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2. Perturbation of Exciton Aggregate Coupling by Optical Excitation in Crystalline Perfluoropentacene Films

Author

Kolata, K., Marquardt, S., Rosemann, N. W., Mager, A., Hansmann, A., Höfer, U., Berger, R., Breuer, T., Witte, G., and Chatterjee, S.

Subjects
Condensed Matter - Materials Science, Physics - Chemical Physics
Abstract

Carrier multiplication by singlet exciton fission enhances photovoltaic conversion efficiencies in organic solids. This decay of one singlet exciton into two triplet states promises to overcome the Shockley-Queisser limit as up to two electrons may be harvested per absorbed photon. Intermolecular coupling is deemed mandatory for both, singlet exciton fission and a band-like transport. Such a coupling is manifested, $e.g.$, by the Davydov-splitting of the lowest-energy exciton transition in crystalline organic solids. For the model system perfluoropentacene, the corresponding transitions in the experimental, polarisation-resolved absorption spectra are identified by theoretical calculations based on the concept of H- and J- aggregation. Optical injection into the first vibronic progression of the fundamental exciton transitions significantly perturbs the higher-energy transitions that are associated to H-type aggregates of the $S_0 \rightarrow S_3$ transition during and following efficient singlet exciton fission. These findings underline the necessity for efficient carrier extraction as triplet accumulation may be detrimental to both, singlet exciton fission and any potentially band like transport. More generally, our observations indicate that electronic excitations can perturb the electronic band structure in organic crystals and highlight their correlated nature by potentially distorting the lattice.

Published
2016

9. Impact of Haemonchus contortus infection on feed intake, digestion, liveweight gain, and enteric methane emission from Red Maasai and Dorper sheep

Author

Mwangi, PM, Eckard, R, Gluecks, I, Merbold, L, Mulat, DG, Gakige, J, Pinares-Patino, CS, Marquardt, S, Mwangi, PM, Eckard, R, Gluecks, I, Merbold, L, Mulat, DG, Gakige, J, Pinares-Patino, CS, and Marquardt, S

Abstract

A study was conducted with Red Maasai and Dorper lambs to evaluate the effects of infection with the gastrointestinal nematode (GIN) Haemonchus contortus on feed intake, liveweight gain (LWG), feed energy and nitrogen partitioning, and enteric methane (CH4) emissions. Six- to seven-month-old Red Maasai (n=12) and Dorper (n=12) lambs were randomly allocated to three treatments (n=8, four lambs per breed) in a 2×3 factorial cross-over study over two periods (P1 and P2) of 36 days each. The treatments consisted of three combinations of GIN infection and feeding level: Infected + ad libitum feeding (I-adlib), uninfected + ad libitum feeding (Un-adlib), and uninfected + restricted feeding (Un-restd), across the two breeds. Lambs in the I-adlib group were trickle-infected daily with 1,000 L3 stage larvae of H. contortus for four consecutive days (Days 1–4), whereas lambs in the other experimental treatments were kept GIN free. The feed intake was measured daily. Liveweight (LW), faecal egg counts (FEC), and packed cell volume (PCV) were measured on Day 1 and weekly thereafter. On Days 29–33 total faecal and urine outputs were determined in metabolic crates. The lambs were then housed in respiration chambers for three consecutive days (Days 34–36). There was a washout period of 21 days before P2 started. Uninfected lambs (Un-adlib and Un-restd) had undetectable FEC throughout the study. On Day 36, FEC did not differ between the breeds (P>0.05). Infected lambs (I-adlib) had lower PCV than uninfected (Un-adlib and Un-restd) lambs on day 36. Neither breed nor infection influenced feed and nutrient intake, but as expected, restricted-fed lambs had a lower intake (P<0.05). The LWG of Un-adlib lambs was significantly higher than that of I-adlib and Un-restd lambs (P<0.05), whereas there was no breed difference (P>0.05). Neither breed nor infection affected feed digestibility, nitrogen retention or energy metabolisability (P>0.05). However, feed

Published
2023

17. Effects of replacing Brachiaria hay with either Desmodium intortum or dairy concentrate on animal performance and enteric methane emissions of low-yielding dairy cows

Author

Korir, D, Eckard, R, Goopy, J, Arndt, C, Merbold, L, Marquardt, S, Korir, D, Eckard, R, Goopy, J, Arndt, C, Merbold, L, and Marquardt, S

