Bridging the size gap between experiment and theory: large-scale DFT calculations on realistic sized Pd particles for acetylene hydrogenation.

Metal nanoparticles, often supported on metal oxide promoters, are a cornerstone of heterogeneous catalysis. Experimentally, size effects are well-established and are manifested through changes to catalyst selectivity, activity and durability. Density Functional Theory (DFT) calculations have provided an attractive way to study these effects and rationalise the change in nanoparticle properties. However such computational studies are typically limited to smaller nanoparticles (approximately up to 50 atoms) due to the large computational cost of DFT. How well can such simulations describe the electronic properties of the much larger nanoparticles that are often used in practice? In this study, we use the ONETEP code, which is able to achieve more favourable computational scaling for metallic nanoparticles, to bridge this size gap. We present DFT calculations on entire Pd and Pd carbide nanoparticles of more than 300 atoms (approximately 2.5 nm diameter), and find major differences in the electronic structure of such large nanoparticles, in comparison to the commonly investigated smaller clusters. These differences are also manifested in the calculated chemical properties such as adsorption energies for C2H2, C2H4 and C2H6 on the pristine Pd and PdC x nanoparticles which are significantly larger (up to twice in value) for the ∼300 atoms structures. Furthermore, the adsorption of C2H2 and C2H4 on PdC x nanoparticles becomes weaker as more C is introduced in the Pd lattice whilst the impact of C concentration is also observed in the calculated reaction energies towards the hydrogenation of C2H2, where the formation of C2H6 is hindered. Our simulations show that PdC x nanoparticles of about 5% C per atom fraction and diameter of 2.5 nm could be potential candidate catalysts of high activity in hydrogenation reactions. The paradigm presented in this study will enable DFT to be applied on similar sized metal catalyst nanoparticles as in experimental investigations, strengthening the synergy between simulation and experiment in catalysis.

Cholecalciferol combined with Satureja rechingeri essential oils improves growth performance and immune response of broiler chickens.

BACKGROUND: Vitamin D possesses an important role in the maintenance and health of broiler chickens. Herbal essential oils (EOs) have been proposed as a suitable alternative to chemical drugs in intensive production management systems for better performance of broilers with slight side effects and admirable therapeutic properties. OBJECTIVES: This experiment was conducted to investigate the effects of feeding cholecalciferol (VD) in combination of Satureja rechingeri EO (SREO) on growth performance, haematological indicators and immunological response of broilers. METHODS: A total of 540 1-day-old mixed-sex broiler chickens (Ross 308) were used in a completely randomized design with a 3 × 3 factorial arrangement of treatments. Experimental treatments included different concentrations of cholecalciferol (VD) (0, 2000 and 4000 IU/kg = 0, 0.05 and 0.1 mg/kg) and SREO (0, 200 and 400 mg/kg) on growth performance, haematological indicators and immunological responses of broiler chickens were investigated. RESULTS: The results showed that the chicken fed diet supplemented with 0.1 mg/kg VD (VD0.1) in combination of 200 mg/kg SREO (SREO200) increased the feed intake during the overall and first 14-day periods of the trial when compared with other dietary treatments. Interaction of VD0.1 × SREO200 led to more body weight gain (BWG) in the grower and finisher phases than all other feed treatment groups. The blood level of lymphocyte at day 42, heterophil at days 28 and 42 and heterophil/lymphocyte (H/L) ratio at 14 and 28 days of age were affected by VD0.1 + SREO200 in comparison with VD0 + SREO0 group. Feeding VD and/or SREO decreased triglyceride, cholesterol and low-density lipoprotein concentrations at days 28 and 42 of the study, especially in VD0.1 + SREO200 treatment. Feeding VD0.1 + SREO200 also resulted in higher serum status of immunoglobulin M, lysozymes and phagocytic percentage among all treatments. CONCLUSION: Considering the outcomes, it is suggested that the combination of suitable concentration of VD and EO of the plant had favourable effects on the immune system and performance criteria of broiler chickens.

Worldwide Research Trends for Chelates in Animal Science: A Bibliometric Analysis.

The purpose of this study was to look at research trends in the application of CTM in animal nutrition in order to identify current and emerging challenges, as well as to examine the intellectual structure of the subject. The intellectual structure of CTM was examined using keyword and reference analysis. The research community includes all research and review articles published in journals indexed in the Web of Science database during the years 1990-2022. The results showed that the terms zinc, co-occurring 331 times, performance (324 times), and copper 216 (times) were the main and hotspots of research in the field of chelate. The data suggest that the most important keywords during the study period were zinc, copper, pig, bovine, metabolism, and bioavailability. The terms health, muscle, beef, trace elements, and dietary supplements represent emerging topics in CTM, as research began to focus on these areas during the years 2017-2022. The country with the greatest number of published articles was the United States of America. This bibliometric analysis showed that countries are focusing on the effects of CTM on the health and musculature of cattle through dietary supplementation with trace elements. According to the identified hot and emerging topics, this research can serve as a roadmap for a global comprehensive scientific plan and policy.

