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1.
Health Sci Rep ; 7(4): e2022, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38572117

ABSTRACT

Background: Dengue is a major public health concern in Bangladesh. This study aimed to assess the perceptions and practices of community members in Dhaka regarding community engagement and social participation for dengue prevention. Methods: A cross-sectional online survey was conducted in Dhaka City from May 2022 to December 2022. The respondents were randomly selected. The association between community participation and prevention practices was tested using the χ 2 test. Results: The findings of this study indicate that the majority of participants (92%) believed that community effort would be relied upon in the event of a dengue outbreak. Environmental cleaning campaigns were the preferred approach, and religious leaders viewed them positively. This study also revealed significant variations in knowledge levels, with those involved in community efforts and mass gatherings demonstrating greater knowledge. This study sheds light on the demographic factors that influence dengue knowledge and provides valuable insights into the development of targeted public health interventions. Conclusion: The study revealed negative perceptions and limited participation in dengue prevention among participants, with the majority demonstrating a poor understanding of preventive measures. While some showed positive attitudes towards community engagement, significant disparities existed in participation, highlighting the need for targeted educational campaigns and enhanced community mobilization efforts. Moreover, the importance of multisectoral collaboration is emphasized, underscoring the need for coordinated efforts among health departments, NGOs, religious institutions, and community leaders to effectively combat dengue transmission. Recommendations include ongoing educational initiatives, targeted interventions to promote community involvement, and fostering collaboration across sectors to strengthen dengue prevention efforts and to safeguard public health.

2.
JACC Case Rep ; 13: 101638, 2023 May 03.
Article in English | MEDLINE | ID: mdl-37153477

ABSTRACT

Disseminated blastomycosis with cardiac manifestations is exceedingly rare. Here we present the first known case of disseminated, cardiac blastomycosis in a pregnant patient. Antifungal medications and a multidisciplinary, nonsurgical approach were successful in eradicating the fungal cardiac mass and in preventing vertical transmission to the fetus. (Level of Difficulty: Advanced.).

3.
Indian J Public Health ; 67(1): 21-27, 2023.
Article in English | MEDLINE | ID: mdl-37039201

ABSTRACT

Background: On January 16, 2021, India rolled out the COVID vaccination drive. A successful and effective vaccination campaign requires much more than the availability of a safe and effective vaccine. This includes identifying vulnerable populations with lower vaccine confidence and identifying the drivers of vaccine hesitancy. Objective: This study aims to find out vaccine hesitancy among the tribal population regarding COVID-19 vaccination. Methods: It was an observational descriptive cross-sectional study, conducted at Manindranagar and Hatinagar gram panchayat of Berhampore Block of Murshidabad district, West Bengal, from June 2021-November 2021, among tribal people aged >18 years. A total of 198 tribal people were selected by applying the probability proportional to size sampling method. Participants were interviewed using predesigned, pretested, and semi-structured schedules. Potential predictors of hesitancy were investigated using the multivariate logistic regression model. Results: Vaccine hesitancy was present among 36.9% of the study participants. Fear of side effects (78.1%) was the most common reason of vaccine hesitancy. Only 30.8% of them received at least one dose of vaccine. Vaccine hesitancy was associated with decreased family income in the last 1 year (adjusted odds ratio [AOR] = 8.23), knowledge regarding vaccine (AOR = 0.41), adherence to COVID-appropriate behavior (AOR = 0.45), and trust on the local health-care worker (AOR = 0.32). Conclusion: Vaccine hesitancy among the tribal population is driven by a lack of knowledge and awareness. Their economic status, attitudes toward the health system, and accessibility factors may also play a major role in vaccine hesitancy. Extensive information, education, and communication activity, more involvement of health-care workers in the awareness campaign, and establishment of vaccination centers in tribal villages may be helpful.


