Decrease In Emission Intensity Research Articles

Photoluminescent Copper Nanoclusters in “Turn-Off/Turn-On” Sensing of Picric Acid/Hydrogen Peroxide

In this paper, we illustrate the synthesis, characterization, and application of a Bovine Serum Albumin-stabilized copper nanocluster (BSA@CuNCs)-based photoluminescence (PL) bifunctional sensor for the selective and rapid sensing of picric acid (PA) and hydrogen peroxide (H2O2). Blue-emitting copper nanoclusters were synthesized using one-pot synthesis at room temperature. The PL intensity of BSA@CuNCs was shown to be quenched (“Turn-off”) with an increase in the concentration of PA and intensified (“Turn-on”) with the addition of H2O2. The quenching of PL intensity of BSA@CuNCs was shown to be extremely selective and rapid towards PA. A linear decrease in the PL emission intensity of BSA@CuNCs was observed with a PA concentration in the range of 0–15 μM. An extremely low detection limit of 60 nM (3σ/k) was calculated. The as-prepared BSA@CuNCs also exhibited superior selectivity for PA detection in aqueous medium. The developed sensor was also utilized for the sensing of PA in natural water samples. The probe was found to be extremely sensitive towards the detection of H2O2. An increase in the PL intensity of BSA@CuNCs was seen with the addition of H2O2, with a detection limit of 0.11 μM.

Evaluation of the Structural, Near-Infrared Luminescence, and Radioluminescence Properties of Nd3+ Activated TTB-Lead Metatantalate Phosphors

The study reports the structural and spectroscopic properties of Nd3+ doped lead metatantalate phosphor series fabricated by conventional solid state method. XRD results of the PbTa2O6 phase confirm the tungsten bronze symmetry and single-phase structure between 0.5 and 10 mol% Nd3+ concentrations. The lead decrease in the structure can be associated with maintaining the charge balance and single phase due to evaporation during sintering. In SEM micrographs, the grains exhibited shapeless morphology, and the grain sizes varied from 0.5 to 7 m. In EDS results, the increase of Ta/Pb ratio in grain surfaces indicated some lead evaporation, as reported in previous studies. The absorption spectrum of PbTa2O6 host peaked around 275-280 nm, and the band gap was found to be 3.7±0.2 eV. The absorptions of Nd3+ doped phophors shifted the high wavelenght or the low band gap, where the band gaps were found between 3.1±0.2 and 3.3±0.2 eV. The PL emissions of the phosphors in near-inrared region were observed with the transitions of 4F3/2→4I9/2 (at 875 nm) and 4F3/2→4I11/2 (at 1060 nm) of Nd3+. The RL emissions or X-ray excited luminescence were monitored with the transitions of 4F3/2→4I9/2 (at 875 nm), 4F3/2→4I11/2 (at 1065 nm) in the infrared region, and the transitions of 2F(2)5/2→4F9/2, 2F(2)5/2→2H(2)11/2, 2F(2)5/2→4G5/2, 2F(2)5/2→4G7/2, 2F(2)5/2→4G9/2 in the visible region corresponding to at around 430, 455, 490, 525, and 570 nm, respectively. PL and RL emissions of the phosphors exhibited the decreasing emission intensity over 5 mol% due to the concentration quenching which may be associated with cross-relaxing mechanism. In the PL and RL spectral profiles, the similarity of splitting levels was attributed to the similarity of the local symmetry of the ligand ions surrounding the Nd3+ ion. The CIE coordinates obtained using RL emissions were found close to the blue region due to visible region transitions.

