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1.
Inorg Chem ; 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38830055

ABSTRACT

This project addresses the urgent need for efficient and cost-effective development of electrocatalysts for the ethanol oxidation reaction (EOR). This reaction offers promising renewable energy solutions but faces challenges due to the slow EOR kinetics, typically requiring costly noble metal catalysts. To overcome these limitations, this study focuses on developing CuZn-based EOR catalysts derived from metal-organic frameworks (MOFs), focusing on understanding the structure-performance relationship between pristine MOF-based electrocatalysts and their pyrolyzed counterparts. Herein, bimetallic MOF materials with varying Cu/Zn ratios were synthesized, followed by pyrolysis to produce carbonized counterparts while preserving the fundamental structure but with altered physicochemical properties. Comparative EOR studies revealed the superior performance of pyrolyzed MOFs, demonstrating that optimized Zn-loading is crucial over Cu-based framework for catalyst performance and durability. Overall, this work highlights the potential of MOF-derived Cu-based catalysts for renewable energy applications and provides insights into optimizing their performance through controlled synthesis and post-treatment strategies.

2.
Angew Chem Int Ed Engl ; 63(10): e202318250, 2024 Mar 04.
Article in English | MEDLINE | ID: mdl-38253820

ABSTRACT

A methanol-based economy offers an efficient solution to current energy transition challenges, where the zeolite-catalyzed methanol-to-hydrocarbons (MTH) process would be a key enabler in yielding synthetic fuels/chemicals from renewable sources. Despite its original discovery over half a century ago over the zeolite ZSM-5, the practical application of this process in a CO2 -neutral scenario has faced several obstacles. One prominent challenge has been the intricate mechanistic complexities inherent in the MTH process over the zeolite ZSM-5, impeding its widespread adoption. This work takes a significant step forward by providing critical insights that bridge the gap in our understanding of the MTH process. It accomplishes this by connecting the (Koch-carbonylation-led) direct and dual cycle mechanisms, which operate during the early and steady-state phases of MTH catalysis, respectively. To unravel these mechanistic intricacies, we have performed catalytic and operando (i.e., UV/Vis coupled with an online mass spectrometer) and solid-state NMR spectroscopic-based investigations on the MTH process, involving co-feeding methanol and acetone (cf. a key Koch-carbonylated species), including selective isotope-labeling studies. Our iterative research approach revealed that (Koch-)carbonyl group selectively promotes the side-chain mechanism within the arene cycle of the dual cycle mechanism, impacting the preferential formation of BTX fraction (i.e., benzene-toluene-xylene) primarily.

3.
Acc Chem Res ; 56(23): 3492-3503, 2023 Dec 05.
Article in English | MEDLINE | ID: mdl-37991494

ABSTRACT

ConspectusThirty years ago, George A. Olah proposed the concept of the methanol economy, where methanol replaces fossil fuels as a means of energy storage, ground transportation fuel, and raw material for the manufacture of other carbon-based products. Over the years, with rising global warming concerns, the concept has evolved. A special interest is devoted to the development of catalytic processes that allow the transformation of carbon dioxide, via methanol, into CO2 neutral liquid hydrocarbons. These products could replace the oil-based fuels currently used by combustion engines. The rapid depletion of such fuels would avoid a considerable amount of CO2 emissions during the current energy transition.Over the past decade, we have focused on different key processes that should allow for maximal atom efficiency and, therefore, minimal energy consumption in a field, CO2 valorization, that can easily become a zero-sum game. In this Account, we highlight the importance of catalyst design to overcome the process challenges in the production of liquid fuels from methanol. Additionally, progress in multifunctional catalysts able to directly convert, in one single reactor, CO2 to liquid fuels is also discussed in detail. This integrated option is of particular interest since it allows an important decrease in operational units while increasing throughput by converting, in situ, a thermodynamically limited intermediate.

