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1.
Chemosphere ; 313: 137515, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36495978

ABSTRACT

Light-induced photocatalytic degradation of ceftiofur sodium (CFS) has been assessed in the presence of plasmonic zinc oxide nanostructures (ZnONSTs), like, ZnO nanoparticles, ZnO nanorods (ZnONRs) and ZnO nanoflowers (ZnONFs). Silver nanoparticles (Ag NPs) loaded ZnO nanostructures (Ag-ZnONSTs) are obtained through seed-assisted chemical reaction followed by chemical reduction of silver. The surface modification of ZnO nanostructures by Ag NPs effectually altered their optical properties. Further, the surface plasmonic effect of Ag NPs facilitates visible light absorption by ZnONSTs and improved the photogenerated electron and hole separation, which makes the ZnONSTs a more active photocatalyst than TiO2 (P25) nanoparticles. Especially, Ag-ZnONRs showed higher CFS oxidation rate constant (k' = 4.6 × 10-4 s-1) when compared to Ag-ZnONFs (k' = 2.8 × 10-4 s-1) and Ag-ZnONPs (k' = 2.5 × 10-4 s-1), owing to their high aspect ratio (60:1). The unidirectional transport of photogenerated charge carriers on the Ag-ZnONRs may be accountable for the observed high photocatalytic oxidation of CFS. The photocatalytic oxidation of CFS mainly proceeds through •OH radicals generated on the Ag-ZnONRs surface under light illumination. In addition, heterogeneous activation of peroxymonosulfate by Ag-ZnONRs accelerates the rate of photocatalytic mineralization of CFS. The quantification of oxidative radicals supports the proposed CFS oxidation mechanism. Stability studies of plasmonic Ag-ZnONSTs strongly suggests that it could be useful to clean large volume of pharmaceutical wastewater under direct solar light irradiation.


Subject(s)
Metal Nanoparticles , Zinc Oxide , Humans , Zinc Oxide/chemistry , Silver/chemistry , Lighting , Metal Nanoparticles/chemistry , Light , Catalysis
2.
Annu Rev Phytopathol ; 60: 357-378, 2022 08 26.
Article in English | MEDLINE | ID: mdl-35650670

ABSTRACT

Plant pathology has developed a wide range of concepts and tools for improving plant disease management, including models for understanding and responding to new risks from climate change. Most of these tools can be improved using new advances in artificial intelligence (AI), such as machine learning to integrate massive data sets in predictive models. There is the potential to develop automated analyses of risk that alert decision-makers, from farm managers to national plant protection organizations, to the likely need for action and provide decision support for targeting responses. We review machine-learning applications in plant pathology and synthesize ideas for the next steps to make the most of these tools in digital agriculture. Global projects, such as the proposed global surveillance system for plant disease, will be strengthened by the integration of the wide range of new data, including data from tools like remote sensors, that are used to evaluate the risk ofplant disease. There is exciting potential for the use of AI to strengthen global capacity building as well, from image analysis for disease diagnostics and associated management recommendations on farmers' phones to future training methodologies for plant pathologists that are customized in real-time for management needs in response to the current risks. International cooperation in integrating data and models will help develop the most effective responses to new challenges from climate change.


Subject(s)
Artificial Intelligence , Big Data , Agriculture , Climate Change , Machine Learning
3.
Chemosphere ; 291(Pt 1): 132782, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34748798

ABSTRACT

ZnO hexagonal tube and ZnO/r-GO nanocomposites were synthesized by hydrothermal method and the nanostructures were characterized by XRD, UV-DRS, PL, FTIR, FESEM, and TEM techniques. The main violet emission peak of the synthesized nanostructures is due to the transition between interstitial zinc and hole (valence band) of ZnO. The potential of ZnO/r-GO nanocomposite was evaluated using methyl orange (MO) and rhodamine-B (RhB), and the results were compared with the activity of synthesized ZnO nanostructures. More than 95% of MO and RhB were by ZnO/r-GO nanocomposite and it was found to be higher than that of ZnO hexagonal tube. The degradation MO and RhB were found to follow first-order kinetics and it has a rate constant of 7.68 × 10-2and 7.83 × 10-2 min-1, respectively. These results are mainly due to the enhanced charge transport property. Trapping experiments show that superoxide radical anion and hydroxide radicals are chief species responsible for the degradation of MO and RhB. The chemical stability of the nanocomposite was evaluated by cycle test experiments and it reveals that the catalyst can be reused up to few cycles without considerable loss of photocatalytic activity. This work affords a simple stratagem to integrate ZnO hexagonal tubes and r-GO nanosheets to construct effective catalysts for the degradation of organic compounds.


