Using risk prediction to case-find frail older people at risk of anticholinergic burden for Structured Medication Reviews: a qualitative study exploring the views and perspectives of primary care professionals

Introduction

Reviewing anticholinergic medicines is an important consideration in the safe care of frail older people. The cumulative effect of taking multiple anticholinergic medicines, known as anticholinergic burden (AB) (1), is associated with physical and cognitive decline, falls, and hospitalisation (2). There is a need to explore the development of integrated tools within clinical IT systems, to support safer prescribing. This includes the use of risk prediction, to case-find frail older patients at risk of AB for structured medication reviews (SMRs). However, using risk prediction in this context is a new concept, and perspectives of end-users in primary care are unknown.

Aim

To explore health care professionals’ (HCPs) views and perspectives of risk prediction, to case-find frail older people at risk of AB for SMRs, in order to inform future development and implementation.

Methods

In-depth, semi-structured interviews conducted virtually. Data analysis used the inductive thematic analysis method, using Nvivo 12. Recruitment involved advertising a flyer on social media, and snowball sampling. A purposive sample of twenty-five HCPs in primary care were interviewed, including pharmacy professionals, GPs, nurses, and a community-based geriatrician.

Results

Six core themes emerged as important factors for future development and implementation, and were mapped to the Theoretical Domains Framework: knowledge and skills, beliefs about capabilities and consequences, decision processes, professional role and identity, motivation and goals, and environmental context and resources. HCPs supported the concept of risk prediction to case-find patients, particularly for more efficient utilisation of health resources. However, despite feeling motivated to reduce anticholinergic prescribing in frail older people, deprescribing in this area was deemed complex, with multiple barriers. A case-finding tool was perceived to be important, but considered only one element of a multi-factorial approach towards safer prescribing, with various other factors influencing decision making processes. HCPs felt prescribing decisions should be made holistically, and not influenced entirely by the outputs of a validated risk prediction tool. Lacking a deeper understanding of AB and frailty was also expressed, with further education and upskilling in deprescribing deemed essential to support uptake. There were concerns that proactive case-finding would lead to an unsustainable number of SMRs. Potential facilitators of future uptake were also identified, including the expansion of the primary care workforce, and financial incentivisation for deprescribing.

Conclusion

The concept of a future risk prediction tool was seen positively by HCPs, supporting a case for its development to facilitate the case-finding of at-risk patients for SMRs, in line with NHS policy. However, this study has identified multiple factors which could influence future uptake, having implications for the design and implementation stages. Strengths include the use of inductive thematic analysis, and how in-depth interviews were conducted with a variety of HCPs. Seeking views and perspectives of a risk prediction tool that is currently not in existence has its limitations however, but indeed are invaluable as early insights. HCPs as potential end-users, in addition to patients and the public, are crucial to future developmental phases and must be included as partners in any further research efforts.

References

(1) Hilmer SN, Gnjidic D. Prescribing for frail older people. Aust Prescr. 2017;40(5):174-178. doi:10.18773/austprescr.2017.055

(2) Welsh TJ, van der Wardt V, Ojo G, Gordon AL, Gladman JRF. Anticholinergic Drug Burden Tools/Scales and Adverse Outcomes in Different Clinical Settings: A Systematic Review of Reviews. Drugs Aging. 2018 Jun;35(6):523-538. doi: 10.1007/s40266-018-0549-z. PMID: 29736815.

Funding disclaimer: This research was funded by the National Institute for Health Research (NIHR) Yorkshire and Humber Patient Safety Translational Research Centre (NIHR YHPSTRC). The views expressed in this article are those of the author(s) and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care.

A255 INCREASED ENERGY EXPENDITURE AND REDUCED EXERCISE CAPACITY IN CELIAC DISEASE PATIENTS ON A GLUTEN-FREE DIET

Background

Celiac disease (CeD) patients often exhibit impaired nutritional status due to nutrient malabsorption and altered metabolism. Accurate clinical assessment of malnutrition, muscle function and energy requirements are thus essential to prevent and treat malnutrition. Indirect calorimetry (IC) is the most accurate method to measure energy needs, but it is underutilized in outpatient settings.

Aims

To assess the use of IC testing in estimating the resting energy expenditure and exercise-related energy utilization in treated CeD patients compared to patients with other gastrointestinal (GI) conditions.