100 Methane Production in Roughage-Lacking Diets Containing Ionized Amino Acids as Antibiotic Alternative

Abstract The use of antibiotics in animal feed, commonly used as a strategy to achieve greater daily weight gains and recently as way to reduce methane emission, might result in the selection of resistant microorganisms and certain bacterial strains isolated from cattle are resistant to multiple antibiotics and could be human health hazards. To evaluate methane production in ruminant diet without roughage containing ionized amino acids as antibiotic alternative, twenty-four Nellore young bulls were allotted into two groups. The first group was fed with high-grain diet without roughage and without antibiotics diet, containing 82 mg/kg of ionized amino acids mixture (L-lysine and L-taurine HCl 99%, pH 9.74) manufactured by MJ Animal Nutrition. The second group was fed with high-grain diet containing Brachiaria brizantha hay (15% dry matter) and sodium monensin (120 mgּּ animal -1 ּּ day-1). It was not used a negative control group to avoid metabolic disturbances. The feedlot time was 100 days. The weight measurements were performed at the beginning of the trial period and monthly, always with water restriction and fasting for 18 hours, even before slaughter. A completely randomized design was used. Methane emission was measured using the sulfur hexafluoride technique and daily dry matter intake were measured in GrowSafe system. There was no detection of lameness or laminitis in any groups and there were no changes in feed conversion ratio (FCR). The total methane emission (-77.11%) and the methane emission per dry matter intake (DMI; -57.12 %), per average daily weight gain (ADG; -71.11%) and per kilogram of carcass (-70.07%) were different between treatments (P < 0.0001), resulting in decreased emission intensities for group fed without roughage with diet containing ionized amino acids. We conclude that fed without roughage with diet containing ionized amino acids was an effective strategy as an antibiotic alternative, mitigate GHG emissions and facilitate feedlot diets management. In field conditions, the roughage-lacking diets represent advantage, especially regarding its administration to a large amount of the animals just once a week or less, no need area, infra-structure and expertise to produce, preserve and feeding roughage.

Impact of International Trade on the Carbon Intensity of Human Well-Being

There has been a longstanding debate about the impact of international trade on the environment and human well-being, yet there is little known about such environment and human well-being trade-off. Here, we explore the effect of international trade on the carbon intensity of human well-being (CIWB) globally under the current global trade system and a hypothetical no-trade scenario. We found that between 1995 and 2015, CIWB of 41% of countries declined and 59% of countries increased, caused by international trade, and this resulted in a reduction of the global CIWB and a decline in CIWB inequality between countries. International trade decreased CIWB for high- and upper-middle-income countries and increased CIWB for lower- and middle-income countries. In addition, our results also show that decreases in emission intensity are the most important driver of lower CIWB and the percentage contribution of emission intensity to the improvement in CIWB increases with income. The reduction of emission intensity, population growth, and increase in life expectancy all contribute to CIWB reduction, while the consumption level is the primary factor driving CIWB growth. Our results underscore the importance of studying the impact of international trade on the CIWB of countries at different stages of development.

Tuning the Thermometric Features in 1D Luminescent EuIII and TbIII Coordination Polymers through Different Bridge Phosphine Oxide Ligands.

TbIII and EuIII systems have been investigated as ratiometric luminescent temperature probes in luminescent coordination polymers due to TbIII → EuIII energy transfer (ET). To help understand how ion-ion separation, chain conformation as well as excitation channel impact their thermometric properties, herein, [Eu(tfaa)3(μ-L)Tb(tfaa)3]n one-dimensional (1D) coordination polymers (tfaa- = trifluoroacetylacetonate, and L = [(diphenylphosphoryl)R](diphenyl)phosphine oxide, R = ethyl - dppeo - or butyl - dppbo) were synthesized. The short μ-dppeo bridge ligand leads to a more linear 1D polymeric chain, while the longer μ-dppbo bridge leads to tighter packed chains. As the temperature rises from 80 K, upon direct TbIII excitation at 488 nm, the TbIII emission intensity decreases, while the EuIII emission intensity increases after 160 and 200 K when L = dppeo or dppbo, respectively. The temperature-dependent emission intensities, due to TbIII → EuIII ET, enable the development of ratiometric luminescent temperature probes featuring maximum relative thermal sensitivity up to 3.8% K-1 (250 K, L = dppbo, excitation at 488 nm). On the other hand, the same system displays maximum thermal sensitivity up to 3.5% K-1 (323 K) upon ligand excitation at 300 nm. Thus, by changing the excitation channel and bridge ligand that leads to modification of the polymer conformations, the maximum relative thermal sensitivity can be tuned.

Effect of Nd3+ Doping on Structural, Near-Infrared, and Cathodoluminescent Properties for Cadmium Tantalate Phosphors

Cd1-xTa2O6:xNd3+ (x=0.5, 1.5, 3, 5, 7, and 10 mol%) phosphor series were fabricated by conventional solid state method at 1100 °C for 17 hours. The samples of cadmium tantalate were investigated by structural (XRD, SEM) and spectroscopic (CL, PL) analyses. In XRD results, the symmetry of CdTa2O6 phase with orthorhombic columbite structure was confirmed between 0.5 and 10 mol% Nd3+ doping concentrations. SEM analysis of the grains revealed round and shapeless morphology while grain sizes ranged from submicron to several microns. The emission spectra of Cd1-xTa2O6:xNd3+ (x=0.5, 1.5, 3, 5, 7 and 10 mol%) phosphor series recorded with the transitions of 4F3/2→4I9/2 and 4F3/2→4I11/2. Among these transitions, the transition 4F3/2→4I9/2 (at 889 nm) has a high near-infrared emission intensity, which can be attributed to the laser potential of the phosphor. The NIR emission of the phosphor increased with increasing concentration of Nd3+ up to 5 mol% and then declined because of concentration quenching phenomenon. The CL emission peak at about 450 nm found in all samples is related to the intrinsic emission of the cadmium tantalate host. In addition, Nd3+ doped phosphors exhibited the 4F3/2→4I9/2 transition of Nd3+ and defect-related CL emissions at 670 nm. Decreasing crystallinity with increasing Nd3+ concentration caused a decrease in host emission intensity at 450 nm.

Target-cycling synchronized rolling circle amplification strategy for biosensing Helicobacter pylori DNA.

Helicobacter pylori is closely linked to many gastric diseases such as gastric ulcers and duodenal ulcers. Therefore, biosensing H. pylori has attracted wide attention from both scientists and clinicians. Here, we proposed an electrochemiluminescence (ECL)-based platform that could sensitively detect H. pylori DNA. In this platform, a novel target-cycling synchronized rolling circle amplification was used for signal amplification. Silver nanoclusters (Ag NCs) were synthesized on the circle DNA products, embedding them with the ability to catalyze the electrochemical reduction of K2 S2 O8 , in turn resulting in rapid consumption of the ECL co-reactant near the working electrode, and leading to a decrease in the ECL emission intensity. In addition to its excellent stability and selectivity, the proposed strategy had a low detection limit of 10 pM, an indication that it can be beneficially applied to test biosamples. Furthermore, a biosensing chip was designed to improve the throughput and shed new light on large-scale clinical biosensing applications.

Refined assessment and decomposition analysis of carbon emissions in high-energy intensive industrial sectors in China

Carbon emissions from high-energy intensive industrial sectors are the focus of this study due to the huge energy consumption of these sectors. A refined carbon emission inventory of Chinese high-energy intensive industrial sectors in 2020 was first developed at the point source level. The results showed that coal-fired power plants (CFPPs) were the leading contributors to carbon emissions, followed by iron and steel smelting (ISS) and cement production (CMP). Provinces with high carbon emission intensity were mainly concentrated in the north and northeast coasts, while exhibiting a developed economic level and a concentration of heavy industries. Additionally, the growth in China's industrial carbon emissions from 1995 to 2020 can be divided into three phases. The largest decrease in emission intensity was observed in Central, Southwest, North, and East China. Furthermore, the economic structure remained the dominant driver of carbon emissions from the 10th to 13th Five-Year Plan (FYP), playing a positive promotional role. The contribution of economic structure, energy intensity, and energy structure to carbon emissions varied substantially by region and period. With the proposal of sustainable development and energy conservation in China, the influence of economic structure on the carbon emissions of industrial sectors has gradually weakened since the 11th FYP. The reduction in industrial carbon emissions in China under three scenarios could reach up to 46.6 % from 2030 to 2050. The results indicate that industrial carbon emission control in China needs to be integrated into the refined control pathway for conventional air pollutants, considering the spatial variability of industrial carbon emissions in China.

Molecular interaction of ethylene glycol to hurt Myoglobin: Insights from spectroscopic and molecular modeling studies

Myoglobin protein as a polypeptide chain with known sequence plays major role in facilitation of transfer, propagation and storage of oxygen in muscular tissue. Organic Osmolytes such as ethylene glycol are among the substances hindering the opening of proteins and besides, they maintain effective folding and protein performance in an improper ambient condition. For this purpose, in the present study the effect of the interaction of ethylene glycol organic solvent with myoglobin protein soluble in 50 mM Sodium Phosphate Buffer was investigated. The ethylene glycol effect on the myoglobin thermal stability was assessed and it was observed that the myoglobin thermal stability in the presence of ethylene glycol would increase. Also considering the effect of ethylene glycol on the myoglobin structure, the increase in UV–Vis adsorption and decrease of intrinsic fluorescence emission intensity in the protein spectra was observed. Quenching is performed statically and the binding between ethylene glycol and myoglobin is done autonomously, while the major complex formation forces between protein and ligand are of an der Waals interaction and hydrogen bonds. The theoretical results obtained from molecular docking technique shows that the binding energy is negative, and the electrostatic energies have minor contribution in the formation of binding as compared to hydrogen and Van der Waals bounds. Also, the results obtained from molecular simulation confirmed the stabilization of myoglobin protein due to the formation of the complex with ethylene glycol and were in full agreement with the experimental results.

Tracking the drivers of global greenhouse gas emissions with spillover effects in the post-financial crisis era

Addressing the challenge of climate change requires information on how to achieve GHG mitigation at the global scale. Here, we use the latest data available on economic interdependencies between economies as well as the associated emission activities to track the drivers of global GHG emissions during the post-financial crisis era from 2009 to 2019, among which the role of spillover in the context of global trade is highlighted. We found that the decrease in GHG emission intensity is the main factor responsible for slowing down global GHG emissions, particularly for the industrial sector. Production technology effect plays an increasingly important role in reducing GHG emissions, yet they are still unable to offset the increasing GHG emissions caused by final demand expansion with the economy rebound after the financial crisis. The bilateral analysis across regions demonstrates that spillover plays an important role in driving global GHG emissions, and it is likely that changes in technology and economic structure could result in more GHG emissions in other economies. This motivates us to raise questions about jurisdiction-based GHG mitigation policies and a call for global cooperation to reduce GHG emissions.

The impact of export tax rebate reform on industrial exporters’ soot emissions: Evidence from China

In this paper, we systematically explore the environmental effects of the export tax rebate rate reduction policy using the China Industrial Enterprise Database, the China Industrial Enterprise Pollution Database, and the China Customs Import and Export Database from 2005 to 2013. Our difference-in-difference (DID) estimates show that the reduction in the export tax rebate rate significantly reduces the intensity of corporate soot emissions, and this finding holds after a series of robustness tests. For every 1-unit reduction in export tax rebate rate, industrial exporters’ soot emission intensity decreases by 2.63%. The mechanism analysis shows that the decrease in soot generation, the decrease in coal use intensity, the increase in total amount and efficiency of soot treatment are important channels. Heterogeneity analysis shows that the reduction of export tax rebate rate has a more significant impact on the intensity of soot emissions of high pollution, high energy consumption and resource-based enterprises. This study may provide a reference for other developing countries that also rely on export tax rebates to adjust their policies to combine economic growth with pollution control.

Degradation of Model Compounds by 1O2-Generating Photosensitizer–Doped Membranes

We report the synthesis, performance, and stability of photosensitizer-doped membranes and their ability to generate singlet oxygen and degrade a model pharmaceutical. Specifically, we doped Clear Flex 50, a polyurethane rubber, with either terthiophene (3T) or one of two 1,8-naphthalimide-based (Nap-cbx and its gadolinium complex [Gd(Nap-cbx)3(NO3)3)] photosensitizers and photodegraded propranolol. After irradiating for 24 h with visible light in the presence of the 3T-doped membrane, the decreased emission intensity of propranolol was consistent with 42% degradation, while irradiation with UV light in the presence of a membrane doped with either Nap-cbx or [Gd(Nap-cbx)3](NO3)3 led to 36 and 41% degradation, respectively. Additionally, the three doped membranes successfully degraded several organic pollutants present in the standard MegaMix. Our findings show that the singlet oxygen-generating membranes experience minimal loss in performance after three 24-hour irradiation cycles.

Manipulating fluorescence by photo-switched spin-state conversions in an iron(ii)-based SCO-MOF.