4.
J Lab Physicians ; 15(4): 562-566, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37780885

ABSTRACT

Introduction Lung cancer is currently the most common cause of cancer-related mortality, with 11.4% of cancers and 18% of cancer-related deaths worldwide whereas Indian figures are 6.9 and 9.3%, respectively. Hence, the need for early diagnosis. Bronchial biopsy has the highest sensitivity among all the samples that can be obtained by bronchoscopic techniques in case of endobronchial lesions. Imprint cytology has emerged as an important cytological method. Toluidine blue has been studied for its use as rapid onsite stain for cytological evaluation on various samples of cytology in different anatomic sites. This has helped in quick and less expensive, preliminary reporting. Objectives This article aims to assess the efficacy of onsite toluidine blue stain on imprint smears of bronchoscopic biopsies to diagnose malignancy in suspected cases of lung carcinoma. Study Type Prospective study on accuracy of a diagnostic test. Materials and Methods A total of 100 cases of bronchoscopy were included in the study. The patients were clinico-radiologically suspected to have brochogenic carcinoma and all of them were subjected to biopsy. Imprint smears were prepared from the bronchoscopy biopsy specimens. Smears were stained onsite with toluidine blue stain, and histopathology sections were stained with hematoxylin and eosin, also confirmed by immunohistochemistry. Results Sensitivity and specificity of onsite toluidine blue stain for malignancy reporting were 97.9 and 80%, respectively, when compared to histopathology as standard. Conclusion Toluidine blue can be used as an onsite staining method on imprint smears of bronchoscopic biopsy for preliminary detection of lung malignancy.

5.
Dalton Trans ; 52(40): 14390-14399, 2023 Oct 17.
Article in English | MEDLINE | ID: mdl-37781869

ABSTRACT

Introducing sustainability into advanced catalytic material design is essential to address growing environmental concerns. Among them, synthesizing inorganic zeolite materials from non-traditional sources (like natural clay) offers several advantages, contributing to sustainability and environmental stewardship. With this objective, we used kaolin to synthesize zeolites with different topologies: SSZ-13 (8-MR with CHA topology), ZSM-5 (10-MR with MFI topology), and Beta (12-MR with BEA topology) (MR: member ring), where a simple and flexible synthetic protocol was adopted without any significant changes. All these zeolites were subjected to catalytic performance evaluation concerning the industrially relevant methanol-to-hydrocarbon (MTH) process. Herein, the kaolin-derived zeolites, especially ZSM-5, led to superior performance and demonstrated enhanced catalyst deactivation-resistant behavior compared to their zeolite counterparts prepared from traditional synthetic routes. Various characterization tools (including under operando conditions) were employed to understand their reactions and deactivation mechanisms. Overall, making zeolites from non-traditional sources presents a pathway for sustainable and environmentally friendly material production, offering benefits such as reduced resource dependence, lower energy consumption, and tailored physicochemical properties beneficial to catalysis. In a broader context, such a research approach contributes to the transition toward a more sustainable and circular economy.

6.
Dalton Trans ; 52(43): 15958-15967, 2023 Nov 07.
Article in English | MEDLINE | ID: mdl-37846524

ABSTRACT

Electrochemical carbon dioxide (CO2) reduction (eCO2R) over Cu-based bimetallic catalysts is a promising technique for converting CO2 into value-added multi-carbon products, such as fuels, chemicals, and materials. For improving the process efficiency, electrocatalyst development for the eCO2R must be integrated with tuning of operating conditions. For example, CuIn-based materials typically lead to preferential C1 product selectivity, which delivers the desired C2+ products upon varying the In/Cu ratio and operating conditions (i.e., in 0.1 M KHCO3 electrolytes using an H-type cell with a cation exchange membrane vs. in 1 M KOH electrolytes using a flow cell with an anion exchange membrane). At lower Cu-loading (i.e., InCu5Ox material), the maximum faradaic efficiency of HCOOH (FEHCOOH) of 70% was achieved at -1 V versus the reversible hydrogen electrode (vs. RHE) in an H-type cell. However, upon increasing the Cu loading, the preferential product selectivity could be altered: the InCu73Ox material led to a high CO selectivity (maximum FE of 51%) in the H-type cell at -0.8 V vs. RHE and delivered a current density of 100 mA cm-2 with a FEC2+ of up to 37% at -0.8 V vs. RHE in the flow cell configuration. Various characterization tools were also employed to probe the catalytic materials to rationalize the electrocatalytic performance.

