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Electron diffraction data are used to obtain the structure solution of a large-pore, high-silica zeolite, SSZ-48 that contains an occluded organic structure directing agent. The structure is determined by electron diffraction refinement and is confirmed by high-resolution transmission electron microscopy and Rietveld refinement of powder synchrotron X-ray data. The structure is found to contain a one-dimensional pore system circumscribed by 12 tetrahedral atoms (12 MR). SSZ-48 is the most complex three-dimensional material to be solved at atomic resolution using electron diffraction methods and illustrates the power of electron diffraction data for resolving the structures of materials that form crystals too small for standard single-crystal X-ray analysis.

The nature of molecular recognition in an imprinted polymer that is formed by the self-assembly of binding monomer and imprint through noncovalent interactions is investigated. The system studied uses ethylene glycol dimethacrylate, methacrylic acid, and l-phenylalanine anilide as the cross-linking monomer, binding monomer, and imprint, respectively, to assemble the imprinted polymer. A proposal for the self-assembly mechanism between the binding monomer and imprint that occurs during polymer synthesis is derived from a single-crystal X-ray structure of a crystal containing binding monomer and imprint and from ¹H NMR and FTIR spectroscopy of solutions of these components. These studies show the presence of a salt-bridge interaction that leads to a 1:1 molecular complex between methacrylic acid and l-phenylalanine anilide and provide no evidence for the formation of higher-order molecular complexes of these species. Furthermore, macroscopic phase separation is observed between the imprint and binding monomer and the cross-linking monomer in this system prior to and after polymerization. These findings suggest a mechanism for enantioselective molecular recognition in the imprinted polymer involving remaining, occluded imprint molecules, which can provide for binding via imprint−imprint intermolecular interactions. Support for this mechanism is provided from polymers prepared using a combination of imprint and mimic, l-phenylalanine 4-vinylanilide; the latter remains covalently bound in the polymer and is shown to increase the rebinding of imprint while not significantly affecting the binding of the opposite enantiomer. The proposed mechanism provides insight into the nature of binding site heterogeneity in imprinted polymer systems.

Zincosilicate CIT-6 (California Institute of Technology number 6) that has the *BEA-type structure is synthesized at hydrothermal conditions in the presence of tetraethylammonium hydroxide (TEAOH), Li⁺, and Zn²⁺. As opposed to zeolite beta, TEA cations can be easily extracted with acetic acid containing solution from CIT-6 because the interaction between the TEA cations and CIT-6 framework is weak. The extraction at 135 °C simultaneously removes TEA cations and zinc and forms a highly hydrophobic Si−CIT-6 with very little defects. Al-containing CIT-6 can be prepared by either extracting TEA cations from as-made Al-containing CIT-6 or inserting aluminum into CIT-6 extracted at 60 °C. ²⁹Si NMR and water adsorption data indicate that the aluminum-containing materials are different from zeolite beta prepared via direct synthesis. CIT-6 is thus shown to be a useful precursor to prepare a wide range of new molecular sieve materials that are of the *BEA type.

Artesunate, the only artemisinin analogue that can be given intravenously, produces rapid parasite and fever clearance in falciparum malaria. A significant therapeutic problem is a high, late recrudescence rate, probably due to short half-lives of both artesunate and its active metabolite dihydroartemisinin relative to conventional dosing intervals. One method of extending the duration of action of artesunate could be to administer the drug by infusion rather than bolus injection, provided that it is chemically stable at ambient temperature.Artesunate was found to be stable in 0ṁ9% w/v sodium chloride at 9°C, 23°C and 36ṁ5°C for 130, 10ṁ6 and 1ṁ6 h, respectively. Interpolating from an Arrhenius plot, artesunate should be stable for approximately 4 h at 30°C, a temperature representative of ambient conditions in tropical countries. Exposure to light did not affect the degradation rate. Single compartment pharmacokinetic modelling was used to evaluate potential differences in artesunate and dihydroartemisinin plasma concentrations following administration of artesunate by intravenous bolus or infusion. A bolus injection of artesunate at a dose of 4 mg kg−1gives a peak concentration of 5ṁ3 mg L−1, falling to 0ṁ005 mg L−1at 5 h. The same dose infused over 4h results in a peak concentration of 0ṁ92 mg L−1falling to 0ṁ005 mg L−1at 8h. Simultaneous modelling of dihydroartemisinin showed that while its peak plasma concentration was reduced by 27% and the peak delayed by 2.5 h following artesunate administration by infusion, substantially higher concentrations were maintained compared with those predicted after bolus artesunate.These data indicate that artesunate can be administered as a high-dose intravenous infusion, thus avoiding high plasma concentrations. This strategy also has the potential to prolong the duration of antimalarial effect and reduce toxicity, and consequently improve clinical outcome in seriously ill patients.

