a culmination of cellular synthesis, efflux, and catabolism to important physiological entities where short chain fatty acid, butyrate embodied as a key player. This discourse probes the mechanistic molecular details of butyrate action in maintaining host-cholesterol balance., Methods: Hepatic mir-122 being the most indispensable regulator of cholesterol metabolic enzymes, we studied upstream players of mir-122 biogenesis in the presence and absence of butyrate in Huh7 cells and mice model. We synthesized unique self-transfecting GMO (guanidinium-morpholino-oligo) linked PMO (Phosphorodiamidate-Morpholino Oligo)-based antisense cell-penetrating reagent to selectively knock down the key player in butyrate mediated cholesterol regulation., Results: We showed that butyrate treatment caused upregulation of RNA-binding protein, AUF1 resulting in RNase-III nuclease, Dicer1 instability, and significant diminution of mir-122. We proved the importance of AUF1 and sequential downstream players in AUF1-knock-down mice. Injection of GMO-PMO of AUF1 in mouse caused near absence of AUF1 coupled with increased Dicer1 and mir-122, and reduced serum cholesterol regardless of butyrate treatment indicating that butyrate acts through AUF1., Conclusion: The roster of intracellular players was as follows: AUF1-Dicer1-mir-122 for triggering butyrate driven hypocholesterolemia. To our knowledge this is the first report linking AUF-1 with cholesterol biogenesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Das, Kundu, Ghosh, Gautam, Ghosh, Chakraborty, Masid, Gauri, Mitra, Dutta, Mukherjee, Sinha and Bhaumik.)
- Published
- 2022
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94. A study of the influence of current ramp rate on the performance of polymer electrolyte membrane fuel cell.
- Author
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Chandran M, Palaniswamy K, Karthik Babu NB, and Das O
- Subjects
- Cross-Sectional Studies, Reproducibility of Results, Electrolytes, Polymers, Allium
- Abstract
Durability and reliability are the key factors that prevent fuel cells from successful implementation in automotive sector. Dynamic load change is a common and frequent condition that the fuel cell has to undergo in automotive applications. Fuel cells are more sensitive to changes in load conditions and degrade based on load variation representing idling, rated power, and high power operating conditions. To examine the influence of dynamic load step on the fuel cell performance, two similar cells of active 25 cm
2 was tested under two different load step for the same dynamic load cycle. The main difference in dynamic load cycle 2 was the ramp rate which was fixed as 0.1, 0.3, and 0.25 A/cm2 /s for 0.2, 0.6, and 1.0 A/cm2 respectively. To investigate the degradative effects, polarization curves, electrochemical impedance spectroscopy, and field emission scanning electron microscopy were used. The results indicated that the degradation rate increased in both dynamic load cycles but however the impact of load change was comparatively minimal in dynamic load cycle 2. The total degradation in performance was 20.67% and 10.72% in dynamic load cycles 1 and 2 respectively. Fuel cell performance degraded in a manner that was consistent with the electrochemical impedance spectroscopy and cross-sectional analysis of field emission scanning electron microscopy. The results prove that the degradation rate is dependent on the load step and the number of load cycles. Severe catalyst degradation and delamination were observed in fuel cells operated under dynamic load cycle 1., (© 2022. The Author(s).)- Published
- 2022
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95. A Comprehensive Review of Self-Healing Polymer, Metal, and Ceramic Matrix Composites and Their Modeling Aspects for Aerospace Applications.
- Author
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Paladugu SRM, Sreekanth PSR, Sahu SK, Naresh K, Karthick SA, Venkateshwaran N, Ramoni M, Mensah RA, Das O, and Shanmugam R
- Abstract
Composites can be divided into three groups based on their matrix materials, namely polymer, metal and ceramic. Composite materials fail due to micro cracks. Repairing is complex and almost impossible if cracks appear on the surface and interior, which minimizes reliability and material life. In order to save the material from failure and prolong its lifetime without compromising mechanical properties, self-healing is one of the emerging and best techniques. The studies to address the advantages and challenges of self-healing properties of different matrix materials are very limited; however, this review addresses all three different groups of composites. Self-healing composites are fabricated to heal cracks, prevent any obstructed failure, and improve the lifetime of structures. They can self-diagnose their structure after being affected by external forces and repair damages and cracks to a certain degree. This review aims to provide information on the recent developments and prospects of self-healing composites and their applications in various fields such as aerospace, automobiles etc. Fabrication and characterization techniques as well as intrinsic and extrinsic self-healing techniques are discussed based on the latest achievements, including microcapsule embedment, fibers embedment, and vascular networks self-healing., Competing Interests: The authors declare no conflict of interest.
- Published
- 2022
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96. Knowledge, attitude, and practice on digital eye strain during coronavirus disease-2019 lockdown: A comparative study.
