High Concentrations Research Articles

Determination of Essential Minerals in the Indigenous Vegetables Solanum nigrum (Stout Shade) and Gynandropsis gynandra (Spider Plant) from Two Agroecological Zones in Kisii County, Kenya.

Vegetables are good sources of essential mineral elements that promote good health and immunity. Information on the nutritional contents of indigenous vegetables is scarce. Therefore, this study sought to ascertain the concentrations of magnesium, manganese, chrome, zinc, copper, and iron in Solanum nigrum and Gynandropsis gynandra indigenous vegetables from two agroecological zones (upper midland and lower highland) of Kisii County, Kenya, using inductively coupled plasma optical emission spectroscopy (ICP‒OES). For Gnandropsis gynandra, the most abundant erythrocytic synthesis element was Fe (1856.67 ± 15.28mg/kg DW) for plants harvested from Nyanchwa (UM), and the least was Cu (8.90 ± 0.44mg/kg DW) in plants harvested from Kari (LH). In addition, Mg was the hypoglycemic element with the highest concentration (5975.00 ± 10.00mg/kg DW), and Cr lowest (3.16 ± 0.45mg/kg DW) in samples harvested from Matongo (UM). For Solanum nigrum, the most erythrocytic synthesis element was Fe (1280.00 ± 10.00mg/kg DW for samples collected from Kiamabundu (UM), and the least was Cu (9.08 ± 0.15mg/kg DW) in the samples from Nyanchwa (UM), whereas Mg in samples from Nyabioto (UM) was the hypoglycemic element with the highest concentration (4920.00 ± 10.00mg/kg DW) and Cr in samples from Mariba (LH had the lowest concentration) (3.95 ± 1.63mg/kg DW). The concentrations of elements in the two indigenous vegetables from the UM agroecological zone were slightly greater than those in the LH agroecological zone. Nonetheless, the variations observed were not statistically significant (P < 0.05). Enzymatically bio accessed concentrations of iron, zinc, chromium, magnesium, manganese, and copper were higher than those obtained aquatically. The indigenous vegetable bio avails substantial amounts of iron and copper to enable them be used in the management pernicious anaemia; on the other hand, the substantial bio availed levels of zinc, manganese, magnesium, and chromium enables the vegetable to be used in the management of diabetes.

Effect of L-arginine on cystic fibrosis Pseudomonas aeruginosa biofilms.

Cystic fibrosis (CF) airways are L-arginine deficient which may affect susceptibility to infection with certain pathogens. The potential impact of L-arginine supplementation on Pseudomonas aeruginosa, a common CF airway pathogen, is unclear. This study investigated the effects of L-arginine on P. aeruginosa biofilm cultures, using the laboratory strain PAO1 and multi-drug resistant CF clinical isolates. P. aeruginosa biofilms were grown in a chambered cover-glass slide model for 24 h, then exposed to either L-arginine alone or combined with tobramycin for an additional 24 h. Biofilms were visualized using confocal microscopy, and viable cells were measured via plating for colony-forming units. Increasing concentrations of L-arginine in bacterial culture medium reduced the biovolume of P. aeruginosa in a dose-dependent manner. Notably, L-arginine concentrations within the physiological range (50 mM and 100 mM) in combination with tobramycin promoted biofilm growth, while higher concentrations (600 mM and 1200 mM) inhibited growth. These findings demonstrate the potential of L-arginine as an adjuvant therapy to inhaled tobramycin in treating P. aeruginosa infections in people with CF.