Subject(s)
COVID-19 , Humans , COVID-19/prevention & control , COVID-19 Vaccines , Cross-Sectional Studies , India/epidemiology , Vaccination , Vaccination Hesitancy
4.
Indian J Public Health ; 67(1): 99-104, 2023.
Article in English | MEDLINE | ID: mdl-37039213

ABSTRACT

Background: To facilitate healthy aging in India, it is important not only to acknowledge older people's contribution but also to understand their perception regarding their impact in the society along with society's attitude toward them. Objectives: This study aims to assess their self-perceived contribution in the society and the factors related with their contribution. Methods: It was an observational, descriptive, cross-sectional study, conducted at Amdanga block of North 24 Parganas district, West Bengal, during July 2021-June 2022. A total 0f 384 geriatrics were interviewed by the house-to-house survey with the help of a predesigned, pretested and semi-structured schedule. Potential predictors of contribution were investigated using the multivariate logistic regression model. Results: 78.9% of participants had contribution in the society. 85.9% were taking care of family members when they were sick. 93.2% were sharing their opinion with the family members. 86.5% were participating in various social works. 79.1% were suffering from at least one physical health problem. With increase in the number of health problems, chances of good contribution decreases. In case of self-perceived contribution in the society family type, employment, physical health and social participation are influencing the most. Conclusion: Elderly people are taking care of not only family members, but even relatives and neighbors also. They are sharing their knowledge and experience with family members and in the society. They are also contributing financially. Employment and proper health-care infrastructure for geriatric may be helpful to maximize their contribution.


Subject(s)
Delivery of Health Care , Family , Aged , Humans , Cross-Sectional Studies , India
5.
Am J Case Rep ; 24: e938415, 2023 01 12.
Article in English | MEDLINE | ID: mdl-36632025

ABSTRACT

BACKGROUND A 39-year-old man with a complex valvular history of recurrent methicillin-resistant Staphylococcus aureus endocarditis with 2 surgical mitral valve replacements (in 2016 and 2017) followed by transcatheter mitral valve replacement (in 2019) presented with orthopnea, paroxysmal nocturnal dyspnea, chest pain, cough, and progressively worsening dyspnea on exertion. CASE REPORT Extensive workup was performed, including transesophageal echocardiogram, which revealed a malfunctioning, severely stenotic bioprosthetic valve. Left and right heart catheterization revealed mild non-obstructive coronary artery disease and severe pulmonary hypertension. Given the patient's complex medical history, he was deemed to be at an elevated risk for repeat sternotomy and repeat valve replacement surgery. Therefore, he underwent a percutaneous transcatheter mitral valve replacement with a 26-mm SAPIEN 3 Edwards valve placed within the previous 29-mm SAPIEN valve. Post-procedural imaging revealed a well-placed valve with an improved mitral valve gradient. CONCLUSIONS This is one of the few rare cases of mitral valve-in-valve via a transcatheter mitral valve replacement approach with successful deployment of a SAPIEN 3 tissue heart valve. The patient experienced significant reversal of heart failure symptoms and improved exertional tolerance following deployment of the valve and was eventually discharged home in a stable condition.


Subject(s)
Heart Valve Prosthesis Implantation , Heart Valve Prosthesis , Methicillin-Resistant Staphylococcus aureus , Male , Humans , Adult , Mitral Valve/diagnostic imaging , Mitral Valve/surgery , Treatment Outcome , Cardiac Catheterization/methods , Prosthesis Design
6.
Exp Hematol ; 118: 53-64.e1, 2023 02.
Article in English | MEDLINE | ID: mdl-36574579

ABSTRACT

The manifestation of coronavirus disease 2019 (COVID-19) severity and mortality has been associated with dysregulation of the immune response, often influenced by racial disparities and conferred by changes in hematologic and immunologic parameters. These biological and hematologic parameters as well as cytokine profiles were investigated in a cohort of 61 COVID-19-positive patients (categorized into mild, moderate, and severe groups) from Bangladesh using standard analytical methods. The data reported that the interleukin (IL)-4 and IL-6 levels were significantly increased, whereas the levels of interferon (IFN)-γ were significantly reduced in patients with severe COVID-19 (p < 0.05) compared with those in patients with mild and/or moderate COVID-19. The extent of erythrocyte sedimentation rate (ESR); neutrophil count; and levels of ferritin, C-reactive protein (CRP), and D-dimer (p < 0.05) were found to be significantly increased, whereas the white blood cell (WBC), lymphocyte, eosinophil, and platelet counts (p < 0.05) were observed to be significantly reduced in patients with severe COVID-19 compared with those in the patients in other 2 groups. Our study exhibited a significantly higher IL-6-to-lymphocyte ratio in patients with severe COVID-19 than in those with mild and moderate COVID-19. The calculated neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and ferritin-to-ESR ratio were significantly increased in patients with severe COVID-19. The increase in the IL-4 and IL-6 levels along with CRP and D-dimer levels may envisage a hyperinflammatory environment and immune dysregulation, which contribute to prolonged viral persistence, leading to severe disease. However, the reduced level of IFN-γ can be attributed to a less fatality toll in Bangladesh compared with that in the rest of the world.


