59 research outputs found

    Exposure-response relationship of residential dampness and mold damage with severe lower respiratory tract infections among under-five children in Nigeria

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    Background: Previous epidemiological studies demonstrated an increased risk of respiratory health effects in children and adults exposed to dampness or mold. This study investigated associations of quantitative indicators of indoor dampness and mold exposure with severe lower respiratory tract infections (LRTI) among children aged 1-59 months in Ibadan, Nigeria. Methods: In-home visits were conducted among 178 children hospitalized with LRTI matched by age (±3 months), sex, and geographical location with 180 community-based children without LRTI. Trained study staff evaluated the indoor environment using a standardized home walkthrough checklist and measured visible dampness and mold damage. Damp-moldy Index (DMI) was also estimated to quantify the level of exposure. Exposure-response relationships of dampness and mold exposure with severe LRTI were assessed using multivariable restricted cubic spline regression models adjusting for relevant child, housing, and environmental characteristics. Results: Severe LRTI cases were more often male than female (61.8%), and the overall mean (SD) age was 7.3 (1.35) months. Children exposed to dampness <0.3 m2 (odds ratio [OR] = 2.11; 95% confidence interval [CI] = 1.05, 4.36), and between 0.3 and 1.0 m2 (OR = 2.34; 95% CI = 1.01, 7.32), had a higher odds of severe LRTI compared with children not exposed to dampness. The restricted cubic spline showed a linear exposure-response association between severe LRTI and residential dampness (P < 0.001) but a nonlinear relationship with DMI (P = 0.01). Conclusions: Residential dampness and DMI were exposure-dependently associated with higher odds of severe LRTI among under-five children. If observed relationships were causal, public health intervention strategies targeted at reducing residential dampness are critically important to mitigate the burden of severe LRTI among under-five children

    Indoor bacterial and fungal aerosols as predictors of lower respiratory tract infections among under-five children in Ibadan, Nigeria

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    Background: This study aimed to investigate the association between exposure to diverse indoor microbial aerosols and lower respiratory tract infections (LRTI) among children aged 1 to 59 months in Ibadan, Nigeria. Methods: One hundred and seventy-eight (178) hospital-based LRTI cases among under-five children were matched for age (± 3 months), sex and geographical location with 180 community-based controls (under-five children without LRTI). Following consent from caregivers of eligible participants, a child’s health questionnaire, clinical proforma and standardized home-walkthrough checklist were used to collect data. Participant homes were visited and sampled for indoor microbial exposures using active sampling approach by Anderson sampler. Indoor microbial count (IMC), total bacterial count (TBC), and total fungal count (TFC) were estimated and dichotomized into high (> median) and low (≤ median) exposures. Alpha diversity measures including richness (R), Shannon (H) and Simpson (D) indices were also estimated. Conditional logistic regression models were used to test association between exposure to indoor microbial aerosols and LRTI risk among under-five children. Results: Significantly higher bacterial and fungal diversities were found in homes of cases (R = 3.00; H = 1.04; D = 2.67 and R = 2.56; H = 0.82; D = 2.33) than homes of controls (R = 2.00; H = 0.64; D = 1.80 and R = 1.89; H = 0.55; D = 1.88) p < 0.001, respectively. In the multivariate models, higher categories of exposure to IMC (aOR = 2.67, 95% CI 1.44–4.97), TBC (aOR = 2.51, 95% CI 1.36–4.65), TFC (aOR = 2.75, 95% CI 1.54–4.89), bacterial diversity (aOR = 1.87, 95% CI 1.08–3.24) and fungal diversity (aOR = 3.00, 95% CI 1.55–5.79) were independently associated with LRTI risk among under-five children. Conclusions: This study suggests an increased risk of LRTI when children under the age of five years are exposed to high levels of indoor microbial aerosols

    High-performance aqueous asymmetric electrochemical capacitors based on graphene oxide/cobalt(ii)-tetrapyrazinoporphyrazine hybrids

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    A novel asymmetric electrochemical capacitor (AEC) with high energy and power densities has been developed using a graphene oxide/cobalt(II)tetrapyrazinoporphyrazine composite (GO/CoTPyzPz) as the positive electrode and graphene oxide/carbon black (GO/CB) as the negative electrode in a neutral aqueous Na2SO4 electrolyte. The excellent specific capacitance, energy and power densities ( 500 F g 1, 44 W h kg 1 and 31 kW kg 1) coupled with long cycle life, excellent short response time, and low equivalent series resistance clearly indicate that this new material has great potential for the development of low-cost and ‘green’ aqueous AECs that operate at high energy and power densities. Interestingly, the energy density of the GO/CoTPyzPz//GOCB based AEC falls within the range usually observed for nickel metal hydride (NiMH) batteries (30–100 W h kg 1), but more importantly, shows better power performance than NiMH batteries (0.25–1 kW kg 1) widely used in hybrid vehicles such as Toyota Prius and Honda Insight.The University of Pretoria, CSIR and NRF Nanotechnology flagship programme (K.I.O), and the US National Science Foundation (CHE-1012258 and DMR-0804049, S.W.C.).http://www.rsc.org/MaterialsAam201

