Interfacial Morphology Addresses Performance of Perovskite Solar Cells Based on Composite Hole Transporting Materials of Functionalized Reduced Graphene Oxide and P3HT

The development of novel hole transporting materials (HTMs) for perovskite solar cells (PSCs) that can enhance device's reproducibility is a largely pursued goal, even to the detriment of a very high efficiency, since it paves the way to an effective industrialization of this technology. In this work, we study the covalent functionalization of reduced graphene oxide (RGO) flakes with different organic functional groups with the aim of increasing the stability and homogeneity of their dispersion within a poly(3-hexylthiophene) (P3HT) HTM. The selected functional groups are indeed those recalling the two characteristic moieties present in P3HT, i.e., the thienyl and alkyl residues. After preparation and characterization of a number of functionalized RGO@P3HT blends, we test the two containing the highest percentage of dispersed RGO as HTMs in PSCs and compare their performance with that of pristine P3HT and of the standard Spiro-OMeTAD HTM. Results reveal the big influence of the morphology adopted by the single RGO flakes contained in the composite HTM in driving the final device performance and allow to distinguish one of these blends as a promising material for the fabrication of highly reproducible PSCs

Evaluation of the efficacy and safety of artemether-lumefantrine in the treatment of acute uncomplicated Plasmodium falciparum malaria in Nigerian infants and children

<p>Abstract</p> <p>Background</p> <p>The six-dose regimen of artemether-lumefantrine (AL) is now considered the gold standard for the treatment of uncomplicated <it>Plasmodium falciparum </it>malaria. There are few reports evaluating co-artemether in very young Nigerian infants and children. Results of the evaluation of the six-dose regimen in very young infants and children in Nigeria are presented in this report.</p> <p>Methods</p> <p>As part of a larger African study, this open label, non-comparative trial, assessed the efficacy and safety of six-dose regimen of AL tablets in 103 Nigerian infants and children weighing between five and 25 kg suffering from acute uncomplicated malaria. Treatment was administered under supervision over three days with children as in-patients. 12-lead ECG tracings were taken pre-treatment and at day 3.</p> <p>Results</p> <p>Ninety-three infants and children completed the study as stipulated by the protocol. Mean fever and parasite clearance times for the intent to treat population (ITT) were 24.9 h ± (1.28) and 26 h ± (4.14) and the corresponding figures for the per-protocol population (PP) were 19.24 h ± 13.9 and 25.62 h ± 11.25 respectively. Day 14 cure rates for the ITT and PP were 95.1% and 100% respectively while day 28 cure rates were 91.3% and 95.7% respectively. The overall PCR corrected day 28 cure rate was 95.1% for the ITT. The six-dose regimen of AL was well tolerated with no drug-related serious adverse events. Although six patients recorded a QTc prolongation of > 60 ms on D3 over D0 recording, no patient recorded a QTc interval > 500 ms.</p> <p>Conclusion</p> <p>The six-dose regimen of AL tablets is safe and effective for the treatment of acute uncomplicated malaria in Nigerian infants and children weighing between five and 25 kg.</p> <p>Trial registration</p> <p>NCT00709969</p

Elimination of the light soaking effect and performance enhancement in perovskite solar cells using a fullerene derivative

In this work, we investigate how electron extraction layers (EELs) with different dielectric constants affect the device performance and the light-soaking phenomenon in hybrid perovskite solar cells (HPSCs). Fulleropyrrolidine with a triethylene glycol monoethyl ether side chain (PTEG-1) having a dielectric constant of 5.9 is employed as an EEL in HPSCs. The commonly used fullerene derivative [60] PCBM, which has identical energy levels but a lower dielectric constant of 3.9, is used as a reference. The device using PTEG-1 as the EEL shows a negligible light soaking effect, with a power conversion efficiency (PCE) of 15.2% before light soaking and a minor increase to 15.7% after light soaking. In contrast, the device using [60] PCBM as the EEL shows severe light soaking, with the PCE improving from 3.8% to 11.7%. Photoluminescence spectroscopy and impedance spectroscopy measurements indicate that trap-assisted recombination at the interface between the hybrid perovskite and the EEL is the cause of the light soaking effect in HPSCs. The trap-assisted recombination is effectively suppressed at the perovskite/PTEG-1 interface, while severe trap assisted recombination takes place at the perovskite/[60] PCBM interface. We attributed these experimental findings to the fact that the higher dielectric constant of PTEG-1 helps to screen the recombination between the traps and free electrons. In addition, the electron donating side chains of PTEG-1 may also contribute to the passivation of the electron traps. As a consequence, the devices using PTEG-1 as the EEL display a considerable increase in the efficiency and a negligible light soaking effect