Subject(s)
COVID-19 , Humans , Interleukin-6 , Lymphocytes , Leukocyte Count , C-Reactive Protein/analysis , Neutrophils , Interferon-gamma , Retrospective Studies
7.
Curr Microbiol ; 80(1): 45, 2022 Dec 20.
Article in English | MEDLINE | ID: mdl-36538096

ABSTRACT

Taxonomic and functional characterization of a total of 90 bacterial isolates representing bulk and rhizosphere soils of diverse niches of Andaman and Nicobar Islands, India were carried out. Twelve bacterial isolates were found promising for the biological suppression of agriculturally important fungal and bacterial plant pathogens such as Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, and Colletotrichum gloeosporioides. The 16S rRNA gene sequence analysis revealed their identity as belonging to Bacillus subtilis, Bacillus amyloliquefaciens, and Lysinibacillus sphaericus. The isolates were positive for plant growth promotion (PGP) traits including siderophore production, and nutrient solubilization especially phosphorous, zinc, and potassium. Interestingly, the PCR test confirmed the presence of 62 antimicrobial peptides (AMP) biosynthesis genes specific to the genus Bacillus. Whilst all tested species of Bacillus harboured the bacD biosynthesis gene, the B. subtilis (Ba_Abi), and B. amyloliquefaciens (Ba_Abi) harboured the maximum AMP biosynthesis genes analysed in the study. Upon in planta evaluation, the biocontrol potential of the bacterial isolates against leaf spot disease of chilli was observed. The study culminated in the isolation and identification of diverse Bacillus species for exploitation as bioinoculants for plant health management programmes.


Subject(s)
Bacillus , Antimicrobial Peptides , Bacillus/genetics , Bacillus subtilis/genetics , Disease Management , Islands , Plants , RNA, Ribosomal, 16S/genetics
8.
Inorg Chem ; 61(45): 18253-18259, 2022 Nov 14.
Article in English | MEDLINE | ID: mdl-36310353

ABSTRACT

Electrocatalytic hydrogen evolution reaction (HER) via water electrolysis has been considered the most effective and sustainable route to produce clean hydrogen. Designing and structure optimization are the two important parameters to develop an affordable, easy to fabricate, and stable non-noble metal electrocatalyst for the production of hydrogen as a clean, sustainable, and green fuel. Herein, we have synthesized Ni-Mo-P on copper foam (Cuf) via a facile single-step electrodeposition method, which can show stratospheric efficiency toward HER with a Tafel slope of 67 mV dec-1 and a very low overpotential of only 53 mV at a current density of 20 mA cm-2. Cuf acts as a conducting substrate support and the existence of the inter-electronic effect between Ni and Mo results in substantial catalytic activity toward hydrogen generation. In addition to this, the catalyst shows long time stability of around 97.5 h with almost negligible degradation under the applied overpotential for HER in alkaline media. This work features the significance of structure design and construction of non-noble metal catalysts via a simple method for efficient hydrogen generation.