Methods

Adult patients attending the Celiac and Nutrition Clinic at McMaster University that underwent rest and exercise testing as a part of their nutritional assessment were enrolled. CeD diagnosis was based on positive CeD serology and confirmed by biopsy, and all of them were on a GFD for at least 6 months. Patients with inflammatory bowel disease (IBD), functional gastrointestinal disorders (FGID) and undernutrition due to other causes (UN) were included as controls. Resting energy expenditure was assessed using 3

methods

1) predictive formula (25kcal/kg), 2) Harris Benedict and 3) estimation of VO2 by IC. Exercise capacity and energy expenditure (EE) during exercise was estimated at baseline, moderate and maximum exercise. Statistical analysis was performed using SPSS. ANOVA with Bonferroni corrections and Chi2 test were used to assess differences between continuous and categorical variables, respectively.

Results

A total of 66 patients (CeD n=24; IBD n=15; FGID n=17; UN n=10) were included in the analysis. The REE of GI patients measured using the HB equation and the predictive formula were significantly underestimated compared to IC [Mean Difference (MD)=229 kcal/day p=0.03 and MD=365 kcal/day p<0.001, respectively]. The EE during exercise increased with intensity of exercise. CeD patients had the highest EE during moderate and strenuous exercise (Mean EE = 286 kcal/h and 494 kcal/h respectively) compared to patients with other GI conditions (Moderate and Strenuous for IBD= 218kcal/h and 373kcal/h; for FGIDs 296kcal/hand 467kcal/h, for UN, Mean EE = 181kcal/h and 294kcal/h). Exercise capacity was reduced in CeD compared to predicted exercise capacity (Mean = 86% predicted work capacity, range 72.5–107%), but was significantly higher than IBD (86% vs 73%; p=0.65) and UN patients (86% vs 46%; p=0.004).

Conclusions

Increased energy consumption and reduced exercise capacity is suggestive of chronic impaired nutritional status in treated CeD patients. Future studies with larger sample sizes are needed to understand whether incorporating accurate estimations of energy expenditure in nutritional practices can improve CeD outcomes.

Funding Agencies

CAG

A194 THE ADDITION OF DEAMIDATED GLIADIN PEPTIDE TO TISSUE TRANSGLUTAMINASE ANTIBODIES DOES NOT INCREASE THE ODDS OF CELIAC DISEASE DIAGNOSIS IN AN IGA SUFFICIENT POPULATION

Background

Previous studies proposed that the combination of IgA anti-tissue transglutaminase 2 IgA (TTG) and IgG deamidated gliadin peptide IgG (DGP) antibodies increases celiac disease (CeD) detection rates. However, this remains controversial.

Aims

To evaluate the performance of adding DGP to TTG antibodies, for the diagnosis of celiac disease (CeD) in the immunoglobulin A (IgA)-sufficient population.

Methods

We included consecutive patients with suspected CeD who had both TTG and DGP serology performed simultaneously from 2017–2020 in Hamilton, Canada. Chart review was performed by 3 reviewers to extract data on biopsies, diagnosis of CeD and genetic HLA-DQ2/DQ8. CeD was defined as positive serology (either TTG and/or DGP) and villous atrophy in duodenal biopsies (≥Marsh-3a). A case was defined as an instance of TTG and DGP performed at a single timepoint. A single patient could have represented multiple cases if TTG and DGP were measured at multiple time points. Sensitivity, specificity, negative and positive predictive values were calculated, and ROC curves were generated. Diagnostic odds ratios (DOR) assessed the performance of each serological strategy compared to duodenal biopsies.

Results

There were 580 patients constituting 823 cases that met inclusion criteria, of whom 441 had CeD. IgA-deficient patients (n=100) were excluded. Of the 723 cases remaining, 337 (214 adult;123 pediatric) had serology performed at the time of CeD diagnosis. TTG increased the odds of CeD diagnosis compared with DGP, Diagnostic Odds Ratio (DOR)=53.22 (95% CI 22.63–119.80) vs DOR=21.28 (95% CI 10.67–42.46). The addition of DGP to TTG did not increase the odds of CeD diagnosis [DGP+TTG DOR=51.39 (95% CI 19.36–135.61) vs TTG alone DOR=53.22 (95% CI 22.63–119.80)]. There were 37 discordant cases where only one of either TTG or DGP was positive. HLA-DQ2/DQ8 were absent in 2/9 cases with isolated increased DGP. Among the discordant cases, TTG outperformed DGP (DOR TTG= 4.29; 95% CI 1.09–16.83 vs DOR DGP=0.23; 95% CI 0.06–0.92).

