Cross-linked single-walled carbon nanotube aerogel electrodes via reductive coupling chemistry

Single-walled carbon nanotube (SWCNT) anions can be cross-linked by a dielectrophile to form covalent, carbon-bonded organogels. Freeze-drying produces cryogels with low density (2.3 mg cm−3), high surface area (766 m2 g−1), and high conductivity (9.4 S m−1), showing promise as supercapacitor electrodes. Counterion concentration controls debundling, grafting ratio, as well as all the resulting properties

Bismuth oxyhalides: synthesis, structure and photoelectrochemical activity

We report the synthesis and photoelectrochemical assessment of phase pure tetragonal matlockite structured BiOX (where X = Cl, Br, I) films. The materials were deposited using aerosol-assisted chemical vapour deposition. The measured optical bandgaps of the oxyhalides, supported by density functional theory calculations, showed a red shift with the increasing size of halide following the binding energy of the anion p-orbitals that form the valence band. Stability and photoelectrochemical studies carried out without a sacrificial electron donor showed the n-type BiOBr film to have the highest photocurrent reported for BiOBr in the literature to date (0.3 mA cm−2 at 1.23 V vs. RHE), indicating it is an excellent candidate for solar fuel production with a very low onset potential of 0.2 V vs. RHE. The high performance was attributed to the preferred growth of the film in the [011] direction, as shown by X-ray diffraction, leading to internal electric fields that minimize charge carrier recombination

The use of time resolved aerosol assisted chemical vapour deposition in mapping metal oxide thin film growth and fine tuning functional properties

Time resolved analysis of a thin film has allowed, for the first time, analysis of how thin film growth occurs and changes over time by aerosol assisted CVD. This method has also allowed tuning of the materials' functional properties. In this report a hydrophobic and highly photocatalytic TiO2/SnO2 system is studied, which exhibits surface segregation of SnO2 and thus the novel formation of a natural hetero-junction charge transfer system. The time resolved samples were investigated by a variety of methods. The films were characterised by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Ultraviolet-visible absorption spectroscopy (UV-vis). Functional properties were investigated by photo-activity measurements and water contact angles before and after UV irradiation. The generation of representative samples at different times during the deposition sequence permitted changes in crystal structure, relative concentrations of atoms, and surface morphology to be linked intrinsically to changes in functional properties

Dopant stability in multifunctional doped TiO 2's under environmental UVA exposure

We present a UV irradiation study of three nanomaterials which have been investigated and published by peer review previously, specifically tantalum, tungsten and phosphorus doped TiO2. These nanomaterials have been previously synthesised, characterised and designed with specific applications in mind, from photo-catalysts to transparent conducting oxides (TCO's) for use in solar cells and touchscreens. We show in this work, using X-ray photoelectron spectroscopy (XPS) that under sustained levels of environmental UVA Irradiation (0.42 mW cm−2) Ta5+ and W6+ substitutional doped TiO2 exhibits little to no variation in dopant concentration and distribution as a function of irradiation time. Interestingly P5+ and P3− co-doped TiO2 experiences a pronounced and nuanced change in dopant distribution and concentration across the surface through to the bulk as a function of irradiation time. Combined with our previous work with nitrogen doped TiO2, whereby 28 days of environmental UVA irradiation causes interstitial dopant loss and the attrition of functional properties, these results demonstrate that much is still to be understood regarding dopant stability in metal oxides such as TiO2 under environmental conditions

Prevalence and Predictors of Intestinal Parasitic Infections at King Abdulaziz University Hospital, Jeddah, Saudi Arabia, from 2019 to 2023: A Retrospective Study