- Author
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Jain S, Das O, Roy A, and Das A
- Abstract
Background: Computer vision syndrome is a group of eye and vision-related problems that result from prolonged computer use. The worldwide pandemic of coronavirus disease-2019 (COVID-19) lockdown has led to an increase in the digital screen exposure as jobs as well as academic learning have majorly shifted online. This has caused an increase in digital eye strain (DES) globally. The aims and objectives of this study were to compare the knowledge, attitude, and practices among medical and nonmedical professionals with regard to DES in a background of COVID-19 lockdown., Materials and Methods: A cross-sectional, observational, online questionnaire-based research survey analysis was conducted among medical professionals with age- and sex-matched nonmedical professionals. Responses were collected over a week and analyzed. The level of significance was set at a P < 0.05. Statistical Package for the Social Sciences software version 23.0 was used for the result analysis., Results: Our study included 353 (50.4%) medical and 347 (49.6%) nonmedical personnel. It was noted that 266 (75.4%) of medical professionals and 268 (77.2%) of nonmedical professionals experienced eye problems after prolonged digital screen exposure. A significant proportion of respondents experienced an increase in symptoms following COVID-19 lockdown with 140 (52.6%) being medical professionals and 163 (60.8%) nonmedical professionals ( P = 0.015)., Conclusions: DES is a preventable lifestyle-associated disorder. Awareness among the masses can reduce the adverse effects. Proper lighting, adequate viewing distance, voluntary blinking, and using lubricating eye drops are a few ways to reduce the chances of DES. Further studies are needed to formulate standardized guidelines for the management of DES., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Oman Journal of Ophthalmology.)
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- 2022
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97. Multi-objective optimization and prediction of surface roughness and printing time in FFF printed ABS polymer.
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Selvam A, Mayilswamy S, Whenish R, Naresh K, Shanmugam V, and Das O
- Abstract
In this study, fused filament fabrication (FFF) printing parameters were optimized to improve the surface quality and reduce the printing time of Acrylonitrile Butadiene Styrene (ABS) polymer using the Analysis of Variance (ANOVA), it is a statistical analysis tool. A multi-objective optimization technique was employed to predict the optimum process parameter values using particle swarm optimization (PSO) and response surface methodology (RSM) techniques. Printing time and surface roughness were analyzed as a function of layer thickness, printing speed and nozzle temperature. A central composite design was preferred by employing the RSM method, and experiments were carried out as per the design of experiments (DoE). To understand the relationship between the identified input parameters and the output responses, several mathematical models were developed. After validating the accuracy of the developed regression model, these models were then coupled with PSO and RSM to predict the optimum parameter values. Moreover, the weighted aggregated sum product assessment (WASPAS) ranking method was employed to compare the RSM and PSO to identify the best optimization technique. WASPAS ranking method shows PSO has finer optimal values [printing speed of 125.6 mm/sec, nozzle temperature of 221 °C and layer thickness of 0.29 mm] than the RSM method. The optimum values were compared with the experimental results. Predicted parameter values through the PSO method showed high surface quality for the type of the surfaces, i.e., the surface roughness value of flat upper and down surfaces is approximately 3.92 µm, and this value for the other surfaces is lower, which is approximately 1.78 µm, at a minimum printing time of 24 min., (© 2022. The Author(s).)
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- 2022
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98. The Flexural Strength and Flexural Modulus of Stereolithography Additively Manufactured Zirconia with Different Porosities.