Increased hepatic putrescine levels as a new potential factor related to the progression of metabolic dysfunction-associated steatotic liver disease.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic liver condition that often progresses to more advanced stages, such as metabolic dysfunction-associated steatohepatitis (MASH). MASH is characterized by inflammation and hepatocellular ballooning, in addition to hepatic steatosis. Despite the relatively high incidence of MASH in the population and its potential detrimental effects on human health, this liver disease is still not fully understood from a pathophysiological perspective. Deregulation of polyamine levels has been detected in various pathological conditions, including neurodegenerative diseases, inflammation, and cancer. However, the role of the polyamine pathway in chronic liver disorders such as MASLD has not been explored. In this study, we measured the expression of liver ornithine decarboxylase (ODC1), the rate-limiting enzyme responsible for the production of putrescine, and the hepatic levels of putrescine, in a preclinical model of MASH as well as in liver biopsies of patients with obesity undergoing bariatric surgery. Our findings reveal that expression of ODC1 and the levels of putrescine, but not spermidine nor spermine, are elevated in hepatic tissue of both diet-induced MASH mice and patients with biopsy-proven MASH compared with control mice and patients without MASH, respectively. Furthermore, we found that the levels of putrescine were positively associated with higher aspartate aminotransferase concentrations in serum and an increased SAF score (steatosis, activity, fibrosis). Additionally, in in vitro assays using human HepG2 cells, we demonstrate that elevated levels of putrescine exacerbate the cellular response to palmitic acid, leading to decreased cell viability and increased release of CK-18. Our results support an association between the expression of ODC1 and the progression of MASLD, which could have translational relevance in understanding the onset of this disease. © 2024 The Pathological Society of Great Britain and Ireland.

Enhanced physical and mechanical properties of Cu-based nanocomposites with bundled multi-layered carbon nanotubes incorporation: fabrication and comparative analysis via conventional sintering and SPS techniques

The current investigation delves into the influence of incorporating bundled multi-layered graphene sheets, specifically multiwalled carbon nanotubes (MWCNTs), on the microstructure, as well as the physical and mechanical attributes of Cu-based nanocomposites. Various weight percentages (1%, 2%, 3%, and 5%) of MWCNTs were infused into the Cu matrix, and the fabrication of these nanocomposites was conducted through the powder technology route. The fabrication process occurred under an argon atmosphere utilizing both conventional sintering and spark plasma sintering (SPS) techniques. The conventionally sintered Cu-based nanocomposite reinforced with 1% MWCNT exhibited the highest relative density (~86%), hardness (~551.12 MPa), compressive strength (~459 MPa), and outstanding resistance to wear. Conversely, the SPS-fabricated nanocomposite reinforced with the same MWCNT concentration demonstrated the highest relative density (approximately 94.25%) and compressive strength (~688 MPa), while the nanocomposite reinforced with 2% MWCNT displayed the highest hardness (~1178 MPa) and resistance to wear. Notably, a higher concentration of MWCNTs was observed to adversely affect the physical, mechanical, and wear properties of the Cu-MWCNT nanocomposites, irrespective of the chosen sintering technique for their production.

Buildup and Consumption of Species in Emulsion Droplets during Aqueous Suzuki Coupling Correlate with Yield.

Fluorescence lifetime imaging microscopy (FLIM) provides spatiotemporal resolution of the changing composition of emulsion droplets during aqueous-surfactant Suzuki coupling. In contrast to previous investigations, the present experiments characterize the full course of a catalytic chemical reaction, addressing key questions about reaction species buildup and correlating these microscale behaviors with bench-scale product yields. At low concentrations of (active) catalyst, droplet environments are stable; however, at higher concentrations, emulsion droplet environments change markedly. These changes are consistent with the buildup and consumption of reaction species inside the droplets. A combination of FLIM and bright-field imaging pinpoints limitations in catalyst solubility as controlling rate and degree of buildup of species in droplets. These solubility limitations are also identified as the cause of a reaction induction period and an origin of the rate-and-reproducibility advantage obtained by adding THF cosolvent. The subsequent mechanistic model from these data led to a bench-scale reaction optimization, wherein premixing the catalyst components bypasses the catalyst induction period, resulting in a faster reaction. The understanding generated by FLIM thus provides an early example of how visualizing changes in droplet compositions on the microscale during ongoing aqueous-organic reactions can be leveraged for enhancing efficiencies in bench-scale reactions.