Shaymaa A Abdalal,1 Hatoon A Niyazi,2 Soa’ad M Alsulami,3 Ala A Azhari,2 Hanouf A Niyazi,2 Jawahir A Mokhtar,2 Dalya M Attallah,3 Faten A Al Braikan,2 Moroj A Aldarmasi1 1Community Medicine Department, Faculty of Medicine, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 2Clinical Microbiology and Immunology Department, Faculty of Medicine, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 3Clinical and Molecular Microbiology Laboratories, King Abdulaziz University Hospital, Jeddah, 21589, Saudi ArabiaCorrespondence: Shaymaa A Abdalal, Email [email protected]: Parasitic infections are a primary cause of illness worldwide and a public health problem. This study highlighted the prevalence of intestinal parasitic (IP) infections and their updated epidemiologic status from 2019 to 2023 at King Abdulaziz University Hospital, Jeddah, Saudi Arabia.Patients and Methods: A retrospective study was conducted from 2019 to 2023 at King Abdulaziz University Hospital. The laboratory results, socio-demographic information, and the year of data collection were collected from the hospital’s parasitology laboratory. The data were analyzed using SPSS version 26. Ethical approval was obtained from the National Committee of Bioethics (NCBE) - King Abdul Aziz City for Science and Technology, with an approval number of 258-22.Results: During the study period, 7673 stool samples were requested for intestinal parasite examination. The prevalence of IP infection from 2019 to 2023 was 212/7673, with a percentage of 2.8%. Infected patients had a mean (SD) age of 37.68 (17.27) years. Most infected patients were females (61%) and from Saudi Arabia (37.1%). Most stool samples were brown (79.1%), and about half were soft (51.7%). 2019 had the highest number of infected cases (28.3%), while the number of cases decreased in 2023 (8.8%), the lowest during five years. The most predominant parasite among study subjects was Blastocystis hominis (48.11%).Conclusion: The prevalence of IP infection is lower than in previous comparable surveys. Maintaining personal hygiene, conducting epidemiological surveillance, and enhancing environmental sanitation can prevent and control infections.Keywords: intestinal parasites, infection, prevalence, Saudi Arabi

Elemental hydrochemistry assessment on its variation and quality status in Langat River, Western Peninsular Malaysia.

This paper discusses the hydrochemistry variation and its quality status in Langat River, based on the chemistry of major ions, metal concentrations and suitability for drinking purposes. Water samples were collected from 30 different stations to assess their hydrochemical characteristics. The physico-chemical parameters selected were temperature, electrical conductivity, total dissolved solids (TDS), salinity, dissolved oxygen , pH, redox potential, HCO3, Cl, SO4, NO3, Ca, Na, K, Mg, 27Al, 138Ba, 9Be, 111Cd, 59Co, 63Cu, 52Cr, 57Fe, 55Mn, 60Ni, 208Pb, 80Se and 66Zn to investigate the variation of the constituents in the river water. Most of the parameters comply with the Drinking Water Quality Standard of the World Health Organization and the Malaysian National Standard for Drinking Water Quality by the Malaysia Ministry of Health except for EC, TDS, Cl, HCO3, SO4, Na, Mg, Al, Fe and Se. The results show that the Langat River is unsuitable for drinking purposes directly without treatment

Ultraviolet Radiation Induced Dopant Loss in a TiO2 Photocatalyst

Doped TiO2 has been studied with intense interest in recent decades because of its ability to utilize visible wavelengths and enhance the efficiency of photocatalytic processes. Thus, as a class of materials, it is of significant interest for use in environmental ambient energy utilization applications. Using a popular and well-studied form of doped TiO2 (nitrogen doped) as an example, we show how 28 days of UVA irradiation which is identical in intensity with solar conditions is sufficient to cause the UV induced surface segregation and eventual loss of nitrogen dopant species in TiO2. This is evidenced by X-ray photoelectron spectroscopy and transient absorption spectroscopy. The loss of interstitial nitrogen dopants correlates with the eventual permanent loss of photocatalytic activity and visible light absorption. The UV induced loss of dopants in a metal oxide is unprecedented and represents a potential problem where the environmental use of doped metal oxides in applications is concerned

Hybrid off-river augmentation system as an alternative raw water resource: the hydrogeochemistry of abandoned mining ponds

The use of water from abandoned mining ponds under a hybrid off-river augmentation system (HORAS) has been initiated as an alternative water resource for raw water. However, it raises the questions over the safety of the use of such waters. In this study, the hydrogeochemical analysis of the waters is presented to assess the degree to which the water has been contaminated. Comparisons were made between sampling sites, i.e. abandoned mining ponds, active sand mining ponds and the receiving streams within Bestari Jaya, Selangor River basin. The aqueous geochemistry analysis showed different hydrochemical signatures of major elements between sites, indicating different sources of minerals in the water. Discharges from the sand mining ponds were found to contain elevated availability of dissolved concentrations of iron, manganese, lead, copper and zinc, among others. However, the quality of the water (from the main river) that is supplied for potable water consumption is at a satisfactory level despite being partly sourced from the abandoned mining ponds. In fact, all the metal concentrations detected were well below the Malaysia Ministry of Health guideline limits for untreated raw water. In addition, the results of the geochemical index analysis (i.e. geoaccumulation index, enrichment factor and modified contamination factor) showed that the rivers and abandoned mining ponds were generally unpolluted with respect to the metals found in sediments