Manipulating fluorescence by photo-switched spin-state conversions is an attractive prospect for applications in smart magneto-optical materials and devices. The challenge is how to modulate the energy transfer paths of the singlet excited state by light-induced spin-state conversions. In this work, a spin crossover (SCO) FeII-based fluorophore was embedded into a metal-organic framework (MOF) to tune the energy transfer paths. Compound 1 {Fe(TPA-diPy)[Ag(CN)2]2}·2EtOH (1) has an interpenetrated Hofmann-type structure, wherein the FeII ion is coordinated by a bidentate fluorophore ligand (TPA-diPy) and four cyanide nitrogen atoms and acts as the fluorescent-SCO unit. Magnetic susceptibility measurements revealed that 1 underwent an incomplete and gradual spin crossover with T1/2 = 161 K. Photomagnetic studies confirmed photo-induced spin state conversions between the low-spin (LS) and high-spin (HS) states, where the irradiation of 532 and 808 nm laser lights converted the LS and HS states to the HS and LS states, respectively. Variable-temperature fluorescence spectra study revealed an anomalous decrease in emission intensity upon the HS → LS transition, confirming the synergetic coupling between the fluorophore and SCO units. Alternating irradiation of 532 and 808 nm laser lights resulted in reversible fluorescence intensity changes, confirming spin state-controlled fluorescence in the SCO-MOF. Photo-monitored structural analyses and UV-vis spectroscopic studies demonstrated that the photo-induced spin state conversions changed energy transfer paths from the TPA fluorophore to the metal-centered charge transfer bands, ultimately leading to the switching of fluorescence intensities. This work represents a new prototype compound showing bidirectional photo-switched fluorescence by manipulating the spin states of iron(ii).

An ultrasensitive "mix-and-detect" kind of fluorescent biosensor for malaoxon detection using the AChE-ATCh-Ag-GO system.

Malaoxon, a highly toxic metabolite of malathion, can lead to severe harm or death if ingested. This study introduces a rapid and innovative fluorescent biosensor that relies on acetylcholinesterase (AChE) inhibition for detecting malaoxon using Ag-GO nanohybrid. The synthesized nanomaterials (GO, Ag-GO) were evaluated with multiple characterization methods to confirm their elemental composition, morphology, and crystalline structure. The fabricated biosensor works by utilizing AChE to catalyze the substrate acetylthiocholine (ATCh), which generates positively charged thiocholine (TCh) and triggers citrate-coated AgNP aggregation on the GO sheet, leading to an increase in fluorescence emission at 423 nm. However, the presence of malaoxon inhibits the AChE action and reduces the production of TCh, resulting in a decrease in fluorescence emission intensity. This mechanism allows the biosensor to detect a wide range of malaoxon concentrations with excellent linearity and low LOD and LOQ values of 0.001 pM to 1000 pM, 0.9 fM, and 3 fM, respectively. The biosensor also demonstrated superior inhibitory efficacy towards malaoxon compared to other OP pesticides, indicating its resistance to external influences. In practical sample testing, the biosensor displayed recoveries of over 98% with extremely low RSD% values. Based on the results obtained from the study, it can be concluded that the developed biosensor has the potential to be used in various real-world applications for detecting malaoxon in food, and water samples, with high sensitivity, accuracy, and reliability.

Experimental and Theoretical Study for Proton Transfer of Aggregated‐Induced Emission Active Fluorescent Schiff Bases

AbstractIn this paper, we studied the effect of increasing the conjugation in compound 3 on the proton transfer and aggregation‐induced emission properties. Compound 3 exhibited the dual absorption peak at 420 nm and 320 nm, which was redshifted by 50 nm compared to compound 2 (previous report). Compound 3 emits exhibited a peak at 530 nm with a Stokes’ shift of 110 nm after photoexcitation at 420 nm. In a high polarity medium, the absorption and emission spectra of compound 3 showed redshifts of 50 nm and 20 nm, respectively. Further, compound 3 displayed the aggregation‐induced emission enhancement in THF/H2O (60 % v/v). Additionally, the proton transfer process in compounds 2 and 3 was evaluated through theoretical calculations via determining the relative free energies of possible tautomeric forms. It was determined that the small energy barriers for compound 2 in the S1 state suggested the presence of the proton transfer process; however, high energy barriers and high stabilization and Boltzmann population of 3.KK tautomeric form at S0 and S1 state for compound 3 discommoded the proton transfer process. Further, the aggregated form of compound 3 (20 μM; CH3OH/HEPES buffer (4 : 1; v/v) pH=7.04) was utilized to recognize Cu2+ ions with the lowest detection limit of 1.5 nM and Stern‐Volmer binding constant of 2.8×105 M−1. A noted decrease in the hydrodynamic size of compound 3 from 400 nm to 40 nm in the presence of Cu2+ ions confirmed the disaggregation with a decrease in emission intensity. Compound 3 was also employed as a Cu2+ ions recognizer in different collected samples with good percentage recovery.