Analysis of glycoalkaloid distribution in the tissues of mealworm larvae (Tenebrio molitor)

Solanine (SOL) and chaconine (CHA) are glycoalkaloids (GAs) produced mainly by Solanum plants. These plant secondary metabolites affect insect metabolism; thus, they have the potential to be applied as natural plant protection products. However, it is not known which GA concentration induces physiological changes in animals. Therefore, the aim of this study was to perform a quantitative analysis of SOL and CHA in the larvae of Tenebrio molitor using LC‒MS to assess how quickly they are eliminated or metabolised. In this experiment, the beetles were injected with 2 μL of 10−5 M SOL or CHA solution, which corresponds to a dosage range of 0.12–0.14 ng/mg body mass. Then, 0.5, 1.5, 8, and 24 h after GA application, the haemolymph (H), gut (G), and the remainder of the larval body (FB) were isolated. GAs were detected in all samples tested for 24 h, with the highest percentage of the amount applied in the FB, while the highest concentration was measured in the H sample. The SOL and CHA concentrations decreased in the haemolymph over time, while they did not change in other tissues. CHA had the highest elimination rate immediately after injection, while SOL slightly later. None of the GA hydrolysis products were detected in the tested samples. One possible mechanism of the detoxification of GAs may be oxidation and/or sequestration. They may be excreted by Malpighian tubules, with faeces or with cuticles during moulting. The results presented are significant because they facilitate the interpretation of studies related to the effects of toxic substances on insect metabolism.

Mapping of uranium concentrations in groundwater samples of Davanagere district, Karnataka, India, and assessment of effective dose to the population.

The geomorphology, geohydrology, lithology and ecological features of the area influence the uranium content in groundwater. The groundwater samples were collected from 75 locations of Davanagere district, Karnataka, India. Uranium analysis in the water samples was done using LED fluorimeter, based on fluorescence of dissolved uranyl salts. The uranium concentration in water samples varied from 18.41 to 173.21μgL-1 with a geometric mean of 39.69μgL-1. Higher uranium concentration in groundwater was observed in Harapanahalli and Jagalur taluk of Davanagere district, which falls in the Eastern Dharwar Craton, which is generally known to contain more radioactive minerals than the Western Dharwar Craton. The effective ingestion dose and lifetime cancer risk to the population were calculated using the obtained uranium concentration in drinking water.

Dose and transfer factor ofn 40K in medicinal plants.

The presence of naturally occurring radionuclides is common in all living and non-living frameworks, which are part of our environment. The activity concentration of 40K radionuclide was estimated using gamma spectrometry in some medicinal plants and transfer factors (TF), and Average Annual Committed Effective Dose (AACED) was evaluated. The standard methods were followed in the process of sample collection and processing. The mean activity concentrations of 40K were 223 and 1330Bqkg-1 in soil and medicinal plants, respectively. The mean TF and AACED were found to be 6.5 and 8.2μSv y-1, respectively. Higher activity concentration was observed in some medicinal plants due to the selective and preferential uptake of this radionuclide depending on their medicinal utility. The study may help to form the database and safety regulations connected with 40K activity in medicinal plants.

Paclitaxel-loaded elastic liposomes synthesised by microfluidics technique for enhance transdermal delivery.

The inherent flexibility of elastic liposomes (EL) allows them to penetrate the small skin pores and reach the dermal region, making them an optimum candidate for topical drug delivery. Loading chemotherapy in ELs could improve chemotherapy's topical delivery and localise its effect on skin carcinogenic tissues. Chemotherapy-loaded EL can overcome the limitations of conventional administration of chemotherapies and control the distribution to specific areas of the skin. In the current studies, Paclitaxel was utilised to develop Paclitaxel-loaded EL. As an alternative to the conventional manufacturing methods of EL, this study is one of the novel investigations utilising microfluidic systems to examine the potential to enhance and optimise the quality of Els by the microfluidics method. The primary aim was to achieve EL with a size of < 200nm, high homogeneity, high encapsulation efficiency, and good stability. A phospholipid (DOPC) combined with neutral and anionic edge activators (Tween 80 and sodium taurocholate hydrate) at various lipid-to-edge activator ratios, was used for the manufacturing of the ELs. A preliminary study was performed to study the size, polydispersity (PDI), and stability to determine the optimum microfluidic parameters and lipid-to-edge activator for paclitaxel encapsulation. Furthermore, physiochemical characterisation was performed on the optimised Paclitaxel-loaded EL using a variety of methods, including Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy, Atomic force microscopy, elasticity, encapsulation efficiency, and In vitro release. The results reveal the microfluidics' significant impact in enhancing the EL characteristics of EL, especially small and controllable size, Low PDI, and high encapsulation efficiency. Moreover, the edge activator type and concentration highly affect the EL characteristics. The Tween 80 formulations with optimised concentration provide the most suitable size and higher encapsulation efficiency. The release profile of the formulations showed more immediate release from the EL with higher edge activator concentration and a higher % of the released dug from the Tween 80 formulations.

