Red clover supplementation modifies rumen fermentation and promotes feed efficiency in ram lambs.

Red clover produces isoflavones, including biochanin A, which have been shown to have microbiological effects on the rumen while also promoting growth in beef cattle. The objective was to determine if supplementation of biochanin A via red clover hay would produce similar effects on the rumen microbiota and improve growth performance of lambs. Twenty-four individually-housed Polypay ram lambs (initial age: 114 ± 1 d; initial weight: 38.1 ± 0.59 kg) were randomly assigned to one of three experimental diets (85:15 concentrate:roughage ratio; N = 8 rams/treatment): CON-control diet in which the roughage component (15.0%, w/w, of the total diet) consisted of orchardgrass hay; 7.5-RC-red clover hay substituted for half (7.5%, w/w, of the total diet) of the roughage component; and 15-RC-the entire roughage component (15.0%, w/w, of the total diet) consisted of red clover hay. Feed intake and weight gain were measured at 14-d intervals for the duration of the 56-d trial, and rumen microbiological measures were assessed on days 0, 28, and 56. Red clover supplementation impacted growth performance of ram lambs. Average daily gains (ADG) were greater in ram lambs supplemented with red clover hay (7.5-RC and 15-RC) than for those fed the CON diet (P < 0.05). Conversely, dry matter intake (DMI) was lower in 7.5-RC and 15-RC than for CON lambs (P = 0.03). Differences in ADG and DMI resulted in greater feed efficiency in ram lambs supplemented with red clover hay (both 7.5-RC and 15-RC) compared to CON (P < 0.01). Rumen microbiota were also altered by red clover supplementation. The total viable number of hyper-ammonia-producing bacteria in 7.5-RC and 15-RC decreased over the course of the experiment and were lower than CON by day 28 (P ≤ 0.04). Amylolytic bacteria were also lower in 15-RC than in CON (P = 0.03), with a trend for lower amylolytic bacteria in 7.5-RC (P = 0.08). In contrast, there was tendency for greater cellulolytic bacteria in red clover supplemented lambs than in CON (P = 0.06). Red clover supplementation also increased fiber utilization, with greater ex vivo dry matter digestibility of hay for both 7.5-RC and 15-RC compared to CON by day 28 (P < 0.03). Results of this study indicate that low levels of red clover hay can elicit production benefits in high-concentrate lamb finishing systems through alteration of the rumen microbiota.

Red clover is rich in the bioactive isoflavone, biochanin A. The goal was to evaluate the impacts of biochanin A supplementation via red clover hay on growth performance of ram lambs as well as the rumen microbiota and fermentation. Low levels of red clover hay inclusion (7.5% and 15.0%, w/w, of the total diet) in high-concentrate finishing diets improved feed efficiency of ram lambs, promoting weight gain while decreasing feed intake. Red clover hay supplementation suppressed ruminal protein-wasting, peptide- and amino-acid degrading and starch-utilizing bacteria compared to control diets without isoflavones. Red clover hay also promoted fiber degrading bacteria and fiber utilization. Lamb growth and microbiological effects of red clover were consistent regardless of supplementation level in the diet. Results of this study indicate that low levels of red clover hay can produce production benefits in lamb finishing systems and demonstrated the efficacy of red clover as a functional feed, or feed with biological activities, in the context of its traditional use as a forage feedstuff.

Polymorphism in paracetamol: evidence of additional forms IV and V at high pressure.

The structural phase stability of N-(4-hydroxyphenyl) acetamide (paracetamol) has been studied at ambient temperature up to 23 GPa using Raman spectroscopy. Spectral changes have provided further evidence for a highly kinetically driven Form I → II transition that occurs as a mixed phase from 4.8 to 6.5 GPa, and might complete as early as 7 GPa. Upon further compression to 8.1 GPa, a drastic shift in spectral signature was observed providing the first evidence for a previously undiscovered Form IV of paracetamol. Additional shifts in mode intensities were observed near 11 GPa indicating a potential restructuring of the hydrogen bonding network and/or structural modification to a potentially new Form V. Phase boundaries at 7 and 8 GPa were confirmed under hydrostatic conditions using Raman spectroscopy. Spectral changes indicate that the transition Form IV → V occurs near 11 GPa. Multiple ab initio harmonic frequency calculations at different levels of theory were performed with a B3LYP/6-31G** being used to provide a more robust mode assignment to our experimentally obtained Raman modes. High pressure X-ray diffraction (XRD) was performed up to 21 GPa, which provided further evidence for a highly kinetically driven Form I → II transition in agreement with our Raman measurements. In addition, the XRD provided further evidence for the existence of Form IV near 8 GPa and Form V near 11 GPa with Form V persisting up to 21 GPa.