Effects of adjusting postweaning feed:gain ratios for differences in maintenance requirements as recommended by the Beef Improvement Federation were examined utilizing 171 individually fed, purebred Angus bulls. The residual correlation (year and sire effects removed) between unadjusted and adjusted feed efficiency was .85 (P<.01). The Spearman correlation between ranks of the bulls based on the two measures of efficiency was .79 (P<.01). Although product-moment and rank correlations between unadjusted and adjusted feed:gain ratios were large, the two methods of evaluating efficiency often identified different bulls as being among the four most or four least efficient in the conversion of feed into postweaning gain. When unadjusted feed:gain ratios were used to evaluate efficiency, bulls that were more efficient were lighter in weight at the beginning of the 140-d postweaning performance test, gained more rapidly and consumed less feed during the test, and were taller and leaner at the conclusion of the test. When differences due to maintenance requirements were removed, bulls that gained more rapidly and were heavier, taller and slightly fatter at the end of the test were superior in the conversion of feed into postweaning gain. Correlations of on-test weight and feed consumption with adjusted feed:gain ratios were near zero. On-test age was not closely related to either adjusted or unadjusted feed efficiency.

Weight and individual feed consumption data collected on 160 beef, dairy and beef × dairy dams and their progeny were used to estimate postweaning feed efficiency of progeny and several measures of lifetime cow efficiency for cows fed either a high or a low energy diet. Cow efficiency was expressed as the ratio of output to input where output included relative values for either progeny slaughter weights, carcass weights or trimmed wholesale cut weights plus cow weight; and input included pre- and postweaning feed consumption of progeny and lifetime feed consumption of the dam. In the first approach, life cycle cow efficiency was estimated by expressing output as a ratio to input when weight and feed consumption were weighted by their expected occurrence in a theoretical herd consisting of 100cows and 20 replacement heifers. Expected occurrence was a function of the age distribution of the cow herd and percentage calf crop. In the second approach, actual lifetime cow efficiency was estimated by expressing output as a ratio to input when all components were weighted equally. Both approaches included efficiency estimates calculated with and without cow calvage value. Diet of dam had little effect on efficiency of postweaning gain when progeny were slaughtered at age-constant end points. Dams fed low energy diets generally were equal or superior to those fed high energy diets in lifetime efficiency. Straightbred Holsteins mated to Hereford sires were less efficient than straightbred Herefords mated to Holstein sires, even though they produced progeny with heavier slaughter weights, carcass weights and trimmed wholesale cut weights, lower preweaning feed consumption and more efficient postweaning gains, in addition to possessing greater salvage value. The low efficiency ratios of Holstein dams were associated with their large metabolizable energy intake. Progeny of Simmental X Holstein and Chianina X Holstein dams tended to be more efficient than progeny of Hereford X Holstein and Angus X Holstein dams in the conversion of feed to postweaning gain. Hereford X Holstein and Simmental X Holstein dams were nearly equal in lifetime efficiency, while Angus X Holstein and Chianina X Holstein dams were slightly less efficient. Efficiency of production improved as number of progeny slaughtered increased.

Postweaning weight gains, feed consumptions and feed efficiencies, and slaughter weights, carcass weights and trimmed wholesale cut weights of progeny of 160 beef, dairy and beef × dairy dams fed high or low energy diets are reported. These traits represent progeny components of input and output needed to estimate lifetime cow efficiency to a slaughter end point. Diet of dam had little effect on postweaning gain, feed consumption and feed efficiency of progeny. Progeny of dams receiving the high and low energy diets also had similar slaughter weights, carcass weights and trimmed wholesale cut weights. In experiments initiated in 1964 and 1969, second and third progeny of Holstein dams had greater postweaning gains, consumed more metabolizable energy (ME) and tended to be more efficient in the conversion of feed into gain than progeny of Hereford, Hereford × dairy or Hereford × beef dams. In the first parity, Holstein progeny were second to Here ford progeny in gain and efficiency of gain. Progeny of Holstein dams had the heaviest slaughter weights, carcass weights and trimmed wholesale cut weights, but tended to have the greatest fat thickness over the longissimus muscle at the 12th rib and the lowest percentage of the carcass in trimmed wholesale cuts. Progeny of the larger breeds (Simmental × Holstein and Chianina X Holstein ) tended to gain more rapidly, consume more feed and convert the feed into gain more efficiently than progeny of the smaller breeds (Hereford X Holstein and Angus X Holstein) in the time constant postweaning interval used in an experiment initiated in 1974. Simmental × Holstein and Chianina X Holstein breed groups ranked highest in progeny output as measured by slaughter weights, carcass weights and weight of trimmed wholesale cuts. Progeny of these two breed groups had low fat thicknesses over the longissimus muscle, low dressing percentages and a high percentage of the carcass in trimmed wholesale cuts relative to Hereford X Holstein and Angus X Holstein progeny.