Associations of exposure to bisphenol-A or parabens with markers of liver injury/function among US adults in NHANES 2011-2016.

Bisphenol-A (BPA) and parabens are common endocrine-disrupting compounds (EDCs) that are used extensively in consumer products worldwide and are widely found in the environment. The purpose of this study was to comprehensively explore the correlations between urinary BPA/parabens levels and liver injury/function markers. In this cross-sectional study, we used National Health and Nutrition Examination Survey (NHANES) data from 2011 to 2016. The exposure variables were urinary BPA and four urinary parabens [methylparaben (MPB), ethylparaben (EPB), propylparaben (PPB), and butylparaben (BPB)], while the outcome variables were indicators of liver function/injury [alanine aminotransferase (ALT), aspartate aminotransferase (AST), AST/ ALT, albumin (ALB), total protein (TP), total bilirubin (TBIL), alkaline phosphatase (ALP), and the fibrosis-4 index (FIB-4)]. Multiple linear regression and weighted quantile sum (WQS) regression analyses were applied to explore the relationships between the individual/combined exposure variables and the liver injury/function indicators, respectively. Furthermore, stratified analysis was employed to detect the associations influenced by age and sex. A total of 2,179 adults were eligible for the present analysis. Multivariate linear regression analysis revealed positive associations of EPB with AST, ALT, TP, and FIB-4 scores and negative associations of BPA with TP and ALB. The effects of urinary parabens on adverse outcomes in the liver (AST and ALT) were significant in the female and middle-aged subgroups. In addition, the WQS analysis revealed that the mixture of four compounds was negatively associated with ALB. BPA had the greatest effect on the serum ALB concentration (weight = 0.688). Our present study provided novel evidence of significant associations between BPA or certain parabens and numerous markers of liver injury/function indicators. We found that higher urinary BPA concentrations were associated with worse liver function. Exposure to high EPB/PPB ratios was significantly associated with biomarkers of liver injury.

Interplay between gender and pollution on the prognosis of resuscitated out-of-hospital cardiac arrest.

Differences between men and women in prognosis after sudden pre-hospital out-of-hospital cardiac arrest (OHCA) have been described in many studies, but the interplay between gender and pollution have not been characterized in detail. We aimed at appraising the interplay between gender and pollution on the prognosis of OHCA. Details on patients with OHCA in whom return of spontaneous circulation was obtained and transferred to a large teaching hospital were obtained from the medical charts of the ambulance service and the Polish National Health Fund. Matching pollutant concentrations (PM 2.5, PM10, As, Ni, Cd, Pb) were obtained from the Polish National Environmental Protection Inspectorate. Details on 948 resuscitated OHCA, 325 (34.3%) of them in women, and occurring between 2018 and 2021, were retrieved. Notably, OHCA in women was associated with significantly higher daily concentrations of PM10 (23.37 [17.09, 37.04] vs. 21.92 [16.32, 29.98] μg/m3, P=0.023) and PM2.5 (16.83 [11.87, 28.24] vs. 15.27 [11.64, 22.72] μg/m3, P=0.026), as well as heightened concentrations of Cd, daily (0.32 [0.19, 0.44] vs. 0.27 [0.17, 0.40] ng/m3, P=0.027) and over 30 days (0.34 [0.20, 0.44] vs. 0.29 [0.18, 0.43] ng/m3, P=0.027). Concurrently, OHCA in females was associated with lower daily temperatures on the day of the incident (8.40 [0.20, 15.40] vs. 9.90 [1.40, 15.90] °C, P=0.042). Despite these differences, survival at 30 days and 12 months was similar in women and men (both P>0.05). OHCA events with successful resuscitation in women occurred in concomitance with higher daily contaminant levels, yet short-term and long-term prognosis was similar in men and women. The interplay between gender and air pollution on OHCA outcomes requires further population-based studies.