Subject(s)
Environmental Pollutants , Nanocomposites , Water Pollutants, Chemical , Zinc Oxide , Light
4.
Indian J Orthop ; 55(3): 723-727, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33995879

ABSTRACT

INTRODUCTION: Latarjet procedure is commonly performed for recurrent anterior shoulder instability with glenoid side bone loss. Classic Latarjet procedure can be performed using specially designed drill guides, jigs, or by freehand technique. Here we have described a technical note on classic Latarjet procedure performed with freehand technique utilizing simple rulers and caliper. The functional and radiological outcomes of our patients have also been analysed. MATERIAL AND METHODS: 149 open classic Latarjet procedures were performed using our technique between March 2015 and July 2018. The mean age of the patients was 32.95 years (Range 22-59 years). The functional outcome of the patients was measured using Western Ontario Shoulder Instability (WOSI) and Oxford Shoulder Instability Score (OSIS) at 2 years of follow-up. Screw and graft positioning were studied in 24 consecutive patients with a postoperative computed tomography (CT) scan. RESULTS: There was no incidence of recurrent subluxation or dislocation post-surgery. Mean OSIS score increased from 15.63 ± 3.20 preoperatively to 42.44 ± 3.88 postoperatively (p value < 0.05). WOSI score decreased significantly from 62.54% ± 8.24 to 10.26 ± 6.33 postoperatively at 2-year follow-up (p value < 0.05). Postoperative CT scan also showed satisfactory screw placement in all patients. CONCLUSION: Open Latarjet procedure performed using freehand technique provides good functional and radiological outcomes in patients with recurrent anterior shoulder instability with glenoid side bone loss. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s43465-021-00385-7.

5.
Vaccines (Basel) ; 8(2)2020 Apr 06.
Article in English | MEDLINE | ID: mdl-32268574

ABSTRACT

Following the successful eradication of rinderpest, the World Organization of Animal Health (OIE) and the Food and Agriculture Organization (FAO) have set a goal to eradicate peste des petits ruminants (PPR) globally by 2030. Vaccination is being taken forward as the key strategy along with epidemiological surveillance to target vaccination efforts and eradicate the disease. PPR is highly contagious and is generally spread by aerosolized droplets and close contact. Currently, two live attenuated vaccines (Nigeria 75/1 and Sungri 96) are in use, and administered subcutaneously to prevent transmission of PPR and protect vaccinated animals. Though the target cells that support primary replication of PPR vaccine strains are largely unknown, it is hypothesized that the immune response could be intensified following intranasal vaccine delivery as this route mimics the natural route of infection. This study aims to compare the immunogenicity and protective efficacy of the two currently available live attenuated PPR vaccines following subcutaneous and intranasal routes of vaccination in target species. Groups of five goats were vaccinated with live attenuated PPR vaccines (Nigeria 75/1 and Sungri 96) by either the subcutaneous or intranasal route, and 28 days later challenged intranasally with virulent PPR virus. All vaccinated animals regardless of vaccination route produced PPRV-specific antibodies post-vaccination. Following challenge, all goats were protected from clinical disease, and vaccination was considered to have induced sterilizing immunity. This study demonstrates that the intranasal route of vaccination is as effective as the subcutaneous route of vaccination when using available live attenuated PPR vaccines.