    Carbon nanotube-enhanced photoelectrochemical properties of metallo-octacarboxyphthalocyanines

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    The photoelectrochemistry of metallo-octacarboxyphthalocyanines (MOCPc, where M = Zn or Si(OH)2) integrated with MWCNTs for the development of dye-sensitized solar cells (DSSCs) is reported. The DSSC performance (obtained from the photo-chronoamperometric and photo-impedimetric data) decreased as ZnOCPc > (OH)2SiOCPc. The incorporation of the MWCNTs on the surface of the TiO2 film (MOCPc–MWCNT systems) gave higher photocurrent density than the bare MOCPc complexes. Also, from the EIS results, the MOCPc–MWCNT hybrids gave faster charge transport kinetics (approximately three times faster) compared to the bare MOCPc complexes. The electron lifetime was slightly longer (ca. 6 ms) at the ZnOCPc systems than at the (OH)2SiOCPc system (ca. 4 ms) meaning that the presence of the MWCNTs on the surface of the TiO2 film did not show any significant improvement on preventing charge recombination process

    Association of childhood pulmonary tuberculosis with exposure to indoor air pollution: a case control study

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    Abstract Background Crude measures of exposure to indicate indoor air pollution have been associated with the increased risk for acquiring tuberculosis. Our study aimed to determine an association between childhood pulmonary tuberculosis (PTB) and exposure to indoor air pollution (IAP), based on crude exposure predictors and directly sampled and modelled pollutant concentrations. Methods In this case control study, children diagnosed with PTB were compared to children without PTB. Questionnaires about children’s health; and house characteristics and activities (including household air pollution) and secondhand smoke (SHS) exposure were administered to caregivers of participants. A subset of the participants’ homes was sampled for measurements of PM10 over a 24-h period (n = 105), and NO2 over a period of 2 to 3 weeks (n = 82). IAP concentrations of PM10 and NO2 were estimated in the remaining homes using predictive models. Logistic regression was used to look for association between IAP concentrations, crude measures of IAP, and PTB. Results Of the 234 participants, 107 were cases and 127 were controls. Pollutants concentrations (μg/m3) for were PM10 median: 48 (range: 6.6–241) and NO2 median: 16.7 (range: 4.5–55). Day-to-day variability within- household was large. In multivariate models adjusted for age, sex, socioeconomic status, TB contact and HIV status, the crude exposure measures of pollution viz. cooking fuel type (clean or dirty fuel) and SHS showed positive non-significant associations with PTB. Presence of dampness in the household was a significant risk factor for childhood TB acquisition with aOR of 2.4 (95% CI: 1.1–5.0). The crude exposure predictors of indoor air pollution are less influenced by day-to-day variability. No risk was observed between pollutant concentrations and PTB in children for PM10 and NO2. Conclusion Our study suggests increased risk of childhood tuberculosis disease when children are exposed to SHS, dirty cooking fuel, and dampness in their homes. Yet, HIV status, age and TB contact are the most important risk factors of childhood PTB in this population

    Microwave Irradiation Controls the Manganese Oxidation States of Nanostructured Li[Li0.2Mn0.52Ni0.13Co0.13Al0.02]O 2 Layered Cathode Materials for High Performance Lithium Ion Batteries

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    A hybrid synthesis procedure, combining microwave irradiation and conventional annealing process, is described for the preparation of lithium-rich manganese-rich cathode materials, Li[Li0.2Mn0.54Ni0.13Co0.13]O2 (LMNC) and its aluminum-doped counterpart, Li[Li0.2Mn0.52Ni0.13Co0.13Al0.02]O2 (LMNCA). Essentially, this study interrogates the structure and electrochemistry of these layered cathode materials when subjected to microwave irradiation (these microwave-based produced are abbreviated herein as LMNC-mic andLMNCA-mic). The nanoparticulate nature of these layered cathode materials were confirmed by SEM. The crystallinity and layeredness were determined from the XRD analysis. The XPS measurements proved a definite change in the oxidation states of the manganese due to microwave irradiation. The galvanostatic charge-discharge characterization showed that the aluminum-doped cathode material obtained with the assistance of microwave irradiation has superior electrochemical properties. In summary, the electrochemical performance of these cathode materials produced with and without the assistance of microwave irradiation decreased as follows: LMNCAmic > LMNCA > LMNCmic > LMNC.CSIR, South Africa’s Department of Science and Technology (DST) and National Research Foundation (NRF) under the “Nanotechnology Flagship Programme” (Grant No: 69849).http://jes.ecsdl.orghb201

