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Light-emitting dendrimer:exciplex host-based solution-processed white organic light-emitting diodes
No full textSolution-processed monochrome and white organic light-emitting diodes (OLEDs) that have a light-emitting layer composed of a 4,4′,4″-tris(carbazol-9-yl)triphenylamine (TCTA) and (5-terphenyl-1,3-phenylene)bis(diphenylphosphine oxide) (POPH) exciplex host and soluble blue, green and/or red phosphorescent dendrimers have been fabricated and characterised. The OLED performance characteristics were found to be scan dependent, with the first scans having large external quantum efficiencies (EQEs) at low luminance, with subsequent scans showing stable performance. The monochrome (blue, green and red) films were found to have high photoluminescence quantum yields, relatively balanced hole and electron mobilities, and the OLEDs had stable EQEs of between 9 and 12% at 100 cd m−2 over multiple scans. The blue, green and red emissive materials were blended with the exciplex host, with their ratio tuned to achieve white emission. The optimal blend ratio provided white OLEDs that had EQEs of 11.7% and 10.6% at 100 cd m−2 and 1000 cd m−2, respectively. The best balance of 1931 Commission Internationale d'Eclairage (CIE) coordinates (0.40,0.40), Colour Rendering Index (70), and Delta uv (0.003) was achieved for an OLED with the light-emitting layer containing the blue, green and red dendrimers in a ratio of 20.0:0.4:0.8 wt%. A feature of the white OLEDs was the stability of the CIE coordinates, with a change of only (0.013,0.005) between a luminance of 100 cd m−2 and 4000 cd m−2
Isolation and self-regulation processes in simulated postfire microsites promote plant species diversity
No full textMechanisms responsible for the high species richness of disturbance-prone floras remain speculative. After fire, speciose shrublands in Australia possess mosaics of microsites that vary widely in seedling density and species richness and provide an ideal context in which to test a) the self-regulation hypothesis that species survive and grow better as they become rarer in the mix, and b) the synergistic hypothesis that species perform relatively better at increasing levels of competition under poorer growing conditions. Both processes should serve to promote species co-occurrence at the local scale. We planted germinants of 10 native shrub species in nutrient-poor sands in 30 cm (high density) and 40 cm (low density) square, buried but open-bottomed, boxes. Each box simulated a field-type microsite, containing one individual (solitary), or 49 individuals with each species contributing three (5% of the total, rare), five (10%, equal), 25 (51%, dominant) or 49 (100%, monoculture) seedlings. Best performance per plant (gauged as % survival × shoot mass per survivor) occurred among all ten species when solitary in the box. When grown in the presence of other plants, mixtures of species performed better on a 1) per plant, and 2) whole microsite, basis than monocultures at both densities, and 3) when rare rather than dominant in the mix, conforming with the self-regulation hypothesis, all independent of species identity. Expected niche differentiation of soil-based resources among species mixes would explain increased fitness per plant with decreasing abundance per species. Overall performance (performance per plant × absolute number of survivors per microsite) was maximized when all species were moderately rare (10% of initial numbers among 10 species) in the mix. Under good (low density) and poor (high density) growing conditions, increasing competition (indexed as total shoot mass) from the dominant species in the mix, led to a gradual fall and merging of shoot mass of the remaining nine species at these two densities, but species richness did not change. This outcome provides only limited support for the synergistic model of species coexistence (species richness should have declined at a decreasing rate) but is consistent with the concept of self-regulation. We conclude that mosaics of microsite types maintain biodiversity of speciose, disturbance-prone ecosystems through both isolating mechanisms (in seed-poor microsites with negligible competition) and compensatory self-regulation mechanisms (in species-rich microsites with intense competition)
How does biochar aging affect NH3 volatilization and GHGs emissions from agricultural soils?