Abstract

In Africa, cattle are often fed low quality tropical roughages resulting in low-yielding animals with high methane (CH4) emission intensity (EI, g CH4/per unit of product). Supplementation with protein is known to improve the nutritive value of the otherwise low-quality diets. However, animal nutrition studies in East Africa that are accompanied by CH4 emission measurements are lacking. Thus, an animal experiment was conducted to quantify the effect of supplementing cattle fed mainly on low-quality Urochloa brizantha hay (control diet; CON; crude protein (CP) = 7.4%) or supplemented with either a tannin-rich leguminous fodder, Desmodium intortum hay (DES) or a commercial dairy concentrate (CUBES) on voluntary dry matter intake (DMI), nutrient apparent total tract digestibility, nitrogen (N) retention, enteric CH4 production and animal performance (milk and average daily gain). Twelve mid-lactating crossbred (Friesian × Boran) cows (initial liveweight = 335 kg) were used in a 3×3 (Period × Diet) Latin square design with each period running for four weeks. Compared to CON, DES decreased nutrient (DM, OM, CP) intake, apparent total tract digestibility and daily milk yield. In contrast, CUBES increased nutrient intake and animal performance compared to CON, while nutrients’ apparent total tract digestibility was not different, except for CP digestibility that increased. Compared to CON, DES and CUBES improved overall N retention by the animals as a proportion of N intake. The DES diet compared with CON and CUBES, shifted the proportion of N excretion via urine to the fecal route, likely because of its tannin content. Both DES and CUBES, compared to CON, reduced methane yield (MY, g CH4/kg DMI) by 15% and 9%, respectively. The DES diet reduced absolute enteric CH4 emissions by 26% while CUBES increased emissions by 11% compared to CON. Based on the present findings, high supplementation levels (>50%) of Desmodium intortum hay is not recommended especially when the

Published
2022

21. Weight gain and enteric methane production of cattle fed on tropical grasses.

Author

Korir, D., Marquardt, S., Eckard, R., Sanchez, A., Dickhoefer, U., Merbold, L., Butterbach-Bahl, K., Jones, C., Robertson-Dean, M., and Goopy, J.

Subjects
*WEIGHT gain, *CATTLE feeding & feeds, *RUMINANTS, *ANIMAL feeds, *GRASSES as feed, *METHANE, *CENCHRUS purpureus
Abstract

Context: Planted grasses are becoming an increasingly important feed resource for tropical smallholder ruminant production; yet, limited research has been conducted to quantify productivity or enteric methane (CH4) production of animals consuming these grasses. Aim: An experiment was conducted to assess yields and nutritional attributes of the following three tropical grasses: Cenchrus purpureus var. Kakamega 1 (Napier), Chloris gayana var. Boma (Rhodes) and Urochloa brizantha var. Xaeres (Brachiaria), and quantify enteric CH4 production of cattle fed on them. Methods: Yearling Boran steers (n :18; initial liveweight 216 ± 5.8 kg (mean ± s.e.m.) were allocated to one of three grasses, in a completely randomised design and fed ad libitum for two feeding periods, each period lasting for 70 days. Intake, liveweight (LW), apparent total-tract digestibility and enteric CH4 production were assessed. The grasses used were grown on site and biomass yields were monitored over a 2-year period. Animal growth was also simulated to a final weight of 350 kg, and the amount of feed and size of land required to produce, and days to reach final weight, were estimated. Key results: Mean voluntary dry-matter intake (DMI) and ADG were higher (P < 0.05) in Period 2 than in Period 1, but did not differ among treatments (P > 0.05) within period. Methane yield (MY; CH4 g/DMI kg) was similar among treatments (26.7–28.5, P = 0.26) but Napier had a higher CH4 conversion factor [ Y m; CH4 (MJ)/gross energy intake (MJ)] than did Rhodes and Brachiaria (0.0987 vs 0.0873 and 0.0903 respectively; P = 0.013). Our modelling indicated that steers consuming Rhodes took at least 30 more days to reach the target LW, required larger land area for feed production and produced more enteric CH4 than did the other two diets. Conclusion: Even though animal performance and MY among treatments did not differ, the animals had higher MY and Y m than currently estimated by the Intergovernmental Panel on Climate Change. Implication: The three grasses supported similar animal growth rate, implying that growing of higher-yielding grasses such as Napier offers an opportunity to optimise land productivity in the tropics. However, suitable feeding practices such as protein supplementation need to be explored to enhance ruminant production and reduce enteric CH4 production. Cultivated grasses are an important feed resource for smallholder livestock keepers in East Africa, but animal performance studies when using these forages are limited and inconclusive. We measured growth rate and enteric methane production in growing Boran steers fed either Napier, Rhodes or Brachiaria and observed similar daily weight gains of about 0.5 kg and a higher methane production than currently estimated for high-forage diets. This implies up to 20% underestimation of enteric methane production by cattle in the region. [ABSTRACT FROM AUTHOR]

