The effects of supplementing feed of cows in mid-to-late lactation with an active yeast product (Actisaf Sc 47) were evaluated using 15 Holstein cows in a replicated 3 × 3 Latin square design. The animals were fed a mixed ration with 33% neutral detergent fiber, consisting of timothy hay (29.8%), a commercial concentrate (70.0%) and commercial calcium triphosphate (0.2%), twice daily to meet 105% of their energy requirement. Yeast supplement was set at 0, 5 and 10 g per day over 21-day periods, each of which consisted of 14 days for adaptation followed by 7 days of data collection. Milking performance, plasma metabolite parameters, rumen volatile fatty acids, lipopolysaccharide and microbial properties were measured. Although there were no significant differences in feeding and milking performance or blood parameters associated with supplementation, the acetate to propionate ratio in the rumen fluid tended to decrease (P = 0.08). The population of Bacteroidetes tended to be less prominent (P = 0.07) and the fibrolytic bacterium Fibrobacter significantly increased (P < 0.05) in the rumen fluid of the yeast 10 g group compared with that of the control. These data suggest that effects of supplementing live yeast to cows in mid-to-late lactation may be limited to microbial composition and fermentation characteristics in the rumen.

To determine changes in reticular pH during the pre- and postpartum periods, when subacute ruminal acidosis (SARA) frequently occurs, we monitored pH in dairy cows up to 12 weeks postpartum using a radio transmission pH sensing system. We designated seven pregnant multiparous Holstein cows for continuous pH monitoring (pH monitoring test), resulting in successful data acquisition for reticular pH. We subsequently evaluated the cows to determine whether active dry yeast supplementation of their feed was effective for SARA prevention (yeast supplementation test). Twenty-nine pregnant cows were allocated to two groups (control [CON, n = 15] and yeast-supplemented [YEA, n = 14]) and fed a mixed ration optimized for dry prepartum cows and a mixed ration that consisted mainly of timothy hay and a commercial concentrate. The feed of the YEA group was supplemented with 10 g/day of commercial active yeast product for three weeks prepartum and twelve weeks postpartum. In the latter test, six cows in each group were selected for reticular pH recording using the pH monitoring system. The pH profiles in the pH monitoring test were relatively high compared to those in the yeast supplementation test throughout the testing period, probably due to differences in starch and fiber levels between experiments despite their identical formula design. Notably, regardless of yeast supplementation, 11 of 12 cows in the latter test exhibited similar trends of pH maintenance (6.5 < pH < 6.8) or gradual decrease during the dry period, whereas average daily reticular pH decreased dramatically after calving. Supplementing the diet of dairy cows with yeast during the transition period provided no significant change in the health and performance measurements of the animals. We demonstrated the application of a radio transmission pH sensing system for assessment and monitoring of the ruminal pH of cows in the transition period. Furthermore, our results imply that SARA incidence in the transition and early- to mid-lactation periods may be attributable to a reticuloruminal pH decrease during the dry period, which is difficult to overcome by means of yeast supplementation during the transition period. (C) 2016 Elsevier B.V. All rights reserved.

Excitation spectra for 5d–4f photoluminescence (PL) bands of Ce3+ and Eu2+ ions doped in SrGa2S4 crystals have been measured at room temperature in the energy region up to 25eV. These spectra allow us to investigate the excitation process of luminescent ions under host excitation with vacuum ultraviolet (VUV) photons. A gentle increase in intensity is commonly observed at around 16.5eV in the excitation spectra. Optical constant spectra were obtained from measurements of reflectivity and absorption edge spectra of undoped SrGa2S4 crystals. These data were compared with the results of a relativistic DV-Xα calculation, to clarify the electronic structure of SrGa2S4. Ultraviolet photoelectron spectroscopy (UPS) has been carried out under the excitation with photons in the 12–20eV range. The detailed analysis of UPS spectra reveals that the multiplication of electronic excitations (MEEs) occurs above 16.5eV. The excitation process of Ce3+ and Eu2+ ions is discussed together with the processes of MEEs.

This paper reports on the optical properties of cerium-doped lutetium oxyorthosilicate (LSO:Ce) crystals. The reflection and X-ray photoelectron spectra are measured, and compared to the electronic structure calculated by a discrete variational Xα method. A sharp exciton band originating from O 2p→Lu 5d transition is observed at 7.27eV at 6K, with the band-gap energy of 7.52eV. Luminescence measurements have also been performed in a wide temperature range of 6–300K. The intensity of Ce luminescence arising from the 5d→4f transition is temperature-independent under the direct excitation of Ce3+ ions, but it is enhanced at around 50K under the excitation of host LSO crystals. This enhancement is found to anti-correlate with a thermal quenching of the intrinsic luminescence due to self-trapped excitons. The present results provide a piece of evidence that thermally-activated energy transfer from host to activator takes place efficiently in LSO:Ce.