6.
Indian J Med Res ; 152(6): 648-655, 2020 Dec.
Article in English | MEDLINE | ID: mdl-34145105

ABSTRACT

BACKGROUND & OBJECTIVES: As India and other developing countries are scaling up isoniazid preventive therapy (IPT) for people living with HIV (PLHIV) in their national programmes, we studied the feasibility and performance of IPT in terms of treatment adherence, outcome and post-treatment effect when given under programmatic settings. METHODS: A multicentre, prospective pilot study was initiated among adults living with HIV on isoniazid 300 mg with pyridoxine 50 mg after ruling out active tuberculosis (TB). Symptom review and counselling were done monthly during IPT and for six-month post-IPT. The TB incidence rate was calculated and risk factors were identified. RESULTS: Among 4528 adults living with HIV who initiated IPT, 4015 (89%) successfully completed IPT. IPT was terminated in 121 adults (3%) due to grade 2 or above adverse events. Twenty five PLHIVs developed TB while on IPT. The incidence of TB while on IPT was 1.17/100 person-years (p-y) [95% confidence interval (CI) 0.8-1.73] as compared to TB incidence of 2.42/100 p-y (95% CI 1.90-3.10) during the pre-IPT period at these centres (P=0.017). The incidence of TB post-IPT was 0.64/100 p-y (95% CI 0.04-1.12). No single factor was significantly associated with the development of TB. INTERPRETATION & CONCLUSIONS: Under programmatic settings, completion of IPT treatment was high, adverse events minimal with good post-treatment protection. After ruling out TB, IPT should be offered to all PLHIVs, irrespective of their antiretroviral therapy (ART) status. Scaling-up of IPT services including active case finding, periodic counselling on adherence and re-training of ART staff should be prioritized to reduce the TB burden in this community.


Subject(s)
HIV Infections , Tuberculosis , Adult , Antitubercular Agents/adverse effects , HIV Infections/complications , HIV Infections/drug therapy , HIV Infections/epidemiology , Humans , Incidence , India/epidemiology , Isoniazid/adverse effects , Pilot Projects , Prospective Studies , Tuberculosis/drug therapy , Tuberculosis/epidemiology , Tuberculosis/prevention & control
7.
Viruses ; 11(3)2019 03 12.
Article in English | MEDLINE | ID: mdl-30871054

ABSTRACT

Following the successful eradication of rinderpest, the World Organization of Animal Health (OIE) and the Food and Agriculture Organisation (FAO) have set a goal to globally eradicate Peste des petits ruminants (PPR) by 2030. To support the eradication programme we have quantified the levels of PPR virus (PPRV) nucleic acid excreted in body fluids (blood, feces, saliva, nasal and eye swabs) of PPRV-infected goats to ascertain which days post-infection animals are potentially infectious, and hence direct quarantine activities. The data will also indicate optimal sample strategies to assess presence of PPR infection in the naturally infected herd. Peak PPRV nucleic acid detection in different bodily fluids was between 5 and 10 days post-infection. As such, this period must be considered the most infectious period for contact transmission, although high viral load was observed through RNA detection in nasal excretions from two days post-infection until at least two weeks post-infection. Percentage sample positivity was low both in eye swabs and saliva samples during the early stage of infection although RNA was detected as late as two weeks post-infection. From the individual animal data, PPRV was detected later post-infection in fecal material than in other body fluids and the detection was intermittent. The results from this study indicate that nasal swabs are the most appropriate to sample when considering molecular diagnosis of PPRV.


Subject(s)
Disease Eradication , Disease Outbreaks/veterinary , Goat Diseases/virology , Peste-des-Petits-Ruminants/prevention & control , Peste-des-petits-ruminants virus/isolation & purification , RNA, Viral/analysis , RNA, Viral/genetics , Animals , Disease Outbreaks/prevention & control , Feces/virology , Goats , Male , Nose/virology , Peste-des-Petits-Ruminants/blood , Peste-des-petits-ruminants virus/genetics , Real-Time Polymerase Chain Reaction , Saliva/virology
8.
J Colloid Interface Sci ; 530: 179-188, 2018 Nov 15.
Article in English | MEDLINE | ID: mdl-29982009

ABSTRACT

Highly catalytic two dimensional and metal-doped two-dimensional nanomaterials (MoS2 and NiMoS) were deposited over free-standing graphene (FSG) paper using electrodeposition method and subsequently used as a counter electrode in quasi solid-state dye-sensitized solar cells (q-DSSCs). The replacement of FTO by FSG facilitates high electrical conductivity and electrodeposited metal sulphides provide electrocatalytic activity. The morphology, structural phase formation and chemical composition of FSG-MoS2 and FSG-NiMoS were investigated using FESEM, XRD, Raman and XPS analysis. The electrochemical behavior of metal sulphide decorated FSG cathodes is investigated using an electrochemical workstation and their effects on the photo-conversion efficiency of DSSCs were assessed. NiMoS with FSG substrate is an intriguing counter electrode material that can be utilized at low fabrication cost than the conventional platinum-based counter electrodes. FSG along with the metallic-two dimensional nanoparticles (NiMoS) functions as an effective catalytic material thereby allowing DSSCs to achieve enhanced efficiency of ∼7% to provide better alternative of FTO and Pt.

9.
Mater Sci Eng C Mater Biol Appl ; 69: 85-94, 2016 Dec 01.
Article in English | MEDLINE | ID: mdl-27612692

ABSTRACT

Sunlight assisted reduction of silver ions were accomplished for the synthesis of silver nanoparticles incorporated within the mesoporous silicate framework of zeolite Y. The zeolite-Y and AgNP/Zeo-Y were characterized by field emission scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption BET isotherm and X-ray diffraction techniques. The incorporation of silver nanoparticles within the porous framework was further confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. An enhanced electrocatalytic oxidation of biologically important molecules like dopamine and uric acid using AgNP/Zeo-Y modified glassy carbon electrode has been developed. A simultaneous oxidation of DA and UA peaks were obtained at +0.31V and +0.43V (vs. Ag/AgCl) using AgNP/Zeo-Y/GCE under the optimum experimental condition. A well-resolved peak potential window (~120mV) for the oxidation of both DA and UA were observed at AgNP/Zeo-Y/GCE system. The calibration curves for DA and UA were obtained within the dynamic linear range of 0.02×10(-6) to 0.18×10(-6)M (R(2)=0.9899) and 0.05×10(-6) to 0.7×10(-6)M (R(2)=0.9996) and the detection limits were found to be 1.6×10(-8)M and 2.51×10(-8)M by using differential pulse voltammetry (DPV) method. The proposed method was successfully applied for the determination of both DA and UA in human urine samples with a related standard deviation was <3%, and n=5 using the standard addition method.


Subject(s)
Chemistry Techniques, Analytical/methods , Dopamine/urine , Electrochemical Techniques , Metal Nanoparticles/chemistry , Silver/chemistry , Sunlight , Uric Acid/urine , Zeolites/chemistry , Carbon/chemistry , Catalysis , Chemistry Techniques, Analytical/instrumentation , Dielectric Spectroscopy , Electrodes , Humans , Hydrogen-Ion Concentration , Limit of Detection , Oxidation-Reduction , Porosity , Reproducibility of Results , X-Ray Diffraction
10.
Natl Med J India ; 29(6): 321-325, 2016.
Article in English | MEDLINE | ID: mdl-28327478

