Photocatalytic materials and semiconductors of appropriate structural and morphological architectures as well as energy band gaps are materials needed for mitigating current environmental problems, ...as these materials have the ability to exploit the full spectrum of solar light in several applications. Thus, constructing a Z-scheme heterojunction is an ideal approach to overcoming the limitations of a single component or traditional heterogeneous catalysts for the competent removal of organic chemicals present in wastewater, to mention just one of the areas of application. A Z-scheme catalyst possesses many attributes, including enhanced light-harvesting capacity, strong redox ability and different oxidation and reduction positions. In the present work, a novel ternary Z-scheme photocatalyst, i.e., Bi2WO6/C-dots/TiO2, has been prepared by a facile chemical wet technique. The prepared solar light-driven Z-scheme composite was characterized by many analytical and spectroscopic practices, including powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption–desorption isotherm, Fourier-transform infrared spectroscopy (FT-IR), photoluminescence (PL) and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the Bi2WO6/C-dots/TiO2 composite was evaluated by studying the degradation of fluoroquinolone drug, levofloxacin under solar light irradiation. Almost complete (99%) decomposition of the levofloxacin drug was observed in 90 min of sunlight irradiation. The effect of catalyst loading, initial substrate concentration and pH of the reaction was also optimized. The photocatalytic activity of the prepared catalyst was also compared with that of bare Bi2WO6, TiO2 and TiO2/C-dots under optimized conditions. Scavenger radical trap studies and terephthalic acid (TPA) fluorescence technique were done to understand the role of the photo-induced active radical ions that witnessed the decomposition of levofloxacin. Based on these studies, the plausible degradation trail of levofloxacin was proposed and was further supported by LC-MS analysis.
Introduction
Deficits in social cognition have been associated with the onset of emotional and behavioural problems, but the biological mechanisms underlying this relationship remain unclear.
...Objectives
This study examined whether diurnal cortisol patterns, systemic inflammation, or both, explained the association between social cognition difficulties and subsequent emotional and behavioural symptoms.
Methods
The sample consisted of 714 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC) with valid data on cortisol measures (age 15 years) and emotional or behavioural problems (age 17 years). Social cognition abilities were measured at 8, 11, and 14 years old. Inflammation was measured using serum levels of interleukin 6 (IL-6, age 9 years) and C-reactive protein (CRP, age 9 and 16 years). Bayesian structural equation modelling was used to investigate the mediating effect of cortisol or inflammation on the association between social cognitive difficulties and emotional or behavioural problems.
Results
Children with social cognition difficulties were associated with later emotional and behavioural problems. Flattened diurnal cortisol slope was associated with the hyperactivity/inattention problem two years later. Mediation analyses revealed that lower morning cortisol significantly mediated the associations between social communication difficulties at 8 years with hyperactivity/inattention and conduct problems in adolescence, with the adjustment of inflammation and all covariates. Systemic inflammation was not related to social cognitive difficulties or future emotional and behavioural problems.
Conclusions
The finding suggests that social cognition is related to cortisol activities longitudinally. It also expands the evidence that adolescents with behavioural problems are characterised by hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis.
Disclosure
No significant relationships.
Despite the growing interest in the involvement of decision-making under conditions of risk in the onset of eating disorders in adolescence, no studies have investigated how the development of ...decision-making across that period may influence such a risk. Using data from the Millennium Cohort Study this study explored whether changes in performance on the Cambridge Gambling Task (CGT) between age 11 and age 14 were associated with presence of eating disorder (ED) symptoms at age 14.
Latent class analysis was used to identify groups with distinct profiles based on their responses to questions investigating eating and dieting at age 14. CGT change scores were used as predictors of latent class membership in a logistic regression while accounting for confounders.
In our sample of 11,303 participants, the best class solution was a two-class one reflecting high and low risk for ED symptoms. Higher risk-taking scores and lower quality of decision-making scores at age 11 were associated with increased odds of belonging to the high-risk group at age 14. Risk-taking was reduced from age 11 to age 14, but a smaller reduction was associated with a higher probability of being in the higher risk group at age 14. The change over time in the other CGT measures was not associated with risk for ED symptoms.
Atypical change in risk-taking from early to middle adolescence may be implicated in the risk of ED symptoms in middle adolescence. These results should be replicated in clinical samples.
This paper deals with a dynamic analysis on a low concentration solar power plants coupled with Organic Rankine Cycles (ORC), which can be an alternative to PV systems because of their capability of ...providing a smoother electricity production due to their thermal inertia. At least within certain restraints, moreover they are able to exploit diffused solar radiation.
The dynamic model of a plant with static Compound Parabolic Collectors and an ORC system, using a rotary volumetric expander, was developed using the simulation tool AMESim. All the main components of the plant are modelled: solar collectors field, heat transfer fluid circuit, heat exchangers and the ORC system. The plant response to the radiation of different days was analyzed to quantify the daily production and the trend of various plant parameters. Real ambient conditions were employed for the simulations by using data obtained by historical series.
The results showed that the employment of a volumetric expansion device with variable rotating speed allows the plant to operate at different radiations and ambient temperatures without the need of any storage system or external heat sources. Results can be extended to other applications, such as low temperature waste heat recovery or geothermal systems.
•We built a transient model of both the solar field and the thermodynamic module.•We performed simulations on five consecutive.•We analyzed the influence of the concentration on the specific production per unit surface of collectors and occupied ground.•A volumetric expansion device can limit the efficiency losses by variable speed operations.•Warm-up and shut down influence is not negligible and a proper control system is needed.
Green synthesis is employed to prepare cobalt/cellulose nanocomposites with cubic (α-cobalt) cobalt as a main component with antibacterial and magnetic properties. An
in situ
reduction of aqueous ...solutions of cobalt ions on a model cellulose substrate surface using hydrogen gas affords spherical, cellulose-stabilised cobalt nanoclusters with magnetic properties and an average diameter of 7 nm that are distributed evenly over the surface of the cellulose fibres. These cobalt/cellulose nanocomposites exhibit good antibacterial action against opportunistic pathogens both Gram-positive (
S. aureus
) and Gram-negative (
E. coli
,
A. baumannii
and
P. aeruginosa
), with zones of inhibition up to 15 mm, thereby encouraging the deployment of these advanced materials for the treatment of wastewater or within medical dressings. This method of preparation is compared with the analogous
in situ
reduction of cobalt ions on a cellulose surface using sodium borohydride as reducing agent.
Green synthesis is employed to prepare cobalt/cellulose nanocomposites with antibacterial and magnetic properties. The cellulose-stabilised, cubic (α-cobalt) cobalt nanoclusters are distributed evenly over the surface of the cellulose fibres.
•We made a numerical and experimental study on a volumetric rotary Wankel expander for small size power plants.•The numerical results were close enough to the experiments with compressed air.•We ...studied the application of several working fluids at low temperature.•We evaluated the power and the efficiency as a function of temperature and working fluid.•The Wankel expander proved to be suitable for a wide range of inlet thermal power at constant isentropic efficiency.
The determination of the most suitable operative fluid for the various types of Organic Rankine Cycle expansion machines has been the object of an abundant literature. In this study an analysis was carried out in a rotary volumetric expander based on the Wankel concept, which was never studied before for this application.
This paper is focused in assessing the proper coupling between the temperature at which the heat is available, and hence the saturation temperature at the inlet, and the working fluid that is to be used in an expander of given displacement to get the desired mechanical power.
This analysis was carried out by means of a numerical model of the expander that was validated by comparison with the data measured at the dyno on a prototype that was built at the University of Pisa and operated with compressed air. The comparison was carried out in terms of indicated pressure, delivered torque and working fluid mass flow rate.
The operative maps of this expander were evaluated by considering the working conditions that give an isentropic efficiency higher than a fixed value. By this way, it was possible to evaluate the relationship between the used working fluid, the inlet temperature and the delivered mechanical power.
The cylindrical drift chamber is the most innovative part of the MEG II detector, the upgraded version of the MEG experiment. The MEG II chamber differs from the MEG one because it is a single volume ...cylindrical structure, instead of a segmented one, chosen to improve its resolutions and efficiency in detecting low energy positrons from muon decays at rest. In this paper, we show the characteristics and performances of this fundamental part of the MEG II apparatus and we discuss the impact of its higher resolution and efficiency on the sensitivity of the MEG II experiment. Because of its innovative structure and high quality resolution and efficiency the MEG II cylindrical drift chamber will be a cornerstone in the development of an ideal tracking detector for future positron-electron collider machines.
Utilisation of CO
as a chemical reagent is challenging, due to the molecule's inherent chemical stability. However, CO
reacts promptly at high temperature (∼1000 °C) with alkaline-earth oxides to ...form carbonates and such reactions are used towards capture and re-utilisation. In this work, this concept is extended and CO
is utilised as a reagent to modify the crystal structure of mixed-metal inorganic solids. Modification of the crystal structure is a "tool" used by materials scientists to tailor the physical property of solids. CO
gas was reacted with several isostructural mixed-metal oxides Sr
CuO
, Sr
Ba
CuO
and Ba
PdO
. These oxides are carefully selected to show anion vacancies in their crystal structure, to act as host sites for CO
molecules, leading to the formation of carbonate anions, (CO
)
. The corresponding oxide carbonates were formed successfully and the favourable formation of SrCO
as secondary phase was minimised via an innovative, yet simple synthetic procedure involving alternating of CO
and air. We also derived a simple model to predict the kinetics of the reactions for the cuprates, using first-principles density functional theory and assimilating the reaction to a gas-surface process.
Utilisation of CO2 as a chemical reagent is challenging, due to the molecule's inherent chemical stability. However, CO2 reacts promptly at high temperature (∼1000 °C) with alkaline‐earth oxides to ...form carbonates and such reactions are used towards capture and re‐utilisation. In this work, this concept is extended and CO2 is utilised as a reagent to modify the crystal structure of mixed‐metal inorganic solids. Modification of the crystal structure is a “tool” used by materials scientists to tailor the physical property of solids. CO2 gas was reacted with several isostructural mixed‐metal oxides Sr2CuO3, Sr1.8Ba0.2CuO3 and Ba2PdO3. These oxides are carefully selected to show anion vacancies in their crystal structure, to act as host sites for CO2 molecules, leading to the formation of carbonate anions, (CO3)2−. The corresponding oxide carbonates were formed successfully and the favourable formation of SrCO3 as secondary phase was minimised via an innovative, yet simple synthetic procedure involving alternating of CO2 and air. We also derived a simple model to predict the kinetics of the reactions for the cuprates, using first‐principles density functional theory and assimilating the reaction to a gas‐surface process.
CO2 is abundant and free but environmentally unfriendly. It is also unreactive, hence re‐purposing can be a challenge. This research article describes how CO2 can be used as a useful reagent towards the preparation and/or chemical and structural modification of inorganic solids. This approach is of wide application hence, in the future, it may become part of a toolbox of methods to reduce the environmental impact of CO2.
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