Atomistic simulations on the carbidisation processes in Pd nanoparticles.

The formation of interstitial PdC x nanoparticles (NPs) is investigated through DFT calculations. Insights on the mechanisms of carbidisation are obtained whilst the material's behaviour under conditions of increasing C-concentration is examined. Incorporation of C atoms in the Pd octahedral interstitial sites is occurring through the [111] facet with an activation energy barrier of 19.3-35.7 kJ mol-1 whilst migration through the [100] facet corresponds to higher activation energy barriers of 124.5-127.4 kJ mol-1. Furthermore, interstitial-type diffusion shows that C will preferentially migrate and reside at the octahedral interstitial sites in the subsurface region with limited mobility towards the core of the NP. For low C-concentrations, migration from the surface into the interstitial sites of the NPs is thermodynamically favored, resulting in the formation of interstitial carbide. Carbidisation reaction energies are exothermic up to 11-14% of C-concentration and slightly vary depending on the shape of the structure. The reaction mechanisms turn to endothermic for higher concentration levels showing that C will preferentially reside on the surface making the interstitial carbide formation unfavorable. As experimentally observed, our simulations confirm that there is a maximum concentration of C in Pd carbide NPs opening the way for further computational investigations on the activity of Pd carbides in directed catalysis.

Manganese-methionine chelate improves antioxidant activity, immune system and egg manganese enrichment in the aged laying hens.

BACKGROUND: It has been reported that supplementation of manganese (Mn) could alleviate the negative effects of age on egg quality in laying hens. However, limited information is available on compensatory ways in order to reduce the adverse effects of hen age on health and Mn deposition in the body. OBJECTIVES: The objectives were to investigate the effect of organic and inorganic sources of Mn on antioxidant activity, immune system, liver enzymes, shell quality and Mn deposition in the tissues of older laying hens. METHODS: A total of 250, 80-week-old Leghorn laying hens (w36) were allocated into five treatment groups with five replications in a completely randomised design. Treatments were control (without Mn supplementation), 100% Mn sulphate, 75% Mn sulphate + 25% organic Mn chelate, 50% Mn sulphate + 50% organic Mn chelate and 25% Mn sulphate + 75% organic Mn chelate. RESULTS: The groups fed 50 and 75% organic Mn chelate exhibited the lowest feed conversion ratio, as well as the maximum laying percentage, and egg weight and mass. Except to those fed 75% Mn sulphate, the hens received Mn supplements either as organic or inorganic, had higher immunoglobulin G and M compared with the control (p < 0.05). A significant elevation in the values of superoxide dismutase was observed in the hens receiving 50 and 75% organic Mn chelate when compared with the other treatments. The ALP activity decreased with increasing organic Mn chelate. Mn supplementation, either as organic or inorganic, increased Mn deposition in bone, egg yolk and shell, serum and liver. CONCLUSION: Dietary supplementation with 50-75% Mn-methionine has the potential to replace Mn-sulphate in laying hens' diet for improving eggshell quality, Mn deposition in the eggshell, antioxidant capacity and immune response, as well as improving laying performance, egg weight and feed conversion ratio.

Impact of dietary supplementation of unsaturated and saturated fatty acids on bone strength, fatty acids profile of thigh muscle and immune responses in broiler chickens under heat stress.

BACKGROUND: There have been some reports that supplementation of fat could alleviate the negative effects of heat stress on performance in broilers. However, information regarding compensation for the adverse effects of heat stress with diets differing in fatty acids source on immune system, bone strength and carcass quality of heat-distressed broilers is limited. OBJECTIVES: The objective of this study was to investigate the effects of diets differing in fat source on performance, immune system, bone strength, and carcass quality of heat-distressed broilers. METHODS: In a completely randomized design with 4 × 2 factorial arrangement of the treatments, 320 24-day-old Ross 308 chickens, with average initial weight of 1220 ± 10 g were divided into eight treatments included sesame oil, tallow, sunflower oil and palm oil in either 22 or 32 degree of centigrade temperature. The broiler performance of each fat source-treated group was not different in this experiment and decreased significantly in heat stress condition. RESULTS: Heat stress showed a significant increase on fat, energy and ash content of thigh muscle. Tibia absolute length, width, ash and bone breaking strength were affected by fat source and increased when sesame and sunflower oil were used. Data analysis revealed that hot temperature decreased tibia weight, length, width, ash and bone breaking strength. Heat stress led to decrease of immune system parameters. CONCLUSION: Results suggest that there is no beneficial effect of broiler performance due to adding different sources of fat in broiler chicken diet under hot condition. Furthermore, the unsaturated fatty acids could improve the profile of fatty acids in thigh and enhance immune responses in broiler chickens.