ABSTRACT

BACKGROUND: WHO recommends the use of a simplified symptom-based algorithm for screening for tuberculosis (TB) among people living with HIV (PLHIV). We assessed the feasibility and effectiveness of this algorithm and determined the prevalence and incidence of TB among PLHIV attending antiretroviral treatment (ART) centres in India. METHODS: We did a prospective multicentric implementation research study in four states of India. To rule out TB, we administered the WHO symptom-screen algorithm to all PLHIV every month for 6 months. If they were found to be symptomatic any time during this period, they were referred for investigations for TB. A case of TB diagnosed during the first month of screening was taken as a prevalent case while those detected TB in the subsequent 5 months were considered cases of incident TB. We calculated the incidence rate using the person-years method. Results . Between May 2012 and October 2013, a total of 6099 adults and 1662 children living with HIV were screened for TB at the ART centres of four states. Of the 6099 adult PLHIV, 1815 (30%) had at least one symptom suggestive of TB, of whom only 634 (35%) were referred for investigations of TB. Of those referred, 97 (15%) PLHIV were diagnosed with TB. Overall, the prevalence of undiagnosed TB was 0.84 person-years and in the subsequent period, the incidence of TB was 2.4/100 person-years (95% CI 1.90-3.10). Among 1662 children, 434 (26%) had at least one symptom suggestive of TB. But only 57 (13%) children were referred for investigations of TB and 13 (23%) of them were diagnosed with TB. The prevalence of TB among children was 0.5% and its incidence among them was 2.7/100 person-years (95% CI 1.60-4.30). CONCLUSION: Prevalence and incidence of TB is high among PLHIV attending ART centres. This emphasizes the need to strengthen regular screening for symptoms of TB and further referral of those symptomatic for diagnosis of TB.


Subject(s)
HIV Infections/complications , Mass Screening/methods , Tuberculosis/diagnosis , Adolescent , Adult , Child , Feasibility Studies , Female , HIV Infections/immunology , Humans , Incidence , India/epidemiology , Male , Middle Aged , Prevalence , Prospective Studies , Tuberculosis/epidemiology , Tuberculosis/immunology
11.
J Nanosci Nanotechnol ; 15(7): 4784-91, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26373038

ABSTRACT

A diamine functionalized cubic mesostructured KIT-6 (N-KIT-6) has been prepared by post-synthetic method using calcined mesoporous KIT-6 with a diamine source, i.e., N-'[3-(tri methoxysilyl)- propyl]'ethylenediamine. The KIT-6 mesoporous silica used for N-KIT-6 was synthesized under weak acidic hydrothermal method using bitemplates, viz., Pluronic P123 and 1-butanol. The synthesized mesoporous materials, KIT-6 and N-KIT-6, have been characterized by the relevant instrumental techniques such as SAXS, N2 sorption isotherm, FT-IR, SEM, TEM and TGA to prove the standard mesoporous materials with the identification of diamine groups. The characterized mesoporous materials, KIT-6 and N-KIT-6, have been extensively used in the potential application of controlled drug delivery, where ibuprofen (IBU) employed as a model drug. The rate of IBU adsorption and release was monitored by UV vis-spectrometer. On the basis of the experimental results of controlled drug delivery system, the results of IBU adsorption and releasing rate in N-KIT-6 are higher than those of KIT-6 because of the higher hydrophobic nature as well as rich basic sites on the surface of inner pore wall silica.


Subject(s)
Analgesics, Non-Narcotic , Diamines/chemistry , Ibuprofen , Silicon Dioxide , Analgesics, Non-Narcotic/chemistry , Analgesics, Non-Narcotic/pharmacokinetics , Analgesics, Non-Narcotic/pharmacology , Delayed-Action Preparations/chemistry , Delayed-Action Preparations/pharmacokinetics , Delayed-Action Preparations/pharmacology , Ibuprofen/chemistry , Ibuprofen/pharmacokinetics , Ibuprofen/pharmacology , Porosity , Silicon Dioxide/chemistry , Silicon Dioxide/pharmacokinetics , Silicon Dioxide/pharmacology
12.
J Acquir Immune Defic Syndr ; 69(3): e109-14, 2015 Jul 01.
Article in English | MEDLINE | ID: mdl-26181709