Effect of incremental tazobactam concentrations on the bactericidal activity of piperacillin against ESBL-producing enterobacterales clinical isolates causing bacteraemia.

We evaluated the activity of piperacillin in relation to INCREASING TAZOBACTAM CONCENTRATION against ESBL-producing Enterobacterales collected from patients with bacteraemia. Increasing tazobactam concentration (4, 12 or 24mg/L) exerted a reduction of piperacillin MICs under the clinical breakpoint in a concentration-dependent manner (0%, 60% and 90% of clinical isolates). Also, activity of piperacillin/tazobactam based at higher achievable serum concentrations (123/14mg/L) is needed to reduce the bacterial growth in 92% of ESBL-producers. CHANGES IN THE PIPERACILLIN MIC IN RELATION TO INCREASING TAZOBACTAM SUGGEST THAT REALTIME TDM COULD BE USED FOR DRIVEN ANTIMICROBIAL THERAPY WITH PIPERACILLIN/TAZOBACTAM IN BSI DUE TO ESBL STRAINS.

Long-term response of anammox process to hydrazine under different exposure strategies

The enhancing effect of hydrazine (N2H4) on anammox has been extensively studied; however, its long-term inhibitory effect remains controversial. This study aims to evaluate the susceptibility and resistance of the anammox bacteria to N2H4 and to follow the dynamic changes in functional microorganisms under two different N2H4 application strategies (L1–136 days; L2–344 days). In the first strategy (L1), ≥ 88 % of NH4+-N and NO2--N were removed during the N2H4 applications at ≤ 150 mg/L dosages. Above 150 mg/L, nitrogen treatment performance deteriorated. When 150 mg/L of N2H4 was continuously fed to the bioreactor in L2, anammox bacteria performed their activity with ≥ 70 % removal efficiency for both NH4+-N and NO2--N up to 2.74 g/L cumulative N2H4 loading. During these periods in both strategies, Candidatus Kuenenia, a sole anammox genus identified in the bioreactors, was found to adapt to higher N2H4 concentrations than those reported in the literature. Although nitrogen removal capacity deteriorated towards the end of the operation periods, N2H4 was still utilized in the bioreactors. Therefore, this study makes an important contribution to the utilization of anammox bacteria as a potential candidate for the treatment of N2H4-containing wastewaters, in addition to their current widespread applications.

Study on seasonal variation of radon, thoron, and their progeny levels in indoor environments and their radiological effects on human health.

Indoor radon (222Rn), thoron (220Rn) and their progeny concentrations have been measured in different types of buildings at different locations in different dwellings in different seasons in Hassan city, Karnataka, using time-integrated passive radon dosemeters containing LR-115 Type II solid-state nuclear track detectors. The annual effective dose due to radon and thoron has been estimated. The activity concentrations were observed to be highest in winter and lowest in summer, and the data also shows that bathrooms and kitchens have significantly higher radon-thoron concentrations and annual effective doses.

Selective Liquid-Liquid Extraction of Thorium(IV) from Rare-Earth Element Mixtures.