As part of a divergent selection experiment (high vs low feed conversion) designed to obtain realized genetic parameter estimates for postweaning feed conversion, 35 Angus bull calves were selected each year from 1979 through 1983 to be fed in a 140-d postweaning performance test. From these 35 individually-fed bulls, the three most efficient and three least efficient (in terms of kilograms of total digestible nutrients required per kilogram of gain) were selected each year to each be mated to approximately 20 purebred Angus cows in a test herd. In the last 2 yr of the experiment, feed:gain ratios were adjusted for differences in maintenance requirements before selection. An alternative to selection based on feed/gain or adjusted feed/gain would have been to select on an index of feed intake and gain (Index3 = −1.0 feed intake + 3.87 gain) where feed intake was either unadjusted or adjusted (Adjlndex3) for differences in maintenance requirements. Residual correlations (year effects removed) among the four selection critera were large (|r|⩾.76; P<.01) as were correlations among ranks of the bulls based on the four selection criteria (|n|⩾.75). Predicted genetic change for feed:gain ratio in both the high and low directions was greatest when selection was based on feed:gain ratio or Index3. Genetic changes expected to result from selection for feed:gain ratio or Index3 were similar, as were genetic changes expected due to selection for adjusted feed:gain ratio or Adjlndex3. Results indicated little advantage to use of an index of feed intake and gain in place of the feed:gain ratio if the goal is to bring about generic improvement in postweaning feed conversion of beef cattle.

Weight and individual feed consumption data collected on 160 beef, dairy and beef × dairy dams and their progeny were used to calculate several measures of life cycle and actual lifetime cow efficiency to weaning and slaughter end points. Accuracy of predictors of cow efficiency that did not require feed intake data for progeny or dams was then examined. Multiple coefficients of determination (R2) for predictors expressed as the ratio of weaning or slaughter weight output to dam weight were similar to those for predictors expressed as the ratio of weight output to metabolic weight of dam. Including progeny metabolic weight along with dam metabolic weight in the denominator of ratio predictors generally reduced R2values. Accuracy of prediction was lower for weaning or slaughter weight alone than for predictors that expressed progeny weight as a ratio to dam weight or dam metabolic weight. The R2values were greater for multiple regression equations that included combinations of progeny weight, dam weight, weight:height ratio of dam, milk production and age of dam at calving than for ratios of progeny and dam weights. A prediction equation that included progeny weaning or slaughter weight, dam weight and age of dam at calving was the most useful from the standpoint of accuracy and simplicity. Life cycle and actual lifetime efficiency were predicted with sufficient accuracy to be useful (R2>.30) at the end of the second parity in all analyses.

Ninety-six crossbred calves from 66 fall-calving cows were utilized to evaluate differences in cow and calf performance and to determine economic differences between cows that weaned calves at approximately 110 or 222 d. No significant differences existed in cow weight or condition score at normal weaning, but differences in cow weight at early weaning were significant between cows with early- and normal-weaned calves. Cows with early-weaned calves gained 2.5 ± 3.3 kg, while cows with normal-weaned calves lost 18.2 ± 2.9 kg between early and normal weaning (P<.01). No significant differences existed between early- and normal-weaned calves for average daily gain from birth to early weaning or weight at early weaning. Early-weaned calves were 25.2 ± 4.4 kg heavier at normal weaning and gained 29.0 ± 3.0 kg more from early to normal weaning than normal-weaned calves. Compared with normal-weaned calves, early-weaned calves were lower (P=.05) in condition score at early weaning, had greater (P<.05) improvement in condition score from early to normal weaning but similar (P=.30) condition scores at time of normal weaning. Cows with early-weaned calves consumed 45.3% less (P=.13) hay, on total digestible nutrients basis, than cows with normal-weaned calves. Early-weaned cow-calf pairs consumed 20.4% (P=.36) less total digestible nutrients than normal weaned cow-calf pairs. The early-weaned cow-calf pairs were 43.0% more (P=.01) efficient in converting total digestible nutrients into calf gain than were normal-weaned cow-calf pairs.