9.
Inorg Chem ; 61(33): 13218-13225, 2022 Aug 22.
Article in English | MEDLINE | ID: mdl-35943819

ABSTRACT

The development of a cost-effective, remarkably competent, and durable bifunctional electrocatalyst is the foremost requirement of water splitting to generate H2 fuel as a renewable energy technology. Three-dimensional porous copper foam (Cuf) when electrochemically decorated with transition metal selenide results in a highly active electrocatalyst for adequate water electrolysis. In terms of water splitting, the role of cobalt selenide and Cuf has already proven to be remarkable. The introduction of a Ni buffer layer between Cuf and cobalt selenide (Cuf@Ni-CoSe2) acts as a valve to enhance the electron thrust from the substrate to the material surface with no compromise in the overall material conductivity, which not only increases the efficiency and activity but also improves the stability of the catalyst. The self-supported synthesized catalyst material showed an admirable activity toward the oxygen evolution reaction and hydrogen evolution reaction in alkaline media. The performance of the catalyst was found to be significantly better than that of the noble catalyst RuO2. The catalyst was very stable up to 93 h and attained a full cell voltage of only 1.52 V at a current density of 10 mA cm-2. Therefore, for large-scale hydrogen production, this as-synthesized catalyst hss the potential to replace conventional fossil fuel-based energy systems.

10.
J Taibah Univ Med Sci ; 17(2): 241-247, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35592794

ABSTRACT

Objectives: Tumour necrosis factor (TNF)-α, an adipocytokine, is closely linked to impaired glucose tolerance (IGT) and insulin resistance (IR) in type 2 diabetes (T2D) subjects. The relationship between the polymorphisms in the TNF-α gene and IR in Bangladeshi prediabetes and T2D subjects has not yet been fully identified. This study aims to reveal the association between TNF-α gene polymorphism and IR in hyperglycaemic patients of Bangladeshi origin. Methods: In our study, 106 IGT, 100 T2D, and 109 healthy subjects of Bangladeshi origin were recruited to identify the impact of TNF-α gene polymorphism at position -308 with a G>A transition using PCR and subsequent restriction fragment length polymorphism (RFLP). Results: The -308G>A TNF-α genotype frequency distribution within the control, IGT, and T2D groups showed a significant association (χ2 = 21.077; P = 0.001), although allele frequency distribution within the groups showed a statistically non-significant difference (χ2 = 1.696; P = 0.091). ß-cell functional deficiency (HOMA-B%) was observed to be significantly (P = 0.034) lower in subjects with a variant genotype. In addition, our results indicate that the study subjects' body mass index (BMI) and residence status were positively correlated (P ≤ 0.05) with -308G>A TNF-α gene polymorphism. Conclusions: Therefore, it can be concluded that -308G>A TNF-α gene polymorphism may have a causative relationship with lower insulin secretory capacity and higher BMI in Bangladeshi IGT and T2D populations, while the urban population's lifestyle might be associated with this polymorphism.

11.
Chem Commun (Camb) ; 58(12): 1934-1937, 2022 Feb 08.
Article in English | MEDLINE | ID: mdl-35043128

ABSTRACT

Towards rational catalyst development, a binary Fe-Co centre has been coordinated with S and N in a nanocarbon matrix. An electronic drift between Fe-Co and an extended +R effect from the S dopants towards the metals through the pz orbital of N are beneficial for oxygen electrocatalysis and a zinc-air battery.

12.
Indian J Public Health ; 65(4): 340-344, 2021.
Article in English | MEDLINE | ID: mdl-34975075

ABSTRACT

BACKGROUND: While a smartphone can be a hugely productive tool, excessive use of this device can interfere with work, education, our physical and mental health, and productivity. Nowadays, we do not just use our smartphones, but we rely on them. OBJECTIVES: The present study aims to develop and validate an instrument measuring the problematic use of smartphones among adults in a rural area of West Bengal, India. METHODS: The questionnaire on problematic use of smartphone is a self-designed tool. The items were selected by literature review. The psychometric properties of the questionnaire were assessed by content validity, construct validity, and reliability. Exploratory factor analysis was performed to identify the factors. RESULTS: Forty-two items were generated by literature review. After final analysis, the main questionnaire contained 28 items with 5 domains, namely "impulsive use of phone," "dependence," "impaired control," "denial," "decreased productivity," and "emotional attachment." The Cronbach's alpha value for three domains was found to be >0.7 and >0.8 for the other three domains. CONCLUSION: Excessive mobile phone use is associated with various adverse consequences which is emerging as a public health problem in a large number of population in India. Problematic use of smartphone questionnaire is a valid and reliable tool to assess the pattern of mobile use among Indian population.