One of the major challenges in processing rare-earth element (REE) materials arises from the large amounts of radioactive thorium (Th) that are often found within REE minerals, encouraging enhanced metal separation procedures. We report here a study aimed at developing improved systems for REE processing with the goal of efficient extraction of Th(IV) from acidic solution. A tripodal ligand, TRPN-CMPO-Ph, was prepared that utilizes carbamoylmethylphosphine oxide (CMPO) chelators tethered to a tris(3-aminopropyl)amine (TRPN) capping scaffold. The ligand and its metal complexes were characterized by using elemental analysis, NMR, Fourier transform infrared spectroscopy, mass spectrometry, and luminescence spectroscopy. Using a liquid-liquid metal extraction protocol, TRPN-CMPO-Ph selectively extracts Th(IV) at an efficiency of 79% from a mixture of Th(IV), UO22+, and all rare-earth metal cations (except promethium) dissolved in nitric acid into an organic solvent. Th(IV) extraction selectivity is maintained upon extraction from a mixture that approximates a typical monazite leach solution containing several relevant lanthanide ions, including two ions at higher concentration relative to Th(IV). Comparative studies with a tris(2-aminoethyl)amine (TREN)-capped derivative are presented and support the need for a larger TRPN capping scaffold in achieving Th(IV) extraction selectivity.

Exposure Effects of Environmentally Relevant Concentrations of the Tricyclic Antidepressant Amitriptyline in Early Life Stage Zebrafish.

Antidepressants are one of the most globally prescribed classes of pharmaceuticals, and drug target conservation across phyla means that nontarget organisms may be at risk from the effects of exposure. Here, we address the knowledge gap for the effects of chronic exposure (28 days) to the tricyclic antidepressant amitriptyline (AMI) on fish, including for concentrations with environmental relevance, using zebrafish (Danio rerio) as our experimental model. AMI was found to bioconcentrate in zebrafish, was readily transformed to its major active metabolite nortriptyline, and induced a pharmacological effect (downregulation of the gene encoding the serotonin transporter; slc6a4a) at environmentally relevant concentrations (0.03 μg/L and above). Exposures to AMI at higher concentrations accelerated the hatch rate and reduced locomotor activity, the latter of which was abolished after a 14 day period of depuration. The lack of any response on the features of physiology and behavior we measured at concentrations found in the environment would indicate that AMI poses a relatively low level of risk to fish populations. The pseudopersistence and likely presence of multiple drugs acting via the same mechanism of action, however, together with a global trend for increased prescription rates, mean that this risk may be underestimated using current ecotoxicological assessment paradigms.

Topical sirolimus in dermatology: a systematic review.

Topical sirolimus is increasingly utilised off-license to manage various dermatological conditions whilst avoiding typical adverse effects associated with systemic sirolimus. However, widespread use is limited by a highly heterogeneous evidence base of mixed quality. to evaluate the current evidence base for the indications, efficacy and safety profile for topical sirolimus in dermatology. A literature search was conducted from 2005 to July 4th, 2023, of English language studies, with the following databases consulted: MEDLINE, PubMed, Embase, CENTRAL and EBSCO. Key words included 'topical', 'rapamycin', 'sirolimus' and 'dermatology'. Data on drug efficacy, concentration, side effects, co-interventions and follow up were extracted. The search identified 202 studies; 71 studies met the inclusion criteria. Efficacy of topical sirolimus was demonstrated in facial angiofibromas (799 patients) compared to placebo across multiple randomised controlled trials with a predominant concentration of 0.1%. Evidence was mixed for sirolimus use in port-wine stains (61 patients), with evidence of effectiveness in combined sirolimus and pulsed-dye laser. Multiple case reports demonstrated clinical improvement with topical sirolimus use in cutaneous vascular abnormalities (33 patients) at a higher concentration of 1%. Other applications of topical sirolimus were predominantly case reports demonstrating generally favourable outcomes. Topical sirolimus was generally well tolerated - most reported adverse effects were localised irritation and pruritus. Ointment-based preparations and once-daily dosing appeared to confer a better side effect profile. Most high-quality data pertain to the efficacy of topical sirolimus in treating facial angiofibromas in tuberous sclerosis. Outcomes are generally promising in other indications and good tolerability, but data quality is mixed.

Extracellular Matrix Protein Signatures of the Outer and Inner Zones of the Rat Adrenal Cortex.