No full textBiochar has been considered as a potential tool to mitigate soil ammonia (NH3) volatilization and greenhouse gases (GHGs) emissions in recent years. However, the aging effect of biochar on soils remains elusive, which introduces uncertainty on the effectiveness of biochar to mitigate global warming in a long term. Here, a meta-analysis of 22 published works of literature with 217 observations was conducted to systematically explore the aging effect of biochar on soil NH3 and GHGs emissions. The results show that, in comparison with the fresh biochar, the aging makes biochar more effective to decrease soil NH3 volatilization by 7% and less risk to contribute CH4 emissions by 11%. However, the mitigation effect of biochar on soil N2O emissions is decreased by 15% due to aging. Additionally, aging leads to a promotion effect on soil CO2 emissions by 25% than fresh biochar. Our findings suggest that along with aging, particularly the effect of artificial aging, biochar could further benefit the alleviation of soil NH3 volatilization, whereas its potential role to mitigate global warming may decrease. This study provides a systematic assessment of the aging effect of biochar to mitigate soil NH3 and GHGs, which can provide a scientific basis for the sustainable green development of biochar application
Transformation of HCl during pyrolysis of biomass and its model compounds
No full textThe release behavior of chlorine (Cl) during biomass pyrolysis has not been fully understood yet due to the complex transformation of hydrogen chloride (HCl). Here, we systematically investigate the transformation of HCl in vapor phase and its interactions with pyrolyzing biomass/char particles during biomass pyrolysis. Four biomass model compounds (cellulose, xylan, pectin, and alkali lignin) and an acid-washed wood were pyrolyzed in a fixed-bed reactor at 300–600 ℃ to produce Cl-free volatiles that reacted with the HCl injected downstream of the reactor. To explore the vapor–solid interactions of HCl with pyrolyzing biomass/char particles, the acid-washed wood was also pyrolyzed in a HCl atmosphere. The role of potassium (K) in the transformation of HCl was revealed via pyrolyzing a wood loaded with potassium carbonate (K2CO3). For all the experiments, the Cl distributed in char, heavy oil (condensed at 110 ℃), light oil (condensed at 0 ℃), and pyrolytic gases (as CH3Cl) was quantified. The results demonstrate that the vapor-phase reactions of HCl with the volatiles from pectin, lignin, and the acid-washed wood generate considerable amounts of methyl chloride (CH3Cl) but do not contribute to organic Cl in bio-oil. Increasing the temperatures of both pyrolysis and vapor-phase reaction promotes the generation of CH3Cl. The vapor–solid interactions of HCl with pyrolyzing biomass/char particles substantially enhance the formation of CH3Cl during the pyrolysis of the acid-washed wood at 300–500 ℃ because of the possible combination of HCl with the methyl radicals released in the initial stage of lignin pyrolysis. In addition, the vapor–solid interactions cause 120–490 μg/g feedstock of water-soluble Cl and 410–1120 μg/g feedstock of water-insoluble Cl being retained in the chars, which are produced from the capture of HCl by pores and carbon active sites in chars, respectively. The addition of K2CO3 catalyzes the cracking of lignin and thereby enhances the methylation of HCl in both vapor-phase reactions and vapor–solid interactions. It also increases the retention of Cl in the chars due to its capture by K
Incremental cost of venous thromboembolism in trauma patients with contraindications to prophylactic anticoagulation: A prospective economic study
No full textVenous thromboembolism (VTE) is common in patients after major trauma. Attributable cost of VTE and whether this is related to the severity of injury have not been thoroughly investigated. We aimed to define the hospitalization costs of VTE and assess whether the costs were related to the severity of injury in this prospective economic study. Cost data of each patient enrolled in the da Vinci trial were drawn from hospital finance departments and standardized to 2020 Australian dollars (A4307) as well as the hospitalization costs (A1210; p < 0.001 and A43,292 (95% confidence interval [CI] 12,624–73,961, p = 0.006) and 41,680 (95%CI 7766–75,594, p = 0.016) after adjusted for Trauma Embolic Scoring System and Injury Severity Scores, respectively. VTE was common after major trauma and incurred a substantial incremental financial cost to the healthcare system, especially among those who had extremely severe injuries
Ionic mass transfer at point electrodes located at cathode support plate in an electrorefining cell in presence of rectangular turbulent promoters
Full text linkCurrent density plays a major role in deciding the plant size, current efficiency, and energy consumption in electrorefining cells. In general, operating current density will be 40% of the limiting current density. Forced circulation of the electrolyte in the presence of promoters improves the mass transfer coefficient. In the present study, rectangular turbulence promoters are fitted at the bottom side of the cell to improve the mass transfer coefficient at the cathode support plate. The limiting current density technique is used to measure the mass transfer coefficient. The variables covered in the present study are the effects of flow rate, promoter height, and spacing among the promoters. The electrolyte consists of copper sulfate and sulphuric acid. At a regulated flow rate, the electrolyte is pumped from the recirculation tank to the cell through an intermediate overhead tank. The limiting current density increased with an increasing flow rate in the presence of promoters, and thus the overall mass transfer coefficient on the cathode support plate also improved. With an increase in the flow rate of the electrolyte from 6.67 × 10−6 to 153.33 m3/s, limiting current density increased from 356.8 to 488.8 A/m2 for spacing of 0.30 m, with a promoter height of 0.01 m. However, it is noteworthy that when the promoter height is increased from 0.01 to 0.07 m, the overall mass transfer coefficient is found to increase up to 60%, but with the further increase in the promoter height to 0.30 m the mass transfer coefficient starts to decrease. Therefore, the optimized cell parameters are established in this work. The current sustainable concept of employing rectangular turbulence promoters will bring benefits to any precious metal refining or electrowinning tank house electrolytes
Lifestyle and complementary therapies in multiple sclerosis guidelines: Systematic review