An overview of anti-diabetic plants used in Gabon: Pharmacology and Toxicology

© 2017 Elsevier B.V. All rights reserved.Ethnopharmacological relevance: The management of diabetes mellitus management in African communities, especially in Gabon, is not well established as more than 60% of population rely on traditional treatments as primary healthcare. The aim of this review was to collect and present the scientific evidence for the use of medicinal plants that are in currect by Gabonese traditional healers to manage diabetes or hyperglycaemia based here on the pharmacological and toxicological profiles of plants with anti-diabetic activity. There are presented in order to promote their therapeutic value, ensure a safer use by population and provide some bases for further study on high potential plants reviewed. Materials and methods: Ethnobotanical studies were sourced using databases such as Online Wiley library, Pubmed, Google Scholar, PROTA, books and unpublished data including Ph.D. and Master thesis, African and Asian journals. Keywords including ‘Diabetes’ ‘Gabon’ ‘Toxicity’ ‘Constituents’ ‘hyperglycaemia’ were used. Results: A total of 69 plants currently used in Gabon with potential anti-diabetic activity have been identified in the literature, all of which have been used in in vivo or in vitro studies. Most of the plants have been studied in human or animal models for their ability to reduce blood glucose, stimulate insulin secretion or inhibit carbohydrates enzymes. Active substances have been identified in 12 out of 69 plants outlined in this review, these include Allium cepa and Tabernanthe iboga. Only eight plants have their active substances tested for anti-diabetic activity and are suitables for further investigation. Toxicological data is scarce and is dose-related to the functional parameters of major organs such as kidney and liver. Conclusion: An in-depth understanding on the pharmacology and toxicology of Gabonese anti-diabetic plants is lacking yet there is a great scope for new treatments. With further research, the use of Gabonese anti-diabetic plants is important to ensure the safety of the diabetic patients in Gabon.Peer reviewedFinal Accepted Versio

The use of plants in the traditional management of diabetes in Nigeria: Pharmacological and toxicological considerations

Ethnopharmacological relevance: The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system. Materials and methods: Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. ‘Diabetes’ and ‘Nigeria’ were used as keywords for the primary searches; and then ‘Plant name – accepted or synonyms’, ‘Constituents’, ‘Drug interaction’ and/or ‘Toxicity’ for the secondary searches. Results: The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs. Conclusion: This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb–drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided

Improving outpatient medication counselling in hospital pharmacy settings: a behavioral analysis using the theoretical domains framework and behavior change wheel

Background : Despite the importance of medication counselling for patients, it is common knowledge that it is often sub - optimally carried out by pharmacy staff. While some interventions have been designed to help improve counselling, no study till date has used the Capability Opportunity and Motivation behavior model (COM - B) or Theoretical Domains Framework (TDF) as a basis for identifying evidence - based intervention strategies to improve medication counselling. Objective : To understand barrie rs/facilitators to optimal medication counselling by conducting a behavioral analysis using the COM - B model and TDF, and use the Behavior Change Wheel (BCW) as a basis for identifying evidence - based intervention strategies and policy categories that could be used to improve outpatient medication counselling by pharmacy staff in hospital settings located within Northwest Nigeria. Methods : Semi - structured interviews were used to collect data from 25 purposively sampled pharmacy staff working at eight major pu blic hospitals, from January till March 2020. Data from the interviews were then transcribed and deductively coded using the COM - B model and TDF. These findings were then used to identify areas requiring change, as well as the intervention type and policy functions required to support these changes. Results : Findings from the behavioral analysis revealed shortfalls in pharmacy staff capability, opportunity and motivation with res pect to outpatient medication counselling. To improve their counselling behavio rs, change was identified as necessary in eight TDF domains namely ‘knowledge’, ‘interpersonal skills’, ‘memory’ ‘environmental context’, ‘social influences’, ‘intentions’, ‘reinforceme nt’ and ‘beliefs about capabilities’. Seven intervention functions incl uding ‘education’, ‘training’, ‘modelling’, ‘enablement’ and ‘environmental restructuring’, in addition to three policy categories (‘guidelines’, ‘regulations’ and ‘environmental/social planning’) were also identified as relevant to future intervention des ign. Conclusions : Various factors were identified as affecting medication counselling by the pharmacy staff, with several of them requiring changes if counselling was to be improved upon. Multi - component interventions combining several of these interventi on function s are recommended for hospital authorities and other relevant stakeholders to improve outpatient medication counsellin