Conclusions

In the IgA-sufficient population, the addition of DGP to TTG testing does not increase the diagnostic accuracy of CeD serologic screening. This has implications in health-care costs as false positive results prompt further investigations. Given these findings, larger prospective studies should be completed prior to adding DGP antibodies to routine TTG serology.

Funding Agencies

None

Au nanoparticles decorated polypyrrole-carbon black/g-C3N4 nanocomposite as ultrafast and efficient visible light photocatalyst

Modification and bandgap engineering are proposed to be extremely significant in improving the photocatalytic activity of novel photocatalysts. The current research focused on the fabrication of ultrafast and efficient visible light-responsive ternary photocatalyst containing g-C₃N₄ nanostructures in conjugation with polypyrrole doped carbon black (PPy-C) and gold (Au) nanoparticles by highly effectual, simple, and straightforward methodology. Various analytical techniques like XRD, FESEM, TEM, XPS, FTIR, and UV-Vis spectroscopy were applied for characterization purposes. The XRD and XPS results confirmed the successful creation of a nanocomposite framework among Au, PPy-C and g-C₃N₄. The TEM images revealed that bare g-C₃N₄ holds sheets or layered graphitic structure with sizes ranging from 100 to 300 nm. The sponge-like PPy-C network intermingled perfectly with g-C₃N₄ sheets along with homogeneously distributed 5-15 nm Au nanoparticles. The band gap energy (E_g) for bare g-C₃N₄, PPy-C/g-C₃N₄ and Au@PPy-C/g-C₃N₄ nanocomposites were found to be 2.74, 2.68, and 2.60 eV, respectively. The photocatalytic activity for all newly designed photocatalysts have been assessed during the degradation of insecticide Imidacloprid and methylene blue (MB) dye, where Au@PPy-C/C₃N₄ was found to be extremely efficient with ultrafast removal of both imidacloprid and MB in just 25 min of visible light irradiation. It was revealed that the Au@PPy-C/g-C₃N₄ ternary photocatalyst removed 96.0% of target analyte imidacloprid, which is ⁓ 2.91 times more efficient than bare g-C₃N₄ in treating imidacloprid. This report provides a distinctly promising, highly effectual and straightforward route to destruct extremely toxic and notorious pollutants and opens a new gateway in the present challenging scenario of environmental concerns.

The new challenge of partial oxidation of methane over Fe2O3/NaY and Fe3O4/NaY heterogeneous catalysts

As one of the most important gases that abundantly contribute to air pollution, methane becomes the most leading gas that challenges researchers to utilize it in more functional products such as methanol. In this study, the conversion process involved iron oxide species supported by sodium Y (NaY-Z) zeolite as the catalysts. This work highlighted the preparation of Fe₂O₃ and Fe₃O₄ modified NaY zeolite to investigate their catalytic performance on partial oxidation of methane to methanol, with trace amount of oxygen (0.5% in N₂), in a batch reactor. The as-prepared catalysts were characterized using FTIR, XRD, SEM, and BET. The structure of NaY zeolite and its modified catalysts were confirmed. The pristine NaY-Z shows the highest activity followed by Fe₂O₃/NaY-3.52 (3.52 wt% of Fe loading) with high selectivity to formaldehyde (80%). Very high selectivity (∼100%) towards methanol was observed in the reactions on Fe₂O₃/NaY-1.70 and Fe₃O₄/NaY-2.55 catalysts, although the total amount of product was decreased. It was noticeable that Fe₃O₄/NaY-3.22 is an active catalyst and has good selectivity to methanol (70%).

Insight Cross-talk between p53 and Toll-like Receptor

Toll-like receptors (TLR) are one of the most-studied receptors for their role in innate immunity. TLRs are reported to binds with conserved pathogen-associated molecular patterns (PAMPS). TLRs and PAMPS interaction leads to several downstream proteins' activation, which further signaled to the various transcription factors. Moreover, these transcription factors play an important role in synthesizing proteins that control cellular immunity. Various TLR proteins have been reported in humans as well several other organisms. Studies show that apart from inducing innate immunity, TLRs have also played an important role in the induction of many proteins, and protein networks associated with initiation apoptosis and cancer prevention. P53 is one of the most important and widely studied proteins. Moreover, various experimental studies suggest that p53 has an important role as tumor suppressor. It is reported that more than 50% of cancerous growth are associated with the mutation of p53. It acts as transcription activator for several proteins that are mostly associated with glycolysis, cell cycle, cell differentiation, apoptosis and cancer. In the present review, we present an insight cross-talk between p53 and Toll-like receptor. In addition, the well-characterized role of p53 in the regulation of the immune system is studied, which would provide a new insight to the broad understanding of p53 role in human biology. Moreover, the association of the p53 and TLRs can lead to therapeutic interventions.