Weights and individual feed consumptions of 160 beef, dairy and beef × dairy dams and their progeny were used to estimate several measures of life cycle cow efficiency. Efficiency was expressed as the ratio of output to input, where output included relative values for slaughter weights, carcass weights and trimmed wholesale cut weights of progeny and weight of the dam, and inputs were pre- and postweaning feed consumption of progeny plus lifetime feed consumption of the dam. In the first approach, inputs and outputs were weighted by their probability of occurrence; probabilities were a function of the age distribution of the cow herd and calf crop percentage in a theoretical herd. The second approach involved dividing the sum of the weight outputs by the sum of the feed inputs when all pieces of information were weighted equally. Weight, height and weight/ height of dam at 240 d of age were not correlated significantly with subsequent efficiency of progeny slaughter weight production, indicating that selection on these traits would be ineffective for increasing lifetime cow efficiency. However, females exhibiting more efficient weight gains from 240 d to first calving tended to produce progeny with more efficient postweaning gains and tended to become more efficient producers on a lifetime basis. Correlations of efficiency estimates with weight of dam at calving were negative and generally highly significant. Height of dam was related positively to postweaning feed efficiency of progeny, but was negatively related to life cycle cow efficiency. Correlations involving weight/ height indicated that fatter dams were less efficient. Level of milk production needed to maximize biological efficiency varied with the breed combinations involved. The importance of fertility and calf survival were demonstrated by the close association of efficiency with slaughter rate and age at calving. Correlations among efficiency ratios calculated at weaning and at slaughter were .88 (P<.01) or above, whereas relationships between pre- and postweaning efficiency were nonsignificant. Correlations between postweaning efficiency and efficiency of slaughter weight, carcass weight and trimmed wholesale cut weight production ranged from .10 (P>.05) to .41 (P<.01).

Several measures of life cycle cow efficiency were calculated using weights and individual feed consumptions of 160 beef, dairy and beef × dairy dams and their progeny. Ratios of output to input were used to estimate efficiency, where outputs included relative values for slaughter weights, carcass weights and trimmed wholesale cut weights of progeny and weight of the dam, and inputs included pre- and postweaning feed consumption of progeny plus feed consumed by the dam over her entire lifetime. In the first approach to estimating efficiency, inputs and outputs were weighted by their probability of occurrence, where probabilities were a function of the age distribution of the cow herd and calf crop percentage in a theoretical herd. The second approach involved dividing the sum of the weight outputs by the sum of the feed inputs when all pieces of information were weighted equally. Both approaches included efficiency estimates calculated with and without cow salvage value. Efficiency estimates that did not include salvage value of the dam were negatively correlated (P<.01) with weight of dam at weaning. Larger, faster-gaining progeny were more efficient in the time constant postweaning phases of experiments initiated in 1964, 1969 and 1974. Correlations of cow efficiency with slaughter weights of progeny summed across parities were positive and highly significant. Metabolizable energy (ME) intake of dams accounted for approximately 69 and 65% of the total ME required to produce slaughter progeny in the first and second approaches, respectively, and showed a large negative association with lifetime efficiency.

The Monte Carlo method was used to simulate selection and inbreeding in a population of beef cattle consisting of 16 closed lines each with one sire and 10 dams. Production of progeny over a 25-yr period that included overlapping generations was simulated. Two traits with initial narrow sense heritabilities of .28 and .52, respectively, were studied. Genotypic values were determined two loci at a time for the 64 independent loci in an individual's genome on the basis of five modes of gene action, including dominance, epistasis and additive gene action. Phenotypic values were generated by the addition of normally distributed, random environmental factors to the genotypic values. Index values were calculated as the simple average of the phenotypes for traits 1 and 2. Selection was entirely within lines, with index values the sole selection criterion. Genetic gains were made despite moderate levels of inbreeding. The genotypic mean for trait 1 increased 5.8% from the base population to the last 5-yr period, while the genotypic mean for trait 2 increased 6.6%. Genetic gains were greatest in the section of the genome in which both traits were controlled by the additive mode of gene action. Substantial genetic progress also was observed in the sections in which both traits were under the influence of the dominance mode. Changes in gene frequency closely paralleled changes in sectional genotypic values with the greatest changes in gene frequency occurring in the sections in which both traits were controlled by the additive or dominance modes. The mean inbreeding coefficient for the entire genome in yr 21 to 25 was .352. Moderately high levels of inbreeding were attained under all modes of gene action. In general, heritabilities, correlations and variances obtained from analysis of the 25 yr of simulation data corresponded well with parameters reported in the literature for weight and gain traits in beef cattle.

Several measures of life cycle cow efficiency were calculated using weights and individual feed consumptions recorded on 160 dams of beef, dairy and beef × dairy breeding and their progeny. Ratios of output to input were used to estimate efficiency, where outputs included weaning weights of progeny plus salvage value of the dam and inputs included creep feed consumed by progeny plus feed consumed by the dam over her entire lifetime. In one approach to estimating efficiency, inputs and outputs were weighted by probabilities that were a function of the cow herd age distribution and percentage calf crop in a theoretical herd. The second approach to estimating cow efficiency involved dividing the sum of the weights by the sum of the feed consumption values, with all pieces of information being given equal weighting. Relationships among efficiency estimates and various traits of dams and progeny were examined. Weights, heights, and weight:height ratios of dams at 240 d of age were not correlated significantly with subsequent efficiency of calf production, indicating that indirect selection for lifetime cow efficiency at an early age based on these traits would be ineffective. However, females exhibiting more efficient weight gains from 240 d to first calving tended to become more efficient dams. Correlations of efficiency with weight of dam at calving and at weaning were negative and generally highly significant. Height at withers was negatively related to efficiency. Ratio of weight to height indicated that fatter dams generally were less efficient. The effect of milk production on efficiency depended upon the breed combinations involved. Dams calving for the first time at an early age and continuing to calve at short intervals were superior in efficiency. Weaning rate was closely related to life cycle efficiency. Large negative correlations between efficiency and feed consumption of dams were observed, while correlations of efficiency with progeny weights and feed consumptions in individual parities tended to be positive though nonsignificant. However, correlations of efficiency with accumulative progeny weights and feed consumptions generally were significant.