No full textManagement of multiple sclerosis (MS) may comprise clinical interventions and self-management strategies, including complementary therapies and modifiable lifestyle factors such as exercise and smoking cessation. Lifestyle modifications and complementary therapies with proven safety and efficacy are essential as part of best-practice MS management, especially when faced with limited access to healthcare services. However, it is unclear to what extent MS clinical practice guidelines and consensus statements address these strategies. A systematic review was conducted, wherein MEDLINE, EMBASE, PsycINFO, CINAHL, Scopus, Web of Science, guideline databases and developer sites were searched for guidelines and consensus statements that addressed lifestyle modifications and complementary therapies of interest. Two researchers independently screened articles, extracted data and assessed guideline quality using the Appraisal of Guidelines for Research and Evaluation version II. Thirty-one guidelines and consensus statements were included. Quality was high for ‘clarity of presentation’ (77%) and ‘scope and purpose’ (73%), moderate for ‘stakeholder development’ (56%), ‘rigour of development’ (48%) and ‘editorial independence’ (47%), and low for ‘applicability’ (29%). Two guidelines, related to physical activity and exercise, mindfulness, smoking cessation, and vitamin D and polyunsaturated fatty acid supplementation, scored high in all domains. These guidelines were two of only four guidelines intended for use by people with MS. High-quality guidelines and consensus statements to guide lifestyle modifications and complementary therapies in MS management are limited. Our findings indicate the need for more guidelines intended for use by people with MS, and a further focus on implementation resources
Densities and Apparent Molar Volumes of Rubidium and Cesium Triflates to High Concentrations in Aqueous Solution at Temperatures from 293.15 to 343.15 K
No full textDensities of aqueous solutions of rubidium triflate (RbTf) and cesium triflate (CsTf), where Tf– is the trifluoromethanesulfonate ion (CF3SO3–), have been measured by vibrating-tube densimetry at temperatures from 293.15 to 343.15 K at 5 K intervals. Concentrations ranged from 0.03 to 5.0 mol·kg–1 for RbTf and from 0.02 to 3.9 mol·kg–1 for CsTf. No volumetric data for either salt appear to have been published previously. Apparent molar volumes (Vϕ) calculated from the densities were well modeled with Pitzer equations. Standard partial molar volumes, Vo, for RbTf(aq) and CsTf(aq) were determined by extrapolation of the Pitzer fits to infinite dilution. Isobaric coefficients of thermal expansion (expansivities), α, derived from the temperature dependence of the densities, increased with concentration, especially at lower T, consistent with the solvent-structure-breaking character of their component ions. Combination of the present Vo values with a common extra-thermodynamic assumption and relevant literature data provided ionic volumes, Vo(Rb+,aq) and Vo(Cs+,aq), that show more realistic temperature dependences than previous estimates
Exacerbation of chronic cigarette-smoke induced lung disease by rhinovirus in mice
No full textA significant proportion of chronic obstructive pulmonary disease exacerbations are strongly associated with rhinovirus infection (HRV). In this study, we combined long-term cigarette smoke exposure with HRV infection in a mouse model. Our aim was to better understand the effects of HRV infection on such exacerbations, using a realistic method for generating a COPD-like phenotype. After 12-weeks of cigarette smoke exposure, adult female BALB/c mice were infected with HRV-1A and three days later we assessed a range of outcomes including lung volume and function, collected lung tissue for measurement of viral titre, bronchoalveolar lavage for assessment of pulmonary inflammation and levels of key mediators, and fixed lungs for stereological structural analyses. Cigarette smoke exposure alone significantly increased total cells and macrophages, and reduced MIP-2 in bronchoalveolar lavage. HRV-1A infection alone increased neutrophilic inflammation, IP-10 and total protein in lavage and also increased specific airway resistance measured at functional residual capacity. Cigarette smoke and HRV-1A together impacted various lung structural parameters including increasing stereological lung volume. Our results show that long-term cigarette smoke exposure and HRV-1A infection both individually impact respiratory outcomes and combine to alter aspects of lung structure in a mouse model, thus providing insight into the development of future mechanistic studies and appropriate interventions in human disease
Does galvanic coupling with pyrite increase the rate of dissolution of chalcopyrite under ambient conditions? An electrochemical study
No full textThe role of galvanic coupling of chalcopyrite and pyrite in the enhanced rate of dissolution of chalcopyrite in acidic sulfate and chloride solutions at 30 °C has been defined in a detailed electrochemical study.
The results indicate that, under ambient conditions, the effect of galvanic contact with pyrite only marginally increases the rate of dissolution of chalcopyrite in both sulfate and chloride solutions containing iron(III) despite significant increases in the mixed potential of chalcopyrite. This has been shown to be due to the fact that the effect of potential on the rate of anodic oxidation of chalcopyrite is small in the relevant potential under these conditions. This is confirmed by the observation that the mixed potential and, therefore, the galvanic current is largely unaffected by a 4-fold decrease in pyrite surface area. The galvanic current transients compared well with potentiostatic current/time transients for chalcopyrite at the mixed potential observed during coupling.
In the case of copper(II) as the oxidant in chloride solutions, the galvanic currents are small due largely to the fact that the increase in chalcopyrite potential and decrease in pyrite potential are small as a result of the lower reduction potential of the copper(II)/copper(I) couple than the iron(III)/iron(II) couple. The galvanic currents with dissolved oxygen as the oxidant are significantly lower than with iron(III) as the oxidant and confirm the well-known fact that oxygen is less effective than iron(III) as an oxidant for chalcopyrite even when galvanic coupled to pyrite.
The electrochemical data obtained in this study indicate that the small galvanic currents observed do likely not account for the relatively large increases in rate previously observed in agitated leaching of chalcopyrite/pyrite slurries at elevated temperatures