Publications by authors named "G Palanisamy"

28 Publications

An efficient and magnetically recoverable g-CN/ZnS/CoFeO nanocomposite for sustainable photodegradation of organic dye under UV-visible light illumination.

Environ Res 2021 Jun 17;201:111429. Epub 2021 Jun 17.

Advanced Materials Research Chair, Chemistry Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.

Effective improvement of an easily recoverable photocatalyst is equally vital to its photocatalytic performance from a practical application view. The magnetically recoverable process is one of the easiest ways, provided the photocatalyst is magnetically strong enough to respond to an external magnetic field. Herein, we prepared graphitic carbon nitride nanosheet (g-CN), and ZnS quantum dots (QDs) supported ferromagnetic CoFeO nanoparticles (NPs) as the gCN/ZnS/CoFeO nanohybrid photocatalyst by a wet-impregnation method. The loading of CoFeO NPs in the g-CN/ZnS nanohybrid resulted in extended visible light absorption. The ferromagnetic g-CN/ZnS/CoFeO nanohybrid exhibited better visible-light-active photocatalytic performance (97.11%) against methylene blue (MB) dye, and it was easily separable from the aqueous solution by an external bar magnet. The g-CN/ZnS/CoFeO nanohybrid displayed excellent photostability and reusability after five consecutive cycles. The favourable band alignment and availability of a large number of active sites affected the better charge separation and enhanced photocatalytic response. The role of active species involved in the degradation of MB dye during photocatalyst by g-CN/ZnS/CoFeO nanohybrid was also investigated. Overall, this study provides a facile method for design eco-friendly and promising g-CN/ZnS/CoFeO nanohybrid photocatalyst as applicable in the eco-friendly dye degradation process.
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http://dx.doi.org/10.1016/j.envres.2021.111429DOI Listing
June 2021

A One Health Approach to Defining Animal and Human Helminth Exposure Risks in a Tribal Village in Southern India.

Am J Trop Med Hyg 2021 May 24. Epub 2021 May 24.

2The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India.

The high burden of soil-transmitted helminth infections has been studied in India; however, little data exist on zoonotic helminths, and on animal-associated exposure to soil-transmitted helminths. Our study took place in the Jawadhu Hills, which is a tribal region in Tamil Nadu, India. Using a One Health approach, we included animal and environmental samples and human risk factors to answer questions about the associations among infected household soil, domestic animals, and human risk factors. Helminth eggs were identified by microscopy in animal and soil samples, and a survey about risk factors was administered to the head of the household. Contact with animals was reported in 71% of households. High levels of helminth infections were found across domestic animal species, especially in goats, chickens, and dogs. Helminth eggs were recorded in 44% of household soil (n = 43/97) and separately in 88% of soil near a water source (n = 28/32). Animal contact was associated with 4.05 higher odds of having helminth eggs in the household soil (P = 0.01), and also having a water source at the household was associated with a 0.33 lower odds of having helminth eggs in the household soil (P = 0.04). Soil moisture was a mediator of this association with a significant indirect effect (P < 0.001). The proportion mediated was 0.50. While our work does not examine transmission, these results support consideration of animal-associated exposure to STH and potentially zoonotic helminths in future interventions to reduce helminth burden. Our study provides support for further investigation of the effects of animals and animal fecal matter on human health.
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http://dx.doi.org/10.4269/ajtmh.20-1476DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8274781PMC
May 2021

Epidemiology of soil transmitted helminths and risk analysis of hookworm infections in the community: Results from the DeWorm3 Trial in southern India.

PLoS Negl Trop Dis 2021 04 30;15(4):e0009338. Epub 2021 Apr 30.

The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America.

Since 2015, India has coordinated the largest school-based deworming program globally, targeting soil-transmitted helminths (STH) in ~250 million children aged 1 to 19 years twice yearly. Despite substantial progress in reduction of morbidity associated with STH, reinfection rates in endemic communities remain high. We conducted a community based parasitological survey in Tamil Nadu as part of the DeWorm3 Project-a cluster-randomised trial evaluating the feasibility of interrupting STH transmission at three geographically distinct sites in Africa and Asia-allowing the estimation of STH prevalence and analysis of associated factors. In India, following a comprehensive census, enumerating 140,932 individuals in 36,536 households along with geospatial mapping of households, an age-stratified sample of individuals was recruited into a longitudinal monitoring cohort (December 2017-February 2018) to be followed for five years. At enrolment, a total of 6089 consenting individuals across 40 study clusters provided a single adequate stool sample for analysis using the Kato-Katz method, as well as answering a questionnaire covering individual and household level factors. The unweighted STH prevalence was 17.0% (95% confidence interval [95%CI]: 16.0-17.9%), increasing to 21.4% when weighted by age and cluster size. Hookworm was the predominant species, with a weighted infection prevalence of 21.0%, the majority of which (92.9%) were light intensity infections. Factors associated with hookworm infection were modelled using mixed-effects multilevel logistic regression for presence of infection and mixed-effects negative binomial regression for intensity. The prevalence of both Ascaris lumbricoides and Trichuris trichiura infections were rare (<1%) and risk factors were therefore not assessed. Increasing age (multivariable odds ratio [mOR] 21.4, 95%CI: 12.3-37.2, p<0.001 for adult age-groups versus pre-school children) and higher vegetation were associated with an increased odds of hookworm infection, whereas recent deworming (mOR 0.3, 95%CI: 0.2-0.5, p<0.001) and belonging to households with higher socioeconomic status (mOR 0.3, 95%CI: 0.2-0.5, p<0.001) and higher education level of the household head (mOR 0.4, 95%CI: 0.3-0.6, p<0.001) were associated with lower odds of hookworm infection in the multilevel model. The same factors were associated with intensity of infection, with the use of improved sanitation facilities also correlated to lower infection intensities (multivariable infection intensity ratio [mIIR] 0.6, 95%CI: 0.4-0.9, p<0.016). Our findings suggest that a community-based approach is required to address the high hookworm burden in adults in this setting. Socioeconomic, education and sanitation improvements alongside mass drug administration would likely accelerate the drive to elimination in these communities. Trial Registration: NCT03014167.
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http://dx.doi.org/10.1371/journal.pntd.0009338DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8184002PMC
April 2021

Visible light driven reduced graphene oxide supported ZnMgAl LTH/ZnO/g-CN nanohybrid photocatalyst with notable two-dimension formation for enhanced photocatalytic activity towards organic dye degradation.

Environ Res 2021 06 26;197:111079. Epub 2021 Mar 26.

Chemistry Department P. O. Box 84428, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11671, Saudi Arabia.

In this study, 2D/2D/2D heterostructured r-GO/LTH/ZnO/g-CN nanohybrid were synthesized through hydrothermal method. The strong electrostatic interaction between the negatively charged g-CN and r-GO nanosheets with positively charged layered triple hydroxide (LTH) nanosheets are effectively influences the successful formation of heterojunction. The LTH nanosheets are well spread on the g-CN nanosheets combined with r-GO. In particular, the as prepared heterojunction shows a better photocatalytic degradation activity compared to pristine samples and the significant enhancement in the photocatalytic performance is mainly accredited to the large interfacial charge transition of photogenerated charge carriers under the visible light irradiation. Although the 2D/2D/2D heterojunction effectively hinders the charge carrier recombination resulting high photocatalytic activity with good stability. In addition, the r-GO supported LTH/ZnO/g-CN heterojunction shows high photo-stability after sequential experimental runs with no obvious change in the dye degradation process. Consequently, the role of active species was investigated over the r-GO/LTH/ZnO/g-CN heterojunction with the help of different scavengers.
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http://dx.doi.org/10.1016/j.envres.2021.111079DOI Listing
June 2021

Construction of magnetically recoverable ZnS-WO-CoFeO nanohybrid enriched photocatalyst for the degradation of MB dye under visible light irradiation.

Chemosphere 2021 Jun 19;273:129687. Epub 2021 Jan 19.

Department of Physics, Vellore Institute of Technology (Amaravati Campus), Amaravati, 522501, Guntur, Andhra Pradesh, India.

Easily recyclable photocatalysts have received considerable attention for their practical application, in order to address the wastewater treatments. Here, we report efficient and magnetically recyclable ZnS-WO-CoFeO nanohybrid prepared through wet impregnation method. The photophysical and optical properties of as-prepared photocatalysts was investigated by different spectroscopic techniques. The photocatalytic activity of as synthesized samples were assessed by the photodegradation of methylene blue (MB) dye under visible light irradiation. Amongst, ZnS-WO-CoFeO nanohybrid exhibit higher photodegradation activity than the other bare and hybrid samples. The enhanced light absorption and lower emission intensity provide the improved photocatalytic activity of ZnS-WO-CoFeO nanohybrid. The ZnS-WO-CoFeO nanohybrid exhibit excellent photostability after four consecutive cycles. The ferromagnetic behavior of the hybrid sample using easily recover from the dye solution using an external bar magnet.
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http://dx.doi.org/10.1016/j.chemosphere.2021.129687DOI Listing
June 2021
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