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Transmission Electron Microscopic and X-ray Diffraction Based Study of Crystallographic Bibliography Demonstrated on Silver, Copper and Titanium Nanocrystals: State of the Art Statical Review

This statistical review compares the crystallographic structures of functional nanocrystals composed of silver (Ag), copper (Cu) and titanium (Ti) using transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses. TEM provides high-resolution imaging to directly visualize individual nanoparticles' size, internal shape and crystallinity. Statistical analysis quantifies variations in lattice parameters, crystal structure, size distributions, phase compositions, lattice strains, preferred orientation and lattice volume of these three crystalline nanomaterials. The review highlights the complementary roles of TEM and XRD in comprehensive Ag, Cu and Ti nanocrystalline materials characterization. The crystallographic functional parameters of Ag were 2θ= 38.1° (111), 44.3° (200) and 64.4° (220); for Cu crystal 43.3° (111), 50.4° (200), 74.1° (220), 89.9° (311) and 95.1° (222) and 35.1° (100), 38.4° (002), 40.2° (101), 53.0° (102), 63.0° (103), 70.7° (110), 76.2° (112), 82.3° (201) demonstrated for Ti nanocrystals. The crystallographic predominant plane or Miller indices were also revealed by selected area electron diffraction (SAED) on TEM. The FCC structure of Ag and Cu is shown in larger lattice volumes compared to the HCP structure of Ti and prefer oriented. The degree of crystallinity of Ti, Cu and Ag nanocrystalline materials was observed at 90.0%, 98.0% and 100.0% respectively. This quantitative comparison provides valuable insights into the structural property relationships in these nanocrystals, enabling rational design strategies for optimizing their performance in various functional applications.

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How Components of Dye-sensitized Solar Cells Contribute to Efficient Solar Energy Capture

Herein, we reviewed the main components of dye-sensitized solar cells (DSSCs) which are an emerging cheap and environmentally benign alternative for solar energy capture and conversion to electricity. The role of individual parts such as the semiconductor electrode, counter electrode, photosensitizer, electrolyte, and substrate and their contribution to the overall efficiency (η) of DSSCs are discussed. In addition, parameters such as short circuit current, open circuit voltage, and fill factor used to quantify the efficiency of DSSCs are addressed. The highest solar-to-electric energy conversion efficiency of 13 % has been achieved using titanium dioxide as a semiconductor electrode, a triiodide system as a redox couple, and platinum counter electrodes. Semiconductors are made up of materials such as glass, carbon, conductive polymers and other metal oxides have lower efficiencies (< 8 %). In addition, synthetic photosensitizers especially ruthenium complexes have higher efficiencies (10-11 %) compared to natural dyes among which the highest efficiency (4.6 %) was achieved using chlorophyll. The performance of natural dyes based on efficiency of the DSSC is generally in the order: chlorophyll > anthocyanins > carotenoids that is highly attributed to their structure which not only dictates electron release and recombination but also attachment to other components. The DSSC performance is not fixed but rather tunable by variations in the components to achieve desired structural and electronic properties such as firm anchorage between the photosensitizer and the semiconductors, the reduction of the energy band gap by incorporation of other metal salts to extend the absorption range and use of additives that prevent electron recombination with the photosensitizer or any hindrances in the electrolyte redox reactions.

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Optimization of Tannin’s Extraction from Cashew (Anacardium occidentale L.) Nut Testa for Use in Leather Tanning

Extensive researches have been conducted over the years, focusing on the use of vegetable tannins to reduce pollution caused by mineral tanning. Vegetable tannins have been utilized commercially, but they remain costly and are not easily accessible. The purpose of this study was to optimize the tannin’s extraction from cashew (Anacardium occidentale L.) nut testa using water in order to determine their suitability in leather tanning. Samples of cashew nut testa were collected randomly from cashew nut processors in Mtwara region, Southern Tanzania. They were shade-dried and ground into powder. Various ratio of powder/water (1:6, 1:9, 1:12 and 1:15) -on weight basis were made for extraction, maintained at a temperature of 70 0C for 90 minutes. Results showed that, depending on the extract ratios, different tannin concentrations were obtained which had an implication on tannin extracted from powder. Experiment was found solution with ratio 1:9 have shown to extract about 50.73% of total tannins presented on cashew nut testa powder followed by solutions with ratio 1:12, ratio 1:15, and ratio 1:6 extracted about 46.27%, 43.51% and 38.95% respectively. Suitability of various tannins solution extracted from cashew nut testa was tested using conventional tanning process on sheepskins. The physical properties of the resultant leathers were determined using the standard methods (TBS/ISO). Under given condition, it has shown that using the ratios of 1:6, 1:9, 1:12 and 1:15 resulted in leather with tensile strength ranging between 19.41+6.36 MPa and 43.00+8.18 MPa and elongation at maximum load in the range of 34.48+10.12 % to 77.56+10.96 %., average shrinkage temperatures were above 75oC, and flexing test gave no damage of leather at 100,000 flexes. The physical properties of leather recorded have shown to meet the minimum recommended values from the standard (ISO 14931-2021). The mixing ratio 1:9 of cashew nut testa powder/water has been recommended for extracting tannin for vegetable tanning.

