19 research outputs found

    Time-lapsed graphene moir\'e superlattice on Cu(111)

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    The detailed study of the graphene (gr) moir\'e superlattices emerging due to the mismatch between the substrate's and gr-overlayer crystal lattices is inevitable because of its high technological relevance. However, little is known about the dynamics of moir\'e superstructures on gr. Here, we report the first classical molecular dynamics simulation (CMD) of the moir\'e superlattice of graphene on Cu(111) using a new parameterized Tersoff-potential for the graphene/Cu(111) interface fitted in this paper to nonlocal van der Waals density functional theory (DFT) calculations. The interfacial force field with time-lapsed CMD provides superlattices in good quantitative agreement with the available experimental results. The long range coincidence supercells of 2×22 \times 2 and 3×33 \times 3 with nonequivalent moir\'e hills have also been identified and analyzed. The moir\'e superlattice exhibits a pattern which is dynamical rather than statically pinned to the support and can be observed mostly via time lapsing. The instantaneous snapshots of the periodic moir\'e pattern already at low temperature are weakly disordered lacking the apparent sharpness of the time averaged pattern and scanning tunneling microscopy images. This suggests the existence of competing orders between a static (1st order) and a dynamical (2nd order) moir\'e superstructures.The revealed random height fluctuations may limit the important electronic properties of supported graphene such as the mobility of charge carriers.Comment: 14 pages, 8 figures, supplementary material included. arXiv admin note: text overlap with arXiv:1401.171

    Rotation misorientated graphene moire superlattices on Cu(111): classical molecular dynamics simulations and scanning tunneling microscopy studies

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    Graphene on copper is a system of high technological relevance, as Cu is one of the most widely used substrates for the CVD growth of graphene. However, very little is known about the details of their interaction. One approach to gain such information is studying the superlattices emerging due to the mismatch of the two crystal lattices. However, graphene on copper is a low-corrugated system making both their experimental and theoretical study highly challenging. Here, we report the observation of a new rotational Moire superlattice of CVD graphene on Cu (111), characterized by a periodicity of 1.5±0.051.5 \pm 0.05 nm and corrugation of 0.15±0.050.15 \pm 0.05 A˚\hbox{\AA} , as measured by Scanning Tunneling Microscopy. To understand the observed superlattice we have developed a newly parameterized Tersoff-potential for the graphene/Cu (111) interface fitted to nonlocal van der Waals density functional theory (DFT) calculations. The interfacial force field with time-lapsed CMD provides superlattices in good quantitative agreement with the experimental results, for a misorientation angle of 10.4±0.5,10.4 \pm 0.5,^{\circ} without any further parameter adjustment. Furthermore, the CMD simulations predict the existence of two non-equivalent high-symmetry directions of the Moir\'e pattern that could also be identified in the experimental STM images.Comment: 7 pages, 2 figures, 2 table

    The theory of recttification in biological systems

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    The theory of biological rectification originated from the study of physiological processes of the human body. Biological processes are defined by certain structures; biological rectification is achieved by biological structures too. These rectifying biological structures are the biological rectifying valves, a definition adopted from physics. An extension of this notion leads to a generalization of the rectification phenomena in biological systems. The practical value of this theoretical concept is widely presumed. Here we show that the loss of rectification may result in dysfunction or even destruction of the biological system, the rectification implies the simplification of biological processes, reduce the utilization of energy in biological systhems and in general can help in understanding the processes in the human body and biology better. We hope that experts of different scientific fields will probably confirm or disprove this hypothesis.

    Comparison of productive and carcass traits and economic value of lines selected for different criteria, slaughtered at similar weights

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    [EN] The aim of the experiment was to compare 3 genetic groups, slaughtered at similar weights, to examine their productive and carcass traits and economic value. Three lines of the Pannon Breeding Programme, selected for different criteria, were examined in the experiment. Pannon Ka (PKa, maternal line) does were inseminated with semen of PKa, Pannon White (PWhite) or Pannon Large (PLarge, terminal line) bucks. The kits (PKa×PKa, PWhite×PKa, PLarge×PKa; n=60 in each genetic group) were weaned at 35 d of age and reared until 88, 83 and 79, respectively, when they reached similar body weights for slaughtering (2.8 kg). The weight gain of PLarge×PKa was the largest (51.0 g/d) and that of PKa×PKa was the smallest (47.2 g/d), while PWhite×PKa (41.8 g/d) was intermediate (P<0.001). Difference was found in feed conversion ratio between weaning and the age of slaughter  PKa×PKa: 3.03 respect to PWhite×PKa: 2.75 and PLarge×PKa: 2.66; , P<0.05). Dressing out percentage and ratio of hind part to reference carcass of PWhite×PKa, PLarge×PKa and PKa×PKa were 62.4 and 37.7, 61.8 and 37.5, 61.3 and 36.8%, respectively (P<0.01). Results show that PLarge×PKa rabbits were able to exceed the average economic indicators compared to other groups. It may be concluded that the production performance of growing rabbits was affected by the adult weight, but the carcass traits were influenced by the computer tomography (CT)-based selection.This paper was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences, and by the GOP-1.1.1-11-2012-0132 project.Szendrő, K.; Szendrő, Z.; Gerencsér, Z.; Radnai, I.; Horn, P.; Matics, Z. (2016). Comparison of productive and carcass traits and economic value of lines selected for different criteria, slaughtered at similar weights. World Rabbit Science. 24(1):15-23. https://doi.org/10.4995/wrs.2016.3684152324