Life cycle assessment of co-firing coal and wood waste for bio-energy with carbon capture and storage – New South Wales study

Bio-Energy with Carbon Capture and Storage (BECCS) is an emerging energy conversion technology with the potential to deliver ‘negative emissions’, a net removal of CO2 from the atmosphere that may be necessary to achieve the net-zero targets adopted in the Glasgow Climate Pact at COP26. This paper uses Life Cycle Assessment (LCA) to investigate the environmental impacts of co-firing dry waste biomass (wood and paper waste) while implementing CCS technology (i.e., BECCS) in a conventional black coal-fired power plant. The LCA covers CO2 emissions and trace contaminants, determined via combustion modelling coupled with chemical-equilibrium-based ash-forming element and trace element calculations. As a case study, the context of New South Wales, Australia, is analysed to assesses the viability and discuss policy implications of waste co-firing BECCS as a future energy source for coal-reliant regions. An increase in co-firing ratio is found to decrease emission intensity. At current typical efficiencies, BECCS with a 10 % co-firing ratio can reduce emission intensity from 938 to 181kgCO2/MWh. At 20 % to 25 % co-firing, the emission intensity of BECCS is comparable with other renewable technologies, and negative emissions are achievable above 30 %, although waste availability in NSW is insufficient to achieve these levels. Moreover, BECCS increases environmental impact in all categories except for global warming potential (GWP), land use, and terrestrial acidification. Nonetheless, when aggregating all impacts, the large reduction in GWP drives an endpoint score reduction, indicating that co-fired BECCS may be preferred over sub-critical black (bituminous) coal-fired power without or with CCS, or other higher emission intensity coal-fired power generation. Therefore, policy makers should consider incentivising waste co-firing BECCS as part of future energy policies towards achieving the net-zero targets, weighing its benefits against other environmental impacts, waste availability and competition with recycling initiatives.

Trade barrier decrease and environmental pollution improvement: new evidence from China’s firm-level pollution data

PurposeTrade and environment are essential issues closely related to the development of the national economy and the improvement of people’s livelihood in the new era. The Report to the 19th National Congress of the Communist Party of China (CPC) listed the construction of a strong trading power as an important part of building a modern economic system and pollution prevention and treatment as one of the three key battles to win the decisive victory of building a moderately prosperous society in all respects. However, the relationship between trade and environmental pollution is still very controversial in the existing literature, and there is a paucity of literature on the relationship between trade and environmental pollution based on micro data.Design/methodology/approachThis paper merged China’s Firm-Level Pollution Database with China’s Industrial Enterprise Database and China’s industry tariff rates. Additionally, by virtue of the quasi-natural experiment of China’s accession to the World Trade Organization (WTO), a difference in difference (DID) model was constructed to alleviate the endogeneity issue.FindingsAccording to the results, the trade barrier decrease (trade liberalization) significantly reduces the intensity of SO2 emissions, a major pollutant of enterprises, as the intensity of SO2 emissions decreased 2.16% for each unit decrease of the trade barrier. The analysis of the mechanisms shows that the SO2 emission intensity of enterprises is mainly due to the decrease of enterprises’ pollution emission rather than the decrease of output, and the decrease of enterprises’ pollution emission is mainly caused by the enterprises’ cleaner production process rather than the end treatment of pollution emission. The decrease of coal use intensity is an important mechanism of the decrease of SO2 emission intensity caused by the decrease of trade barriers. Among the technical effects of the change of the trade barrier affecting enterprises’ pollution emission, biased technical change rather than neutral technical change dominates.Originality/valueThe findings of this paper imply that expanding openness can enhance China’s social welfare not only through the economic growth mechanisms identified in the classical literature, but also through environmental improvements. This provides useful policy insights for promoting the construction of a strong trading power and winning the battle against pollution in the new era.

N-fertilization of tropical pastures improves performance but not methane emission of Nellore growing bulls.