Subject(s)
Rural Population , Smartphone , Adult , Humans , India , Reproducibility of Results , Surveys and Questionnaires
13.
Front Chem ; 9: 803860, 2021.
Article in English | MEDLINE | ID: mdl-35004623

ABSTRACT

The development of an efficient, sustainable, and inexpensive metal-free catalyst for oxygen evolution reaction (OER) via photoelectrochemical water splitting is very demanding for energy conversion processes such as green fuel generators, fuel cells, and metal-air batteries. Herein, we have developed a metal-free pyrene-based nitrogen and sulfur containing conjugated microporous polymer having a high Brunauer-Emmett-Teller surface area (761 m2 g-1) and a low bandgap of 2.09 eV for oxygen evolution reaction (OER) in alkaline solution. The π-conjugated as-synthesized porous organic material (PBTDZ) has been characterized by Fourier transform infrared spectroscopy (FT-IR), solid-state 13C (cross-polarization magic angle spinning-nuclear magnetic resonance) CP-MAS NMR, N2 adsorption/desorption analysis, field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) experiments. The material acts as an efficient catalyst for photoelectrochemical OER with a current density of 80 mA/cm2 at 0.8 V vs. Ag/AgCl and delivered 104 µmol of oxygen in a 2 h run. The presence of low bandgap energy, π-conjugated conducting polymeric skeleton bearing donor heteroatoms (N and S), and higher specific surface area associated with inherent microporosity are responsible for this admirable photoelectrocatalytic activity of PBTDZ catalyst.

14.
Inorg Chem ; 59(22): 16385-16397, 2020 Nov 16.
Article in English | MEDLINE | ID: mdl-33147411

ABSTRACT

Toward the realm of sustainable energy, the development of efficient methods to enhance the performance of electrocatalysts with molecular level perception has gained immense attention. Inspite of untiring attempts, the production cost and scaling-up issues have been a step back toward the commercialization of the electrocatalysts. Herein, we report a one-pot electrophoretic exfoliation technique with minimum time and power input to synthesize iron phthalocyanine functionalized high-quality graphene sheets (G-FePc). The π-stacked co-assembly excels in oxygen reduction performance (major criterion for fuel cells) with a high positive E1/2 of 0.91 V (vs RHE) and a reproducible reduction peak potential of 0.90 V (vs RHE). An overpotential as low as 29 mV dec-1 and complete tolerance toward the methanol crossover effect confirm the authentication of the catalytic performance of our designed catalyst G-FePc. The catalyst simultaneously exhibits hydrogen storage efficacy by means of nitrogen fixation, yielding 27.74 µg h-1 mgcat-1 NH3 at a potential of -0.3 V (vs RHE) in an acidic electrolyte. The structure-function relationship of the catalyst is revealed via molecular orbital chemistry for the bonding of the Fe(II) active center with O2 and N2 during catalysis.

16.
Inorg Chem ; 59(7): 5194-5205, 2020 Apr 06.
Article in English | MEDLINE | ID: mdl-32191443

ABSTRACT

Transition-metal atoms and/or heteroatom-doped carbon nanostructures is a crucial alternative to find a nonprecious metal catalyst for electrocatalytic oxygen reduction reaction (ORR). Herein, for the first time, we demonstrated the formation of binary (Fe-Mn) active sites in hierarchically porous nanostructure composed of Fe, Mn, and N-doped fish gill derived carbon (Fe,Mn,N-FGC). The Fe,Mn,N-FGC catalyst shows remarkable ORR performance with onset potential (Eonset) of 1.03 V and half-wave potential (E1/2) of 0.89 V, slightly better than commercial Pt/C (Eonset = 1.01 V, E1/2 = 0.88 V) in alkaline medium (pH > 13), which is attributed to the synergistic effect of Fe-Mn dual metal center as evidenced from X-ray absorption spectroscopic study. We proposed that the presence of Fe-Mn binary sites is actually beneficial for the O2 binding and boosting the ORR by weakening the O═O bonds. The homemade rechargeable Zn-air battery performance reveals the open-circuit voltage of 1.41 V and a large power density of 220 mW cm-2 at 260 mA cm-2 current density outperforming Pt/C (1.40 V, 158 mW cm-2) with almost stable charge-discharge voltage plateaus at high current density. The present strategy enriches a route to synthesize low-cost bioinspired electrocatalyst that is comparable to/better than any nonprecious-metal catalysts as well as commercial Pt/C.