Weights and individual feed consumption collected on 160 beef, dairy and beef × dairy dams and their progeny were used to estimate several measures of lifetime cow efficiency. Dams were fed either a high or a low energy diet. Efficiency was expressed as the ratio of outputs to inputs. Outputs included progeny weaning weights plus cow salvage weight, and inputs were progeny creep feed consumption plus the dam's lifetime feed consumption. In the first approach, life cycle cow efficiency was estimated by expressing weight output as a ratio to feed inputs when weights and feed consumptions were weighted by their probabilities; probabilities were a function of age distribution and percentage calf crop in a theoretical herd consisting of 100 cows and 20 yearling replacement heifers. In the second approach, actual lifetime cow efficiency was estimated by expressing weight outputs as a ratio to feed inputs when all components were weighted equally. Both approaches included efficiency estimates calculated with and without cow salvage value. Dams receiving low energy diets generally had lifetime efficiencies equal or superior to those fed high energy diets in spite of older ages at calving. Dams on the high energy diet had greater salvage value, but did not wean calves of sufficient additional size to offset their own increased metabolizable energy (ME) intake. Dam breeds and breed crosses of smaller size tended to be more efficient than those of large size, demonstrating the effectiveness of mating small dams to large sire breeds for improving cow efficiency. Breeds calving at later ages were less efficient. Efficiency ratios improved as number of progeny weaned increased.

The Monte Carlo method was used to simulate selection and inbreeding in three populations of beef cattle. Population 1 had 16 closed lines, each with one sire and 10 dams; population 2 had eight lines, each with two sires and 20 dams and population 3 was analogous to one large line, with 16 sires and 160 dams. Production of progeny over a 25-yr period that included overlapping generations was simulated in each population. Two traits with initial narrow sense heritabilities of .098 and .161, respectively, were studied. Genotypic values were determined two loci at a time for the 64 independent loci in an individual's genome on the basis of nine different modes of gene action, including dominance, overdominance, epistasis and additive gene action. The genome was divided arbitrarily into eight sections of eight unlinked loci each, with one of the nine modes of gene action controlling the determination of genotypic values in each section. Phenotypic values were generated by the addition of normally distributed random environmental factors to the genotypic values. Index values were calculated as the simple average of the phenotypes for traits 1 and 2. Selection was entirely within lines, with index values the sole selection criterion. The highest indexing males and females within each line were mated, with no attention given to relationships among animals during selection or mating. Genetic improvement was small in all three populations. The mean genotypic value for trait 1 remained virtually unchanged in population 1, increased by 1.8% in population 2 and increased by 2.2% in population 3 from the base population to the last 5-yr period. Corresponding increases for trait 2 were 1.6, 1.3 and 2.2% in populations 1, 2 and 3, respectively. Nearly all of the increase observed in overall genotypic values for traits 1 and 2 resulted from increased genotypic values in the sections of the genome exhibiting additive and additive × additive gene action. Large changes in gene frequency occurred only in the section of the genome in which the additive mode of gene action controlled both traits. Frequencies in the remaining sections fluctuated slightly, but always remained near the initial values of .5. Higher inbreeding levels were attained as size of line decreased. Additive and additive × additive sections of the genome contributed most to increases in overall inbreeding levels. A great deal of variation in response to inbreeding was observed among lines, with genotypic means for the majority of lines declining with increased inbreeding. Inbreeding depression estimates were largest when the traits were influenced by the overdominance mode of gene action, followed, in order, by estimates obtained when traits were influenced by the dominance and dominance × dominance modes.