Grazing management and N-fertilizer have been reported to improve tropical forage productivity and quality, however, their effect on methane emission of grazing animals remains uncertain. Therefore, this study aimed to assess the effects of increasing application rates of nitrogen (N) fertilization of Marandu palisadegrass under continuous stocking on intake, digestibility, nitrogen balance, and enteric methane emissions of Nellore growing bulls. We hypothesized that changes in the forage nutritive value caused by N fertilization of pastures combined with adequate grazing management (e.g., greater crude protein [CP] and digestibility) would lead to an increase in animal productivity (e.g., greater average daily gain [ADG] and gain per area), and then, to a decrease in methane emission intensity. Treatments consisted of different annual application rates of nitrogen fertilization: 0, 75, and 150 kg N/ha using ammonium nitrate (32% N) as the nitrogen source. The experimental design was completely randomized, with three treatments and four replications (12 paddocks). Intake, digestibility, N balance, and methane emissions were measured in eight animals per treatment. CP intake, digestibility and N balance increased linearly with the increase in N fertilization (P < 0.05). In addition, stocking rate (SR) and ADG linearly increased from 1.75 animal unit (AU = 450 kg)/ha and 0.62 kg/d (0 kg N/ha) to 3.75 AU/ha and 0.82 kg/d (150 kg N/ha), respectively. Individual methane emissions nor methane emission intensity were affected by treatment with an average of 164.7 g/d and 199.7 g/kg ADG (P > 0.05). Annual N fertilization with ammonium nitrate between 75 and 150 kg N/ha in palisadegrass pastures under continuous stocking enhances animal performance per unit area yet not affecting neither methane production nor intensity.

Nitrogen ion beam induced modifications on the properties of carbon quantum dots/TiO2 nanocomposite

The present study reports the modifying the properties of carbon quantum dots/titanium dioxide (CQDs/TiO2, termed as CT) nanocomposite by Nitrogen (N+) ion beam irradiation in the energy range of 10 keV–40 keV at a fluence of 3 × 1015 ions cm−2. Transmission electron microscopic results reveals the anchoring of (3–5) nm CQDs on TiO2 nanoparticles of size ∼25 nm. UV–Visible spectroscopic results show the decrease in the bandgap of CT nanocomposite after N+ ion irradiation. X-ray Diffractogram exhibits the shift in the planes of CT nanocomposite due to irradiation. X-ray photoelectron spectroscopic results indicate the presence of nitrogen functional groups after irradiation. Raman spectroscopy results reveal the enhancement in disorder parameters due to irradiation-induced large number of small sp2 domains of carbon. Photoluminescence spectroscopy results show the decrease in emission intensity of CT nanocomposite after irradiation due to suppression in the recombination rate of photoexcited electron-hole pairs. The work function of CT nanocomposite decreases after ion irradiation indicating the shifting of Fermi energy level towards conduction band as studied by Ultraviolet photoelectron spectroscopy. Photoelectrochemical measurement studies reveals that improvement in the photoelectrochemical performance of 40 keV N+ ion irradiated CT compared to TiO2.

Novel insights on energy transfer processes in [Ce4+/Ce3+]-Er3+-doped tellurite glass

Previous works have been already reported on multiphonon-assisted non-resonant energy transfer in Ce3+-Er3+-doped tellurite glasses. However, it is not clear the mechanism of the radiative emission of Er3+ centered at 1530 nm. In this paper, we reported a better understanding of the mechanism of interactions between those two rare-earth ions via a systematic study. For that, we will explore the energy transitions between Ce4+/Ce3+ and Er3+ ions in a tungsten-tellurite glass to both emission (in the near infrared) and upconversion (in the visible) spectrum. Here, Ce4+ and Ce3+ were obtained in an Er3+-doped tellurite glasses via the addition of different concentrations of CeO2 as part of the composition of the samples. Emission spectrum, under a 980 nm excitation, giving rise to a series of interactions between Ce3+↔Er3+ resulting in: (i) a subtle increase of the Er3+ emission intensity in the near-infrared region for 0.1 mol% of CeO2, and then a decrease in the emission for higher CeO2 concentration in both cases without any significant increase in the bandwidth, and (ii) a decrease of the visible upconversion emission intensity with the addition of CeO2. Such interactions are achieved via a coupling yielding and energy transfer from both rare-earth ions.