Rediscovery of Kurians types of Hymenoptera at Forest Research Institute, Dehradun, India with notes on Indian bethylid fauna

The types specimens of many taxa described by Chandy Kurian were considered lost for many years, which prevented the recognition of the species delimited by him. Fifty holotypes have been rediscovered in the National Forest Insect Collection of Forest Research Institute, Dehradun, Uttarakhand, India. Forty-five types belong to Bethylidae (Cephalonomia tritici, Chlorepyris biharina, C. mackenziei, C. pusana, C. sanctipauli, Epyris agraensis, E. agrensis, E. bombayensis, E. delhiensis, E. duni, E. duttai, E. indicae, E. manii, E. patnae, E. pusae, E. shishami, Goniozus ahmeadi, G. chatterjii, G. chowdhari, G. hybleae, G. lygropiae, G. madrassippattanami, G. marasmi, G. mori, G. morindae, G. nephoterycis, G. nilamburensis, G. pulveriae, G. salvadorae, G. sanctijohannis, G. thalasodi, Laelius agraensis, Odontepyris argyriae, O. batrae, O. cirphi, O. hypsipylae, O. indicus, Pristepyris agraensis, Pristocera govindrami, Sclerodermus delhiensis, Sc. hardwickiae, Sc. mori, Sc. raonis, Sulcomesitius bahaduri and Su. duni), one to Chrysididae (Lustrina assamensis), three to Dryinidae (Lestodryinus guptai, Neodryinus karnalensis and N. pusae) and one to Formicidae (Neoclystopsenella luffae). Six new combinations are proposed: Epyris mackenziei comb. nov. from Chlorepyris; Formosiepyris agraensis comb. nov. from Epyris; Holepyris raonis comb. nov. from Sclerodermus; Holepyris patnae comb. nov. from Epyris; Pristocera agraensis comb. nov. from Pristepyris; and Trachepyris sanctipauli comb. nov. from Chlorepyris. We also provide updated diagnoses, as well as detailed remarks and photographs for all types rediscovered. In addition, we provide researchers worldwide with valuable taxonomic information for the Bethylidae, Chrysididae, Dryinidae and Formicidae described by Kurian. A review of Bethylidae from India and a tribute to Chandy Kurian has also been provided.

Variation in chemical composition and sources of PM2.5 during the COVID-19 lockdown in Delhi

The Government of India (GOI) announced a nationwide lockdown starting 25th March 2020 to contain the spread of COVID-19, leading to an unprecedented decline in anthropogenic activities and, in turn, improvements in ambient air quality. This is the first study to focus on highly time-resolved chemical speciation and source apportionment of PM_2.5 to assess the impact of the lockdown and subsequent relaxations on the sources of ambient PM_2.5 in Delhi, India. The elemental, organic, and black carbon fractions of PM_2.5 were measured at the IIT Delhi campus from February 2020 to May 2020. We report source apportionment results using positive matrix factorization (PMF) of organic and elemental fractions of PM_2.5 during the different phases of the lockdown. The resolved sources such as vehicular emissions, domestic coal combustion, and semi-volatile oxygenated organic aerosol (SVOOA) were found to decrease by 96%, 95%, and 86%, respectively, during lockdown phase-1 as compared to pre-lockdown. An unforeseen rise in O₃ concentrations with declining NO_x levels was observed, similar to other parts of the globe, leading to the low-volatility oxygenated organic aerosols (LVOOA) increasing to almost double the pre-lockdown concentrations during the last phase of the lockdown. The effect of the lockdown was found to be less pronounced on other resolved sources like secondary chloride, power plants, dust-related, hydrocarbon-like organic aerosols (HOA), and biomass burning related emissions, which were also swayed by the changing meteorological conditions during the four lockdown phases. The results presented in this study provide a basis for future emission control strategies, quantifying the extent to which constraining certain anthropogenic activities can ameliorate the ambient air. These results have direct relevance to not only Delhi but the entire Indo-Gangetic plain (IGP), citing similar geographical and meteorological conditions common to the region along with overlapping regional emission sources. SUMMARY OF MAIN FINDINGS: We identify sources like vehicular emissions, domestic coal combustion, and semi-volatile oxygenated organic aerosol (SVOOA) to be severely impacted by the lockdown, whereas ozone levels and, in turn, low-volatility oxygenated organic aerosols (LVOOA) rise by more than 95% compared to the pre-lockdown concentrations during the last phase of the lockdown. However, other sources resolved in this study, like secondary chloride, power plants, dust-related, hydrocarbon-like organic aerosols (HOA), and biomass burning related emissions, were mainly driven by the changes in the meteorological conditions rather than the lockdown.