ABSTRACT

BACKGROUND: Information on the follow-up of HIV-infected children enrolled into preantiretroviral therapy (Pre-ART) care under routine program settings is limited in India. Knowledge on the magnitude of loss to follow-up (LFU) and its reasons will help programs to retain children in HIV care. We aimed to assess the proportion of LFU among children in Pre-ART care and its associated factors. METHODS: In this retrospective cohort study, we reviewed the records of all HIV-infected children (aged <15 years) registered from 2005 to 2012 at an ART center, Madurai, South India. LFU during Pre-ART care was defined as having not visited the ART center within a year of registration. RESULTS: Of 426 children enrolled in Pre-ART care, 211 (49%) were females and 301 (71%) were in the 5- to 14-year age group. At 1 year of registration, 348 (82%) were lost to follow-up. Of 348, 81 returned to care after 1 year of enrollment, whereas 267 (63% of all children) were permanently lost to follow-up. The proportion of LFU remained high from 2005 to 2012. WHO staging, CD4 count, and opportunistic infection were the significant factors associated with lost to follow-up on multivariate analysis. CONCLUSIONS: LFU was alarmingly high indicating poor clinical and programmatic monitoring among HIV-infected children enrolled in Pre-ART care. A system for active tracing of those missing a clinic appointment intensified supervision, and monitoring along with qualitative research is urgently needed. This will help to understand the exact reasons for LFU based on which effective interventions may be planned for reducing such losses.


Subject(s)
Anti-HIV Agents/administration & dosage , HIV Infections/drug therapy , Lost to Follow-Up , National Health Programs/organization & administration , Patient Dropouts/statistics & numerical data , Acquired Immunodeficiency Syndrome/epidemiology , Acquired Immunodeficiency Syndrome/prevention & control , Adolescent , Anti-HIV Agents/therapeutic use , Child , Child, Preschool , Cohort Studies , Female , HIV Infections/epidemiology , HIV Infections/prevention & control , Humans , India/epidemiology , Male , Retrospective Studies
13.
J Nanosci Nanotechnol ; 14(4): 2864-70, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24734702

ABSTRACT

The Ce1-xMnxO2 nanocatalysts (x = 0.25, 0.50 and 0.75 wt.%) were synthesized by sol-gel method. The catalysts were characterized using various techniques such as XRD, N2 sorption study, DRSUV-Vis, TPR, SEM and TEM. The incorporation of Mn ions into the ceria lattice was confirmed by XRD analysis. DRUV-Vis spectra confirm the presence of Ce3+ ions in the lattice of Ce1-xMnxO2. H2-TPR study revealed the oxygen storage capacity of the catalyst. The 3D flowerlike morphology of the nanocatalysts was confirmed from FESEM and HRTEM images. The catalytic activity was tested for the vapor phase oxidation of cyclohexane using air as an oxidant. The key reaction parameters were varied to study the stability, activity and selectivity of the catalysts. The study concluded that suitable amount of manganese content is essential for the selective oxidation of cyclohexane at low temperature and Ce0.25Mn0.75O2 is the most suitable catalyst for high conversion and selectivity under the given reaction conditions. The activity of the catalyst is correlated with the characterization results.

14.
Dalton Trans ; 43(14): 5299-308, 2014 Apr 14.
Article in English | MEDLINE | ID: mdl-24590246

ABSTRACT

A novel incessant formation of chain like mesoporous silica (ICMS) has been easily materialized using a mixed surfactant (Pluronic P123 and FC-4) as a structuring reagent in conjunction with a thiol precursor (3-MPS) through a one-pot synthetic method. A particular thiol concentration facilitated the interaction of the micelle head groups to form long-chain micelles, where FC-4 enhanced further growth. The rapid interactions of the micelles and the condensation of silicic acid and its oligomeric derivatives by coordinating 3-MPS through hydrogen bonding interactions leads to form ICMS. The characterization results for the ICMS illustrated that it has an ordered hexagonal pore geometry. The capability of the ICMS for Hg(2+) adsorption was extensively studied under different optimal parameters and the adsorption isothermal values clearly fit with the Langmuir and Freundlich isothermal plots. This novel material exhibited an unprecedentedly high binding affinity toward even microgram levels of mercury ions in wastewater, compared to other thiol-based mesoporous silica.