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Occurrence and Removal Efficiencies of Four Antibiotics in Kisii and Kabarnet Waste Water Treatment Plants, Kenya

Background: Antibiotics are presently considered as emerging contaminants with adverse effects in the environment and the population such as the development of antimicrobial resistant genes (ARG) and antimicrobial resistant bacteria (ARB). This study was guided by objective entailing to determine the seasonal occurrences and removal efficiencies of four antibiotics in Kisii and Kabarnet waste water treatment plants in Kenya. 
 Place and Duration of Study: Waste water samples were picked from Suneka wastewater treatment plant in Kisii county and Kabarnet Level V Hospital in Baringo County Kenya in the months of June and December 2020
 Methodology: Multiple samples were picked in Kisii and Kabarnet waste water treatment plants in the months of June and December correspond to the dry and wet seasons in Kenya. Collected waste water samples were centrifuged and filtered with glass microfiber filter papers and subsequently passed through a Solid phase extractor cartridge. High Performance Liquid Chromatography was used for quantification of antibiotics as per international commission for harmonization and subsequently applied for analysis.
 Results: The results revealed that the dry season had higher antibiotic concentrations at 1.29, 0.09, 2.92 and 1.82 µg/l for sulphamethoxazole, trimethoprim, ampicillin and amoxicillin respectively for the Kisii waste water treatment plant and 0.18, 0.05, 1.34 and 0.09 µg/l respectively for Kabarnet waste water treatment plant. During the wet seasons the measured concentrations were 1.11, 0.14, 2.04 and 1.34 µg/l for sulphamethoxazole, trimethoprim, ampicillin and amoxicillin at the Kisii WWTP, and 0.14, 0.06, 1.01 and 0.09 µg/l for Kabarnet WWTP. The removal efficiencies in the WWTPs, ranged from a high of 94 % to a low of 11.11 % depending on the type of antibiotic in both wet and dry seasons.
 Conclusion: Amoxicillin, ampicillin, trimethoprim and sulphamethaxazole were found in both Kisii WWTPs and Kabarnet WWTPs with nearly all antibiotics having a higher concentration of in the dry season than in the wet season. The highest calculated percentage removal was 94.03 % while the lowest calculated percentage removal was 7.14 %. The results suggest that the two WWTPs are effective for the removal of different types of antibiotics.

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Antibacterial Effect of Nanoparticles Synthesized from Ficus exaseprata (Sandpaper Leaves)

The eco-friendly, cost effectiveness, and the less toxic nature of synthesized green nanoparticles to the environment have become a global attraction to many studies. The study aim to synthesize Silver (Ag) nanoparticles from Ficus exasperata (Sandpaper leave) leaves and to determine its antimicrobial effect on bacteria isolates. Silver (Ag) nanoparticles were synthesized from the plant extracts using standard extracting techniques and their presence was verified and confirmed using an ultraviolet-visible (UV-Vis) Spectrophotometer. A prepared series of silver nitrate (AgNO3) solutions were mixed with the plant extracts at a ratio of 1:1 (v/v) to a total volume of 20ml in a text-tube. The test tubes were rapped with aluminum foil and heated in a water bath at 60OC for 3 hours and allowed to cool and analyzed using UV-Vis Spectrophotometer. The UV-Vis spectra confirmed the different concentrations of silver nitrate (AgNO3) that produced Ag nanoparticles and their average size was more than 50nm and less than 100nm. The mixture of the leave extract was tested for its antimicrobial activity against gram-positive and gram-negative organisms such as Staphylococcus aureus Bacillus cereus and Escherichia coli respectively. The results showed that the growth of the different bacteria was inhibited by the extracts containing silver nitrate on Staphylococcus aureus and Escherichia coli and not on Bacillus cereus using Ficus exaseprata nanoparticles. Statistical evaluation showed that zones of inhibition on the three bacteria produced by the aqueous leave extracts containing different concentration of silver nitrate (AgNO3¬¬) precursor was significantly different from the silver nitrate (AgNO3) precursor. It were observed that the higher the concentration of the silver nitrate (AgNO3) the greater the zone of inhibition. It can be concluded that Ficus exaseprata leave extracts dope with silver nanoparticles, can produce antimicrobial effects on some microorganisms.

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Physicochemical Analysis of Biofilms from Cocos nucifera Linn. (Coconut) Flour and Manihot esculenta Crantz (Cassava) Starch with Polyvinyl Alcohol (PVA)

The province of Northern Samar, its municipalities including Pambujan, is a place abundant of Manihot esculenta Crantz (cassava), and Cocos nucifera Linn. (coconut). However, its industry is mainly limited to food production. This study developed biofilms from cassava starch (CasS), and coconut flour (CoF) with polyvinyl alcohol (PVA). The physicochemical properties were analyzed to determine their pH, solubility, moisture content, and tensile strength. Functional groups were investigated using FTIR, and the antibacterial properties were evaluated. The results showed that both biofilms with PVA were weakly acidic and insoluble in all solvents. Meanwhile, CoF biofilm contained higher moisture content than the CasS biofilm. CoF biofilms also carried more weight and higher force than CasS biofilm. Hydroxyl, alkyl, and alkene functional groups were identified for both biofilms. Meanwhile, both biofilms showed no inhibitory effect against E. coli, and S. aureus. Therefore, the developed biofilms with PVA showed good physicochemical properties and can be used for packaging applications. The slight acidity can prolong their shelf-life. Moreover, both will not easily dissolve. CoF biofilm comprised more water than CasS but both are still suitable for packaging due to their tensile strength attributed to the presence of the functional groups. However, CasS, CoF, and PVA do not have antibacterial properties. More physicochemical tests, further characterization, and incorporation of antibacterial agents were recommended.

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