Immersion-plated palladium nanoparticles onto meso-porous silicon layer as novel SERS substrate for sensitive detection of imidacloprid pesticide

Herein, we demonstrate the effectiveness of surface-enhanced Raman scattering (SERS) to detect trace concentration of potentially harmful imidacloprid pesticide. To achieve this ultimate objective, a rapid and highly effective methodology for the fabrication of active and stable porous silicon (PSi) plated palladium nanoparticles (PdNPs) SERS substrates by an electrochemical anodization and immersion plating routes was applied. The PSi layers were fabricated by the electrochemical anodization of a silicon wafer in ethanoic fluoride solution, followed by uniformly deposition of PdNPs via a simple immersion plating technique. The structural features and morphology of fabricated frameworks of PSi-Pd NPs have been investigated by field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra. The PSi substrate demonstrates a meso-porous morphology with good distribution, good pore density and average pore sizes around 20 nm. The SERS performance of Si-Pd NPs and PSi-Pd NPs substrates has been examined taking imidacloprid (an insecticide) as a target analyte. The SERS signal of imidacloprid using PSi-Pd NPs substrate exhibited immense enhancement compared to the Si-Pd NPs substrate. The active substrate revealed excellent detectable performance with a concentration as low as 10^-9 M imidacloprid and an enhancement factor (EF) of 1.2 × 10⁵. This large EF is fundamentally ascribed to the combined effect of the electromagnetic improvement and charge transfer mechanisms. Additionally, no aging effect was observed for the present substrates kept in air for two weeks. Striking enhancement in Raman spectral signals obtained with the current PSi-Pd NPs substrates can provide a simple and smooth platform towards the sensitive detection of various target analytes.

Case of paediatric catatonia precipitated by antipsychotic withdrawal in a child with autism spectrum disorder

A 13-year-old girl with moderate intellectual disability and autism spectrum disorder (ASD) was admitted to the paediatric high-dependency unit following an 8-week history of altered mental status and motor behaviour. Her symptoms emerged followed shortly after discontinuation of risperidone, an atypical antipsychotic previously commenced to manage disruptive behaviour associated with ASD. On physical examination, the patient presented with negativism, grimacing, automatic obedience, waxy flexibility and ambitendency. Blood tests, neuroimaging and lumbar puncture failed to reveal an acute infectious or neurological precipitant. She responded immediately to a trial of intramuscular lorazepam titrated to a total daily dose of 12 mg. This case presents challenges of accurately diagnosing and managing catatonic symptoms in adolescent patients with ASD. We also discuss the potential risk of precipitating catatonia following the discontinuation of antipsychotic treatment that has been prescribed for a prolonged duration.

Gold nanoparticles plated porous silicon nanopowder for nonenzymatic voltammetric detection of hydrogen peroxide

A voltammetric approach was developed for the selective and sensitive determination of hydrogen peroxide using Au plated porous silicon (PSi) nanopowder modified glassy carbon electrode (GCE). The AuNPs-PSi hybrid structure was synthesized via stain etching procedure followed by an immersion plating method to deposit AuNPs onto PSi via a simple galvanic displacement reaction with no external reducing agent to convert Au³⁺ to Au⁰. The as-fabricated AuNPs-PSi catalyst was successfully characterized by XRD, Raman, FTIR, XPS, SEM, TEM and EDS techniques. Well crystalline nature of the as-fabricated hybrid structure with AuNPs size ranging from 5 to 40 nm was observed. The specific surface area and total pore volume for both PSi and AuNPs plated PSi were evaluated using N₂ adsorption isotherm technique. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were applied to investigate the catalytic efficiency of AuNPs-PSi modified electrode compared to pure PSi/GCE and unmodified GCE. The sensing performance of the active material modified GCE was thoroughly examined with linear sweep voltammetry (LSV) and square wave voltammetry (SWV) techniques. The AuNPs-PSi/GCE exhibited a remarkable linear dynamic range between 2.0 and 13.81 mM (for LSV) and 0.5-6.91 mM for (SWV) with high sensitivity and low detection limit of 10.65 μAmM^-1cm^-2 and 14.84 μM for LSV, whereas 10.41 μAmM^-1cm^-2 and 15.16 μM using SWV techniques, respectively. The fabricated sensor electrode showed excellent anti-interfering ability in the presence of several common biomolecules as well as demonstrated good operational stability and reproducibility with low relative standard deviation. Moreover, the modified electrode showed acceptable recovery of H₂O₂ in a real sample analysis. Thus, the developed AuNPs-PSi hybrid nanomaterial represents an excellent electrocatalyst for the efficient detection and quantification of H₂O₂ by the electrochemical approach.