Subject(s)
Mercury/chemistry , Silicon Dioxide/chemistry , Water Pollutants, Chemical/chemistry , Adsorption , Fluorocarbons/chemistry , Micelles , Organosilicon Compounds , Poloxalene/chemistry , Silanes/chemistry , Surface-Active Agents/chemistry , Waste Disposal, Fluid/methods , Water Purification/methods
15.
Dalton Trans ; 43(3): 958-66, 2014 Jan 21.
Article in English | MEDLINE | ID: mdl-24158466

ABSTRACT

We have developed a green method for the production of 2,6-disubstituted p-benzoquinones (DSBQs) by liquid-phase oxidations of di/tri-substituted phenols using two-dimensional hexagonally thick-walled mesoporous vanadosilicate catalysts. In particular, 2,6-di-tert-butyl-p-benzoquinone was synthesized by the oxidation of 2,6-di-tert-butylphenol, using various reaction parameters, over mesoporous VSBA-15 catalysts synthesized with various vanadium contents. A promising chemical treatment method for the preparation of green mesoporous VSBA-15(5) or W-VSBA-15(5) (W: washed) catalysts was successfully used in the presence of ammonium acetate solution to remove moderately toxic non-framework V2O5 crystallite species from the active surface, and the catalytic activity of the recovered green mesoporous VSBA-15(5) catalyst was determined. To confirm the green aspects, recyclability and hot-catalytic filtration experiments were performed. The combined results show that the green mesoporous VSBA-15(5) is a highly active, recyclable, and promising heterogeneous catalyst for the selective synthesis of DSBQs (98-100%), and has unprecedented catalytic activity compared with other mesoporous vanadosilicate catalysts.


Subject(s)
Benzoquinones/chemical synthesis , Butylated Hydroxytoluene/analogs & derivatives , Silicon Dioxide/chemistry , Silicon Dioxide/chemical synthesis , Vanadium Compounds/chemistry , Vanadium Compounds/chemical synthesis , Benzoquinones/chemistry , Butylated Hydroxytoluene/chemical synthesis , Butylated Hydroxytoluene/chemistry , Catalysis , Oxidation-Reduction , Phenols/chemistry , Porosity , Temperature
16.
J Nanosci Nanotechnol ; 14(11): 8891-7, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25958623

ABSTRACT

Hard donor atoms (N and O) containing macrocyclic ligand was synthesized and further functionalized with mesoporous SBA-15 materials by chemical modification method. The modification was achieved by the immobilization of 3-chloropropyltriethoxysilane (CIPTES) onto mesoporous silica surface followed by post grafting route. The resulting material (Py-Cy-SBA-15) has been characterized by low angle X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm, Fourier-transform infrared (FT-IR) spectroscopy, 29Si and 13C CP MAS NMR spectroscopic analyses, Thermogravimetric analysis (TGA) and elemental analysis. The long range orders of the materials were identified by transmission electron microscopy (TEM). The functionalized material was employed to the heavy metal ions adsorption from aqueous solution containing Cu2+, Co2+, Zn2+, Cd2+ and Cr2+. The prepared hybrid material showed high selectivity and adsorption capacity for Co2+ ion at pH 8.0.


Subject(s)
Cobalt/chemistry , Nanostructures/chemistry , Seawater/chemistry , Silicon Dioxide/chemistry , Water Pollutants, Chemical/chemistry , Adsorption , Cobalt/analysis , Ligands , Metals, Heavy/analysis , Metals, Heavy/chemistry , Models, Chemical , Water Pollutants, Chemical/analysis
17.
J Biosci ; 38(5): 845-55, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24296887

ABSTRACT

Internal mobility of the two domain molecule of ribosome recycling factor (RRF) is known to be important for its action. Mycobacterium tuberculosis RRF does not complement E. coli for its deficiency of RRF (in the presence of E. coli EF-G alone). Crystal structure had revealed higher rigidity of the M. tuberculosis RRF due to the presence of additional salt bridges between domains. Two inter-domain salt bridges and one between the linker region and the domain containing C-terminal residues were disrupted by appropriate mutations. Except for a C-terminal deletion mutant, all mutants showed RRF activity in E. coli when M. tuberculosis EF-G was also co-expressed. The crystal structures of the point mutants, that of the C-terminal deletion mutant and that of the protein grown in the presence of a detergent, were determined. The increased mobility resulting from the disruption of the salt bridge involving the hinge region allows the appropriate mutant to weakly complement E. coli for its deficiency of RRF even in the absence of simultaneous expression of the mycobacterial EF-G. The loss of activity of the C-terminal deletion mutant appears to be partly due to the rigidification of the molecule consequent to changes in the hinge region.