Conformational Analysis of Retinoic Acids: Effects of Steric Interactions on Nonplanar Conjugated Polyenes.

Retinoic acids and other vitamin A analogs contain a trimethylcyclohexenyl ring in conjugation with a polyene chain joined at carbon-6 (C6) and carbon-7 (C7). A MP2-SCS/cc-pVDZ// B3LYP/6-31G(d) 2-D potential energy surface was computed for all-trans retinoic acid, which had 6 minima (3 enantiomeric pairs). The global minima were distorted s-gauche enantiomers (6-7 = 53°) with half-chair conformations of the ring. Distorted s-gauche enantiomers (6-7 = 55°) with inverted half-chair ring conformations were 1.7 kJ/mol above the global minima. The s-trans enantiomers (6-7 = 164°) were 11.3 kJ/mol above the global minima. Steric energies were computed by the method of Guo and Karplus to identify key structural elements in retinoic acids which determines their conformation. Small molecule crystal structures in the CCDC database with trimethylcyclohexenyl ring and exocyclic double bonds have ring-chain geometries near to one of the 6 energy minima of retinoic acids, except for retinaldehyde iminium cations.

Syntheses, X-ray crystal structures, and optical, fluorescence, and nonlinear optical characterizations of diphenylphosphino-substituted bithiophenes.

A series of bithiophene derivatives that are either symmetrically disubstituted with two Ph(2)(X)P groups (X = O, S, Se) or monosubstituted with one Ph(2)(X)P group (X = O, S, Se) and an organic functional group (H, CHO, CH(2)OH, CO(2)Me) have been synthesized. The X-ray crystal structures of Ph(2)(Se)P(C(4)H(2)S)(2)P(Se)Ph(2), Ph(2)(O)P(C(4)H(2)S)(2)H, Ph(2)(S)P(C(4)H(2)S)(2)H, and Ph(2)(O)P(C(4)H(2)S)(2)CH(2)OH exhibit very different solid-state structures depending on the type of intermolecular π-π interactions that occur. The compounds have been characterized by electronic absorption and fluorescence studies. Of particular interest is that the quantum yields of Ph(2)(O)P(C(4)H(2)S)(2)H, Ph(2)(O)P(C(4)H(2)S)(2)P(O)Ph(2), Ph(2)(O)P(C(4)H(2)S)(2)CO(2)Me, and Ph(2)(O)P(C(4)H(2)S)(2)CH(2)OH are significantly larger than that of bithiophene (factors of 13, 14, 14, and 22, respectively). This behavior is quite different from that of analogously substituted terthiophenes in which substitution results in only modest increases in the quantum yields over that of terthiophene (factors of 0.94, 2.7, 1.3, and 1.5, respectively). DFT studies of the emission process suggest that modifying the Ph(2)(X)P group affects both the fluorescence and nonradiative rate constants while modifications of the organic substituents primarily affect the nonradiative rate constants. The higher quantum yields of the substituted bithiophenes make them promising for application in organic light-emitting devices (OLED). The optical power limiting (OPL) performances of these Ph(2)(X)P-substituted bithiophenes were evaluated by nonlinear transmission measurements in the violet-blue spectral region (430-480 nm) with picosecond laser pulses. The OPL performances are enhanced by heavier X groups and when by higher solubilities. Saturated chloroform solutions of Ph(2)(O)P(C(4)H(2)S)(2)H and Ph(2)(S)P(C(4)H(2)S)(2)H exhibit significantly stronger nonlinear absorption than any previously reported compounds and are promising candidates for use in broadband optical power limiters.

A cw EPR and ENDOR investigation on a series of Cr(I) carbonyl complexes with relevance to alkene oligomerization catalysis: [Cr(CO)4L]+ (L = Ph2PN(R)PPh2, Ph2P(R)PPh2).