    Quality measures for palliative care in patients living with cancer in low- and middle-income countries: a scoping review protocol

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    Abstract Introduction Quality assessment is a critical component of determining the value of medical services, including palliative care. The utilisation of palliative care quality measures could assist in assessing the degree to which patients living with cancer conform to best practice of palliative care, identifying gaps and monitoring changes in cancer care delivery models in different setting. This scoping review aims to map the available data on the usage of palliative care quality indicators that are relevant to cancer patients in low- and middle-income countries (LMICs). Methods To structure this study, we will use the framework developed by Arksey and O’Malley, the Levac et al. recommendations and the Joanna Briggs Institute recommendations. We will search EBSCOHost, Web of Science, ProQuest One Academic, MEDLINE and Google Scholar for evidence on palliative care quality measures applicable for patients living with cancer published from inception till 2022. We will search grey literature in the form of dissertations, conference proceedings and websites of international organisations such as the World Health Organisation (WHO) reporting palliative care quality measures applicable to patients living with cancer in LMICs. Discussion The purpose of this study is to establish the extent of existing research on the palliative care quality measures in LMICs. Although palliative care is still a new phenomenon, understanding of the palliative care quality measures applicable for cancer patients will assist to improve care across all components of health systems. Ethics and dissemination No ethical approval is required for the study as the data collection and results of the proposed scoping review will be conducted and disseminated electronically using peer-reviewed journals, print and presentations at scientific conferences and stakeholder presentations

    Association of indoor microbial aerosols with respiratory symptoms among under-five children: a systematic review and meta-analysis

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    BACKGROUND: Despite the recognition of the importance of indoor microbial exposures on children's health, the role of different microbial agents in development and aggravation of respiratory symptoms and diseases is only poorly understood. This study aimed to assess whether exposure to microbial aerosols within the indoor environment are associated with respiratory symptoms among children under-5 years of age. METHODS: A systematic literature search was conducted on PubMed, Web of Science, GreenFILE, ScienceDirect, EMBASE and Cochrane library through February 2020. Studies that investigated the exposure-response relationship between components of the indoor microbial communities and respiratory symptoms among under-five children were eligible for inclusion. A random-effect meta-analysis was applied to estimate pooled relative risk (RR) and 95% confidence interval (CI) for study specific high versus low microbial exposures. The potential effect of individual studies on the overall estimate was evaluated using leave-one-out analysis, while heterogeneity was evaluated by I2 statistics using RevMan 5.3. RESULTS: Fifteen studies were eligible for inclusion in a meta-analysis. The pooled risk estimate suggested that increased microbial exposure was associated with an increased risk of respiratory symptoms [pooled relative risk (RR): 1.24 (1.09, 1.41), P = 0.001]. The association was strongest with exposure to a combination of Aspergillus, Penicillium, Cladosporium and Alternaria species [pooled RR: 1.73 (1.30, 2.31), P = 0.0002]. Stratified analysis revealed an increased risk of wheeze [pooled RR: 1.20 (1.05, 1.37), P = 0.007 and allergic rhinitis [RR: 1.18 (0.94, 1.98), P = 0.16] from any microbial exposure. CONCLUSIONS: Microbial exposures are, in general, associated with risk of respiratory symptoms. Future studies are needed to study the indoor microbiome more comprehensively, and to investigate the mechanism of these associations

    Multidimensional operando analysis of macroscopic structure evolution in lithium sulfur cells by X ray radiography

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    Lithium sulfur cells are the most promising candidate for the post lithium ion battery era. Their major drawback is rapid capacity fading attributed to the complex electrochemical processes during charge and discharge which are not known precisely. Here we present for the first time a multidimensional operando measurement by combining X ray radiography with impedance spectroscopy while galvanostatically charging and discharging a lithium sulfur cell. The formation of macroscopic sulfur crystals at the end of charge can be seen directly by X ray radiography. These crystals can be assigned to stable a sulfur rhombic and metastable b sulfur monoclinic by their characteristic crystal habit. These crystal structures with a length of more than 1 mm form and dissolve rapidly during cycling. Their appearance is accompanied by characteristic signals in impedance spectroscopy. Macroscopic crystals of Li2S cannot be observed in full agreement with earlier studies by operando X ray diffraction. In addition, X ray radiography reveals non wetted areas on the carbon cathode. These regions grow during discharge and are reduced during charge. The area of these electrochemically inactive spots is inversely proportional to discharge capacit
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