    Effect of late weaning and use of alternative cages on performance of does, suckling and fattening rabbits under extensive reproductive management

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    The effects of the combined use of long lactation periods (46 days) with alternative cages on the reproductive and growth performance of 104 rabbit does and their litters during five consecutive reproductive cycles were studied. Half of does were housed in conventional polyvalent cages (39 cm×100 cm×30 cm) and the other half in alternative polyvalent cages (39 cm×100 cm×60 cm), with a raised platform. Half of the rabbit does in each type of cage were weaned at 32 and the other half at 46 days after parturition. Longer lactation negatively affected the body weight (P<0.001), fat and energy content (P<0.05) of rabbit does at the end of the lactation period, but this effect decreased with the number of parturitions. Fertility, prolificacy and doe mortality were not affected by lactation length. Late weaning led to higher litter size (by 8.9%) and litter weight (by 11.3%) at the end of growing period (P<0.001) and lower feed conversion ratio per cage during the experimental period (13.5%) than weaning at 32 day (P<0.001). These results were paralleled by lower mortality (12.6 vs. 17.6%; P<0.01) of young rabbits weaned later during the overall experimental period. Differences in performance as a result of different weaning ages were only observed during cycles with worst health status (third and fifth cycles) in which late weaning decreased mortality. Type of cage did not affect doe body weight and body condition, mortality, fertility, prolificacy and litter size during the five reproductive cycles. Nevertheless, at day 21 litter weight and feed conversion ratio between 3 and 21 day were 4.2% higher (P<0.01) and 5.0% lower (P<0.05), respectively, in animals housed in alternative rather than in conventional cages. Alternative cages also led to heavier litters at 59 days (P<0.01). It was concluded that the combined use of longer lactations and cages with higher available surface with a raised platform could be alternatives to improve animal welfare in farmed rabbit

    Carcass traits and meat quality of growing rabbits in pens with and without different multilevel platforms

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    [EN] The aim of this trial was to determine the effect of the presence of wire or plastic mesh elevated platforms on carcass traits and meat quality characteristics, with particular attention to the oxidative status of growing rabbits. A total of 174 five-week old rabbits were randomly divided into 3 groups with 2 replications (6 pens; 29 rabbits/pen): pens without platforms (NoP) with a stocking density of 16 rabbits/m2 and pens with wire-mesh platforms (WP) or plastic-mesh platforms (PP) that were placed on 2 levels, with a stocking density of 16 rabbits/m2 on the floor or 9.14 rabbits/m2 when the platform were included. At 84 d rabbits were slaughtered. The slaughter traits and Longissimus lumborum (LL) physical and chemical compositition were not affected by treatments. Rabbits from the PP group showed the highest retinol and γ-tocotrienol content on LL muscle, whereas the NoP ones showed a higher α-tocotrienol and α-tocopherol level. The absence of platforms led to decreased (P<0.001) thiobarbituric acid-reactive substances values and induced an improvement in n-3 polyunsaturated fatty acids. Levels of linoleic, linolenic and docosahexaenoic acids were equal to those of the WP group (23.45, 3.75, 0.64% in NoP and 22.6, 4.14, 0.53% in WP, respectively) but higher than in PP rabbits (20.86, 3.05, 0.45%, respectively). It can be concluded that the pens with elevated platforms provide greater possibilities for movement, which is beneficial from the viewpoint of animal welfare. However, this greater activity influences the oxidative status of the meat, decreasing the antioxidant content and worsening the lipid oxidation of rabbit meat.This research was supported by the GOP-1.3.1-11/B-2011-0045 project and by the János Bolyai Research Scholarship (BO/00373/14/4) of the Hungarian Academy of Sciences.138Martino, M.; Mattioli, S.; Farkas, P.; Szendrő, Z.; Dal Bosco, A.; Ruggeri, S.; Matics, Z.... (2016). Carcass traits and meat quality of growing rabbits in pens with and without different multilevel platforms. World Rabbit Science. 24(2). https://doi.org/10.4995/wrs.2016.392212924