This study analyzes the extracellular matrix (ECM) signatures of the outer (OF = capsule + subcapsular + zona glomerulosa cells) and inner fractions (IF = zona fasciculata cells) of the rat adrenal cortex, which comprise two distinct microenvironment niches. Proteomic profiles of decellularized OF and IF samples, male and female rats, identified 252 proteins, with 32 classified as ECM-component and ECM-related. Among these, 25 proteins were differentially regulated: 17 more abundant in OF, including Col1a1, Col1a2, Col6a1, Col6a2, Col6a3, Col12a1, Col14a1, Lama5, Lamb2, Lamc1, Eln, Emilin, Fbln5, Fbn1, Fbn2, Nid1, and Ltbp4, and eight more abundant in IF, including Col4a1, Col4a2, Lama2, Lama4, Lamb1, Fn1, Hspg2, and Ecm1. Eln, Tnc, and Nid2 were abundant in the female OF, while Lama2, Lama5, Lamb2, and Lamc1 were more abundant in the male IF. The complex protein signature of the OF suggests areas of tissue stress, stiffness, and regulatory proteins for growth factor signaling. The higher concentrations of Col4a1 and Col4a2 and their role in steroidogenesis should be further investigated in IF. These findings could significantly enhance our understanding of adrenal cortex functionality and its implications for human health and disease. Key findings were validated, and data are available in ProteomeXchange (PXD046828).

Rapid Synthesis of α-Hemihydrate Phosphogypsum in MgCl2 Solution by Microwave Heating.

The preparation of α-hemihydrate phosphogypsum (α-HPG) is hindered by a lengthy reaction time due to using traditional electric heating. Microwave heating was proposed for the rapid synthesis of α-HPG in MgCl2 solution. The effects of MgCl2 concentration on the heating rate of solution and conversion rate of α-HPG were investigated; the morphology of α-HPG was regulated by citric acid, and the adsorption mechanism of citric acid on the α-HPG surface was clarified. The results show that α-HPG was successfully synthesized in a MgCl2 solution by microwave heating. Increasing the MgCl2 concentration can improve both the dielectric constant and conductivity of the solution, which is advantageous for the solution to absorb more microwave energy. Consequently, the conversion rate of phosphogypsum (PG) into α-HPG was improved at higher MgCl2 concentrations. In 2.62 mol/L MgCl2 solution, the heating time is shortened to 7 min from room temperature to 95 °C, and PG was converted to α-HPG within 60 min. The morphology of α-HPG could be controlled by chemical adsorption of citric acid onto its terminal surface. In a solution containing 2.62 mol/L MgCl2 and 1.63 × 10-2 mol/L citric acid, PG was completely transformed into α-HPG at 90 min by microwave heating, whereas the reaction time was delayed to 180 min using electric heating. Accordingly, microwave heating is a highly efficient and energy-saving method for the preparation of α-HPG.

Novel TiO2-Supported Gold Nanoflowers for Efficient Photocatalytic NOx Abatement

In this study, we pioneered the synthesis of nanoflower-shaped TiO2-supported Au photocatalysts and investigated their properties. Au nanoflowers (Au NFs) were prepared by a Na-citrate and hydroquinone-based preparation method, followed by wet impregnation of the derived Au NFs on the surface of TiO2 nanorods (TNR). A uniform and homogeneous distribution of Au NFs was observed in the TNR + NF(0.7) sample (lower Na-citrate concentration), while their distribution was heterogeneous in the TNR + NF(1.4) sample (higher Na-citrate concentration). The UV-Vis DR spectra revealed the size- and shape-dependent optical properties of the Au NFs, with the LSPR effect observed in the visible region. The solid-state EPR spectra showed the presence of Ti3+, oxygen vacancies and electron interactions with organic compounds on the catalyst surface. In the case of the TNR + NF(0.7) sample, high photocatalytic activity was observed in the H2-assisted reduction of NO2 to N2 at room temperature under visible-light illumination. In contrast, the TNR + NF(1.4) catalyst as well as the heat-treated samples showed no ability to reduce NO2 under visible light, indicating the presence of deformed Au NFs limiting the LSPR effect. These results emphasized the importance of the choice of synthesis method, as this could strongly influence the photocatalytic activity of the Au NFs.