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1.
J Synchrotron Radiat ; 25(Pt 1): 151-165, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29271765

RESUMEN

Observing the electronic structure, compositional change and morphological evolution of the surface and interface of a battery during operation provides essential information for developing new electrode materials for Li-ion batteries (LIBs); this is because such observations demonstrate the fundamental reactions occurring inside the electrode materials. Moreover, obtaining detailed data on chemical phase changes and distributions by analyzing an operating LIB is the most effective method for exploring the intercalation/de-intercalation process, kinetics and the relationship between phase change or phase distribution and battery performance, as well as for further optimizing the material synthesis routes for advanced battery materials. However, most conventional in situ electrochemical techniques (other than by using synchrotron radiation) cannot clearly or precisely demonstrate structural change, electron valence change and chemical mapping information. In situ electrochemical-synchrotron radiation techniques such as X-ray absorption spectroscopy, X-ray diffraction spectroscopy and transmission X-ray microscopy can deliver accurate information regarding LIBs. This paper reviews studies regarding various applications of in situ electrochemical-synchrotron radiation such as crystallographic transformation, oxidation-state changes, characterization of the solid electrolyte interphase and Li-dendrite growth mechanism during the intercalation/de-intercalation process. The paper also presents the findings of previous review articles and the future direction of these methods.

2.
Heliyon ; 9(7): e17474, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37501970

RESUMEN

The objective of this research was to investigate the variation of water quality parameters at different depths of the Gilgel Gibe I reservoir in Oromia Jimma zone during wet seasons. Five stations within the reservoir were selected, and water quality parameters were determined at four different depths (surface, 5 m, 10 m, and 15 m). Water quality parameters were analyzed on-site using a HACH, HQ40d portable multi-meter, and turbidity was measured using Wag tech turbidity meter and in the laboratory using the standard method. Comparison of water quality parameters among depths were conducted using one-way ANOVA and Tukey's pairwise comparisons with 5% significance level. The probable contributing source of the investigated physicochemical water quality parameters at different depth was identified using Principal components analysis. The results show that depth wise except for total suspended solids (TSS), total dissolved solids (TDS), total phosphorus (TP) and soluble reactive phosphorus (SRP) the rest showed statistically significant difference at p < 0.05 level. Negative correlations were found between depth and dissolved oxygen (DO), water temperature, pH, nitrate (N03-) and chlorophyll a (Chl.a) while positive correlations were found between electrical conductivity (EC), biochemical oxygen demand (BOD5), turbidity and N03-. The study revealed that the release of nutrients associated with increased concentration of BOD5 at the bottom depth caused low concentration of dissolved oxygen due to oxygen consumption. This was further aggravated through the decomposition of organic matter, indicating organic pollution resulting from runoff from the catchment. The presence of dense masses of blue-green algae in the pelagic zone of Gilgel Gibe I reservoir suggested the presence of ample nutrients for its blooming and significant reduction of water quality, indicating possible eutrophic conditions. Therefore, catchment management is required to protect aquatic life and the reservoir function as a whole from reservoir water quality degradation.

3.
Heliyon ; 9(9): e19783, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37809595

RESUMEN

Wildlife-vehicle collision (WVC) is one of the major causes of wildlife mortality and a concern for conservationists worldwide. The study of roadkill data that can be used to develop appropriate measures and strategies for both wildlife conservation and traffic safety to mitigate the WVC and animals' mortality. Extensive studies have been conducted in the developed countries on the identification of WVC hotspots and its potential impact; however, less attention is given in developing countries. Because of this, the problem is not well understood in developing countries. This study was intended to identify victim species, hotspot areas for roadkill, and factors that contribute to WVC in Jimma Zone, along three roads leading from Jimma City. Data were collected using a citizen science approach and a skilled man power road survey (March-September 2022) to document the number and type of species killed. Three road segments (135 km in total) were surveyed weekly as a baseline for future research. All statistical analyses were carried out using R-software. In the present study, a total of 84 roadkill specimens were collected from 16 different mammal species, of which 85.7% were medium-sized carnivores. The findings showed that Jackals (Canis mesomalis and Canis adustus) were the most frequently killed species (25%, n is 21), followed by Civettictis civetta (22.62%, n is 19). The study revealed that the major factors causing collisions include habitat type (forest cover) and wildlife behavior (nocturnal or diurnal). Further, the study revealed that the majority of WVC occurred at night (dusk) and at dawn in areas that are covered with dense forests. To minimize the potential risks of WVC and animals' mortality, we suggest putting warning signs in hotspot areas where roadkill usually occur frequently. In addition, we recommend creating awareness among drivers, traffic police, and all communities about the negative impacts and consequences of collisions on the ecological and economic value of wildlife.