Published
2023
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23. A research perspective towards a more complete biodiversity footprint: a report from the World Biodiversity Forum

Author

Marques, A., Robuchon, M., Hellweg, S., Newbold, T., Beher, J., Bekker, S., Essl, F., Ehrlich, D., Hill, S., Jung, M., Marquardt, S., Rosa, F., Rugani, B., Suárez-Castro, A.F., Silva, A.P., Williams, D.R., Dubois, G., Sala, S., Marques, A., Robuchon, M., Hellweg, S., Newbold, T., Beher, J., Bekker, S., Essl, F., Ehrlich, D., Hill, S., Jung, M., Marquardt, S., Rosa, F., Rugani, B., Suárez-Castro, A.F., Silva, A.P., Williams, D.R., Dubois, G., and Sala, S.

Published
2021

29. Digestibility, nitrogen utilization and milk fatty acid profile of dairy cows fed hay from species rich mountainous grasslands with elevated herbal and phenolic contents

Author

Ineichen, Simon, Kuenzler, A.D., Kreuzer, M., Marquardt, S., and Reidy, Beat

Subjects
SF Animal culture, SB Plant culture, S Agriculture (General)
Abstract

In the present study, the influence of mountain hay diets with elevated proportions of herbs and phenolic contents on nitrogen utilization and milk fatty acid profile of dairy cows was investigated. Two grass hay-based diets, either low or high in nitrogen (N) content (GN−, GN+) and similar in fiber content and lignification, and two diets consisting of hays with high proportion of herbs (H) with either low or high phenolic (P) content (HP−, HP+) were fed isoenergetically and without concentrate. All diets contained a Lolium perenne dominated basal hay and experimental hay in proportions of 0.45:0.55, except for diet GN+ (0.80:0.20) with excessive N. Feed intake, milk yield and total amount of feces and urine were recorded and sampled from 24 multiparous mid-lactation cows (eight Brown Swiss, 16 Holstein) producing on average 33 kg/ day of energy-corrected milk. The experiment was performed in three runs with two cows per diet. Data was analyzed by a general linear model considering diet and run as effects. Intake was highest in GN+ and HP+ and lower with GN− and HP−. No condensed tannins (CT) were detected in GN− and GN+. Intake of phenolic compounds (g/day per cow) was high in HP+ (402) lower with HP− (302) and lowest with GN− and GN+ (ca. 190). The intake of CT was higher in HP+ (115 g/day) compared to HP− (31 g/day). Yield of milk and energy-corrected milk as well as gross milk constituents were not affected by diet. Apparent total tract nutrient digestibility was higher for the grass-based diets (GN−, GN+) than for the diets with high herbal proportion (HP−, HP+). With GN+, absolute urinary N losses and those in proportion of total excreta N were higher than in the other diets and was lowest with HP+. Utilization of N was lower with GN+ and HP+ compared to HP−. The milk fat of cows fed HP+ had higher proportions of polyunsaturated fatty acids compared to that of GN−. The transfer rate of C18:3 n-3 from feed to milk was highest for the two herbal hay diets. The secretion of C18:1 t11 in relation to the amount of C18:2 n-6 + C18:3 n-3 ingested was highest for diet HP−. In conclusion, mountain hay rich in herbs was found to be a dietary means to lower the N emission potential of the manure by lower urinary N excretion demonstrating that inclusion of herbs into grasslands may be beneficial.

Published
2019
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36. Direct determination of molecular handedness via coulomb explosion imaging

Author

Pitzer, M, Kunitski, M, Kastirke, G, Jahnke, T, Bauer, T, Goihl, C, Trinter, F, Schober, C, Henrichs, K, Becht, J, Zeller, S, Gassert, H, Waitz, M, Kuhlins, A, Wiegandt, F, Wallauer, R, Schmidt, L Ph H, Mazenauer, Manuel, Spenger, Benjamin, Marquardt, S, Schmidt-Böcking, H, Stohner, Jürgen, Dörner, R, Schöffler, M S, Berger, R, Pitzer, M, Kunitski, M, Kastirke, G, Jahnke, T, Bauer, T, Goihl, C, Trinter, F, Schober, C, Henrichs, K, Becht, J, Zeller, S, Gassert, H, Waitz, M, Kuhlins, A, Wiegandt, F, Wallauer, R, Schmidt, L Ph H, Mazenauer, Manuel, Spenger, Benjamin, Marquardt, S, Schmidt-Böcking, H, Stohner, Jürgen, Dörner, R, Schöffler, M S, and Berger, R