Guessability of standard pharmaceutical pictograms in members of the Nigerian public

Background: Pharmaceutical pictograms are standardized images used to visually convey medication instructions. Very little is known about the ability of Africans to interpret these images. Objectives: Thus, the aim of this study was to assess the guessability (ability to correctly guess meaning) of selected International Pharmaceutical Federation (FIP) and United States Pharmacopoeia (USP) pictograms in members of the Nigerian public. Methods: A cross-sectional survey was carried out between May and August 2021 on 400 randomly sampled members of Nigerian public. Selected pictograms (24 FIP and 22 USP pictograms) were grouped and printed on A3 sheets of paper which were used to interview members of the public who fulfilled the study's' eligibility criteria. Respondents were asked to guess the meanings of either the FIP or USP pictograms, and their answers written down verbatim. Descriptive and inferential statistics were used to report the data collected. Results: Four hundred respondents were interviewed, with 200 respondents each assessing the guessability of the FIP and USP pictograms. The guessability of assessed FIP pictograms ranged between 3.5 and 95%, while that for the USP pictograms was 27.5–97%. Eleven FIP and Thirteen USP pictograms respectively achieved the International Organization for Standardization (ISO) comprehensibility cutoff point of 67%. Guessing performance (the total number of pictograms correctly guessed by an individual) of respondents that assessed the FIP pictograms was significantly associated with their age (p = 0.044) and highest level of education completed (p = 0.003). For the USP pictograms, guessing performance was only significantly associated with the highest educational level completed (p < 0.001). Conclusions: Guessability of both pictogram types varied widely, but the guessability of the USP pictograms was generally better than that for the FIP pictograms. Many of the tested pictograms may however need to be redesigned before they can be correctly interpreted by members of the Nigerian public

Probing photoinduced electron-transfer in graphene-dye hybrid materials for DSSC

We investigated the photophysical properties of a newly synthesized hybrid material composed of a triphenylamine dye covalently bound to reduced graphene oxide, potentially relevant as a stable photosensitizer in dye-sensitized solar cells. The photophysical characterization has been carried out by means of fluorescence quenching and fluorescence lifetime measurements, complemented by Electron Paramagnetic Resonance (EPR) spectroscopy, aimed at the detailed description of the photoinduced processes occurring in the hybrid and in the mixed hybrid/N-doped TiO2 material. The combined optical/magnetic study unequivocally demonstrates a fast quenching of the dye excited state in the isolated hybrid and an efficient electron transfer to N-doped titania nanopowders. In the latter case, a metastable radical cation on the dye moiety is photogenerated and the corresponding negative charge, an electron, is trapped in defect sites of the doped semiconductor oxide. The spin distribution in the stable radical has been determined by EPR spectroscopy and correlated with DFT calculations

Comparative analgesic effects of paracetamol with paracetamol-caffeine formulation

This study was designed to evaluate the contribution of caffeine to analgesia in paracetamol-caffeine preparation. Analgesic properties were evaluated in mice using acetic acid-induced writhing and hot plate methods. In the acetic acid method, the test drugs were administered orally to the mice. After 30 min. all the mice received 0.7% aqueous solution of acetic acid (10ml/kg i.p) and writhing was counted for 30 min. after acid injection. The percentage inhibition was then determined. In the case of hot plate method, the mice were placed singly on a hot plate maintained at 45±0.50C before and at 15, 30, 45, 60 and 90 min. after administration of the tested drugs orally. The latency of nociceptive responses (time taken before the mouse jumped out of the hot plate) was measured each time the mouse was placed on the hot plate. The mean percentage maximum possible effect (% MPE) was determined. The results revealed dose dependent analgesic activities in both paracetamol alone and paracetamol-caffeine combination. The activities were significantly higher compared to the control which received normal saline (