7.
Article in English | MEDLINE | ID: mdl-37594111

ABSTRACT

BACKGROUND: Urinary tract infections (UTIs) are the most common form of nosocomial infection primarily caused by Escherichia coli. Complicated UTIs carry a higher risk of treatment failure, recurrent infections, and increased morbidity. Methionine aminopeptidase (MetAP) has gained tremendous importance as a bacterial drug target due to its role in cell growth and membrane integrity. However, the participation of metal-chelating residues and the occurrence of the enzyme in the human body complicate the process of selecting a suitable inhibitor. AIMS: This study aimed to find new molecules with more stable binding against urinary tract infection drug targets. OBJECTIVE: The objective of this study was to find new molecules with more stable binding against urinary tract infection drug targets using computational approaches. METHOD: The drug target was selected based on a literature study. Catechol derivatives were prepared and an ADME/T study was performed, followed by molecular docking and molecular dynamics. RESULT: The docking score of Met592 (-20.95) was found to be much better than that of known inhibitors (-12.88). The overall study on Rg signified that the ligand binding compels the respective proteins to become more compact and less flexible in the case of Met592. Binding free energy analysis also showed a better affinity for Met592 (-46.60) than the known inhibitor (-31.37). CONCLUSION: The increased binding score, good oral bioavailability, and better binding free energy endorse the reliability of the ligand Met592, i.e., (R, E)-4-(4-(2-(((9H-purin-6-yl)amino)methyl)- 4,5-dimethylphenyl)thiazol-2-yl)-4-aminobut-2-enoic acid, as the probable drug candidate to treat uropathogenic E. coli.

8.
ChemSusChem ; 16(19): e202300608, 2023 Oct 06.
Article in English | MEDLINE | ID: mdl-37313791

ABSTRACT

The CO2 -to-aromatics process is a chemical reaction that converts carbon dioxide (CO2 ) into valuable petrochemical, i. e., aromatics (especially, benzene, toluene, and xylene) over the metal/zeolite bifunctional catalytic systems. These aromatics are used in producing plastics, fibers, and other industrial products, which are currently exclusively sourced from fossil-derived feedstocks. The significance of this process lies in its potential to mitigate climate change by reducing greenhouse gas emissions and simultaneously producing valuable chemicals. Consequently, these CO2 -derived aromatics can reduce the reliance on fossil fuels as a source of feedstocks, which can help to promote a more sustainable and circular economy. Owing to the existence of a wider straight channel favoring the aromatization process, zeolite ZSM-5 is extensively used to yield aromatics during CO2 hydrogenation over bifunctional (metal/zeolite) catalytic systems. To provide a better understanding of this unique property of zeolite ZSM-5, this work investigates the impact of particle size and hierarchy of the zeolite and how these govern the reaction performance and the overall selectivity. As a result, an improved understanding of the zeolite-catalyzed hydrocarbon conversion process has been obtained.

9.
Inorg Chem ; 62(23): 8803-8811, 2023 Jun 12.
Article in English | MEDLINE | ID: mdl-37249100

ABSTRACT

The suitable choice of an electrocatalyst is crucial in controlling the selectivity of electrocatalytic CO2 reduction products. Herein, we have explored the effect of different ligand environments in 2D metal-organic frameworks (MOFs), viz., copper naphthalenedicarboxylate (Cu-UNDC) and copper benzenedicarboxylate (Cu-UBDC). The change of ligand modulates the structure of the MOFs as well as the electronic environment around the copper center. The variation in the electronic structure and the coordination environment of the active Cu center changes the selectivity toward C2 products. In the electrocatalytic process, Cu-UNDC produced 24.3% Faradaic efficiency (FE) for the C2 products─far better than that of Cu-UBDC (13.2%). In contrast to electrocatalytic CO2RR, in the presence of light, Cu-UBDC (26.2%) achieved a better FE for the C2 products than Cu-UNDC (21.8%).