Subject(s)
Bacterial Proteins/chemistry , Mycobacterium tuberculosis , Ribosomal Proteins/chemistry , Amino Acid Substitution , Bacterial Proteins/genetics , Crystallography, X-Ray , Detergents/chemistry , Hydrophobic and Hydrophilic Interactions , Maltose/analogs & derivatives , Maltose/chemistry , Models, Molecular , Mutagenesis, Site-Directed , Protein Structure, Secondary , Protein Structure, Tertiary , Ribosomal Proteins/genetics , Structural Homology, Protein
18.
J Colloid Interface Sci ; 406: 69-74, 2013 Sep 15.
Article in English | MEDLINE | ID: mdl-23820072

ABSTRACT

We prepared stable colloidal suspension graphene in aqueous medium by surface modification of graphene with 4-benzenediazonium sulfonate. The sulfonate group on graphene surface interacts with water, exhibits well dispersibility and which prevents the aggregation even at neutral pH. This dispersion shows stability for three months and facile to produce films. Using such a modified graphene dispersion, transparent conductive film (TCF) has been fabricated on glass substrate by spin coating method. At appropriate concentration, the film exhibits an excellent optoelectrical property with resistivity of 1.1 kΩ with the transparency of 89% at the wavelength of 550 nm. Further, we also demonstrated the mechanical, thermal, and optoelectrical properties of prepared films.

19.
J Biosci ; 37(6): 953-63, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23151785

ABSTRACT

The discrepancy between the X-ray and NMR structures of Mycobacterium tuberculosis peptidyl-tRNA hydrolase in relation to the functionally important plasticity of the molecule led to molecular dynamics simulations. The X-ray and the NMR studies along with the simulations indicated an inverse correlation between crowding and molecular volume. A detailed comparison of proteins for which X-ray and the NMR structures appears to confirm this correlation. In consonance with the reported results of the investigations in cellular compartments and aqueous solution, the comparison indicates that the crowding results in compaction of the molecule as well as change in its shape, which could specifically involve regions of the molecule important in function. Crowding could thus influence the action of proteins through modulation of the functionally important plasticity of the molecule.


Subject(s)
Crystallography, X-Ray/methods , Magnetic Resonance Spectroscopy/methods , Molecular Dynamics Simulation , Models, Molecular
20.
Dalton Trans ; 41(46): 14197-203, 2012 Dec 14.
Article in English | MEDLINE | ID: mdl-23047727

ABSTRACT

We demonstrate a much green synthesis method for highly selective synthesis of 6,8-di-t-butylated flavan (6,8-DTBF) by liquid phase alkylation of 2,4-di-t-butylphenol (2,4-DTBP) with cinnamyl alcohol (Cin-OH) over mesoporous Zn-Al-MCM-41 catalysts synthesized under direct basic hydrothermal method. The main alkylated product, 6,8-DTBF is importantly used as an intermediate in the manufacture of biosynthetic organic compounds. The recyclable mesoporous Zn-Al-MCM-41 catalysts have also been reused in this reaction to study their catalytic activities. The influences of various reaction parameters such as temperature, time, ratios of reactant (2,4-DTBP-to-Cin-OH) have been extensively investigated for the synthesis of 6,8-DTBF. In addition, dimethyl sulfoxide (DMSO) has also been used as a solvent in this catalytic reaction. The mesoporous Zn-Al-MCM-41(75) gives excellent catalytic activity with 6,8-DTBF selectivity (86.0%) and 2,4-DTBP conversion (63.1%), and these catalytic results have also compared with that obtained using other mesoporous and microporous catalysts. On the basis of catalytic activity obtained by using the all catalysts, the Zn-Al-MCM-41(75) catalyst is found to be a highly active, recyclable and eco-friendly heterogeneous catalyst in the liquid-phase alkylation of 2,4-DTBP.

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