We conducted two experiments to evaluate the efficacy of a stable source of vitamin C for improving performance and iron status in early-weaned pigs. A preparation of L-ascorbyl-2-poly-phosphate (Rovimix®Stay-C®25, Roche Vitamins, Ames, IA and Bramus, NJ), which supplies 25% ascorbic acid activity in a stable form, served as the vitamin C source and was incorporated at dietary vitamin C levels of 0, 75, or 150 ppm. In Exp. 1, 72 pigs (14 ± 2 d of age and 4.98 kg BW) were blocked based on initial BW and penned in groups of three (eight pens per treatment) in an off-site nursery for 42 d. Phase 1 lasted from d 0 to 14, Phase 2 from d 14 to 28, and Phase 3 from d 28 to 42 after weaning. Daily gain and gain:feed ratio (G/F) increased during Phase 1 (quadratic, P< .1 and P< .05, respectively), Phase 3 (linear, P< .1 and P< .01, respectively), and for the overall 42-d experiment (linear, P< .05 and P< .1, respectively) in response to increasing dietary vitamin C. At 14 d after weaning, plasma vitamin C increased (linear, P< .05) with increasing dietary vitamin C, but plasma iron, hemoglobin, and hematocrit were not influenced by dietary vitamin C. In Exp. 2, 120 pigs (20 ± 3 d of age and 7.2 kg BW) were blocked based on initial BW and penned in groups of five (eight pens per treatment) in a conventional nursery system for 31 d. Phase 1 consisted of d 0 to 7, Phase 2 from d 7 to 17, and Phase 3 from d 17 to 31 after weaning. During the period from d 0 to 17 after weaning, ADG and G/F were improved (linear, P< .1) with increasing dietary vitamin C. At d 17 after weaning, plasma vitamin C and serum iron increased (linear, P< .05), but unbound iron-binding capacity and total iron-binding capacity decreased (linear, P< .05 and P< .1, respectively) with increasing dietary vitamin C. These results suggest that dietary vitamin C is needed during the first 42 d after weaning when pigs are weaned as early as 12 d of age and reared in an offsite nursery and during the first 17 d after weaning when pigs are weaned as early as 17 d of age and reared in a conventional nursery system. L-Ascorbyl-2-polyphosphate at a supplemental level of 75 ppm was adequate to meet the dietary vitamin C requirement of early-weaned pigs. Vitamin C supplementation with a stable product will improve performance in young pigs during the high-stress postweaning period and may be particularly beneficial to pigs weaned at a very early age.

Experiments were conducted in 1985 and 1986 at the Eastern Ohio Resource Development Center, Belle Valley, to examine the feasibility of using embryo transfer to induce twinning and to examine the influence of twinning on traits of the cow and calf. Embryos were collected from a total of 14 superovulated Angus donors on two dates each in 1985 and 1986 and were transferred to Angus recipients. A total of 124 embryos were transferred to 79 recipients, with 43 (34.7%) calves born alive. Seven of 45 (15.6%) recipients implanted with two embryos produced twins. In no case did both halves of the 15 embryos that were split to produce identical twins and implanted in the same recipient survive to birth. Proportion of calves born alive did not differ among transfer codes 3 (nonsplit embryos from two different donors implanted in separate uterine horns of the same recipient), 6 (nonsplit embryos from one embryo flush implanted in separate uterine horns of the same recipient) and 7 (nonsplit embryos from two different donors implanted in the same uterine horn of one recipient). Surgical transfers tended to result in a higher proportion of embryos surviving to birth (.43 vs .21 ; P= .16) and a higher twinning rate (.29 vs .04 ; P= .36) than did nonsurgical transfers. Age of recipient did not influence embryo survival (P= .98) or twinning rate (P= .99). Gestation length was 5 d shorter (P< .01) for twin calves than for singles. Singles were 9 kg heavier (P< .01) at birth and 32 kg heavier (P< .01) at weaning than twins. However, cows raising twins produced 108 kg (51%) more total weaning weight than did cows raising singles.

This study was designed to evaluate the ontogeny of serum IGF-I (SI) concentrations and its relationship to animal performance in a 140-d postweaning feeding trial. Ninety-eight progeny representing six sires (three high and three low feed conversion) and two sexes (43 bulls and 55 heifers) with ad libitum access to feed were allocated by sire and sex to monitor individual weights and pen feed consumption. Blood serum samples were obtained at the beginning of test (average age of 230 d) and every 28 d thereafter until each animal reached a fat thickness (estimated by sonoray) of 8.9 mm. Individual serum samples were acid-ethanol extracted and measured for IGF-I peptide by heterologous RIA. Serum IGF-I concentrations differed (P< .10) between high (H) and low (L) feed conversion progeny groups at the end of the first 28-d period (125.12 vs 89.52 ng/ml) and tended to differ at the conclusion of the second 28-d period (P< .15). Weight gains of H and L groups tended to differ in the second and third 28-d periods (P= .11 and .10, respectively). Serum IGF-I concentrations differed (P< .05) between bulls and heifers for the first through fourth 28-d periods (P< .01, P< .05, P< .10 and P< .01, respectively). Phenotypic correlations indicated that pens with higher mean SI concentrations at the beginning of the test consumed less feed and had lower cumulative feed:gain ratios. This study demonstrates that selection for an improved economic trait, such as feed conversion, can alter the expression of a single gene product.