17.
Inorg Chem ; 59(2): 1332-1339, 2020 Jan 21.
Article in English | MEDLINE | ID: mdl-31898905

ABSTRACT

The rational design of electronically tuned transition-metal-doped conductive carbon nanostructures has emerged as a potential substitution of a platinum-group-metal (PGM)-free electrocatalyst for oxygen reduction reaction (ORR). We report here a universal strategy using a one-step thermal polymerization reaction for transition-metal-doped graphitic carbon nitride (g-C3N4) without any conductive carbon support as a highly efficient ORR electrocatalyst. X-ray absorption spectroscopy evidences the presence of Fe-Nx active sites with a possible three-coordinated Fe atom with N atoms. The as-prepared Fe-g-C3N4 with improved surface area, graphitic nature, and conductive carbon framework exhibits a superior electrochemical performance toward ORR activity in an alkaline medium. Interestingly, it displays a 0.88 V (vs reversible hydrogen electrode, RHE) half-wave potential (E1/2) with a four-electron-transfer pathway and excellent stability outperforming platinum/carbon (Pt/C) in an alkaline medium. More impressively, when the Fe-g-C3N4 catalyst is used as a cathode material in a zinc-air battery, it presents a higher peak power density (148 mW cm-2) than Pt/C (133 mW cm-2), which further established the importance of the low-cost material synthesis approach toward the development of an earth-abundant PGM-free catalyst for fuel-cell and air battery fabrication.

18.
J Colloid Interface Sci ; 558: 182-189, 2020 Jan 15.
Article in English | MEDLINE | ID: mdl-31586738

ABSTRACT

Non-precious metal doped carbonaceous materials are currently the most promising alternative towards oxygen reduction reaction (ORR) electrocatalysts in terms of cost, accessibility, efficiency and durability. In this work, a simple one-step pyrolysis process was used for the synthesis of copper doped graphitic carbon nitride (Cu-g-C3N4) as electrocatalyst. The as-synthesized Cu-g-C3N4 material is displaying excellent electrocatalytic response towards ORR in alkaline medium. In comparison to commercial Pt/C catalyst, Cu-g-C3N4 exhibits high methanol tolerance, long term stability, without compromising (4e-) electron transfer pathway process and attaining less than 4% H2O2 formation. The enhanced electrocatalytic behaviour may be ascribed to the formation of active sites strongly coupled into the nitrogen-rich carbon matrix. Such a low-cost, extremely durable and stable electrocatalyst can therefore be regarded as an efficient cathodic material, which can be utilized for several renewable energy conversion technologies such as fuel cell, biofuel cell and metal-air battery.

19.
Chem Asian J ; 14(21): 3898-3914, 2019 Nov 04.
Article in English | MEDLINE | ID: mdl-31545553

ABSTRACT

Simultaneous incorporation of both CoII and CoIII ions within a new thioether S-bearing phenol-based ligand system, H3 L (2,6-bis-[{2-(2-hydroxyethylthio)ethylimino}methyl]-4-methylphenol) formed [Co5 ] aggregates [CoII CoIII 4 L2 (µ-OH)2 (µ1,3 -O2 CCH3 )2 ](ClO4 )4 ⋅H2 O (1) and [CoII CoIII 4 L2 (µ-OH)2 (µ1,3 -O2 CC2 H5 )2 ](ClO4 )4 ⋅H2 O (2). The magnetic studies revealed axial zero-field splitting (ZFS) parameter, D/hc=-23.6 and -24.3 cm-1 , and E/D=0.03 and 0.00, respectively for 1 and 2. Dynamic magnetic data confirmed the complexes as SIMs with Ueff /kB =30 K (1) and 33 K (2), and τ0 =9.1×10-8  s (1), and 4.3×10-8  s (2). The larger atomic radius of S compared to N gave rise to less variation in the distortion of tetrahedral geometry around central CoII centers, thus affecting the D and Ueff /kB values. Theoretical studies also support the experimental findings and reveal the origin of the anisotropy parameters. In solutions, both 1 and 2 which produce {CoIII 2 (µ-L)} units, display solvent-dependent catechol oxidation behavior toward 3,5-di-tert-butylcatechol in air. The presence of an adjacent CoIII ion tends to assist the electron transfer from the substrate to the metal ion center, enhancing the catalytic oxidation rate.