Saffron extract feed improves the antioxidant status of laying hens and the inhibitory effect on cancer cells (PC3 and MCF7) Growth.

BACKGROUND: There have been some reports regarding supplementation of saffron petal extract on performance and egg quality in laying hens. However, the effect of saffron petal extract fed diet at different amounts on antioxidant status of laying hens and the impact of the resulting egg yolk on growth/inhibitory activity of cancer cells has not been fully studied. OBJECTIVES: The effect of dried saffron petal extract on the laying performance, egg qualitative traits, antioxidant status, and its inhibitory effect on cancer cells was studied. METHODS: A total of 200 39-week-old Hy-line W36 Leghorn laying hens were selected based on a completely randomised design in four treatments with five replications (10 hens per replication). The four treatment diets consisted of a basal diet with no supplement (control), and three diet supplement groups containing 40, 60 and 80 ppm of saffron petal extract. RESULTS: Adding 80 ppm of saffron petal extract to layer diets increased egg production (p < 0.05). Malondialdehyde,1,1-diphenyl-2-picrylhydrazyl value and Superoxide dismutase significantly improved by saffron petal dietary supplementation. The yolk weight and colour, Haugh unit and shell weight and thickness were also influenced (p < 0.05) with highest values achieved in the 60 ppm saffron extract supplemented diet. Results demonstrated a significant effect of saffron extract inclusion in the diet on the growth of Michigan Cancer Foundation-7 and Prostate Cancer Cell in a positive dose-dependent manner (p < 0.05) and the most intense inhibitory effect on cancer cells was observed with 60-80 ppm extract. CONCLUSIONS: Saffron petal extract can be used to potentially modulate the antioxidant status of laying hens and the inhibitory effect on cancer cells, best achieved with 60-80 ppm extract.

Zinc supplementation improves antioxidant status, and organic zinc is more efficient than inorganic zinc in improving the bone strength of aged laying hens.

BACKGROUND: There have been some reports indicating that supplementation of zinc could alleviate the negative effects of age on egg quality in laying hens. However, information regarding these positive effects on health and zinc deposition in the body is limited. OBJECTIVES: The aim of the present study was to investigate the effect of organic and inorganic sources of zinc on the antioxidant activity, bone strength, and zinc deposition in the tissues of older laying hens. METHODS: In a completely randomized design, 175 Leghorn laying hens (w36) aged 80 weeks were allocated into seven treatment groups and five replications: control (without zinc supplementation), zinc sulphate treatments (15, 30, and 45 mg/kg), and organic zinc treatments (15, 30, and 45 mg/kg). RESULTS: There was a significant increase in feed intake in the zinc sulphate and organic zinc treatments compared to the control treatment (p < 0.05). The egg mass in organic and sulphate zinc showed a significant increase. The feed conversion ratio was decreased significantly in the organic zinc treatments (p < 0.05). Both organic and sulphate zinc supplements enhanced serum superoxide dismutase activity as an antioxidant index (p < 0.05). The cortical thickness of the tibia was improved in laying hens receiving 30 mg/kg organic zinc. Supplementation of zinc could lead to an increase in zinc deposition in tissues, and organic zinc boosts bone strength. CONCLUSION: Zinc supplementation can improve antioxidant activity, feed intake, and feed conversion ratio and enhance egg mass and optimal absorption of zinc in tissues. The use of 30 mg/kg organic zinc is recommended for improving the cortical thickness of the tibia in aged laying hens.

Understanding the CO Oxidation on Pt Nanoparticles Supported on MOFs by Operando XPS.

Metal-organic frameworks (MOFs) are playing a key role in developing the next generation of heterogeneous catalysts. In this work, near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) is applied to study in operando the CO oxidation on Pt@MOFs (UiO-67) and Pt@ZrO2 catalysts, revealing the same Pt surface dynamics under the stoichiometric CO/O2 ambient at 3 mbar. Upon the ignition at ca. 200 °C, the signature Pt binding energy (BE) shift towards the lower BE (from 71.8 to 71.2 eV) is observed for all catalysts, confirming metallic Pt nanoparticles (NPs) as the active phase. Additionally, the plug-flow light-off experiments show the superior activity of the Pt@MOFs catalyst in CO oxidation than the control Pt@ZrO2 catalyst with ca. 28 % drop in the T 50% light-off temperature, as well as high stability, due to their sintering-resistance feature. These results provide evidence that the uniqueness of MOFs as the catalyst supports lies in the structural confinement effect.