We have assembled a first-generation anchor map of the mouse genome using a panel of 94 whole-genome-radiation hybrids (WG-RHs) and 271 sequence-tagged sites (STSs). This is the first genome-wide RH anchor map of a model organism. All of the STSs have been previously localized on the genetic map and are located 8.8 Mb apart on average. This mouse WG-RH panel, known as T31, has an average retention frequency of 27.6% and an estimated potential resolution of 145 kb, making it a powerful resource for efficient large-scale expressed sequence tag mapping. [All of the mapping data for the maps presented here have been deposited at the Research Genetics, Inc., web site and can be freely accessed and downloaded at http://www.resgen.com/.]

Progress on the use of imprinting (templating) for the synthesis of nanostructured catalysts is reviewed. In the context of providing a foundation for synthetic mimics, the basic principles of enzyme catalysis are enumerated. With these paradigms in mind, catalytic antibodies, imprinted polymers, imprinted amorphous metal oxides, and zeolites are discussed with respect to their preparation procedures and catalytic properties. These synthetic catalysts are contrasted to one another in order to highlight the advantages and disadvantages of each system. Suggestions for future work on preparing enzyme-mimicking materials by imprinting are provided.

Alumina mesophases have been synthesized by reacting aluminum alkoxides and carboxylic acids with controlled amounts of water in low-molecular-weight alcoholic solvents. Calcination of these materials yields aluminas that are thermally stable to 1073 K and contain randomly ordered pores. Specific surface areas as high as 710 m²/g and narrow pore size distributions centered at 20 Å that do not contain “zeolitic” micropores are exhibited by the calcined solids.

Postweaning performance data were obtained on 401 group-fed, purebred Angus calves from 24 selected sires (12 high- and 12 low-feed-conversion sires) from 1983 through 1986 at the Northwestern Branch of the Ohio Agricultural Research and Development Center. Body measurements of progeny were taken from 1983 through 1986 for hip height and backfat, whereas others, except chest measurements (depth and width) that were available only in 1985, were taken from 183 progeny born in 1985 and 1986. The objective of this portion of the study was to determine whether differences in linear body measurements exist between progeny of high-and low-feed-conversion sires. Differences between progeny of high- and low-feed-conversion sires tended to exist (P< .10) for heart girth (176.3 ± 1.2 vs 173.2 ± 1.2 cm) and were significant for backfat thickness (.94 ± .01 vs .87 ± .02 cm). No significant differences were observed for hip height (115.3 ± .5 vs 115.5 ± .5 cm), chest depth (58.8 ± .6 vs 57.4 ± .6 cm), chest width (44.4 ± .5 vs 44.0 ± .5 cm), head width (21.2 ± .2 vs 21.1 ± .2 cm), head length (42.4 ± .3 vs 41.6 ± .3 cm), muzzle circumference (41.0 ± .4 vs 41.6 ± .3 cm), length between hooks and pins (46.7 ± .5 vs 46.2 ± .5 cm), length between shoulder and hooks (94.9 ± 1.0 vs 93.1 ± 1.0 cm), or volume (361,199 ± 4,885 vs 352,718 ± 5,026 cm3).

27Al double rotation NMR (DOR) spectroscopy is used to investigate structural changes in the framework of several aluminophosphate molecular sieves upon adsorption of water. The shapes, widths, and positions of the spectral lines yield information on the aluminum environments, adsorption sites, and degree of structural disorder undergone upon water adsorption.

The formation of precursor particles in the crystallization of zeolites from gelating systems has been studied using X-ray scattering at small angles. The crystallization of Si−MFI using trimethylene-bis(N-hexyl, N-methyl-piperidinium) as the structure-directing agent shows the formation of two categories of precursors:  gel particles and nanometer-scaled primary units. The size of the primary units for the crystallization of Si−MFI is found to be 2.8 nm both for gelating and nongelating systems using different structure-directing agents. Zeolites Si−BEA and Si−MTW have been prepared using the same organic (trimethylene-bis(N-benzyl, N-methyl-piperidinium)) at different concentrations. Primary units with a size of 2.6 nm are found to be present in the synthesis of Si−BEA, while their size is 1.5 nm in the synthesis mixture directing to Si−MTW. Our data suggest that the nanometer-scaled primary units are specific for the zeolite topology formed.

Radiation hybrid panels are already available for genome mapping in human and mouse. In this study we have used two model organisms (chicken and zebrafish) to show that hybrid panels that contain a full complement of the donor genome can be generated by fusion to hamster cells. The quality of the resulting hybrids has been assessed using PCR and FISH. We confirmed the utility of our panels by establishing the percentage of donor DNA present in the hybrids. Our hybrid resources will allow inexpensive gene mapping and we expect that this technology can be transferred to many other species. Such successes are providing the basis for a new era of mapping tools, in the form of whole genome radiation hybrid panels, and are opening new possibilities for systematic genome analysis in the animal genetics community.