4.
Heliyon ; 8(11): e11608, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36425416

RESUMEN

The quality of natural waters could be deteriorated by organic pollutants which can impose a risk to the ecosystem as well as human health. These organic contaminants are often needed to be removed with adequate techniques. In this study, the photocatalysts of CdO nanoparticles (NPs), Ag-CdO nanocomposites (NCs), and Ag-CdO/polyaniline (PANI) NCs were successfully synthesized in order to investigate their degradation performance against 3',3″,5',5″-tetrabromophenolsulfonphthalein (bromophenol blue, BPB) dye. The crystal structure, functional groups, morphological change, and degradation efficiency of as-synthesized photocatalysts were characterized using XRD, FTIR, SEM and UV-Visible spectroscopic techniques respectively. The SEM result showed that the surface morphology of the nanomaterials seems the agglomerated micron-scaled grains as compared to CdO NPs and Ag-CdO NCs. The FT-IR spectrum demonstrated the absorption peaks which strongly confirmed that Ag-CdO NCs surface was successfully modified with PANI. The highly sharp and intensive XRD patterns attributed to the cubic structure for CdO NPs and Ag-CdO NCs structures with decreasing crystalline size from 40.58 nm to 36.43 nm and 10.29 nm upon CdO NPs photocatalyst surface treatment with Ag metal and PANI. The decreased particle size brought about to narrow the bandgap from 2.76 eV to 1.61 eV and 1.58 eV respectively. Among the synthesized photocatalysts, Ag-CdO/PANI NCs exhibited the best degradation efficiency of 97.30 % at pH 6, 10 ppm concentration of dye, 0.140 g of catalyst load, and 210 min irradiation time. Moreover, the kinetics of photodegradation of model dye at optimum conditions followed pseudo-second order reaction with the rate constant of 8.56 × 10-2 M-1min-1. The results suggested that, the developed treatment method for this particular dye could be applicable for the treatment of wastewater samples containing acidic dyes.

5.
ACS Appl Mater Interfaces ; 11(43): 39827-39840, 2019 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-31597424

RESUMEN

Self-terminated oligomer additives synthesized from bismaleimide and barbituric acid derivatives improve the safety and performance of lithium-ion batteries (LIBs). This study investigates the interface interaction of these additives and the cathode material. Two additives were synthesized by Michael addition (additive A) and aza-Michael addition (additive B). The electrochemical performances of bare and modified LiNi0.6Mn0.2Co0.2O2 (NMC622) materials are studied. The cycling stability and rate capability of NMC622 considerably improve on surface modification with additive B. According to the differential scanning calorimetry results, the exothermic heat of fully deliathiated NMC622 is dramatically decreased through surface modification with both additives. The electrode surface kinetics and interface interaction phenomena of the additives are determined through surface plasma resonance measurements in operando gas chromatography-mass spectroscopy (GCMS) and in situ soft X-ray absorption spectroscopy (XAS). The binding rate constant of additive B onto NMC622 particles is 1.2-2.3 × 104 M-1 s-1 in the temperature range of 299-311 K, which is ascribed to the strong binding affinity toward the electrode surface. This affinity enhances Li+ diffusion, which allows the electrode modified by additive B to provide high electrochemical performance with superior thermal stability. In operando GCMS reveals that gas evolution due to the electrolyte degradation at the NMC622 surface contributes to safety hazards in the bare NMC622 material. In situ soft XAS indicates the occurrence of structural transformation in the bare NMC622 material after it is fully charged and at elevated temperatures. The NMC622 material is stabilized by incorporating additives. The unique performance of additive B can be attributed to its linear structure that allows superior electrode surface adhesion compared with that of additive A. Therefore, this study presents an optimized working principle of self-terminated oligomers, which can be developed and applied to improve the safety and performance of LIBs.

6.
Artículo en Inglés | MEDLINE | ID: mdl-29743923

RESUMEN

This paper presents a review of relevant antidiarrhoeal medicinal plants based on the fundamental knowledge accumulated by indigenous people of Ethiopia. The review includes an inventory carried out on the phytochemical and pharmacological analysis of plant species used in the treatments of diarrhoeal diseases. This study is based on a review of the literature published in scientific journals, books, theses, proceedings, and reports. A total of 132 medicinal plants used by local people of Ethiopia are reported in the reviewed literature. Herbs (43.6%) were the primary source of medicinal plants, followed by trees (27%). Some findings include the predominance of leaf material used (78%), as well as the frequent use of crushing of the plant parts (38%) as a mode of preparation. This study demonstrates the importance of traditional medicines in the treatment of basic human ailments such as diarrhoeal diseases in Ethiopia. Baseline information gaps were observed in different regions of Ethiopia. Thus, documentation of the knowledge held by other regions of Ethiopia that have so far received less attention and urban ethnobotany is recommended for future ethnobotanical studies. In addition, phytochemical studies are recommended mainly on frequently utilized medicinal plants for treatment of diarrhoeal diseases which can serve as a basis for future investigation of modern drug development. Although societies in Ethiopia have long used medicinal plants for diarrhoeal diseases treatment, it is also a good practice to perform toxicological tests.

7.
Int J Genomics ; 2016: 5304028, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27195280

RESUMEN

In recent years the human microbiome has become a growing area of research and it is becoming clear that the microbiome of humans plays an important role for human health. Extensive research is now going into cataloging and annotating the functional role of the human microbiome. The ability to explore and describe the microbiome of any species has become possible due to new methods for sequencing. These techniques allow comprehensive surveys of the composition of the microbiome of nonmodel organisms of which relatively little is known. Some attention has been paid to the microbiome of insect species including important vectors of pathogens of human and veterinary importance, agricultural pests, and model species. Together these studies suggest that the microbiome of insects is highly dependent on the environment, species, and populations and affects the fitness of species. These fitness effects can have important implications for the conservation and management of species and populations. Further, these results are important for our understanding of invasion of nonnative species, responses to pathogens, and responses to chemicals and global climate change in the present and future.

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