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Zandinejad A, Das O, Barmak AB, Kuttolamadom M, and Revilla-León M
- Subjects
- Ceramics, Materials Testing, Porosity, Surface Properties, Zirconium, Flexural Strength, Stereolithography
- Abstract
Purpose: Additive manufacturing (AM) technologies are capable of fabricating complex geometries with different porosities. However, the effect of such porosities on mechanical properties of stereolithography (SLA) AM zirconia with different porosities is unclear. The purpose of this in vitro study was to investigate the mechanical properties namely flexural strength, and flexural modulus of AM zirconia with different porosities., Materials and Methods: A bar (25 × 4 × 3 mm) for flexural strength test (ISO standard 6872/2015) was designed by CAD software program and standard tessellation language (STL) file was obtained. The STL file was used to fabricate a total of 80 bars in four groups. Three experimental groups each containing 20 samples were manufactured using an SLA ceramic printer (CeraMaker 900; 3DCeram Co) and zirconia material (3DMix ZrO
2 paste; 3DCeram Co) with different sintering post processing to achieve different porosities including 0%-porosity (AMZ0), 20%-porosity (AMZ20), and 40%-porosity (AMZ40). The same STL file was used for subtractive manufacturing or milling of 20 zirconia bars as control group (CNCZ) with the same dimensions using a commercial zirconia. Three-point bending tests were performed for all groups following ISO standard 6872/2015 specification using a universal testing machine. Outcomes measured included load at fracture, mean flexural strength, and flexural modulus and they were compared across the experimental groups using a one-way ANOVA. Post hoc pair wise comparison between each pair of the groups were performed using Tukey test., Results: There was a significant difference between the four groups, in terms of fracture load, flexural strength and flexural modulus using one-way ANOVA. AM zirconia with 0% porosity (AMZ0) showed the highest value for fracture load (1132.7 ± 220.6 N), flexural strength (755.1 ± 147.1 MPa) and flexural modulus (41,273 ± 2193 MPa) and AM zirconia with 40% porosity (AMZ40) showed the lowest fracture load (72.13 ± 13.42 N), flexural strength (48.09 ± 8.95 MPa) and flexural modulus (7177 ± 506 MPa). Tukey's pairwise comparisons detected a significant difference between all the possible pairs for all variables except flexural modulus between AMZ0 and CNCZ. The Weibull moduli presented the lowest value for AMZ20 (4.4) followed by AMZ40 (6.1), AMZ0 (6.1), and the highest value was for CNCZ (8.1)., Conclusion: AM zirconia with 0% porosity showed significantly higher flexural strength and flexural modulus when compared to milled and AM zirconia with 20% and 40% porosities., (© 2021 by the American College of Prosthodontists.)- Published
- 2022
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99. Fire Retardancy and Leaching Resistance of Furfurylated Pine Wood ( Pinus sylvestris L.) Treated with Guanyl-Urea Phosphate.
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Lin CF, Karlsson O, Kim I, Myronycheva O, Mensah RA, Försth M, Das O, Mantanis GI, Jones D, and Sandberg D
- Abstract
Guanyl-urea phosphate (GUP) was introduced into furfurylated wood in order to improve fire retardancy. Modified wood was produced via vacuum-pressure impregnation of the GUP-furfuryl alcohol (FA) aqueous solution, which was then polymerized at elevated temperature. The water leaching resistance of the treated wood was tested according to European standard EN 84, while the leached water was analyzed using ultra-performance liquid chromatography (UPLC) and inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). This new type of furfurylated wood was further characterized in the laboratory by evaluating its morphology and elemental composition using optical microscopy and electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDX). The chemical functionality was detected using infrared spectroscopy (FTIR), and the fire resistance was tested using cone calorimetry. The dimensional stability was evaluated in wet-dry soaking cycle tests, along with the mechanical properties, such as the Brinell hardness and bending strength. The fire retardancy of the modified furfurylated wood indicated that the flammability of wood can be depressed to some extent by introducing GUP. This was reflected in an observed reduction in heat release rate (HRR
2 ) from 454.8 to 264.9 kW/m2 , without a reduction in the material properties. In addition, this leaching-resistant furfurylated wood exhibited higher fire retardancy compared to conventional furfurylated wood. A potential method for producing fire-retardant treated furfurylated wood stable to water exposure has been suggested.- Published
- 2022
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100. Cutting-Edge Progress in Stimuli-Responsive Bioadhesives: From Synthesis to Clinical Applications.
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Khadem E, Kharaziha M, Bakhsheshi-Rad HR, Das O, and Berto F
- Abstract
With the advent of "intelligent" materials, the design of smart bioadhesives responding to chemical, physical, or biological stimuli has been widely developed in biomedical applications to minimize the risk of wounds reopening, chronic pain, and inflammation. Intelligent bioadhesives are free-flowing liquid solutions passing through a phase shift in the physiological environment due to stimuli such as light, temperature, pH, and electric field. They possess great merits, such as ease to access and the ability to sustained release as well as the spatial transfer of a biomolecule with reduced side effects. Tissue engineering, wound healing, drug delivery, regenerative biomedicine, cancer therapy, and other fields have benefited from smart bioadhesives. Recently, many disciplinary attempts have been performed to promote the functionality of smart bioadhesives and discover innovative compositions. However, according to our knowledge, the development of multifunctional bioadhesives for various biomedical applications has not been adequately explored. This review aims to summarize the most recent cutting-edge strategies (years 2015-2021) developed for stimuli-sensitive bioadhesives responding to external stimuli. We first focus on five primary categories of stimuli-responsive bioadhesive systems (pH, thermal, light, electric field, and biomolecules), their properties, and limitations. Following the introduction of principal criteria for smart bioadhesives, their performances are discussed, and certain smart polymeric materials employed in their creation in 2015 are studied. Finally, advantages, disadvantages, and future directions regarding smart bioadhesives for biomedical applications are surveyed.
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- 2022
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