Previous studies revealed that the characteristics of opiate binding sites are different in brainstem slices and homogenates. In the present study, the binding of opiate agonists, morphine and etorphine, and that of the antagonist, naloxone, to thin slices of rat brain stem was studied. Sodium ion inhibits agonist binding and enhances antagonist binding in brainstem slices. Development of the analgesic tolerance to morphine is accompanied by a reduction of opiate binding. The opiate binding recovers partially toward control values during morphine withdrawal. Kinetic analyses indicate that sodium-induced changes in opiate binding sites are different from those caused by chronic morphine treatment. These results provide evidence that analgesic tolerance is associated with changes in opiate receptors.

Biliary and urinary excretory functions were determined in animals pretreated with a hepatotoxin (CCl4) or a nephrotoxin (K2Cr2O7), using polar metabolites of imipramine (PMIMP) and digoxin as models for anionic and neutral transport systems. Biliary excretion of PMIMP was decreased in CCl4-treated rats; urinary excretion was increased. Urinary and biliary excretion of digoxin were both unaffected by CCl4 treatment, but accumulation of digoxin by liver was impaired. K2 Cr2 O7 treatment resulted in severe nephrotoxicity accompanied by decreased urinary excretion of both model compounds. Hepatic excretion of digoxin, but not PMIMP, was increased in these animals. With minimal nephrotoxicity, urinary excretion of both compounds was unaffected. Thus the effect of toxicity on hepatic or renal excretion depends on the properties of the compounds used for excretion studies. In addition, for compounds excreted by both routes, impaired excretion by one route may be accompanied by increased excretion by the other. The extent of this compensatory mechanism may depend on several factors including the physicochemical properties of the compounds and the degree to which they are excreted by each route normally. In addition, specific cellular transport mechanisms may be important factors if involved in the excretory events.

The synthesis, structure solution, and characterization of the high-silica molecular sieve CIT-5 (California Institute of Technology Number 5) is described. CIT-5 is synthesized at hydrothermal conditions in the presence of N(16)-methylsparteinium and preferrably lithium cations. The structural solution of CIT-5 shows that it contains one-dimensional pores circumscribed by 14 tetrahedral atoms (14 MR). Rietveld refinement of the synchrotron X-ray powder data gives a symmetry and space group assignment for the structure of Pmn21 (no. 31) with refined unit cell parameters of a = 13.6738(8) Å, b = 5.0216(3) Å, and c = 25.4883(7) Å (V = 1750.1 ų). Electron diffraction and transmission electron microscopy confirm the space group and the topology of the structure viewed along the [010] direction. Solid-state ²⁹Si NMR spectroscopy results are consistent with the space group assignment. The thermal/hydrothermal stability of CIT-5 compares well to that of other large- and extra-large-pore, high-silica molecular sieves. The acid form of CIT-5 is able to perform hydrocarbon reactions such as cracking and alkylation and shows behaviors that are different from other zeolites.

Nutrition models are important in predicting animal growth; however, little research has focused on nursing calf performance submodels. This project’s objective was to determine the accuracy and precision of two equations to compute nursing calves’ feed intake. Data were collected on 394 nursing calves from 4 sets of cows (years 1953, 1959, 1964, 1974) of various breeds in which monthly milk yield and butterfat content, individual calf feed intake, and birth and weaning weights were measured during their first three lactations. Cows were milked at 14-d intervals to determine milk yield. The calf feed intake equations used to predict observed feed intake were Equation 9.1 (TED06; Tedeschi et al., 2006, In “Nutrient Digestion and Utilization in Farm Animals: Modeling Approaches”) and Equation 25 (TED09; Tedeschi and Fox, 2009, J. Anim. Sci. 87:3380). Peak milk was estimated from lactation yield using the NASEM (2016) milk yield equation. The average (SD) peak milk, calf ME intake (MEI) over a 240-day preweaning period, and weaning weight were 10.84 (5.64) kg/d, 1,286 (328.71) Mcal of ME, and 280.93 (46.70) kg, respectively. When compared to the observed calf feed intake, TED06 and TED09 had Pearson correlation coefficients of 0.19 and 0.59, respectively. The MEI mean biases were -355.3 and 190.7 Mcal of for TED06 and TED09, respectively, indicating a 27.6% over prediction and 14.8% under prediction, respectively. The RMSE and R2from linear regression of observed on predicted values of calf MEI were 308.7 Mcal and 0.0365 for TED06, and 253.2 Mcal and 0.3514 for TED09, respectively. In conclusion, neither equation adequately predicted calf feed intake, but the TED09 equation was more accurate and precise than the TED06 equation. Further research is needed to enhance our understanding of factors affecting feed intake of nursing calves to develop better prediction equations.