The preparation and characterisation of the Cr(I) complexes [Cr(CO)(4)L](+) (L = Ph(2)PN(R)PPh(2), Ph(2)P(R)PPh(2)), which are used as pre-catalysts for the selective oligomerization of ethylene, are reported. The electronic properties and structural features of these complexes in frozen solution have been established via continuous wave X-band Electron Paramagnetic Resonance (cw-EPR) and continuous wave (1)H, (14)N and (31)P Electron Nuclear Double Resonance (cw-ENDOR) spectroscopy. The EPR spectra are dominated by the g anisotropy, with notably large (P)A couplings from the two equivalent (31)P nuclei. The spin Hamiltonian parameters (g(perpendicular) (g(xx) = g(yy)) > g(e) > g(parallel) (g(zz))) are consistent with a low-spin d(5) system possessing C(2v) symmetry, with a SOMO where the metal contribution is primarily d(xy) for all complexes. The isotropic Fermi contact term ((P)a(iso), determined by EPR and ENDOR) was found to be largest for complexes containing ligands e, d, f and g, indicating that the (31)P 3 s character in the SOMO is higher for the PNP type ligands than the PCP type. Subtle structural differences in the complexes were also identified through variations in the Deltag shifts (identified by EPR), and through differences in the phenyl ring conformations (identified by (1)H ENDOR). Attempts to correlate trends in EPR-derived parameters with data measured for catalysis using these pre-catalysts are also made, but no clear connections were found.

Nonplanarity at tri-coordinated aluminum and gallium: cyclic structures for X3Hn(m) (X = B, Al, Ga).

Structures and energies of X3H3(2-), X3H4-, X3H5, and X3H6+ (X = B, Al and Ga) were investigated theoretically at B3LYP/6-311G(d) level. The global minimum structures of B are not found to be global minima for Al and Ga. The hydrides of the heavier elements Al and Ga have shown a total of seven, six and eight minima for X3H3(2-), X3H(4-), and X3H5, respectively. However, X3H(6+) has three and four minima for Al and Ga, respectively. The nonplanar arrangements of hydrogens with respect to X3 ring is found to be very common for Al and Ga species. Similarly, species with lone pairs on heavy atoms dominate the potential energy surfaces of Al and Ga three-ring systems. The first example of a structure with tri-coordinate pyramidal arrangement at Al and Ga is found in X3H(4-) (2g), contrary to the conventional wisdom of C3H3+, B3H3, etc. The influence of pi-delocalization in stabilizing the structures decreases from X3H3(2-) to X3H6+ for heavier elements Al and Ga. In general, minimum energy structures of X3H4-, X3H5, and X3H6+ may be arrived at by protonating the minimum energy structures sequentially starting from X3H3(2-). The resonance stabilization energy (RSE) for the global minimum structures (or nearest structures to global minimum which contains pi-delocalization) is computed using isodesmic equations.

Carbene Rearrangements Unsurpassed: Details of the C(7)H(6) Potential Energy Surface Revealed.

The rearrangement of phenylcarbene (1) to 1,2,4,6-cycloheptatetraene (3) has been studied theoretically, using SCF, CASSCF, CASPT2N, DFT (B3LYP), CISD, CCSD, and CCSD(T) methods in conjunction with the 6-31G, 6-311+G, 6-311G(2d,p), cc-pVDZ, and DZd basis sets. Stationary points were characterized by vibrational frequency analyses at CASSCF(8,8)/6-31G and B3LYP/6-31G. Phenylcarbene (1) has a triplet ground state ((3)A") with a singlet-triplet separation (DeltaE(ST)) of 3-5 kcal mol(-)(1). In agreement with experiment, chiral 3 is the lowest lying structure on this part of the C(7)H(6) potential energy surface. Bicyclo[4.1.0]hepta-2,4,6-triene (2) is an intermediate in the rearrangement of 1 into 3, but it is unlikely to be observable experimentally due to a barrier height of only 1-2 kcal mol(-)(1). The enantiomers of 3 interconvert via the (1)A(2) state of cycloheptatrienylidene (4) with an activation energy of 20 kcal mol(-)(1). The "aromatic" (1)A(1) state, previously believed to be the lowest singlet state of 4, is roughly 10 kcal mol(-)(1) higher in energy than the (1)A(2) state, and, in violation of Hund's rule, (3)A(2) is also calculated to lie above (1)A(2) in energy. Thus, even if (3)A(2) were populated, it is likely to undergo rapid intersystem crossing to (1)A(2). We suggest (3)B(1)-4 is the metastable triplet observed by EPR.