10.
Nat Mater ; 22(6): 669-670, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37142738
11.
Angew Chem Int Ed Engl ; 62(24): e202303124, 2023 Jun 12.
Article in English | MEDLINE | ID: mdl-37040129

ABSTRACT

Decarbonizing the transportation sector is among the biggest challenges in the fight against climate change. CO2 -neutral fuels, such as those obtained from renewable methanol, have the potential to account for a large share of the solution, since these could be directly compatible with existing power trains. Although discovered in 1977, the zeolite-catalyzed methanol-to-gasoline (MTG) process has hardly reached industrial maturity, among other reasons, because maximizing the production of gasoline range hydrocarbons from methanol has proved complicated. In this work, we apply multimodal operando UV/Vis diffuse reflectance spectroscopy coupled with an online mass spectrometer and "mobility-dependent" solid-state NMR spectroscopy to better understand the reaction mechanism over zeolites H-Beta and Zn-Beta. Significantly, the influential co-catalytic role of oxymethylene species is linked to gasoline formation, which impacts the MTG process more than carbonylated species.

12.
Dalton Trans ; 52(16): 5155-5168, 2023 Apr 25.
Article in English | MEDLINE | ID: mdl-36961280

ABSTRACT

The increased awareness of carbon management has prompted the scientific community towards delivering sustainable catalytic technologies, preferably from CO2. Copper-based multifunctional catalysts are the most frequently used for thermal hydrogenation and electrocatalytic reduction of CO2 (CO2R) processes. To improve the understanding and efficacy of these materials for the CO2R reaction, Cu-Zn oxides combined with Al2O3 and ZrO2 were synthesized by the coprecipitation method and annealed at 500 °C, 600 °C, and 700 °C (i.e., Cu/ZnO/Al2O3-x and Cu/ZnO/ZrO2 systems-x, where x is the annealing temperature) to tune their multi-functionality. We demonstrate that the composition of Cu-Zn oxides and pretreatment temperature impact the electrocatalytic CO2R performance, where CuZnZr-600 and CuZnAl-700 materials are superior. Different characterization tools were employed to rationalize the results described in this work, which could provide a way to design an efficient catalytic system for the CO2R process.

13.
Neurosci Lett ; 795: 137051, 2023 01 31.
Article in English | MEDLINE | ID: mdl-36603736

ABSTRACT

Parkinson's disease (PD) is a progressive neurodegenerative disorder with a complex etiology. Presence of autosomal mutations in PARK7/DJ-1 gene has been associated with early-onset PD. Growing evidence has suggested that DJ-1 acts as a putative sensor of oxidative stress. Reduced levels of DJ-1 protein have been reported in the cerebrospinal fluid of sporadic PD patients. Several case-control association studies have identified DJ-1 g.168_185del (rs200968609) variants conferring susceptibility towards PD pathogenesis. Similarly, among the PD patients in eastern India, the deletion allele (g.168_185) of this DJ-1 promoter polymorphism was found to be associated with PD. Hence, we aimed to find out the functional contribution of this promoter variant of DJ-1 in PD pathogenesis. The expression of DJ-1 was observed to be significantly reduced in the presence of both deletion and duplication sequences as identified from the luciferase promoter activity assay. The transcription factor binding prediction tool identified DJ-1 promoter 18 bp insertion polymorphism as the only binding partner of REST (RE1 Silencing Transcription Factor). Transient Chromatin Immuno-precipitation (ChIP) assay further confirmed this prediction. Previous reports have highlighted the role of REST in regulating the expression of stress-responsive genes. Our study has identified the functional involvement of DJ-1 promoter variants and REST-mediated regulation of DJ-1 expression in PD pathogenesis.


Subject(s)
Parkinson Disease , Protein Deglycase DJ-1 , Repressor Proteins , Humans , Mutation , Parkinson Disease/genetics , Parkinson Disease/metabolism , Polymorphism, Genetic , Promoter Regions, Genetic , Protein Deglycase DJ-1/genetics , Protein Deglycase DJ-1/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism , Transcription Factors/genetics
14.
FEBS Lett ; 597(3): 437-447, 2023 02.
Article in English | MEDLINE | ID: mdl-36520528

ABSTRACT

Among various post-translational modifications of histones, ubiquitylation plays a crucial role in transcription regulation. Histone mono-ubiquitylation by RING finger motif-containing ubiquitin ligases is documented in this respect. The RING finger ligases primarily regulate the cell cycle, where the anaphase-promoting complex/cyclosome (APC/C) takes charge as mitotic ubiquitin machinery. Reportedly, APC/C participates in transcriptional activation of the ubiquitin carrier protein UbcH10. However, the ubiquitylation activity of APC/C on the UBCH10 promoter remains elusive. This study shows that APC/C, with its adapter protein Cdc20, catalyses mono-ubiquitylation of Lysine-120 in histone 2B on the UBCH10 promoter. This study also identified a cell-cycle-specific pattern of this modification. Finally, APC/C-driven crosstalk of acetylation and ubiquitylation was found operational on UBCH10 trans-regulation. Together, these findings suggest a role for APC/C catalysed promoter ubiquitylation in managing transcription of cell cycle regulatory genes.


Subject(s)
Cell Cycle Proteins , Histones , Anaphase-Promoting Complex-Cyclosome/genetics , Anaphase-Promoting Complex-Cyclosome/metabolism , Histones/genetics , Histones/metabolism , Transcriptional Activation , Ubiquitination , Cell Cycle Proteins/genetics , Ubiquitin/metabolism , Ubiquitin-Protein Ligases/metabolism , Cdc20 Proteins/genetics
15.
J Clin Neurol ; 18(6): 692-710, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36367067

ABSTRACT

BACKGROUND AND PURPOSE: Autoimmune encephalitis (AIE) following coronavirus disease 2019 (COVID-19) is an underexplored condition. This study aims to systematically review the clinico-investigational and pathophysiologic aspects of COVID-19 and its vaccines in association with AIE, and identify the factors predicting neurological severity and outcomes. METHODS: Relevant data sources were searched using appropriate search terms on January 15, 2022. Studies meeting the criteria for AIE having a temporal association with COVID-19 or its vaccines were included. RESULTS: Out of 1,894 citations, we included 61 articles comprising 88 cases: 71 of COVID-19-associated AIE, 3 of possible Bickerstaff encephalitis, and 14 of vaccine-associated AIE.There were 23 definite and 48 possible seronegative AIE cases. Anti-NMDAR (N-methyl-D-aspartate receptor; n=12, 16.9%) was the most common definite AIE. Males were more commonly affected (sex ratio=1.63) in the AIE subgroup. The neurological symptoms included alteredmental state (n=53, 74.6%), movement disorders (n=28, 39.4%), seizures (n=24, 33.8%), behavioural (n=25, 35.2%), and speech disturbances (n=17, 23.9%). The median latency to AIE diagnosis was 14 days (interquartile range=4-22 days). Female sex and ICU admission had higherrisks of sequelae, with odds ratio (OR) of 2.925 (95% confidence interval [CI]=1.005-8.516)and 3.515 (95% CI=1.160-10.650), respectively. Good immunotherapy response was seen in42/48 (87.5%) and 13/13 (100%) of COVID-19-associated and vaccine-associated AIE patients, respectively. Sequelae were reported in 22/60 (36.7%) COVID-19 associated and 10/13 (76.9%) vaccine-associated cases. CONCLUSIONS: The study has revealed diagnostic, therapeutic, and pathophysiological aspects of AIE associated with COVID-19 and its vaccines, and its differences from postinfectious AIE. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42021299215.

16.
Chem Rev ; 122(18): 14275-14345, 2022 09 28.
Article in English | MEDLINE | ID: mdl-35947790

ABSTRACT

Zeolite chemistry and catalysis are expected to play a decisive role in the next decade(s) to build a more decentralized renewable feedstock-dependent sustainable society owing to the increased scrutiny over carbon emissions. Therefore, the lack of fundamental and mechanistic understanding of these processes is a critical "technical bottleneck" that must be eliminated to maximize economic value and minimize waste. We have identified, considering this objective, that the chemistry related to the first-generation reaction intermediates (i.e., carbocations, radicals, carbenes, ketenes, and carbanions) in zeolite chemistry and catalysis is highly underdeveloped or undervalued compared to other catalysis streams (e.g., homogeneous catalysis). This limitation can often be attributed to the technological restrictions to detect such "short-lived and highly reactive" intermediates at the interface (gas-solid/solid-liquid); however, the recent rise of sophisticated spectroscopic/analytical techniques (including under in situ/operando conditions) and modern data analysis methods collectively compete to unravel the impact of these organic intermediates. This comprehensive review summarizes the state-of-the-art first-generation organic reaction intermediates in zeolite chemistry and catalysis and evaluates their existing challenges and future prospects, to contribute significantly to the "circular carbon economy" initiatives.


Subject(s)
Zeolites , Carbon , Catalysis
17.
Article in English | MEDLINE | ID: mdl-35433110

ABSTRACT

Background: Abnormal involuntary movement of paralyzed upper limb during yawning is a rare phenomenon termed as parakinesia brachialis oscitans. Case Report: We describe a 59-year-old gentleman with abnormal involuntary movement of paralyzed right upper limb during yawning 2 weeks following ischemic stroke of left middle cerebral artery territory. Discussion: This is a rare post-stroke phenomenon and its pathophysiological mechanism is poorly understood but this entity highlights possible preserved extrapyramidal pathway which might help in rehabilitating stroke survivors.


Subject(s)
Dyskinesias , Stroke , Yawning , Arm , Humans , Male , Middle Aged , Stroke/complications , Upper Extremity , Yawning/physiology
18.
Nat Commun ; 12(1): 5914, 2021 Oct 08.
Article in English | MEDLINE | ID: mdl-34625554

ABSTRACT

Cascade processes are gaining momentum in heterogeneous catalysis. The combination of several catalytic solids within one reactor has shown great promise for the one-step valorization of C1-feedstocks. The combination of metal-based catalysts and zeolites in the gas phase hydrogenation of CO2 leads to a large degree of product selectivity control, defined mainly by zeolites. However, a great deal of mechanistic understanding remains unclear: metal-based catalysts usually lead to complex product compositions that may result in unexpected zeolite reactivity. Here we present an in-depth multivariate analysis of the chemistry involved in eight different zeolite topologies when combined with a highly active Fe-based catalyst in the hydrogenation of CO2 to olefins, aromatics, and paraffins. Solid-state NMR spectroscopy and computational analysis demonstrate that the hybrid nature of the active zeolite catalyst and its preferred CO2-derived reaction intermediates (CO/ester/ketone/hydrocarbons, i.e., inorganic-organic supramolecular reactive centers), along with 10 MR-zeolite topology, act as descriptors governing the ultimate product selectivity.

20.
Inorg Chem ; 60(8): 5791-5803, 2021 Apr 19.
Article in English | MEDLINE | ID: mdl-33829771

ABSTRACT

The synthesis and characterization of the isomeric ruthenium complexes with the general formula cis- and trans-[Ru(trpy)(qc)X]n+ (trpy is 2,2':6',2″-terpyridine, qc is 8-quinolinecarboxylate, cis-1 and trans-1, X = Cl, n = 0; cis-2 and trans-2, X=OH2, n = 1) with respect to the relative disposition of the carboxylate and X ligands are reported. For comparison purposes, another set of ruthenium complexes with general formula cis- and trans-[Ru(trpy)(pic)(OH2)]+ (pic is 2-picolinate (cis-3, trans-3)) have been prepared. The complexes with a qc ligand show a more distorted geometry compared to the complexes with a pic ligand. In all of the cases, the trans isomers show lower potential values for all of the redox couples relative to the cis isomers. Complexes cis-2 and trans-2 with six-member chelate rings show higher catalytic activity than cis-3 and trans-3. Overall, it was shown that the electronic perturbation to the metal center exerted by different orientation and geometry of the ligands significantly influences both redox properties and catalytic performance.

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