Subject(s)
Catechol Oxidase/chemistry , Cobalt/chemistry , Coordination Complexes/chemical synthesis , Sulfides/chemistry , Sulfur/chemistry , Catechol Oxidase/metabolism , Cobalt/metabolism , Coordination Complexes/chemistry , Coordination Complexes/metabolism , Crystallography, X-Ray , Hydrogen Peroxide/analysis , Kinetics , Ligands , Magnetic Fields , Models, Molecular , Molecular Structure , Oxidation-Reduction , Sulfides/metabolism , Sulfur/metabolism
20.
Dalton Trans ; 48(4): 1292-1313, 2019 Jan 22.
Article in English | MEDLINE | ID: mdl-30608086

ABSTRACT

Rational ligand design approaches allowed {Cu2(µ-OH/OMe)} cores to be accommodated within µ-phenoxido bis(tetradentate) and µ-phenoxido bis(tridentate) ligands having thioether donors. The complexes [Cu2(µ-H2L1)(µ-OH)](ClO4)2·2H2O (1), [Cu2(µ-L2)(µ-OH)(OH2)](ClO4)2 (2a) and [Cu2(µ-L2)(µ-OCH3)(OH2)](ClO4)2 (2b) were obtained from an N2O3S2 donor set bearing the H3L1 ligand (2,6-bis-[{2-(2-hydroxyethylthio)ethylimino}methyl]-4-methylphenol) and N2OS2 donor set containing the HL2 ligand (4-methyl-2,6-bis-[{2-(methylthio)phenylimino}methyl]phenol) without showing double phenoxido bridging or any type of preformed inter-fragment aggregation. Previously, we showed that H3L (2,6-bis[((2-(2-hydroxyethoxy)ethyl)imino)methyl]-4-methylphenol), the ether analogue of H3L1, in the presence of carboxylate anions, was responsible for the self-aggregation of preformed {Cu2} fragments and gave two types of [Cu4] complexes comprising [Cu4O] and [Cu4(OH)2] cores (T. S. Mahapatra, A. Bauzá, D. Dutta, S. Mishra, A. Frontera and D. Ray, ChemistrySelect, 2016, 1, 64-74). The molecular structures of 1, 2a and 2b were determined via single crystal X-ray diffraction and solution studies, which indicated the presence of [Cu2] species. This was further confirmed via UV-vis spectroscopy and HRMS analysis. The synthesized complexes were screened for their potential as catalysts for the catalytic oxidation of 3,5-di-tert-butylcatechol (3,5-DTBCH2). A change in the mechanism of catalytic oxidation was observed with a change in the ligand backbone. All three complexes also showed DNA binding properties, which were further substantiated via molecular docking studies. Their DNA binding affinities were quantitatively ascertained using their intrinsic binding constant, Kb, values which were found to be 4.2 × 104, 5.6 × 104 and 4.8 × 104 M-1, respectively. Furthermore, the complexes displayed efficient DNA cleavage behaviour with pBR322 and the oxidative path was established in presence of ROS, singlet oxygen, 1O2, and the superoxide anion, O2·-.


Subject(s)
Catechol Oxidase/metabolism , Coordination Complexes/pharmacology , DNA Cleavage/drug effects , DNA/metabolism , Catechols/metabolism , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Copper/chemistry , Copper/pharmacology , DNA/drug effects , Dose-Response Relationship, Drug , Ethers/chemistry , Ethers/pharmacology , Hydrogen Peroxide/analysis , Hydrogen-Ion Concentration , Kinetics , Ligands , Molecular Docking Simulation , Molecular Structure , Oxidation-Reduction , Structure-Activity Relationship , Sulfhydryl Compounds/chemistry , Sulfhydryl Compounds/pharmacology , Sulfur/chemistry , Sulfur/pharmacology
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