    Effect of different weaning age (21, 28 or 35 days) on production, growth and certain parameters of the digestive tract in rabbits

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    The effect of different weaning ages, that is, 21 (G21), 28 (G28) or 35 (G35) days, on growth and certain parameters of the digestive tract was examined in rabbits to assess the risk of early weaning attributable to the less-developed digestive system. On days 35 and 42, G35 rabbits had 10% to 14% and 10% higher BW, respectively ( P,0.05), than those weaned at days 21 and 28. In the 4th week of life, early weaned animals had 75% higher feed intake than G28 and G35 rabbits ( P,0.05). The relative weight of the liver increased by 62% between 21 and 28 days of age, and thereafter it decreased by 76% between 35 and 42 days of age ( P,0.05), with G21 rabbits having 29% higher weight compared with G35 animals on day 35 ( P,0.05). The relative weight of the whole gastrointestinal (GI) tract increased by 49% and 22% after weaning in G21 and G28 rabbits, respectively ( P,0.05). On day 28, the relative weight of the GI tract was 19% higher in G21 than in G28 rabbits, whereas on day 35 G21 and G28 animals had a 12% heavier GI tract compared with G35 rabbits ( P,0.05). Age influenced the ratio of stomach, small intestine and caecum within the GI tract; however, no effect of different weaning age was demonstrated. The pH value of the stomach and caecum decreased from 5.7 to 1.6 and from 7.1 to 6.3, respectively, whereas that of the small intestine increased from 6.8 to 8.4 ( P,0.05); the differences between groups were not statistically significant. Strictly anaerobic culturable bacteria were present in the caecum in high amounts (108), already at 14 days of age; no significant difference attributable to weaning age was demonstrable. The concentration of total volatile fatty acids (tVFA) was higher in G21 than in G28 and G35 throughout the experimental period ( P,0.05). The proportion of acetic and butyric acid within tVFA increased, whereas that of propionic acid decreased, resulting in a C3 : C4 ratio decreasing with age. Early weaning (G21) resulted in higher butyric acid and lower propionic acid proportions on day 28 ( P,0.05). No interaction between age and treatment was found, except in relative weight of the GI tract and caecal content. In conclusion, early weaning did not cause considerable changes in the digestive physiological parameters measured, but it resulted in 10% lower growth in rabbits

    The Influence of Temperature Conditions on Position Control of Fluidic Muscle

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    Pneumatic artificial muscles (PAMs) are of special importance in the field of pneumatic drives and in robotics. Different designs have been developed, but the McKibben muscle is the most popular and is made commercially available by different companies, e.g. Fluidic Muscle manufactured by Festo Company. There are a lot of advantages of PAMs like the high strength, good power/weight ratio, good power/volume ratio, low price, little maintenance needed, great compliance, compactness, flexibility, inherent safety and usage under rough environments. The objective of this research note is to determine the error of positioning with a Fluidic Muscle at cold and at normal operating temperature of the system with sliding mode control. The results of the experiments showed that the positioning error of the Fluidic Muscle under the experimental conditions was 0.01 mm

    Metabolic changes induced by regular submaximal aerobic exercise in meat-type rabbits

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    Pannon White growing rabbits (a group of 8) were exposed to treadmill exercise (3-9 m/s, 1.2-1.6 km/day) twice a day for 4 weeks, while additional 8 animals, kept inactive, were assigned as the control group. Weekly, 12 hours after exercise, venous blood was taken for serum metabolite and enzyme activity measurements. Total serum protein, albumin and creatinine levels significantly increased during the second half of the training, as compared to the control group. Triacylglycerol levels in the exercised group as compared to controls, however, were higher only after the first and the fourth weeks of the experiment. Resting non-esterified fatty acid (NEFA) concentration of the trained rabbits was lower at the end of the trial. On the other hand, there were no significant differences, as compared to the respective controls, in serum urea, total and HDL cholesterol levels. At the end of the exercise alkaline phosphatase activity was higher and total lactate dehydrogenase activity was lower in the trained rabbits. Serum alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transpeptidase activities were not changed, while creatine kinase activity was slightly lower in the trained group. The serum cortisol concentration was not different in the trained and control rabbits

    Sustainable approach for the collection and processing of medicinal and aromatic plants in Hungary

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    Hungary is a Central European country that is rich in medicinal and aromatic wild plant species; in rural livelihoods, the collection, use, process, and trade of these plants are traditionally important contributors. However, due to several recent changes touching the sector, the natural ecosystems, biodiversity, and collectors - who generally belong to poorer social groups – are affected negatively
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