[Bone marrow fibrosis in primary myelofibrosis in relation to myelodysplasia- and age-related mutations of hematopoietic cells]

Besides histopathological findings, there are no indicators of increased risk for fibrotic progression in myeloproliferative neoplasms (MPNs). Age-related clonal hematopoiesis (ARCH) or clonal hematopoiesis of indetermined potential (CHIP) are frequent findings in the elderly and combinations with MPN driver mutations (JAK2, MPL, and CALR) have been described. To determine the impact of ARCH/CHIP-related mutations for the development of fibrosis in primary myelofibrosis (PMF), the mutational status of cases with fibrotic progression from grade 0 to grade 2/3 (n = 77) as evidenced by follow-up bone marrow biopsies (median 6.2 years) was compared to prefibrotic PMF samples without the development of fibrosis (n = 27; median follow-up 7.3 years). Frequent ARCH/CHIP-associated mutations (TET2, ASXL1, DNMT3A) demonstrable at presentation were not connected with fibrotic progression. However, mutations that are rarely found in ARCH/CHIP (SRSF2, U2AF1, SF3B1, IDH1/2, and EZH2) were present in 24.7% of cases with later development of fibrosis and not detectable in cases staying free from fibrosis (P = 0.0028). Determination of tumor mutational burden (TMB) in a subgroup of cases (n = 32) did not show significant differences (7.68 mutations/MB vs. 6.85 mutations/MB). We conclude that mutations rarely found in ARCH/CHIP provide an independent risk factor for rapid fibrotic progression (median 2.0 years) when already manifest at first presentation.

Short-course modified regimen intrapleural alteplase and pulmozyme (DNase) in pleural infection

Pleural infection is a common clinical condition leading to hospitalisation. In the last decade, advances in pleural research have led to a paradigm shift in the treatment of complex effusion from a surgical approach to a less invasive non-surgical approach using a combination of intrapleural fibrinolytics and pulmozyme (DNase). We report 3 patients with pleural infection. Intercostal chest catheter failed to drain the complex effusion. They were subsequently treated with a modified short-course regimen of alteplase and DNase. They received 3 cycles of 16 mg alteplase with 5 mg DNase each within 24 hours and all three had a favourable outcome with no adverse effects. This modified regimen appears effective with good safety profile and adds to the current literature on the safety and effectiveness of different dose combinations of alteplase and DNase.

Doping Strontium into Neodymium Manganites Nanocomposites for Enhanced Visible light Driven Photocatalysis

Nd_1-xSr_xMnO₃ nanocomposites perovskites were synthesized using sol gel method at different Sr content x = 0.3, 0.5, 0.7, and 0.9. The photocatalytic performance of the Nd_1-xSr_xMnO₃ nanocomposites for photodegradation of Acridine orange dye (AO) was evaluated over visible light illumination. The single phase of orthorhombic pbnm was formed for x = 0.3 and 0.5; however monoclinic and orthorhombic were observed at x = 0.7 and 0.9. The Energy gap of the Nd_1-xSr_xMnO₃ nanocomposites were estimated for all concentrations to be in the range of 3 ± 0.05 eV. The photocatalytic efficiency of Nd_0.3Sr_0.7MnO₃ nanocomposite was 95% of the initial AO dye concentration within 3 h illumination time. The linear increase of the photodegradation rate was found in our samples as a result of the increase of Sr contents from 0.3 to 0.7wt %. Interestingly, the Nd_0.3Sr_0.7MnO₃ content has the highest degradation rate of AO which is two times faster than undoped NdMnO₃. This superior behavior in photocatalytic activity of Nd_0.3Sr_0.7MnO₃ nanocomposite emerges from large surface area, structural anisotropy, and small particle size. These findings shows convincingly that the Nd_1-xSr_xMnO₃ photocatalysts possess great promise for visible light driven photodegradation of AO dye.