Published
2018

37. Maternaler und direkter Einfluss von Traubenzuckerextrakt auf Leistung und Methanemission vom Lämmern und Gitzi

Author

Kreuzer, Michael; https://orcid.org/0000-0002-9978-1171, Lanzini, T, Liesegang, Annette; https://orcid.org/0000-0002-4292-8515, Bruckmaier, R, Hess, H D, Ulbrich, S E, Kreuzer, M ( Michael ), Lanzini, T ( T ), Liesegang, A ( Annette ), Bruckmaier, R ( R ), Hess, H D ( H D ), Ulbrich, S E ( S E ), Sinz, S, Soliva, C R, Marquardt, S, Kreuzer, Michael; https://orcid.org/0000-0002-9978-1171, Lanzini, T, Liesegang, Annette; https://orcid.org/0000-0002-4292-8515, Bruckmaier, R, Hess, H D, Ulbrich, S E, Kreuzer, M ( Michael ), Lanzini, T ( T ), Liesegang, A ( Annette ), Bruckmaier, R ( R ), Hess, H D ( H D ), Ulbrich, S E ( S E ), Sinz, S, Soliva, C R, and Marquardt, S

Published
2018

38. Direct determination of molecular handedness via coulomb explosion imaging

Author

Pitzer, M., Kunitski, M., Kastirke, G., Jahnke, T., Bauer, T., Goihl, C., Trinter, F., Schober, C., Henrichs, K., Becht, J., Zeller, S., Gassert, H., Waitz, M., Kuhlins, A., Wiegandt, F., Wallauer, R., Schmidt, L.Ph.H., Mazenauer, M., Spenger, B., Marquardt, S., Schmidt-Böcking, H., Stohner, J., Dörner, R., Schöffler, M.S., Berger, R., Pitzer, M., Kunitski, M., Kastirke, G., Jahnke, T., Bauer, T., Goihl, C., Trinter, F., Schober, C., Henrichs, K., Becht, J., Zeller, S., Gassert, H., Waitz, M., Kuhlins, A., Wiegandt, F., Wallauer, R., Schmidt, L.Ph.H., Mazenauer, M., Spenger, B., Marquardt, S., Schmidt-Böcking, H., Stohner, J., Dörner, R., Schöffler, M.S., and Berger, R.

Abstract

In this work, we show that the direct determination of a chiral molecule's absolute configuration can be achieved with Coulomb Explosion Imaging in a COLTRIMS reaction microscope. We compare the results after ionisation with femto-second laser pulses and with X-ray synchrotron light. Different fragmentation pathways of the prototypical chiral molecule CHBrClF are identified that carry information on the handedness. The applicabilty of the technique towards bigger molecules is discussed.

Published
2018

49. Influence of experience on intake and feeding behaviour of diary sheep when offered forages from woody plants in a multiple-choice situation

Author

Meier, J S, Liesegang, Annette, Rischkowsky, B, Louhaichi, M, Zaklouta, M, Kreuzer, Michael, Marquardt, S, University of Zurich, and Marquardt, S

Subjects
experience, woody plants, 630 Agriculture, 1311 Genetics, feed choice, diary sheep, 570 Life sciences, biology, feeding behavior, 1103 Animal Science and Zoology, intake, 1106 Food Science, 10227 Institute of Animal Nutrition
Published
2013

50. Fatty acid profile of ghee derived from two genotypes (cattle-ak vs yak) grazing different alpine Himalayan pasture sites.

Author

Marquardt, S., Barsila, S. R., Amelchanka, S. L., Devkota, N. R., Kreuzer, M., and Leiber, F.

Subjects
*FATTY acids, *GHEE, *MILK
Abstract

The fatty acid (FA) profile of ghee produced from milk of cattle-yak hybrids grazing five mountain pasture sites along a high-alpine transhumance route in Nepal was analysed. Pastures differed in altitude above sea level (2600-4500 m), time period of being grazed and phytochemical composition of the swards. Additionally, a comparison of ghee from purebred yak and hybrid was performed, with samples produced at two of the sites. Pasture site had a strong effect on almost all FAs. Proportions of oleic, linoleic and κ-linolenic acid in ghee were smallest on the highest pasture at 4500 m where the largest condensed tannin concentrations in the forages were found. No systematic site effects were found for c9,t11 conjugated linoleic acid and total polyunsaturated FAs. Ghee produced from the hybrids' milk was richer in major functional FAs such as κ-linolenic and linoleic acid, while yak ghee contained more saturated FAs and eicosapentaenoic, docosapentaenoic and docosahexaenoic acids. [ABSTRACT FROM AUTHOR]

Published
2018
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