The green luminescence from the triplet states of a self-trapped exciton (STE) located on a tetrahedral (MoO4)(2)-ion in PbMoO4 splits into three bands, I, II, and III, as a result of the symmetry lowering of the (MoO4)(2)-ion due to a Jahn-Teller effect. Time-resolved luminescence measurements have been performed for polarizations with the electric vector parallel to the crystallographic c axis (E parallel to c) and perpendicular to it (E perpendicular to c) in a temperature range between 8 and 225 K. All three bands are confirmed to exhibit significant polarizations. The main band II at 520 nm is polarized with E parallel to c at low temperatures (T < 75 K) but changes its polarization from E parallel to c to E perpendicular to c at T > 125 K. Band III at 600 nm is polarized with E perpendicular to c at T = 170 and 225 K. The degree of polarization of these two bands does not depend on the polarization of excitation light. On the other hand, band I at 405 nm is polarized with E perpendicular to c (E parallel to c) under the excitation by photons polarized parallel (perpendicular) to the c axis, in the range of T = 150-225 K. The observation of polarized luminescence provides convincing evidence for further lowering of the symmetry of (MoO4)(2)-ions due to a uniaxial crystal field in addition to the Jahn-Teller distortion. The sublevels of the triplet STE state responsible for the PbMoO4 luminescence are identified on the basis of group-theoretical considerations. DOI: 10.1103/PhysRevB.87.085201

T. Tsujibayashi, J. Azuma, M. Watanabe, O. Arimoto, M. Itoh, S. Nakanishi, H. Itoh, M. Kamada Department of Physics, Osaka Dental Univ., Hirakata 573-1121, Japan Synchrotron Light Application Center, Saga Univ., Saga 840-8502, Japan Department of Interdisciplinary Environment, Kyoto Univ., Kyoto 606-8501, Japan Department of Physics, Okayama Univ., Okayama 700-8530, Japan Department of Electrical & Electronic Engineering, Shinshu Univ., Nagano 380-8553, Japan Department of Advanced Materials Science, Kagawa Univ., Takamatsu 761-0396, Japan

On the basis of the electronic structure determined from measurements of reflection and X-ray photoelectron spectra, Auger-free luminescence (AFL) of Cs2ZnCl4 has been studied under the outermost-core band excitation in a temperature range of 10-300 K. A band is found at 4.8 eV, in addition to the 3.3 and 4.2 eV bands observed previously. The present study clarifies that the 4.8 eV band, as well as the 3.3 and 4.2 eV bands, originates from the Auger-free transition between the Cs 5p outermost-core band and the Cl 3p valence band. When the sample temperature is increased, spectral widths of the 3.3 and 4.8 eV bands become broadened, while that of the 4.2 eV band is almost kept unchanged. This suggests that the core hole created on a Cs+ ion interacts with the surrounding lattice vibration. The decay profiles are found to be essentially the same for all the AFL bands. Three-peaked structure of AFL is discussed in comparison with experimental and theoretical results in CsCl.

It is reported that Auger-free (AF) luminescence appears with two bands at 4.5 and 6.3eV in Rb2ZnCl4. This luminescence originates from a radiative transition of the Cl 3p valence electrons into the Zn 3d outermost-core holes. The present work is the first observation of AF luminescence due to interatomic p–d transitions in halide crystals. The appearance of two AF luminescence bands suggests the existence of two types of AF transitions following core hole creation. A largely Stokes-shifted luminescence band is also found to appear at 1.9eV. This band has an excitation threshold at the fundamental absorption edge, and is ascribed to the radiative decay of a self-trapped exciton.

Luminescence properties of CdMoO4 crystals have been investigated in a wide temperature range of T=5–300K. The luminescence-excitation spectra are examined by using synchrotron radiation as a light source. A broad structureless emission band appears with a maximum at nearly 550nm when excited with photons in the fundamental absorption region (<350nm) at T=5K. This luminescence is ascribed to a radiative transition from the triplet state of a self-trapped exciton (STE) located on a (MoO4)2− complex anion. Time-resolved luminescence spectra are also measured under the excitation with 266nm light from a Nd:YAG laser. It is confirmed that triplet luminescence consists of three emission bands with different decay times. Such composite nature is explained in terms of a Jahn–Teller splitting of the triplet STE state. The triplet luminescence at 550nm is found to be greatly polarized in the direction along the crystallographic c axis at low temperatures, but change the degree of polarization from positive to negative at T>180K. This remarkable polarization is accounted for by introducing further symmetry lowering of tetrahedral (MoO4)2− ions due to a uniaxial crystal field, in addition to the Jahn–Teller distortion. Furthermore, weak luminescence from a singlet state locating above the triplet state is time-resolved just after the pulse excitation, with a polarization parallel to the c axis. The excited sublevels of STEs responsible for CdMoO4 luminescence are assigned on the basis of these experimental results and a group-theoretical consideration.

Femtosecond reflection spectroscopy was performed on a perovskite-type cobalt oxide, namely, Pr${}_{0.5}$Ca${}_{0.5}$CoO${}_{3}$, that undergoes a photoinduced spin-state transition. After photoirradiation at 30 K, the time profile of the reflectance change shows a broad peak reflecting the propagation of the photodomain (about 60 Co sites per one photon). Analysis of the peak position indicates the sudden increase of the velocity of the propagation with increasing the excitation intensity. Such acceleration with increase in fluence originates from an abrupt sound velocity change driven by a cooperative photoinduced structural transition.

Time-resolved luminescence measurements have been carried out for PbMoO4 crystals with the scheelite structure. A fast-decaying luminescence band with a lifetime of the order of 10 ns is observed at 400 nm at low temperatures (T < 170 K). This luminescence is tentatively assigned to the radiative transition of a singlet excited state of a self-trapped exciton (STE) located on a (MoO4)(2-) ion. The green luminescence, which is ascribed to the triplet STE states in PbMoO4, is found to consist of three emission bands peaking at 405, 520, and 600 nm at T = 150-220 K. Such a composite nature is explained by taking into account the symmetry lowering of (MoO4)(2-) ions due to the Jahn-Teller effect. The present observation provides strong support to the previous results of PbWO4, in which the triplet STE luminescence is also decomposed into three individual bands. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim